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Flashcards in Differentials Deck (13)
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1

DDx for new right axis differentiation (give 10)

  • Pulmonary Hypertension
  • Na+ Channel blocker toxicity
  • Hyperkalemia
  • Old lateral MI (Q-waves)
  • RVH
  • LPFB
  • Ventricular ectopy
  • Misplaced leads
  • Situs Inversus
  • Newborns/infants

2

DDx for new left axis differentiation (give 8)

  • LBBB
  • Paced rhythm
  • Pre-excitation (WPW)
  • Prior inferior MI (Q-waves)
  • LAFB
  • LVH
  • Hyperkalemia
  • Elderly/obese patients

3

DDx for ST elevation (16)

  • Acute myocardial injury (trauma, ACO/MI)
  • Global Ischemia (Dissection, GI bleed)
  • Early repolarization
  • Myo/Pericarditis
  • Vasospasm
  • Ventricular aneurysm
  • LBBB/Pacemaker
  • Pulmonary Embolism
  • High Voltage (LVH, Athlete's heart, WPW, etc.)
  • Na+ Channelopathies (TCA, Na-blockers, Brugada, hyperK)
  • Hypothermia
  • Takotsubo
  • Intracranial abnmls
  • "Spiked Helmet" sign
  • Hypercalcemia

4

Key acute causes of diffuse STE with differential indicators

  • STEMI
    • Often with reciprocal STD, sometimes Q-waves
  • Pericarditis
    • Often with PR depression and concave upwards STE, no Qs
  • Myocarditis
    • Similar to STEMI, no Qs
  • BER
    • No reciprocal changes, concave upwards STE, no Qs
  • Ventricular aneurysm
    • Large Q-waves with no reciprocal depression

5

DDx for poor R-wave progression (r<3mm in V3) (the 6 Ls)

  • LAFB
  • LBBB
  • LVH
  • Low voltage
  • Lead Misplacement
  • Prior AS MI

6

Criteria for "pathologic" Q-waves

  • >40ms (>1 small square)
  • >2mm deep
  • >25% depth of QRS
    • especially for inferior leads, where 2mm may be normal
  • any q-waves in v1-v3

7

Signs of hypokalemia

  • U-waves ("camel-hump" T's)
    • Especially in precordial leads
  • QTc prolongation
  • Flattened/inverted Ts with sagging or depressed ST-segments
  • "reverse Wellen's" biphasic T-waves
  • STE in aVR
  • PVCs and pseudo-ischemic patterns

Mimic for aVR MI! Look for biphasic precordial Ts and grossly prolonged QTc

8

Describe Ashman phenomenon

  • intermittent abberant conduction during AFib with RVR
  • usually follows a "long-short" cycle of AFib
  • aberrant conduction mimics short runs of VTach
  • Usually mimics RBBB morphology

9

What are normal HR and QRSD for VTach?

  • HR >120-130
  • QRSD<200ms
    • Unusually slow/wide VTach may indicate severe hyperkalemia!

10

ECG features of Na+-channel blockade (TCA OD, Class I antiarrhythmic OD)

  • Interventricular conduction delay >100ms in II
  • RAD with terminal R deflection >3mm or R/S ratio >0.7 in aVR
  • Sinus tachycardia due to antimuscarinic effects in TCA OD

11

Criteria for differentiating between acute pericarditis and STEMI

Suggests STEMI:

  • STD in ANY lead except for aVR or V1 (definitive)
  • STE in III > II (definitive)
  • Horizontal or convex upwards STE (definitive)
  • Known NEW Q-waves

Suggests AP:

  • Friction Rub
  • PR depression in multiple leads

STEMI findings trump AP findings!

12

Universal criteria for STEMI

  • STE at J-point in 2 contiguous leads
  • Men >=40: 2mm in V2/3, 1mm in all other leads
  • Men <40: 2.5mm in V2/V3, 1mm in all other leads
  • Women: 1.5mm in V2/V3, 1mm in all other leads
  • Posterior STEMI
    • tall R-waves, STD, and upright Ts in V1/2/3

13

Indicators for BER

  • Widespread, concave-up STE most prevalent in V2-5
  • Notching or slurring at the J-point
  • STE is <25% the amplitude of the T
  • Prominent, assymetrical T-waves
  • No other signs of STEMI (reciprocal changes, TWIs, pathological Qs, etc.)
  • ST changes are stable over time