O'Keefe - Complete Guide to ECGs Notes

ECG 1

[ ]it looks like diffuse ST changes, no?

-Acute MI Repol abnormalities transition:

-Peaked T waves (hyperacute T waves) very early on

-ST segment elevation (after a few minutes of MI) - usually convex

-DDx acute pericarditis & abNl repol - usually concave

-Decrease ST elevation & T waves invert, becoming deeper as ST elevation stops

-T waves- hyperacute within minutes, lasting min-hours, then inverted for days/weeks/indefinitely

-ST seg- elevated within minutes to hours, resolves within hours but takes days to get to Nl, if persist beyond 4 wks, c/s ventric aneurysm

-Q waves- hours to days p acute MI, usually persist indefinetely but may regress/resolve in some pts

-can have a non-Q wave MI at times, even w transmural infarct (not just w subendocard infarct)

-Isoelectric ST w upward convexity and deep T wave inversoin- assoc w subacute or recent MI (but may last weeks/months)

-Upward, concave ST segments- seen w pericarditis or Nl variant of early repol.

-Additional DDx acute MI fr pericarditis/Nl var:

-ST elevation diffuseness- usually in just a few lads in acute MI, vs all but aVR in pericarditis, vs V2-V5 in early repol

-Reciprocal ST depression- seen w MI but not pericard/early repol

-PR depression sen w acute pericardidits, sometimes w early repol, rare w MI

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CNS d/o ECG findings

-Precordials: large upright or deep inverted T waves, prolong QT, prominent U waves

-ST changes mimicing acute MI or acute pericarditis, or ST depression

-abNl Q waves mimicking MI

-rhythm xx- sinus tach/brady, jctl rhythm, PVC, VT...

Myxedema

-low QRS voltages

-sinus brady

-T wave flat/inverted

-PR prolonged

-pericard effusion

-electrical alternans

Hypothermia

-sinus brady

-PR, QRS, QT prolong

-Osborne J wave - late upright terminal deflection of QRS

-a-fib in >1/2

ECG 2

-LVH

-can Dx by voltage criteria, and non voltage criteria:

-prominent U at R precordials V2-3 (low Sn/Sp)

-ST and T wave changes common if advanced

-I, III, L, F, V4-6 see ST depression; and sutbtle ST elevation in V1-3 (<2mm change)

-see inverted T waves in I, L, V4-6

-see prominent U waves

-V4-6 - see downsloping ST segment depression w slight upward concavity, and asymmetrical T wave inversion w more gentle sloping of the desc part compared to the asc part

-can see recipr changes in V1-3 w ST elevation & tall T waves

-poor R wave progression

-IVCD

-inferior Q waves

-QRS notching

-LAD

-U waves

-see with hypOK+, digox, quinidine, amio, CNS xx, and LVH

-T waves

-mild hypErK+ --> tall, peaked, symmetric T wave and shortened QT

-mod hypErK+ --> decreased P wave and R wave amp, lengthen PR interval and QRS duration, depress or elevate ST, and PVCs

-sev hypErK+ --> cant find P wave, QRS very wide looking like a sine wave

-may have a sinoventric rhythm w no P waves apparent, idiovetric rhythm, accelerated idioventric rhythm, VT, VF, asystole

-QRS amplitude

-decreased by obesity, COPD/PTx, pericardial/plerual effusion, cor art dz, sarcoid/amyloid (bc fibrous tissue) ==> all incr body tissue bn myocardium and ECG

-sev RVH can alo underestimate the LVH bc the LVH forces are canceled out...,

-LBBB may reduce QRS amp

-thin body and L ant fascic block may increase QRS amp

ECG 3

[ ] ?find the retrograde P waves

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-Limb Lead reversal - see ECG mimicking dextrocardia w inverted PQRST in I and L

-Sinus Pause/Arrest- PP Interval >1.6-2 sec, w resumption of sinus rhythm at a PP interval that is NOT a multiple of the basic sinus PP interval

-Wandering Atrial Pacemaker- at least 3 p wave morphs, PR, RR, RP intervals vary

ECG 4

[ ] ?is there really LA and RA abNly?, is I R wave really prominent?

-Q waves can rep

-prior MI

-WPW, LBBB, COPD, PTx, CM, Pulm embolis

-WPW- negative delta wave can occur in inf leads--> mimic MI

-LBBB- QS complex in V1-V4 (often w some ST elevation of 1-2mm) can look like ant-sept MI

-COPD- Q usually at inf and/or R/mid precordials, along w poor R wave progression, P pulmonale, low voltage QRS, S1S2S3 pattern

-PTx- can lose R waves in R precordials--> QS complex, along w symmetric T wave inversion (looks like ant MI)

-HCM- abNl Q in I, L, V4-6- bc of septal hypertrophy

-RCM-infiltrative dz- bc electrically active tissue is replaced by fibrous tissue or electrically inert stuff (amyloid), see Q wave

-Pulm Embolism - Q waves in III and F, also w ST/T changes, ddx acute inf MI but unlike w inf MI, there's ~no Q waves in lead II

ECG 5

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ECG 6