AF causes: PIRATES SHIP
Pericarditis
Pulmonary disease (COPD)
Pheochromocytoma
IHD/AMI/CHF
RHD/VHD
Atrial myxoma
Anemia
DM
OSA
Thyroid disease: thyrotoxicosis or hypothyroidism
Ethanol
Sepsis
Surgery Cardiac, atrial myxoma
HTN
Stimulant toxicity: theophylline, cocaine,
PE
CHADS2 SCORE: CHF, HTN, Age >75, DM, stroke/TIA. Patients receive one point for the presence of each of the first four risk factors (congestive heart failure, HTN, age = 75 or DM) and 2 points if there is a history of stroke or TIA.
CHADS2: score: 0 - 1: low, 2 - 3 moderate, 4- 6 high
Tx:
Rate control
Without evidence of accessory pathway
Esmolol, 0.5 mg/kg, IV x 1 min, maintenance dose 0.05 - 0.2 mg/kg/min. Very effective.
Metoprolol, 2.5 - 5 mg IV over 2 min q5 min x 3.
Diltiazem, 0.25 mg/kg/ over 2 min, maintenance dose 5 - 15 mg/hr
Verapamil, 0.075 - 0.15 mg/kg over 2 min
Propranolol, 0.15 mg/kg
With evidence of accessory pathway
Amiodarone, 150 mg IV x 1q0 min. Maintenance 1 mg/min x 6 hr, then 0.5 mg/min x 18 hr
In patients with heart failure and without accessory pathway
Digoxin, 0.25 mg IV q2h upto 1.5 mg. Maintenance 0.125 - 0.375 mg/d IV or PO
Amiodarone, 150 mg IV x 10 min. Maintenance dose 1 mg/min x 6 h, then 0.5 mg/min x 18 h
Prevention of thromboembolism events
Rhythm control
DC cardioversion, synchronized is the safest and most effective method of acutely restoring sinus rhythm.
Prior to cardioversion, consider thromboembolic risk and anticoagulation if possible.
AF with RVR in the setting of myocardial ischemia, MI, hypotension, or respiratory distress should receive prompt cardioversion regardless of anticoagulation status.
If duration of AF is documented <48 hours, cardiovert without anticoagulation.
If duration of AF is documented >48 hours (or unknown duration), anticoagulate with warfarin, with an INR goal of 2 - 3 for at least 3 weeks prior to cardioversion, and continue anticoagulation in the same therapeutic range for at least until a normal rhythm has been maintained for 4 weeks.
An alternative to anticoagulation for 3 weeks is cardioversion after doing a TEE to rule out left atrial appendage thrombus. Therapeutic anticoagulation with warfarin is indicated after the cardioversion for a minimum of 4 weeks, although the AFFIRM trial suggest patients with high risk of stroke should receive anticoagulation indefinitely.
Midazolam(Versed) 1 - 2 mg IV q2 min to a max of 5 mg, methohexital 25 - 75 mg IV, etomidate 0.2 - 0.6 mg/kg IV, or propofol IV with initial dose of 5 mg/kg/hr.
Proper synchronization to the QRS is critical to avoid induction of VF by a cardioversion shock delivered during a vulnerable period. Check for the synchronization marker superimposed on the QRS complex.
Ibitulide is the only drug that is approved bye USFDA for pharmacologic cardioversion.
45% conversion rate in AF and 60% conversion rate in AFL
Causes TdP in 4% - 8%, especially 2 - 4 hours of admission.
1 mg IV bolus (0.01 mg/kg if Pt <60 kg), given over 10 min. Fast push in TdP.
Esmolol:
Intraoperative tachycardia and/or hypertension (immediate control): I.V.: Initial bolus: 80 mg (1 mg/kg) over 30 seconds, followed by a 150 mcg/kg/minute infusion, if necessary. Adjust infusion rate as needed to maintain desired heart rate and/or blood pressure, up to 300 mcg/kg/minute.
For control of postoperative hypertension, as many as one-third of patients may require higher doses (250-300 mcg/kg/minute) to control blood pressure; the safety of doses >300 mcg/kg/minute has not been studied.
Supraventricular tachycardia (SVT) or gradual control of postoperative tachycardia/hypertension: I.V.: Loading dose: 500 mcg/kg over 1 minute; follow with a 50 mcg/kg/minute infusion for 4 minutes; response to this initial infusion rate may be a rough indication of the responsiveness of the ventricular rate.
Infusion may be continued at 50 mcg/kg/minute or, if the response is inadequate, titrated upward in 50 mcg/kg/minute increments (increased no more frequently than every 4 minutes) to a maximum of 200 mcg/kg/minute.
Note: To achieve more rapid response, following the initial loading dose and 50 mcg/kg/minute infusion, rebolus with a second 500 mcg/kg loading dose over 1 minute, and increase the maintenance infusion to 100 mcg/kg/minute for 4 minutes. If necessary, a third (and final) 500 mcg/kg loading dose may be administered, prior to increasing to an infusion rate of 150 mcg/kg/minute. After 4 minutes of the 150 mcg/kg/minute infusion, the infusion rate may be increased to a maximum rate of 200 mcg/kg/minute (without a bolus dose).
Guidelines for transfer to oral therapy (beta-blocker, calcium channel blocker):
Infusion should be reduced by 50% 30 minutes following the first dose of the alternative agent
Manufacturer suggests following the second dose of the alternative drug, patient's response should be monitored and if control is adequate for the first hour, esmolol may be discontinued.
Suprventricular tachycradia - Esomolol.
Dosage needs to be titrated, using ventricular rate as the guide.
An initial loading dose of 0.5 mg/kg (500 mcg/kg) infused x 1 min duration followed by a maintenance infusion of 0.05 mg/kg/min (50 mcg/kg/min) for the next 4 minutes is recommended. This should give a rough guide with respect to the responsiveness of ventricular rate
After the 4 minutes of initial maintenance infusion (total treatment duration being 5 minutes), depending on the desired ventricular response, the maintenance infusion may be continued at 0.05 mg/kg/min or increased in a step-wise fashion (0.1 mg/kg/min, 0.15 mg/kg/min to a maximum of 0.2 mg/kg/min) with each step being maintained for 4 or more minutes.
If more rapid slowing of ventricular is imperative, the 0.5 mg/kg loading dose infused over a minute may be repeated, followed by a maintenance infusion of 0.1 mg/kg/min x 4 min. Then, depending upon ventricular rate, another (and final) loading dose of 0.5 mg/kg/min infused x 1 min period may be administered followed by a maintenance infusion of 0.15 mg/kg/min. If needed, after 4 min of the 0.15 mg/kg/min maintenance infusion, the maintenance infusion may be increased to a maximum of 0.2 mg/kg/min.