Summary:

The aims of autonomic function tests are to detect the presence of autonomic failure, quantitate its severity, localize the site of autonomic lesion and evaluate its distribution (sympathetic, postganglionic sympathetic sudomotor, parasympathetic cardiovagal, and sympathetic cardiovascular adrenergic). 

The tests include quantitative sudomotor axon reflex testing (QSART) at 4 standardized sites: forearm, proximal leg, distal leg, and foot; heart rate response to deep breathing (HRDBv); blood pressure (BP) and heart rate (HR) responses to Valslava maneuver, BP and HR responses to head-up tilt (HUT).  The tests are performed in a specific sequence: QSART > HRDBv > Valsava maneuver > HUT.  This sequence ensures that the patient has had supine rest for at least 30 minutes by the time HUT is performed. 

In preparation for these tests and in order to minimize the effects of medications, stimulants, and food intake, patients should be given instructions to follow prior to testing. 

Alcohol and excessive exercise is avoided for at least 24 hours, prior to testing; coffee and nicotine are not permitted for 8 hours, prior to the ARS studies.  No food is allowed for at least 3 hour prior to testing. Compressive clothing, including Jobst stockings and abdominal binders are not allowed to be work during the tests. There are many medication that can influence the result of autonomic testing, and many of these effects are still unknown.  For holding the medications the referring provider must carefully weigh the potential risk of holding the medication against the value of an uncompromised test result.  Ideally, all medication with theoretical impact on autonomic testing must be held for at least 4 half-lives.  As this can be difficult and impractical the following guidelines have been a reasonable compromise.  Medications that should be held

Indications for the laboratory evaluation of the autonomic function are:

1. Diagnosis of generalized autonomic failure

   • Diagnostic pearl (amyloidosis, MSA, PAF), prognosis, management.

2. Diagnosis of benign autonomic disorders

   • Benign syncope, chronic idiopathic anhidrosis, mimickers of life-threaterning disorders.

   • Chronic idiopathic anhidrosis cannot be diagnosed without the demonstration of normal adrenergic and cardiovagal function

3. Diagnosis of distal small fiber neuropathy

   • Autonomic testing abnormal in over 80%.

4. Detection of mild/limited autonomic neuropathies.

5. Evaluation of autonomic involvement in peripheral neuropathies. 

   • (4&5): diabetic autonomic neuropathy, amyloid neuropathy, autonomic neuropathy related to Sjogren syndrome, acute ganglionpathies. 

6. Evaluation of orthostatic intolerance or spells

7. Evaulation of course or treatment response. 

In preparation for autonomic testing, in order to minimize effects of medications, stimulants, and food intake, patients should be given instructions to follow prior testing.

• Alcohol and excessive exercise is to be avoided for at least 24 hours prior to the test. 

• Coffee and nicotine are not permitted at least 8 hours prior to the test. 

• Compressive clothing including Jobst stockings and abdominal binders are not to be worn during the test.  

Postganglionic sympathetic sudomotor function is assessed using quantitative sudomotor axon refex testing (QSART), cardiovagal function by quantifying heart rate responses to deep breathing and heart rate responses to the Valsalva maneuver, and cardiovascular adrenergic function by assessing blood pressure responses to the Valsalva maneuver and passive head-up tilt.  All indices are then compared to normative values for age and sex.  A composite autonomic severity score (CASS) is derived from the ARS, which allows for quantification of severity and distribution of autonomic failure. CASS is a validated instrument and is composed of three subdomains: sudomotor (score range 0–3), cardiovagal (0–3), and adrenergic (0–4). Total CASS ranges from 0 to 10, with scores from 7 to 10 indicating severe autonomic failure. 

The TST investigates sudomotor pathways from the hypothalamus to the eccrine sweat gland by quantifying areas of anhidrosis across the entire anterior body surface. It is a standardized clinical procedure performed in a temperature and humidity-controlled environment. The body core temperature is raised to 38 °C by standardized elevation of the environmental temperature while the patient is lying supine. The skin is covered with an indicator powder that changes color when exposed to sweat.  Quantifcation of the percentage of anhidrosis is performed using digital photography.

Typical referral Indications:

Orthostatic hypotension

Orthostatic intolerance

POTS

Syncope / neurocardiogenic syncope

Syncope vs seizures

Sinus tachycardia

Loss of sweating

Peripheral neuropathy

Polyneuropathy

Small Fiber Neuropathy

Sensory Neuropathy/Neuronopathy

Diabetic neuropathy

CIDP

Polyradiculopathy

Dysautonomia”

Parkinson disease

MSA (Multiple System Atrophy)

PAF (Pure Autonomic Failure)

Amyloidosis

Sjogren’s Disease

Guillain Barre Syndrome

Chronic Fatigue Syndrome

PASC (Post-acute sequelae of COVID)

CMT (Charcot Marie Tooth)

Erythromelalgia

Gastric motility disorders

WR Medical User Manual

Timeline tips for Autonomic Reflex Screen (ARS) 

There are 4 components to the ARS 

1.Quantitative Sudomotor Axon Reflex Test (QSART) 

2.Heart Rate Response to Deep Breathing  (HRDB).  This test is performed twice. 

3.Valsalva Maneuver (VM): This test is performed 4 times, 2 matching responses are required. 

4.Heat-up Tilt (HUT): The table is tilted to 70 degrees for up to 10 minutes. 

1.  QSART: Acquire baseline.  Place solution in the syringe and check for leaks, mark the start of stimulation (2 mA for 5 minutes), mark end of stimulation, and mark the end of test (total test 10 minutes), end test.  Replace the capsule back on the docking station/parking fixture. 

Next: HRDB, VM, and HUT 

Patient should have the following attached before starting cardiovagal/adrenergic testing.  Beat-to-Beat BP device, 3 lead ECG and chest expansion belt. 

Take Manual BP to ensure BP matches beat-to-beat BP device.  If BPs don’t match, follow guide to get within 10 mmHg. 

Manual BP ______________________.  Beat-to-Beat BP ________________________ 

2.  HRDB: 1 minute baseline, then perform test. 1 minute post-test , then STOP (data will be saved automatically).  Start new HRDB test: 1 minute baseline, then perform test, 1 minute post-test, STOP test (data will be saved automatically). 

3.  Valsalva Maneuver (VM):  Record 1 minute baseline.  Perform Valsalva, then wait for 3 minutes, perform a second Valsalva, then wait 2 minutes postest.  STOP recording (data will be saved automatically). 

• Note up to four Valsalva Maneuvers can be performed with a 3-minute rest between each. Two like responses are needed for analysis.  Patients are tilted to 20 degrees if a flat top response is identified.  If flat top is still present at 20 degrees, tilt the table further to a 40 degrees and repeat the test until 2 like responses are obtained with the patient in the same tilted up position. 

4.  HUT (Head up tilt): Place straps above and below the knees.  Place the patient’s left arm on the arm board. Record 5 minutes baseline.  Tilt for 10 minutes, then 3-minute post-tilt, then STOP screen (data will be saved automatically).  TURN OFF beat-to-beat BP device.  Document patient symptoms.  

Take chest expansion belt off and disconnect from HRV Acquire device.  Disconnect ECG leads.  Remove all equipment and electrodes from patient.  Dismiss patient. 

Manual BPs are taken and recorded at the following times: 

• Supine (pre-tilt): 1 minute and 4 minutes 

• Tilt at 70°: 0.5, 1, 2, 3, 5, 7, 9, and 10 minutes (or as needed for patient safety).  

• Supine (post-tilt):  after 1 minute 

• Note: Recordings need to be back at baseline before continuing to next test or stopping.  This is more important than adhering to strict timelines. 

QSART Protocol 

Q-Sweat Device Preparation: Prior to starting a test, the Q-Sweat device should be powered on for AT LEAST 30 minutes prior to the first patient and left running until the testing is completed to ensure that all channels are dried out.  During this time the measurement capsules must remain seated on the parking fixture in their color-coded spots, arranged in a row along the side of the Q-Sweat Main Unit.  This is to allow the system to purge any accumulated moisture.  If a channel becomes saturated, it must be left running for 24-48 hours to ensure the channel is dried out before using again.  The desiccant should be checked to determine the remaining time (See hardware manual).  

TIP: A Q-Sweat test recording may be started to monitor the drying process.  

USB version only:  

The “Power” LED on the front panel of a USB based Q-Sweat also indicates the operational status:  

Steady green - unit is in use  

Pulsing green - unit is ready for patient testing  

Steady amber - unit is warming up (or drying out)  

Flashing yellow - power-on self-test error* (contact WR Medical) - Logan M. Huber (651) 604-8461 

Light off - device powered off, or micro not running  

*The self-test error is indicated in the device status window on the monitor of a Q-Sweat test.  

A.  Personnel: QSART should be performed by personnel (physicians, nurses, technicians) trained to perform the test.    

B. QSART Equipment:  The QSWEAT machine provided by WR Electronics is used to perform the test along with the following:   

1. Acetone  

2. Isopropyl alcohol (rubbing alcohol)  

3. Water  

4. Sweat capsules – Meridian electrodes snapped on and mounted on their measurement capsule. 

5. Grounds - Geltrodes. 

6. AA battery powered stimulators (4) set to provide 2.0 mA of current.  

7. Acetylcholine (reagent) in liquid form  

8. Equipment to warm the patient if needed.   

D. The Sites: The following sites are used:  

1. Medial forearm, 75% of the distance from the medial ulnar epicondyle to the pisiform bone (ulnar nerve distribution): RED  

2. Proximal leg, lateral aspect 5 cm distal to the fibular head (fibular nerve distribution): BLUE  

3. Distal leg, medial aspect 5 cm proximal to the medial malleolus (saphenous nerve distribution): GREEN  

4. Dorsal proximal foot on EDB muscle or near (sural nerve distribution): YELLOW 

 PROCEDURE: 

1. Have the patient come in, relaxed and comfortable, with an empty bladder.  

2. Attach the chest bellows to the patient for the next tests: HRDB, VM, HUT.  

3. Prepare the skin surrounding the area to be tested.  Shave the hair over the recording sites, if necessary, with a razor.  Use gauze soaked in acetone to defat and clear skin oils.  Use alcohol to wipe off acetone and dry skin.  Then use liberally, water-soaked gauze.  Use brown napkin paper to wipe and rub to gently and superficially abrade the skin (gentle abrasion); it must not result in breakdown of skin or result in “weeping” and seepage of serum fluid or blood from the skin capillaries.  

4. Select the patient in the Test Explorer (if you need to add new patient, then select the sweat drop test icon).   

5. Enter patient visit information, then click “Save”.  

6. Open the QSART program on the machine. Select the Start Test button and follow the test dialogue (hit: next > next > next > record).  Check that all the channels are reading at a similar level and are <50.  

1. Confirm that the channels have dried sufficiently (sweat rates low and traces flat).  

7. The meridian electrodes are mounted on (“snapped in”) measurement capsule (round white disc with two metallic posts, sticking up) to form a “sweat-cell assembly.”  The meridian electrodes must be mounted on the measurement capsules connected to the tubings at the end of their hoses.  

8. The meridian electrodes are secured on to the skin with silicone straps.  Note, the capsules must be placed flush against the skin and the straps must secure tight enough to ensure a good seal.  The open end of the meridian electrode with the metal rim must be towards patient skin; corresponds to the flat end of the red-wire attached to the meridian electrode.  Secure with the silicone straps using “Down and around” techniques.  Down (directed towards the bed) and around the limb of the patient.  For example: For the forearm (ulnar) site (red-coded) will mean that the silicone strap is secured to the inner metal post of the channel, goes down the medial border of the forearm and comes-up around the radial border of the forearm and is secured the outer metal post of the channel.  

9. The hole should be slightly stretched to from an oval.  It should not be too tight. Confirm that there are no air leaks, and adjust capsules as needed. To adjust, gently lift and lower the capsule to ensure it is lying flat and there are no skin wrinkles or gaps, and the strap are snug and tight.  

10. Ensure that the correct channel is being applied (color-coded) to the patient. The first hose (red-color coded) should be attached to the forearm, the second (blue) to the proximal leg, the 3rd (green) to distal leg, and the 4th (yellow) to the foot.  

11. Use the baseline on the screen to help indicate if any of the channels have a potential leak as you go.  

12. Attach a Geltrode/return electrode to each site:  

1. Attach over a non-bony area. 

2. Ensure that the return electrode is within 3 inches of each meridian electrode.  

13. Attach the IONTO-4 channels to the meridian electrodes and Geltrode.  

1. Attach the correct channels to the correct sites. 

2. Follow the color codes.  

3. The black wire with the black alligator clip is attached to the Geltrode/return electrode.  Make sure the metal ring in the alligator clip for the Geltrode/return electrodes is secured around the metal button on the surface of the Geltrode.  The metal ring in the alligator clip should be facing down towards the patient.  

4. The red wire from the meridian electrode is attached to either of the Drug ports (they are two, choose one – next to the return electrode)  

14. Attach the syringes (4 total) containing reagent (acetylcholine) solution to the tubing of the meridian capsule.  It is to the tubing without the knobbed Luer lock and in the slide-in Luer lock.  The syringe is attached to the inner tube at the fore-arm site.  The other tube is open.  The syringes are attached to the outer tube at the proximal leg; to the inner tube at the distal leg, and again to the outer tube at the dorsal proximal foot (EDB) site, all into the slide-in Luer lock. 

15. The reagent is filled slowly into the lower tubing and into the meridian electrode, until the reagent is seen ½ level up in the stem of the adjacent upper tubing.  Make sure there are no air-bubbles within the tubing.  About 10-15 ml of reagent is used on all 4 sites (2.5 - 3 mL at each capsule).  

16. If leaking of the reagent occurs (the patient will feel the reagent flowing over the limb, or you will see the liquid running down the leg/arm.  Also watch the monitor screen for any jumps to indicate a leak.  You will also see the level in the upper tube decrease in the presence of a leak.  

1. If there is a LEAK, quickly retract the plunger on the syringe and remove the electrode and channel, keeping it horizontal to avoid acetylcholine reagent from entering into the channel tubing.  

2. Dry the channel and place it back in its cradle while you reattach the meridian capsule and get rid of the leak.  

3. Repeat the attachment process and try again.  

17. Turn on the IONTO-4.  Ensure that the iontophoresis rate is correct on the screen. It should be set to provide 2.0 mA of current for 5 minutes.  

18. Clear the data on Test Works.   

19. Bring the Test Works 3 SCREEN INTO FOCUS  

20. Ensure that the screen is in focus by clicking anywhere in the black area (monitor screen).  This ensures that when you hit the spacebar on the keyboard; the machine will make the mark in the recording  

21. Press Start Test and press the button with arrowhead on the IONTO-4 and SPACEBAR on the keyboard to the computer screen at the same time (or as close to the same time as possible).  

22. At the end of the iontophoresis (5 minutes) the IONTO-4 will BEEP.  Press spacebar on the keyboard to the computer screen again to make the 2nd mark  

23. After another 5 minutes, the IONTO-4 will BEEP.  Press spacebar again on the keyboard to the computer to make the 3rd and final mark in Test Works. Click STOP RECORDING and SAVE TEST.  

24. Carefully withdraw the acetylcholine reagent from each tubing attached to the meridian electrodes.  

25. Disconnect the electrodes, ensuring that you wipe the ends of the each channel, holding the assembly horizontal and at patient level (do not hold it vertically as the reagent may trickle into the channel tubing) with a towel before placing back into the cradle.  

26. Wipe down the patient's skin with warm wash-cloth and replace their sock  

Q-SWEAT ANALYSIS TECHNIQUES  

SWEAT TOTAL: Perform a totalized sweat analysis (for Sweat Response and Resting tests).  

Click the “Start Analysis” icon from the toolbar under the ‘Total Sweat’ tab to open the analysis toolbar. Follow the instructions in the dialog box to analyze the test (one channel at a time). 

Evaluation of cardiovagal function

The vagus exerts a beat-to-beat control of the heart rate; under normal resting conditions, heart rate is primarily influenced by low tonic vagal activity, which is higher in fit, trained subjects. Vagal influence decreases during the inspiratory phase and increases during the expiratory phase of respiration, leading to respiratory sinus arrhythmia.  

The vagus nerve is the longest of the cranial nerves and therefore susceptible to injury and pathology.  It contains abundant parasympathetic fibers.  Cardiovagal impairment occurs early in many autonomic neuropathies and is a sensitive marker for diabetic and amyloid autonomic neuropathies for example.  Cardiovagal function is easily assessed using standardized maneuvers that result in heart rate responses.  From a 3 lead ECG the R-R interval can be converted to heart rate and displayed/recorded continuously on a beat-by-beat basis.  The most reliable and reproducible tests of cardiovagal function are hear rate response to deep breathing (HRDBv) and the Valsalva ration (VR).  These are done following QSART.  It is performed with the patient supine on the tilt-table for 20 minutes,  By performing QSART first, the supine test requirement will have been met. 

The physiology underlying HRDB is quite complex.  It involves a number of physiologic reflexes and mechanisms involved such as Hering Breuer reflex ("lung stretch"), Bainbridge reflex ("cardiac filling"), baroreflex, central neural coupling and local intracardiac stretch reflexes.  Ultimately, feedback from these mechanisms results in modulation of cardiovagal outflow from the nucleus ambiguus resulting in a heart rate increased (vagal influence decreases) with inspiration, and the heart rate decreased with expiration (vagal infuences increases), resulting in respiratory sinus arrhythmia.

Along with heart rate/RR interval recordings, it is recommended monitoring of respiration.  2 series of 8 to 9 breaths are recorded with an intervening 3 minutes of supine rest.  Patient are instructed to take smooth, maximal breath in and out and are cued to follow 10 seconds breath cycles (5 seconds in, 5 seconds out).  For analysis, the best 5 consecutive responses are chosen and the average difference between the heart rate on inspiration and expiration are calculated.  The depth and rate of breathing have profound influence on the RR variation.  The variation is maximal with maximal effort and at a breathing rate of 6 breaths/min.

Other confounding variables affecting HRDB include age, posture, analytical method, medications, obesity, hypocapnia, and excessive sympathetic activity.  HRDB is unaffected by the time of the day and gender of the subject.  Normative data exist which account for the confounding effects of age.  HRDB cannot be assessed when they are frequent ectopic beats, atrial fibrillation or flutter, or if the subject has a paced rhythm.

Heart Rate Response to Deep Breathing  Performing HRDB 

Several items affect Heart-Rate Deep Breathing (HRDB). These must be considered by the technician and controlled to maintain standardization and consistency between test subjects and for repeated tests on the same patient.  

If you have attached the chest expansion bellows before beginning the QSART, skip to step 2.  

1. Have the patient sit on the bed and attach the chest expansion bellows. To start, expand the bellows by 4-5 inches, stretching it over the patient’s chest, with the black rubber bellows material on the front of the patient and the ball chain with the velcro material on the back.  The endpoints should be at the mid-axillary line on both sides, and should be snug, but not crushing.  For men, it should go across the chest.  For women, it should go just below the breast. 

1. If the bellows ends cannot be stretched to the mid-axillary line, then have the ends move forward but maintain equidistance from the mid-axillary line on both sides. 

2. Do not place bellows over the reference ECG electrode as it may cause ECG artifact. 

2. Plug in the chest expansion bellows hose Luer fitting to the specified location of the HRV box on the bottom. 

3. Remind the patient to keep their legs uncrossed and arms relaxed at their sides.   

4. Prepare the skin where the ECG leads will be placed with NuPrep and Signa spray on a gauze.  

5. Attach the ECG electrodes 

1. Right side under the dip of the clavicle (white-right) 

2. Left side under the dip of the clavicle (black-left) 

3. Left side in the intercostal space of the left fifth rib (red-rib) 

6. If you are getting a lot of artifact, remove the ECG electrodes, prepare the skin, and then start again with fresh pads. 

7. Locate the brachial pulse in the crook of the elbows, while one technician is attaching the CNAP blood pressure cuff to the left arm, the second technician should record a manual blood pressure in the right arm. 

8. Apply the blood pressure cuff, making sure to use the correct size, and lining up artery indicator with the brachial pulse.  

9. Next, attach the finger cuffs the the patient’s hand. 

1. Use the correct size to fit finger 

2. May use index and middle finger OR middle finger and ring finger 

3. May have cuff at the base of fingers OR over middle knuckles depending on length of joints.   

10. Turn on the CNAP and begin the calibration 

1. Once the baseline is acquired open the HRDB in Test Work. Click on Start Test. 

2. Allow one minute for a baseline. 

11. With the metronome angled above the patient (avoid it to the side to prevent Bainbridge/atrial reflex being triggered). 

12. Explain how to follow the light on the metronome 

1. “When you see the light go up, breathe in slowly through the nose, then, exhale slowly out of the mouth, as the light goes down.  At no point should you hold your breath. When you see the light the first-time exhale all of your air as it goes down. 

2. I will ask you to breathe deeply at the same rate as the oscillating bar (or to breathe in and out according to my hand movements) for a total of 9 breaths. After that you will rest quietly for 1-minute.  We will ask you to repeat the test with another 9 breaths. It is important to breathe as deeply as possible. You can breathe in through your nose and out through your mouth if that is comfortable for you. Do not hold your breath at any time, but use a full 5 seconds for breathing in and a full 5 seconds for breathing out.” 

13. Click start metronome 

1. 90 seconds of deep breathing 

1. Each cycle is 10 seconds 

1. 5 seconds inhale 

2. 5 seconds exhale 

2. After the last cycle, press again to stop metronome after set is completed. If automatic event markers are enabled (default), event marks will be inserted into the recording at the start and stop points.   

3. Have the patient lie still. 

1. No talking 

2. No head turning 

14. Allow recording to go for 1 full minute before ending test 

15. End Test and Close window 

16. Repeat steps 9 – 14 (Turn CNAP ...Open HRD) 

NOTE: If chest expansion trace is not visible during the recording, disconnect the bellows from the HRV Acquire, ask the patient to breath out completely, and reattach the bellows to the HRV. 

 HRDB ANALYSIS TECHNIQUES 

HRDB using HR:  Analysis based on Heart Rate 

HRDB using R-R:  Analysis based on the R-R Interval 

 Spectrum/Frequency  Analysis of ECG Signal:  

Select the desired analysis icon from the analysis ribbon. Then, click the “Start Analysis”  button to begin. Follow the instructions in the dialog box to analyze the test (Figure 4).  

In most tests, zooming on charts with calculated values (R-R or HR) will not automatically scale the analog chart as well. Press the button (two square partially superimposed - on any chart to impose its current x-axis and y-axis scale to all other charts. 

Click the “Next” button and the software will choose the highest consecutive 5 valley-peak points shown on the R-R frame (Figure 5).  

When the desired points are selected, click the “Next” button and the resulting analysis data is shown in the analysis window (Figure 6). 

Click the “Finish” button in the user guide, then click “Save”.  

Valsalva Maneuver

Valsalva ratio:

For Valsalva ratio, the subject rested and recumbent, is asked to maintain an expiratory pressure of 40 mmHg for 15 seconds via a bugle with an air leak to ensure an open glottis.  The responses should be repeated until 2 responses with similar blood pressure and heart rate responses are obtained.  We perform up to 4 maneuvers.  The VR is derived from the maximum heart rate generated by the Valsalva maneuver divided by the lowest heart rate occurring within 30 seconds of peak heart rate following the maneuver.  The choice of 40 mmHg is made since the pressure of 40 mmHg seems to yield reproducible results while a pressure below 20 mmHg is inadequate and above 60 mmHg results and lower reproducibility.  Studies also suggest 40 mmHg as a practical optimal pressure.  It is important that beat-to-beat blood pressure recordings to be also recorded during the maneuver, since the heart rate responses to the Valsalva maneuver are baroreflex responses to changes in blood pressure. In patients with exaggerated blood pressure responses, Valsalva maneuver can be falsely normal.  On the other hand, patient in whom there is no blood pressure drop elicited by the maneuver result in a "flattop" response and VR can be spuriously low.  This variant response appears to depend on preload as it is more commonly encountered in patients with congestive heart failure and can be reverted to a normal pattern with position change (sitting, slight tilt up).  In clinical practice, when such a varying responses is encountered, the technician will tilt the table slightly to 20 degrees and repeat the maneuver; if the flat top profile persists, another attempt is made at a 40 degree angle.

The increase in heart rate occurs in response to fall and blood pressure during the maneuver and the baroreflex response to the blood pressure overshoot following the maneuver is responsible for the transient bradycardia.  

Factors that affect the Valsalva ratio: Age, posture, analytical method, and medications.  Other factors include the magnitude of the expiratory pressure, duration of the maneuver, volume status, as well as gender.  Normative data exist which take into account the confounding effects of age and gender.

Performing Valsalva – Sample Protocol

The heart is monitored by ECG, pressure recording, or other methods while the patient performs the Valsalva maneuver; cardiac volume decreases in unaffected patients but may dilate in a patient with impaired myocardial reserve; there is a characteristic complex sequence of cardiocirculatory events, departure from which may indicate disease or malfunction.

Several items affect the Valsalva Recording. These must be considered by the technician and controlled in order to maintain standardization and consistency between test subjects, for repeated tests on the same patient.

Instructions:

1. Attach the bugle to tubing and hand it to the patient to hold in the hand without the cuffs. 

2. Record a 3-minute baseline 

3. Explain to the patient that he/she will need to take a deep breath in, then put the bugle in their mouth and exhale with enough force to hold the light-bar at 40 mmHg (if possible) for 15 seconds.   

1. Explain the procedure to the subject: “We are going to be testing your autonomic nerves. This test is quite simple. We will ask you to exhale into the mouthpiece and cause the light bar to move upwards to the 40 mmHg line and continue blowing for 15 seconds. After a 3 minute rest, we will ask you to repeat the test. It is important to try and reach 40 mmHg of pressure and hold it as steady as possible.  Do not hold your breath at any time.” 

2. There is a timer on the metronome for the patient 

3. If the patient struggles to maintain 40 mmHg then have him/her to aim for 30 mmHg.  If 30 is not obtainable, have patient try to maintain 20 mmHg.  Less than 20mmHg is not acceptable.   

4. Patient should not raise head or arch off the table in an attempt during the exhalation (blowing) 

1. Forcibly blowing out 

2. Can gently place hand on forehead if patient needs a cue to remember to lay flat. 

4. TestWorks will mark the start of the exhalation and at the end of 15 seconds.   

1. Clinic on the screen to FOCUS the study.

2. A mark will automatically be placed when the patient’s expiratory pressure goes above 20 mmHg by default, and another marker will automatically be placed after the set Valsalva maneuver time (15 seconds by default). 

5. Wait 3 minutes and repeat 2 more times.  You must obtain 2 reproducible responses from the same position.   

1. If a flat-top response is obtained (does not dip below baseline), tilt the table to 20° with feet NOT touching the foot plate, and repeat the test.   

2. If a flat top response is again present, tilt the table to 40° with feet NOT touching the foot plate, and repeat the test.  

6. Wait 2-3 minutes before the end test. 

7. Close Test 

8. Press Start/Stop to releast finger cuff.  

9. Detach the hose from the chest expansion bellows before unhooking from the patient.   

Only unhook if not doing the head-up tilt.  Otherwise leave everything attached to the patient until the very end of the testing (Tilt-table). 

VALSALVA ANALYSIS TECHNIQUES

HRDB using HR:  Analysis based on Heart Rate

HRDB using R-R:  Analysis based on the R-R Interval

Heart Rate, Blood Pressure Changes with Stimulus:  Analysis based on Linear Regression

Adrenergic:  Analysis based on BP

Pressure Recovery Time:  Analysis based on BP

Select the desired test analysis icon from the analysis ribbon. Then, click the “Start Analysis” button to begin. Follow the instructions in the user guide dialog box to analyze the test.

Select the desired Valsalva maneuvers by clicking and dragging the mouse in the chart area. The area to be analyzed should include from the start of the first maneuver to 30-45 seconds beyond the end of the final maneuver.

The Valsalva maneuver is divided into 4 phases.

Phase I is marked by  the onset of patient straining or bearing down to blow into the mouthpiece of the “bugle.  There is a transient rise in BP due to increased intrathoracic and intra-abdominal pressure causing mechanical compression of the aorta. This will result in a transient rise is LV stroke volume. What happens to the HR, it decreases transiently.  It provides evidence that the vagus response is intact.  Phase 1 duration is about 2 to 4 seconds.

Phase II is biphasic:  

In early phase II (II_E), the act of patient blowing in the bugle results in reduced venous return to the heart, and reduced stroke volume leading to a fall in cardiac output.  The dropping BP resultis in unloading of the baroreflex leading to withdrawal of cardiovagal influence leading to tachycardia.  This is followed by activation of efferent sympathetic vasomotor and cardiac adrenergic response.  As a result of the efferent sympathetic discharge to the arterioles the total peripheral resistance increases.  Within 4 seconds after the increase in sympathetic discharge, the fall in blood pressure is arrested.  This is represented by late phase II (II_L).  In normal subjects late phase II is so efficient that by beginning of phase III, the MAP is normalized <4 seconds, and late phase II (II_E) does not fall below 10 mmHg. 

Phase III starts when the patient ceases blowing against fixed resistance causing a mechanical decompression of aorta.  It is the reciprocal of phase I and reflects mechanical events.  It last 1 to 2 seconds, during which the BP transiently falls due to the sudden fall in intrathoracic pressure and sudden expansion of intrathoracic blood vessels at the end of the maneuver.  There is a further burst of sympathetic activity during this phase. 

In phase IV, the vasomotor and cardiac sympathetic tone which started in II_L becomes "boosted" due to the transient drop in BP in Phase III.  So there is a situation where the venous return and cardiac output have returned to normal, while the arteriolar bed remains vasoconstricted due to the long time constant (lag) involved in sympathetic responses, hence there is an overshoot of BP above baseline values. The baroreflex response to this overshoot is activation of the cardioinhibitory pathways resulting in transient bradycardia. 

What Parameters to Rely on in VM?

• III_L:

  • BP recovery during late phase II from early phase II

  • BP recovery during late phase II from baseline (ΔBPVM2).

• IV:

  • Presence of phase IV

  • BP overshoot during phase IV

  • Phase IV duration

• PRT:  Time required for the SBP to recover from the nadir SBP of phase III and reach baseline levels during phase IV

• II_E: 

  • Early phase II BP drop

  • Early phase II pulse pressure compression

• BRSv (ms/mmHg) and BRSa (mmHg/s) indices

HUTT

Head up tilt test has been used for over 3 decades to study the physiologic response to orthostatic stress.  It is often used in clinical practice as a useful diagnostic test for patients with an intermediate pretest probability of vasovagal syncope.  In addition it is also useful in differentiating between certain causes of transient loss of consciousness, and for patient training and education.

The head up tilt table study testing is designed to simulate the physiologic parameters that result from prolonged sitting or passive standing in the absence of active contraction of muscles in the lower extremities.  In this way, HUTT allows for blood to pool in the lower extremities and mimics the cardiovascular and neurological responses.  Head up tilt table study is most commonly performed to investigate causes of fainting ("syncope") and especially to diagnose syncope with an orthostatic component.  With some ancillary monitoring, head up tilt table study can be useful for distinguishing syncope from other causes of transient loss of consciousness.

During a head up tilt table study (HUTT), patient rests in supine position on a special table that has a footboard, and is secured to the table with straps.  While monitoring several physiologic parameters of interest, the table is tilted to a "head up" position of 60 to 70 degrees very rapidly.  The test is usually continued until: 

1. The patient faints; 

2. The patient developed severe lightheadedness ("presyncope") and hypotension; 

3. The head up tilt table protocol has completed the test.

Physiology of the head up tilt table test:

Changes in body position from supine to upright leads to a rapid descent of about 500 to 800 mL of blood from the thorax to the abdomen and lower extremities, resulting in a rapid shift of plasma volume out of the vasculature and into the interstitial space.  Overall, this leads to decrease cardiac venous return.  The normal physiologic response to this involves the baroreflex unloading.  The output of this baroreflex unloading results in a decrease in parasympathetic nervous system tone and an increase in the sympathetic nervous system tone, resulting in tachycardia and vasoconstriction.  The net effect typically calls for 10 to 20 bpm increase in heart rate, small decrease to systolic blood pressure, a small increase in diastolic blood pressure, and a negligible change in mean arterial pressure.

In patients that experience vasovagal syncope the "ventricular hypothesis" or "Sharpey-Shaffer model" outlines the current understanding of the pathophysiology of fainting.  This hypothesis argues that the increased sympathetic activation leads to increased cardiac inotropy, which when combined with left ventricular underfilling can trigger the activation of unmyelinated ventricular mechanoreceptors ("C fibers"). Afferent signals are sent to the brainstem, with baroreflex actions to counter these changes.  This leads to heightened vagal tone and withdrawal of sympathetic tone, resulting in hypotension and/or bradycardia and eventually cerebral hypoperfusion and syncope.  The head up tilt table study creates a physical environment that allows for these fluid shifts that trigger vasovagal syncope in a controlled laboratory setting.  The decreased venous return is thought to be the most critical trigger for vasovagal syncope.

Early HUTT protocols involve tilting subjects to a near vertical position and maintaining that position for up to 45 to 60 minutes.  This is usually called "passive head up tilt test" to reflect the fact that no medications were used during the test to elicit a response.  These protocols may be time-consuming, but they have the benefit of only using orthostatic stress as the trigger and are free of confounding effects from medications.  More recently, it has become more common to perform shorter (20 to 45 minutes) drug-free tilt followed by administration of provocative agents.  Medications used during these tests protocols are administered with the intention of physiologically stressing the cardiovascular and/or neurological system into a response.  In other words, it lowers the threshold for a positive result.  Agents that are commonly used for  provocation include:

1. Intravenous isoproterenol-of beta agonist that increases myocardial contractility and promotes vasodilation

2. Intravenous or sublingual nitroglycerin ("Italian protocol")-a potent venodilator that leads to preload reduction

3. Intravenous clomipramine-alternatives Central serotonin levels; use of this provocative agent is uncommon.

There are also variations in the head up tilt table study that can improve the diagnostic accuracy of the testing in specific circumstances.  Venipuncture, real provocation, or other tailored provocation scenarios during monitoring could lead to symptom reproduction in patients with history of situational syncope.  Carotid sinus massage (CSM) can be useful for patients over 40 years with a history of unexplained syncope with fainting triggered by specific head and neck positions, or fainting with pressure in the carotid sinus.  CSM for up to 10 seconds that produces a ventricular pause of greater than 3 seconds and/or a fall in systolic blood pressure of more than 50 mmHg is considered a positive test.

So what kind of monitoring is before clearing head up tilt table study testing?

The minimum monitoring requirements for both safety and diagnostic information during head up tilt test is heart rate and blood pressure monitoring.  Heart rate monitoring is typically performed by using a continuous ECG.  This allows for identification of causes of cardiac syncope, such as bradycardia and cardiac arrhythmias, and can alert medical staff to dangerous heart rhythm disturbances during the test.  Blood pressure monitoring should be accomplished with continuous beat-to-beat noninvasive blood pressure monitoring techniques.  These include finger photo plethysmography technologies (most common) and arterial applanation tonometry devices.  Blood pressure monitoring can also be accomplished with an automated brachial blood pressure cuff, but a manual brachial blood pressure monitor may be needed around the time of a faint, as automated monitors often have difficulties detecting rapid changes in blood pressure, unfortunately intermittent blood pressure monitoring techniques will miss rapid and transient oscillations in blood pressure that often occur prior to syncopal episodes, and may actually miss the drop in blood pressure with syncope.  Radial arterial lines have been used, but this is likely overly invasive for head up tilt test monitoring alone.  Many beat-to-beat blood pressure monitors can provide estimates of stroke-volume vascular resistance, and cardiac output during head up tilt test, and allow for insights into the relative importance of vasodilation and cardioinhibitory and in her particular individuals syncope.

In addition to the requisite heart rate and blood pressure monitoring, ancillary monitoring may be diagnostically useful.  End-tidal carbon dioxide monitoring may allow for detection of hypocapnia and hyperventilation that may precede some syncope.  Blood sampling for fractionated plasma catecholamines before and during head up tilt table testing may also provide important insights into the mechanism of syncope.  Plasma norepinephrine levels can provide some insights into sympathetic neural tone, and may be particularly useful in patients with orthostatic hypotension or postural tachycardia syndrome.  This should be done with an indwelling venous catheter, which can also be used for rescue medications (e.g., atropine) or fluids following a positive head up tilt table test.

Transcranial Doppler ultrasound (TCD) and/or electroencephalography (EEG) monitoring can be used during head up tilt test to confirm the cerebral hypoperfusion required in syncope or to detect other known syncopal causes of transient loss of consciousness.  During head up tilt, diastolic blood pressure flow in the head diminishes and this can be detected with TCD.  The associated EEG will reveal delta wave slowing or even silence during an episode.  In patients who experience symptoms in the absence of hypotension during head up tilt, EEG and TCD can be useful in identifying rare disorders such as "cerebral syncope" (due to isolated cerebral vasospasm) and normal hemodynamic (or psychogenic) spells.  Adding video monitoring to head up tilt test can further increase the probability of detecting psychogenic forms of transient loss of consciousness.  The ability to record and replay transient episodes to detect changes in facial expression, eye closure, skin color, and muscle movement and tone has proven advantageous in discriminating psychogenic transient loss of consciousness with epileptic seizures.

Instructions:

1. Position the patient so the feet are touching the foot-plate and their a placed approximately shoulder width apart.  

2. Place 3-5 lead ECG, finger-cuff of the beat-to-beat BP device (CNAP), BP cuff, chest-expansion bellows, and manual BP cuff. 

1. Ensure the correct BP cuff is used.  

2. The left arm resting on the arm board has finger cuff and BP cuff to CNAP 

3. The right arm has BP attached to manual BP device for the technician to record manual BP.  

4. The other technician positioned on the other side of the patient operates the TestWork, computer (clicks on to the screen – FOCUS – and presses the space bar to mark).  Will also record the BP and HR (manual BP recordings and CNAP)  on the sheet.  Also will observe the patient for any overt signs of distress.  

3. Position left arm so it is resting on arm board at heart-level with the hand palm up.  

1. May be necessary to lower arm an inch or two below heart level if needed.  Abduction attenuates the arterial BP waveform. 

4. Ensure safety be securing body straps are secured, just above and below the knees of the patient  

1. Straps should not be across the abdomen 

2. Straps can be across the chest 

5. NEVER LEAVE PATIENT UNATTENDED DURING THE STUDY 

6. Obtain 5 minute of baseline BP manual and CNAP recording with patient in supine position.  

1. Manual BP measurements should be taken during 1st and 4th minutes from right arm. 

2. Manual BPs should be withing 6-8 mmHg of each other.  

3. Manual BP should be withing 10 mmHg of the beat-to-beat (CNAP) device.  

7. Tilt patient to 70° head-up tilt in one continuous motion 

1. Click on the screen for FOCUS and click the space bar to place the marker 

2. Patients are typically tilted for 5-10 minutes depending on the referring indication. 

3. Manual BP measurements should be taken at 30 sec. 1, 2, 3, 5, 7, and 10 minutes or as needed to ensure patient safety. 

8. Return patient to supine position and obtain 3 minute of recording.  

1. Click on the screen for FOCUS and click the space bar to place the marker 

2. Manual BP measurements should be taken 1 minute post HUT 

TILT ANALYSIS TECHNIQUES 

30:15 using HR:   30:15 Ratio based on Heart Rate 

30:15 using R-R:   30:15 Ratio based on the R-R Interval 

Tilt using R-R:   Tilt analysis based on the R-R Interval 

Tilt analysis based on the R-R Interval 

ECG Spectrum:  Tilt analysis based on ECG spectrum analysis

Select the desired analysis icon from the analysis ribbon. Follow the instructions in the dialog box to analyze the test. the Tilt (R-R) analysis can be seen in Figure 8 below. 

Click the “Next” button to proceed to choosing the minimum SBP level, and again to advance to the selection of the minimum and maximum heart rate points. The resulting analysis is shown in the analysis window in Figure 9 below. 

Click the “Finish” button in the user guide to complete the analysis. Click the “Save” button to save the analysis, then exit the test and analysis tabs. 

The current emphasis is a slow tilt over 10 to 20 seconds,  The patient is left tilted for 20 minutes.  Manual BP is obtained at 5 minute and 1 minute supine, before head-up tilt, and at 0,5, 1, 2, 3, 5, 7,and 10 minutes during head-up tilt, and 1 minute post head-up tilt.  

Notes;  

When the question is that of orthostatic intolerance, such as POTS, head-up tilt is maintained for 10 minutes.  To detect neurocardiogenic syncope, a longer duration of head-up tilt is desirable.  Patients with orthostatic intolerance can develop a delayed fall and blood pressure, a condition designated as delayed orthostatic hypotension, and a longer duration of head-up tilt has been suggested.  

Orthostatic blood pressure and heart rate recordings to 70 degrees head-up tilt.  It is important to perform the upright tilt procedure at a standard time after lying down because the orthostatic reduction in blood pressure is greater after 20 minutes (17/19 mmHg) of preceding rest than 1 minute (8/9 mmHg).  Several methods have been used to maintain proper arm position.  The preferred method is to keep the arm in the abducted position onto an armrest at heart level at all angles of tilt.  It is preferable and permissible to lower the arm 2 to 1 inches below heart level.

In normal individuals, during the tilt table test, at 70 degrees of tilting for 10 minutes, there is a brief 5 to 15 mm Hg reduction in systolic blood pressure, a 5 to 10 mm Hg increase in diastolic blood pressure, and a 10 to 15 bpm increase in heart rate. 

If there is early, gradual, and sustained hypotension (>20 mm Hg reduction in systolic blood pressure) without compensatory tachycardia, this is an indication of insufficient sympathetic tone and impaired baroreceptor function. 

Hypotension with compensatory tachycardia suggests hypovolemia. 

If hypotension is delayed for several minutes but then occurs abruptly with bradycardia, this is more suggestive of a neurocardiogenic mechanism. Most neurogenic causes of syncope lead to gradual hypotension without a compensatory tachycardia that occurs within the first 5 to 10 minutes of tilting.

Utility and Clinical Applicationss of HUTT testing and indications;

2018 European Society of cardiology (ESC) guidelines and the combined 2017 American (ACC/AHA/HRS) guidelines make recommendations about when HUTT testing is appropriate and different clinical situations.

The Fainting Assessment Study (FAST) revealed that the diagnostic yield of experienced physicians rises from 60% to 70% to nearly 85% when HUTT is implemented for carefully selected syncope patients. HUTT is also useful in distinguishing between rare causes of transient loss of consciousness, such as seizures and psychogenic causes.

Sensitivity: 61% to 69%.  Specificity 70% to 85%.  This is when the symptoms that patients experience during HUTT match the clinical symptoms that initiated the testing.

Indications:

• Reflex syncope: Class IIa.  To increase the probability of reflex syncope when a diagnosis is suspected but not definite.

• Orthostatic hypotension: Class IIa.  HUTT testing is especially useful in identifying delayed orthostatic hypotension with bedside testing is negative but clinical history suggestive of OH..

• Postural tachycardia syndrome.  Class IIa.  HUTT testing can support a diagnosis of POTS.

• Psychogenic pseudosyncope.  Class IIa.  To differentiate vasovagal syncope from a normal neurogenic cause (psychogenic).

• Epilepsy versus convulsive syncope.  Class IIa.  To differentiate seizure disorder as a cause of transient loss of consciousness versus syncope associated with convulsive movements such as myoclonus.

• Patient education.  Class IIb.  Recognition of symptoms and training therapeutic physical maneuvers.

HUTT as a diagnostic tool has low utility in patients with high or very low clinical pretest probability for the diagnosis of vasovagal syncope.  For patient's with greater diagnostic uncertainty as to the etiology of fainting (those patients with and "intermediate pretest probability" for vasovagal syncope), the head up tilt table study can be useful.  Understanding the role of the head up tilt table study in this context requires some familiarity with Bayesian analysis.  When applied to clinical situations, Bayesian inference shows how the utility of a test depends on the pretest probability of the conditions in testing for in a specific subject.  If the patient has a very low pretest probability for vasovagal syncope, the diagnosis is likely not vasovagal syncope, even with a positive head up tilt table study.  Conversely, if the patient has a very high pretest probability for vasovagal syncope the diagnosis is likely to be vasovagal syncope even with a negative head up tilt table study.

However, for patient also with an uncertain diagnosis after a thorough history and examination (that is some typical features and some atypical features), head up tilt table study may provide enough information to sway the diagnosis in one direction or the other.  This situation is particularly common in middle-aged and older patients, and in whom the "typical) presyncopal prodrome of vasovagal syncope is often absent.

Head up tilt table study and postural tachycardia syndrome (POTS).  

POTS is a clinical syndrome with cardinal hemodynamic criterion of an excessive increase in heart rate upon assuming an upright posture from supine.  The heart rate increases greater than 30 bpm within 10 minutes in adults in the absence of orthostatic hypotension. Many autonomic labs used a short 10-minute head up tilt table study assessment of orthostatic tachycardia.  POTS patient can also have vasovagal syncope but only a minority of patients with POTS report frank syncope.  It should be stressed that orthostatic tachycardia without symptoms is a very nonspecific finding, and POTS should not be diagnosed based on head up tilt table findings alone.

Head up tilt and orthostatic hypotension.  

Patient with neurogenic orthostatic hypotension present with a decrease in blood pressure greater than 20/10 mmHg within 3 minutes of standing from supine, and only a modest reflex increase in heart rate.  More recently described variant is the so called delayed orthostatic hypotension.  This is characterized by a slow and gradual decrease in blood pressure that does not occur rapidly within the first 3 minutes, as is observed with classic neurogenic orthostatic hypotension.  The pattern of gradual decrease in blood pressure ("rolling down a ramp") in the late orthostatic hypotension is in stark contrast to neurally-mediated syncope, which has an initial stable BP followed by a sudden drop ("falling off a cliff").

Vasodepressor Syncope.

Prolonged tilt test and the Bezold-Jarisch reflex

The detection of autonomic failure is well standardized.  Less well-defined are younger subjects who do not have classical autonomic failure but have orthostatic intolerance.  Some of these patients do not faint or have orthostatic hypotension but after a long period of orthostatic stress, may suddenly faint.  They develop what is called vasodepressive syncope.  

Vasodepressive syncope is recognized as the development of the sudden onset of reduction in blood pressure and heart rate.  Preceding may be oscillations of blood pressure and heart rate.  Often there are dips in heart rate that corrects themselves prior to presyncope.

The mechanism of vasodepressive syncope is suggested to be the Bezold-Jarisch reflex.  The stimulus is vigorous contraction of a near empty left ventricle which activates mechanoreceptors withing the ventricular wall.  Impulses pass up unmyelinated fibers of the vagus nerve to the nucleus of the tractus solitarius.  The efferent response consists of the abrupt inhibition of sympathetic outflow, causing vasodilation and vagal stimulation, causing bradycardia.

The sequence of events is suggested to be as follows.  The subjects have relative hypovolemia.  Therefore there is reduced venous return, resulting in less blood delivered to the left ventricle.  Prolonged standing, as well as discomfort, results in increased norepinephrine release, increasing cardiac contractility.  

These patients often have beta-supersensitivity, so that the heart muscle responds to catecholamines by contracting more vigorously.  

The combination of a near empty heart (reduced venous return) and increased contractility results and excessive stimulation of these mechanical receptors to trigger this reflex.

For young subjects, the tilt test may be done to detect the presence of vasodepressive syncope.  For that test, a test duration of 40 minutes is adequate.

Protocol (AJ) to Cardiologist HFM -

Head-up Tilt protocol for POTS.

1.  Have the patient come in, relaxed and comfortable, with an empty bladder.

2.  The patient is placed supine on the tilt-table for 20 minutes with arm on the armrest at heart level, prior to starting the test.   

3.  Record baseline ( BP, HR, SpO2) with the patient lying supine at 5 minutes (i.e. 15 minutes prior to the head-up tilt) and then 1 minute before the head-up tilt.  Blood pressure is recorded in the arm on the armrest at heart level. 

4.  Tilt the table slowly (10-20 seconds) to reach an angle of 70 degrees.

5.  Record BP, HR, SpO2 during the head-up tilt at 1, 3, 5, and 10 minutes, and record any symptoms that the patient may report.

Termination of the test prior to 20 minutes may be done in the event of profound symptoms, i.e., syncope, ECG pauses, severe hypotension, severe bradycardia, asystole, patient's request, or operator's discretion (related to patient's safety, the patient is to be placed flat (supine) or Tredelengurg position immediately, and 0.9 sodium chloride IV fluid opened until symptoms resolve.  Have an AED available in the room.  Please do not place IV lines before the Head-up tilt procedure to avoid iatrogenic changes in HR and BP.  Use IV access only when starting 0.9 sodium chloride to resuscitate the patient.  

6.  The patient remains tilted-up for 20 minutes, if nothing untowards happen.

DO NOT administer pharmacological agents such as nitroglycerin or isoproterenol during the tilt-table study, for neurology protocol.

7.  Lower the tilt-table at the end of 20 minutes.

8.  Record BP, HR, SpO2, 1 minute, post-tilt. 

I will instruct patients to hold certain specific medications prior to the procedure and place the specific instructions in the scheduling section of the order.  It will also be in the clinic note.  

NASA 10 minute lean test Instructions

https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3196175/

https://www.myhealthtoolkitbsa.com/web/public/brands/medicalpolicy/external-policies/autonomic-nervous-system-testing/

https://neurocenter.com/diagnostic_testing/autonomic-testing/

Autonomic reflex screening, University of Michigan (Report example)

Autonomic studies in a quiet room at 72 degrees ambient temperature. The resting heart rate was in the 60s. 

QSWEAT testing was performed. The sweat volumes were as follows: 

Forearm 0.02uL (nl>0.08) 

Proximal leg 0.16uL (nl>0.19) 

Distal leg 0.20uL (nl>0.14) 

Foot 0.34ul (nl>0.07) 

Heart rate variability during deep breathing was evaluated. 

The average HR difference was 22.8 (nl>14). 

Valsalva maneuver was performed with continuous monitoring of heart rate and blood pressure.  

The valsalva HR ratio was 1.68 (nl>1.46).  

The blood pressure responses during phases I, early and late II, III and IV were as follows: 

Phase I: Normal 

Early phase II: Normal 

Late phase II: Normal 

Phase III: Normal 

Phase IV: Overshoot 

Head up tilt table testing was performed with continuous monitoring of heart rate and blood pressure. 

Tilt time: 10min 

HR change: +60bpm 

SBP change: +70mmHg 

DBP change: -10mmHg 

Impression:  Findings showed an excessive and inappropriate tachycardic response to tilt, with hypertensive features, consistent with a hyperadrenergic subset of POTS.   Sympathetic sudomotor post-ganglionic function was reduced at the forearm and proximal leg sites, of indeterminate clinical significance. Cardiac vagal, cardiac adrenergic, and vascular adrenergic function were otherwise intact. 

Transthoracic echocardiogram (08/08/2022):  Unremarkable.  LVEF:  60%.  No valvular heart disease.  No aortic root dilatation.

EMG/NCS, ARS, University of Michigan (9/7/2022):

Autonomic studies in a quiet room at 72 degrees ambient temperature. The resting heart rate was 90. 

QSWEAT testing was performed. The sweat volumes were as follows: 

Forearm   .02 uL(nl>.0.2) 

Proximal leg .08 uL(nl 0.36> ) 

Distal leg .15 uL(nl>0.39) 

Foot .15 ul(nl>0.18) 

Heart rate variability during deep breathing was evaluated. 

The I/E ratio was  1.41(nl>1.15).  The average HR difference was 31(nl>10). 

Valsalva maneuver was performed with continuous monitoring of heart rate and blood pressure.  The valsalva HR ratio was 1.6 (nl>1.5).  

the blood pressure responses during phases I, early and late II, III and IV were as follows: 

Phase I: Normal 

Early phase II: Normal 

Late phase II: sl blunted 

Phase III: Normal 

Phase IV: Normal 

Head up tilt table testing was performed with continuous monitoring of heart rate and blood pressure. 

Tilt time: 5 min 

HR change: +60 bpm 

SBP change: -3 mmHg 

The right sural sensory response was normal. 

Interpretation: The primary finding on this test of autonomic function was an excessive heart rate acceleration on the tilt test.  This is consistent with a diagnosis of postural tachycardia syndrome (POTS). Orthostatic hypotension was not noted.  Sweat volumes were reduced at all sites indicating a defect in sympathetic post-ganglionic sudomotor function. This is seen in some patients with POTS.   Heart rate response to deep breathing was normal indicating normal parasympathetic cardiovagal function.  The blood pressure response to Valsalva was essentially normal, indicating normal sympathetic adrenergic function.  The normal sural sensory response indicates that there is no evidence of polyneuropathy, but does not exclude small fiber neuropathy. 

ARS UNC

Patient is a 36 year-old woman with history of fibromyalgia, anxeity, MVP, and small fiber neuropathy being evaluated for orthostatic intolerance.  

Autonomic studies in a quiet room at 72 degrees ambient temperature.  The resting heart rate was in the 80s. 

QSWEAT testing was performed. The sweat volumes were as follows: 

Forearm  0.01 uL (nl>0.2) - Red 

Proximal leg:  0.04 uL(nl>0.4) - Blue

Distal leg:  0.05 uL (nl>0.4)  - Green

Foot:  0.11ul (nl>0.2)  - Yellow

Heart rate variability during deep breathing (HRDBv) was evaluated.  The average HR difference was 22.2 (nl>10). 

Valsalva maneuver was performed with continuous monitoring of heart rate and blood pressure.  The valsalva HR ratio was 2.18 (nl>1.51).  

The blood pressure responses during phases I, early and late II, III and IV were as follows:

Phase I: Normal 

Early phase II: Normal 

Late phase II: Normal 

Phase III: Normal 

Phase IV: Exaggerated overshoot

Head up tilt table testing was performed with continuous monitoring of heart rate and blood pressure. 

Tilt time: 10min 

HR change: +35 bpm 

SBP change: +40mmHg 

DBP change: +30mmHg 

Impression:  Findings are consistent with a clinical diagnosis of postural tachycardial syndrome  (PoTS), in the setting of an excessive and inappropriate tachycardic response to tilt.  There was evidence of global sympathetic post- ganglionic sudomotor  dysfunction, which can be part of a more widespread dysautonomia, or suggest small fiber neuropathy, in the proper clinical context.  Cardiac vagal funciton was intact. 

ARS Univ of MI

Patient is a 68y F with history of RA, CAD s/p stenting, hypothyroidism, HTN,  FMS, fibromuscular dysplasia, being evaluated for numbness/tingling hands/feet and compensatory chest/truncal hyperhidrosis since age 45. 

Autonomic studies in a quiet room at 72 degrees ambient temperature. The resting heart rate was in the 80s. 

QSWEAT testing was performed. The sweat volumes were as follows: 

Forearm 0.09uL(nl>0.08) 

Proximal leg 0.09uL(nl>0.19) 

Distal leg 0.03uL(nl>0.14) 

Foot 0.11ul (nl>0.07) 

Heart rate variability during deep breathing was evaluated. 

The average HR difference was 5.2 (nl>7). 

Valsalva maneuver was performed with continuous monitoring of heart rate and blood pressure.  The valsalva HR ratio was 1.70 (nl>1.39).  The blood pressure responses during phases I, early and late II, III and IV were as follows: 

Phase I: Normal 

Early phase II: Exaggerated 

Late phase II: Attenuated 

Phase III: Normal 

Phase IV: Normal 

Head up tilt table testing was performed with continuous monitoring of heart rate and blood pressure. 

Tilt time: 10min 

HR change: <5bpm 

SBP change: +80mmHg 

DBP change: +50mmHg 

Impression:  Sympathetic post-ganglionic sudomotor function was reduced at the distal and proximal leg sites, and borderline reduced at the forearm, but normal at the foot site, suggestive of a possible length-independent small fiber sensory polyneuropathy, which would account for the chest/truncal hyperhidrosis.  Due to family history of multiple similarly affected family members, considerations would be in order for such conditions as hereditary amyloidosis or HSAN.  In addition, there was evidence of early vascular adrenergic insufficiency and borderline cardiac vagal insufficiency, albeit with normal cardiac adrenergic function. 

ARS Univ of MI template

Patient is a 69 year old woman with migraine and cervical spondylosis being evaluated for dysautonomia. 

Autonomic studies in a quiet room at 72 degrees ambient temperature. 

The resting heart rate was 74/min. 

QSWEAT testing was performed. The sweat volumes were as follows: 

Forearm 0.34uL (nl>0.2) 

Proximal leg 0.02uL (nl>0.4) 

Distal leg 0.02u L(nl>0.2) 

Foot 0.07u l(nl>0.07) 

Heart rate variability during deep breathing was evaluated. The average HR difference was 9.6 (nl>7.0). 

Valsalva maneuver was performed with continuous monitoring of heart rate and blood pressure.  The valsalva HR ratio was 1.24 (nl>1.39).  

The blood pressure responses during phases I, early and late II, III and IV were as follows: 

Phase I: Normal 

Early phase II: Normal 

Late phase II: Attenuated 

Phase III: Normal 

Phase IV: Attenuated with delayed blood pressure recovery time 

Head up tilt table testing was performed with continuous monitoring of heart rate and blood pressure. 

Tilt time: 5 min 

HR change: <5bpm 

SBP change: -40mmHg 

DBP change: -20mmHg 

Impression:  There was evidence of sympathetic  post-ganglionic sudomotor dysfunction.  There was evidence of cardiac vagal impairment.  In addition, there was evidence of cardiac and vascular adrenergic insufficiency, with evidence of neurogenic orthostatic hypotension.  

Tilt-table template (cardiology)

PROCEDURE PERFORMED: 

Tilt table test. 

PROCEDURE STAFF:

Emily Vidri AGACNP-BC

Vinayak Manohar MD, FACC, RPVI

INDICATION: 

41 y.o. year old female who presents for syncope. 

INTERPRETATION: 

An informed consent was obtained and the pros and cons, complications, alternatives and expected results of tilt table testing were discussed with the patient and all questions were answered.  The tilt table testing was then performed.  Prior to this, the patient understood and did wish to proceed with tilt table testing.  It was done in the usual fashion and the usual protocol.  The patient tolerated the procedure well without any immediate complications. 

Procedural Details:  

Approximately 20 minutes of supine heart rate, blood pressure and telemetry monitoring were obtained.  The patient remained in sinus rhythm with ventricular rates between 62-76 beats a minute and average heart rate of 69 bpm.  The blood pressures ranged between 110-122/69-79 diastolic.  The patient denied any significant symptoms during this initial supine period. As per referral request, supine catecholamines were drawn approximately 20 minutes into the resting supine phase

The patient was then tilted to 70 degrees of head upright tilt.  Through this phase of the procedure the patient admitted to lightheadedness, leg tingling, dyspnea, headache, sternal chest pain and presyncope symptoms.  The rhythm was sinus tachycardia at a rate of between 102-129 beats a minute with max heart rates seen 16 minutes. Heart rates increased to > 120 bpm by minute 3. Patient increased average heart rate by 30 bpm by minute 1. The blood pressure ranged between 102-134/67-88. At minute 3, as per referral request, upright catecholamines were drawn.  

After 20 minutes of head upright tilt, the patient's blood pressure was 102/78 with a heart rate of 125 bpm.  The patient was in sinus tachycardia.  The patient was given 1 sublingual nitroglycerin. Within 4 minutes patient had worsening of all above symptoms coupled with dyspnea, blurred vision and abrupt syncope. During this time blood pressures declined from 108/74 to 92/64. Heart rates increased as high as 164 bpm before dropping to 140 bpm during syncope.   

The patient was then recovered in head-down Trendelenburg and fluids were given wide open.  The patient was recovered for  greater than 5 minutes with monitoring being obtained and also with the patient sitting upright in recovery and drinking water without difficulty.  Once her blood pressure was back to the baseline of 118/70 with a heart rate of 80 bpm, in sinus rhythm, the test was terminated.  

SUMMARY:

Most patient symptoms correspond to postural orthostatic tachycardia syndrome

Syncope was provoked with nitroglycerin and occurred during a mild vasodepressor and cardioinhibitory response not sufficient by established criteria to diagnose vasovagal syncope 

ARS Univ of MI Temp

Autonomic studies in a quiet room at 72 degrees ambient temperature. The resting heart rate was in the 80s. 

QSWEAT testing was performed. The sweat volumes were as follows: 

Forearm 0.09uL (nl>0.08) 

Proximal leg 0.09uL (nl>0.19) 

Distal leg 0.03uL (nl>0.14) 

Foot 0.11ul (nl>0.07) 

Heart rate variability during deep breathing was evaluated. 

The average HR difference was 5.2 (nl>7). 

Valsalva maneuver was performed with continuous monitoring of heart rate and blood pressure.  The valsalva HR ratio was 1.70 (nl>1.39).  

The blood pressure responses during phases I, early and late II, III and IV were as follows: 

Phase I: Normal 

Early phase II: Exaggerated 

Late phase II: Attenuated 

Phase III: Normal 

Phase IV: Normal 

Head up tilt table testing was performed with continuous monitoring of heart rate and blood pressure. 

Tilt time: 10min 

HR change: <5bpm 

SBP change: +80mmHg 

DBP change: +50mmHg 

Impression:  Sympathetic sudomotor post-ganglionic function was reduced at the distal and proximal leg sites, and borderline reduced at the forearm, but normal at the foot site, suggestive of a possible length-independent small fiber sensory polyneuropathy, which would account for the chest/truncal hyperhidrosis.  Due to family history of multiple similarly affected family members, considerations would be in order for such conditions as hereditary amyloidosis or HSAN.  In addition, there was evidence of early vascular adrenergic insufficiency and borderline cardiac vagal insufficiency, albeit with normal cardiac adrenergic function. 

ARS Temp Univ of MI

Summary: 

Autonomic studies in a quiet room at 72 degrees ambient temperature. 

The resting heart rate was 80. 

QSWEAT testing was performed. The sweat volumes were as follows: 

Forearm .01 uL(nl>.2) 

Proximal leg .005 uL(nl>.36) 

Distal leg .005 uL(nl>.39) 

Foot .01 ul(nl>.18) 

Heart rate variability during deep breathing was evaluated. 

The I/E ratio was  1.12(nl>1.1).  The average HR difference was 12(nl>10). 

Valsalva maneuver was performed with continuous monitoring of heart rate and blood pressure.  The valsalva HR ratio was 1.9(nl>1.51).  

The blood pressure responses during phases I, early and late II, III and IV were as follows: 

Phase I: Normal 

Early phase II: Normal 

Late phase II: Normal 

Phase III: Normal 

Phase IV: Normal 

Head up tilt table testing was performed with continuous monitoring of heart rate and blood pressure. 

Tilt time: 5 min 

HR change: +25 bpm 

SBP change:  increase upon tilt, with gradual decline to baseline, no fall below baseline. 

Interpretation: Sweat volumes were markedly reduced, indicating a defect in sudomotor sympathetic function.  Heart rate variability to breathing was normal.  The blood pressure response to valsalva was normal, indicating normal sympathetic adrenergic function.  On the tilt test, no abnormal heart rate acceleration was noted.   Orthostatic hypotension was not noted.  When seen in relative isolation, reduced sweat volumes may be a feature of small fiber neuropathy.  The normal sural sensory response indicates there is not an axonal polyneuropathy involving medium to large fibers. 

Patient Name  : 

Referred From : 

Referred For  : vasovagal syncopeAge: 26 Years        Sex: F

EMG Consultant: 

Diag Codes: 

SUMMARY and INTERPRETATION:  Patient is a 26 y F with history of joint hypermobility, fibromyalgia, and migraine, presenting with episodic vertigo with associated presyncopal symptoms of warmth, clamminess, migraines, diarrhea, and fatigue.

Autonomic studies in a quiet room at 72 degrees ambient temperature.

The resting heart rate was in the 60s.

QSWEAT testing was performed. The sweat volumes were as follows:

Forearm 0.02 uL (nl>0.08)

Proximal leg 0.16 uL (nl>0.19)

Distal leg 0.20uL (nl>0.14)

Foot 0.34ul (nl>0.07)

Heart rate variability during deep breathing was evaluated.

The average HR difference was 22.8 (nl>14).

Valsalva maneuver was performed with continuous monitoring of heart rate and blood pressure.  

The valsalva HR ratio was 1.68 (nl>1.46).  

The blood pressure responses during phases I, early and late II, III and IV were as follows:

Phase I: Normal

Early phase II: Normal

Late phase II: Normal

Phase III: Normal

Phase IV: Overshoot

Head up tilt table testing was performed with continuous monitoring of heart rate and blood pressure.

Tilt time: 10min

HR change: +60bpm

SBP change: +70mmHg

DBP change: -10mmHg

SUMMARY and INTERPRETATION

Impression:  Findings showed an excessive and inappropriate tachycardic response to tilt, with hypertensive features, consistent with a hyperadrenergic subset of POTS.  Cardiac vagal, cardiac adrenergic, and vascular adrenergic function were otherwise intact.  Sympathetic sudomotor post-ganglionic function was reduced at the forearm and proximal leg sites, of indeterminate clinical significance.  

Autonomic studies in a quiet room at 72 degrees ambient temperature. 

The resting heart rate was in the 50s. 

QSWEAT testing was performed. The sweat volumes were as follows: 

Forearm    0.29uL(nl>0.25) 

Proximal leg  0.74uL(nl>0.48) 

Distal leg  0.19uL(nl>0.62) 

Foot 0.52ul(nl>0.15) 

Heart rate variability during deep breathing was evaluated. 

The average HR difference was 4.23 (nl>7). 

Valsalva maneuver was performed with continuous monitoring of heart rate and 

blood pressure.  The valsalva HR ratio was 1.51 (nl>1.29).  The blood pressure 

responses during phases I, early and late II, III and IV were as follows: 

Phase I: Normal 

Early phase II: Normal 

Late phase II: Attenuated 

Phase III: Normal 

Phase IV: Attenuated 

Head up tilt table testing was performed with continuous monitoring of heart rate 

and blood pressure. 

Tilt time:  10min 

HR change:  +20bpm 

SBP change:  +40mmHg 

DBP change:  +40mmHg 

Impression:  Sympathetic sudomotor post-ganglionic function was reduced at only 

the distal leg site, of indeterminate clinical significance.  Cardiac vagal 

function was borderline reduced.  There was evidence of advanced adrenergic 

insufficiency, with combined vascular and cardiac adrenergic impairment, which 

would predispose to orthostatic intolerance.  

SUMMARY and INTERPRETATION Patient is a 36 year old woman with fibromyalgia,

anxiety, MVP, and small fiber neuropathy being evaluated for orthostatic intolerance.

Autonomic studies in a quiet room at 72 degrees ambient temperature. The resting heart rate was in the 60s.

QSWEAT testing was performed. The sweat volumes were as follows: 

Forearm 0.01uL(nl>0.2)

Proximal leg 0.04uL(nl>0.4) 

Distal leg 0.05uL(nl>0.4) 

Foot 0.01ul(nl>0.2)

Heart rate variability during deep breathing was evaluated. The average HR difference was 22.2

(nl>10).

Valsalva maneuver was performed with continuous monitoring of heart rate and blood

pressure. 

The valsalva HR ratio was 2.18 (nl>1.51). 

The blood pressure responses during

phases I, early and late II, III and IV were as follows: 

Phase I: Normal 

Early phase II: Normal

Late phase II: Normal 

Phase III: Normal 

Phase IV: Exaggerated

Head up tilt table testing was performed with continuous monitoring of heart rate and blood

pressure. Tilt time: 10min 

HR change: +35bpm 

SBP change: +40mmHg 

DBP change: +30mmHg

Impression: Findings were consistent with a clinical diagnosis of postural tachycardia syndrome (PoTS), in the setting of an excessive, and inappropriate tachycardic response to tilt. There was evidence of global sympathetic sudomotor post-ganglionic dysfunction, which can be part of a more widespread dysautonomia, or suggest small fiber neuropathy, in the proper clinical context. Cardiac vagal function was intact. 

Autonomic Sympathetic Skin Response and Parasympathetic Cardiovagal Function:

Using the Natus Viking Machine:

Technique:

Sympathetic Skin Response:

Recording electrodes were placed on the palms of the *** hand and sole of the *** foot, with the reference electrodes on the dorsum of the hand and foot.   The low-frequency filter was set at 0.1 HZ, and the high-frequency filter at 30 HZ.  Stimulus was provided to evoke a response.

Cardiovagal Testing:

Heart Rate and Rhythm analysis was recorded at rest for at least 1 minute.  The patient then was asked to take six deep breath over one minute while the heart rate was monitored continuously for 1 minute.  

Summary:

The Sympathetic Skin Response was:  ***

Parasympathetic Cardiovagal Function:

R-R variability during normal breathing was: *** beats/minute

R-R variability during deep breathing at six breaths per minute [Heart Rate difference (beats/minute)] :  ***

Normal Values 1:

Age (years): Heart Rate Difference (beats/minute):

10-29 20 (15-19)

30-49 15 (11-14)

50-65 12 (9-11)

E/I (Expiratory/Inspiratory) ratio: ***

Normal values by age for single deep breaths2:

Age: E/I Ratio

16-20 >1.16

21-25 >1.20

26-30 >1.18

31-35 >1.14

36-40 >1.12

41-45 >1.12

46-50 >1.11

51-55 >1.09

56-60 >1.08

61-65 >1.07

66-75 >1.06

76-80 >1.05

References:

1. Wieling W et al.  Diabetologia 22: 164, 1982

2. Ravits. Muscle Nerve 1997; 20(8); 919-937

Dr. Ali Shakir (Cardiology Protocol)

Baseline vitals are performed supine and post vitals are performed supine as well.

During Procedure

Table will be tilted to head upright position at 70 degrees.

Blood pressure, heart rate, Sa02 and patient's subjective symptoms will be recorded every three minutes or more frequently when symptoms occur.

Termination of the test and return to supine position will occur when symptoms occur if concurrent with a drop in blood pressure or heart rate, or per patient's request.

At 20 minutes if no symptoms have occurred, Nitroglycerin 0.4 mg SL 1 tablet will be given to patient.

Nitroglycerin exclusion: Baseline hypotension with a systolic blood pressure of less than 100.

The patient will then remain upright for an additional 20 minutes, or until the patient experiences symptoms and/or concurrent drop in blood pressure or heart rate.

In the event of profound symptoms, i.e., syncope, ECG pauses, severe hypotension, severe bradycardia, etc., patient is to be placed flat immediately and 0.9 sodium chloride IV fluid opened until symptoms resolve. 

https://pmc.ncbi.nlm.nih.gov/articles/PMC10023507/pdf/nihms-1865159.pdf

ARS Template Texts

Normal

Sympathetic sudomotor post-ganglionic function was normal at the foot, distal leg, proximal leg, and forearm sites. Cardiac vagal and adrenergic function were intact. Specifically, there was no evidence of orthostatic hypotension or postural tachycardia syndrome.

POTS

Findings were consistent with a clinical diagnosis of postural tachycardia syndrome (PoTS), in the setting of an excessive, and inappropriate tachycardic response to tilt. There was evidence of distal arm and foot sympathetic sudomotor post-ganglionic dysfunction, which can suggest small fiber neuropathy, in the proper clinical context. Hung-up responses can be seen in pain syndromes such as SFN or complex regional pain syndrome. Cardiac vagal function was intact.

Sympathetic sudomotor post-ganglionic function was normal at the foot, distal leg, and proximal leg sites, but borderline low at the forearm site.  Cardiac vagal function is intact.  There is exaggerated blood pressure overshoot during phase IV of Valsalva maneuver, and tachycardia with HR increase of 32 from baseline resting HR.  There is also postural orthostatic hypertension.  Findings are consistent with a clinical diagnosis of postural tachycardia syndrome (POTS), in the setting of an excessive, and inappropriate tachycardic response to tilt consistent with hyperadrenergic POTS. 

MSA

Sympathetic sudomotor post-ganglionic function was globally reduced. Cardiac vagal function was also compromised.  There was evidence of advanced adrenergic insufficiency, affecting both the cardiac and vascular adrenergic components, with evidence of supine hypertension.  In summary, these findings of pan-dysautonomia are suggestive of an alpha synucleinopathy, which when taken together with history, raise concern for multi-system atrophy. 

Mod MSA

Sympathetic sudomotor post-ganglionic function was intact and hung-up responses can be seen in pain syndromes such as SFN or complex regional pain syndrome. Cardiac vagal function was moderately compromised. There was evidence of moderate adrenergic insufficiency, affecting both the cardiac and vascular adrenergic components, with neurogenic orthostatic hypotension and evidence of supine hypertension.  

In summary, these findings of pan-dysautonomia with intact sudomotor function are suggestive of a central autonomic disorder such as multiple system atrophy. 

Peripheral Synucleinopathy

Sympathetic sudomotor post-ganglionic function was reduced distally (with no SFN on skin biopsy). Cardiac vagal function was also compromised (borderline on HRDB but low on VR). There was evidence of advanced cardiac and vascular adrenergic dysfunction on the Valsalva and the head up tilt. In summary, these findings of pan-dysautonomia with impaired distal sudomotor function are suggestive of a peripheral autonomic synucleinopathy (eg, PAF, PD, or DLB) and should be interpreted in the clinical context.

SFN

Sympathetic sudomotor post-ganglionic function was reduced at the foot, distal leg, and forearm sites, as can be seen in small fiber polyneuropathy.  Cardiac vagal function was borderline impaired, as was vascular adrenergic function.  Cardiac adrenergic function was intact.  Specifically, there was no evidence of orthostatic hypotension or postural tachycardia syndrome.

PAN

Sympathetic sudomotor post-ganglionic function is globally reduced with the left forearm site showing a Hung-up response.  Hung-up responses can be seen in pain syndromes such as SFN. Cardiac vagal function is significantly compromised.  There is evidence of advanced cardiac adrenergic insufficiency, however no changes consistent with neurogenic orthostatic hypotension are seen.

Comments:
In summary, these findings on today's ARS denote impaired distal sudomotor function are suggestive of a peripheral autonomic neuropathy such as small fiber neuropathy. The findings of cardiovagal and cardiac adrenergic insufficiency are suggestive of disorder of central autonomic network. 

During the testing patient had mild discomfort during the tilt-table study but denies any symptoms such as light-headedness, dizziness, vertigo or palpitations. 

Generalized Diabetic Autonomic Neuropathy.

This is an ABNORMAL autonomic reflex screen.

Sympathetic sudomotor post-ganglionic function is intact and hung-up responses are seen at the forearm site.  Cardiac vagal function is moderately compromised. There is evidence of moderate adrenergic insufficiency, affecting both the cardiac and vascular adrenergic components and evidence of neurogenic orthostatic hypotension. While these features may be consistent with Generalized Diabetic Autonomic Neuropathy; findings of pan-dysautonomia with intact sudomotor function are suggestive of a central autonomic disorder.

Comments:
Patient complained of dizziness and lightheadedness, beginning 2 minutes into the head up tilt table study.

Orthostatic tachycardia without POTS.

There is no evidence of autonomic failure. The tilt study shows mild pulse pressure compression and symptomatic exaggerated tachycardia response which can be seen in deconditioning, dehydration, as a constitutional trait, in hyper-adrenergic states (including anxiety), and primary disorders of orthostatic tolerance.  

OH

Sympathetic sudomotor post-ganglionic function was normal at the foot, distal leg, proximal leg, and forearm sites. Cardiac vagal function is intact.  Cardiovascular adrenergic function is mildly imparied and there is presence of orthostatic hypotension is noted <3 minutes in tilt-table study.  The findings are consistent with non-neurogenic orthostatic hypotension.

Labile HTN

Sympathetic sudomotor post-ganglionic function was reduced at the foot and distal leg sites, as can be seen in a length-dependent small fiber polyneuropathy.  Cardiac vagal function is moderately compromised. There is evidence of moderate adrenergic insufficiency, affecting both the cardiac and vascular adrenergic components and evidence of neurogenic orthostatic hypotension. These features may be consistent with peripheral autonomic neuropathy such as small fiber neuropathy.  She also has labile hypertension, in particular supine hypertension and this may reflect impairment of baroreflex suggestive of disorder of central autonomic network.

 Comments:

• She complained of lightheadedness and headache during the Valsalva maneuver.

• Patient reported headache and dizziness during tilt table study when upright.

• Supine blood pressure 1 minute post tilt: 210/110 mmHg.  HR: 112.  Patient complained of headache and felt dizzy.

Patient is a 36y F with history of ADHD, fibromyalgia, and undifferentiated connective tissue disease, being evaluated for heat intolerance with acral symptoms, with concern for dysautonomia. 

Autonomic studies in a quiet room at 72 degrees ambient temperature. 

The resting heart rate was in the 80s. 

QSWEAT testing was performed. The sweat volumes were as follows: 

Forearm    0.5uL(nl>0.08) 

Proximal leg  0.73uL(nl>0.19) 

Distal leg  0.22uL(nl>0.14) 

Foot 0.53ul(nl>0.07) 

Heart rate variability during deep breathing was evaluated. 

The average HR difference was 18.74 (nl>10). 

Valsalva maneuver was performed with continuous monitoring of heart rate and 

blood pressure.  The valsalva HR ratio was 2.39 (nl>1.51).  The blood pressure 

responses during phases I, early and late II, III and IV were as follows: 

Phase I: Normal 

Early phase II: Normal 

Late phase II: Attenuated 

Phase III: Normal 

Phase IV: Normal 

Head up tilt table testing was performed with continuous monitoring of heart rate 

and blood pressure. 

Tilt time:  10min 

HR change:  +20bpm 

SBP change:  <5mmHg 

DBP change:  <5mmHg 

Impression: Sympathetic sudomotor post-ganglionic function was intact.  Cardiac  vagal function was intact.  There was suggestion of early vascular adrenergic insufficiency or venous pooling, which may predispose to orthostatic intolerance, while cardiac adrenergic function was intact.  However, there was no frank evidence of orthostatic hypotension or postural tachycardia syndrome. 

 NOTE:  She discontinued all medications prior to the test, including mirtazapine, but continued low-dose naltrexone. She also ceased taking Zyrtec well before the test. She has not taken Bentyl in the past 2 years and uses hydroxyzine sparingly as needed.

Sympathetic sudomotor post-ganglionic function was reduced at the distal and proximal leg sites, and borderline reduced at the forearm, but normal at the foot site, suggestive of a possible length-independent small fiber sensory polyneuropathy, which would account for the chest/truncal hyperhidrosis.  Due to family history of multiple similarly affected family members, considerations would be in order for such conditions as hereditary amyloidosis or HSAN.  In addition, there was evidence of early vascular adrenergic insufficiency and borderline cardiac vagal insufficiency, albeit with normal cardiac adrenergic function. 

Sympathetic sudomotor post-ganglionic function was reduced at the foot and distal leg sites, as can be seen in a length-dependent small fiber polyneuropathy.  Cardiac vagal function is moderately compromised. There is evidence of moderate adrenergic insufficiency, affecting both the cardiac and vascular adrenergic components and evidence of neurogenic orthostatic hypotension. These features may be consistent with peripheral autonomic neuropathy such as small fiber neuropathy.  She also has labile hypertension, in particular supine hypertension and this may reflect impairment of baroreflex suggestive of disorder of central autonomic network.

Comments:

• She complained of lightheadedness and headache during the Valsalva maneuver.

• Patient reported headache and dizziness during tilt table study when upright.

• Supine blood pressure 1 minute post tilt: 210/110 mmHg.  HR: 112.  Patient complained of headache and felt dizzy.

Sympathetic sudomotor post-ganglionic function was normal at the foot, distal leg, and proximal leg sites, but low at the forearm site, and with hung-up responses at left proximal and distal leg sites.  Hung-up responses can be seen in pain syndromes such as SFN or complex regional pain syndrome.  Cardiac vagal function is intact.  There is exaggerated blood pressure overshoot during phase IV of Valsalva maneuver, and tachycardia with HR increase of 30 from baseline resting HR.  There is also mild postural orthostatic hypertension.  Findings are consistent with a clinical diagnosis of postural tachycardia syndrome (POTS), in the setting of an excessive, and inappropriate tachycardic response to tilt consistent with hyperadrenergic POTS. 

Sympathetic sudomotor post-ganglionic function was normal at all sites, with hung-up responses at left proximal and distal leg sites.  Hung-up responses can be seen in pain syndromes such as SFN or complex regional pain syndrome.  Cardiac vagal function is intact.  Cardiovascular adrenergic function is mildly imparied and there is presence of orthostatic hypotension is noted <3 minutes in tilt-table study. 

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