Differentials Flashcards
1
Q
DDx for new right axis differentiation (give 10)
A
- Pulmonary Hypertension
- Na+ Channel blocker toxicity
- Hyperkalemia
- Old lateral MI (Q-waves)
- RVH
- LPFB
- Ventricular ectopy
- Misplaced leads
- Situs Inversus
- Newborns/infants
2
Q
DDx for new left axis differentiation (give 8)
A
- LBBB
- Paced rhythm
- Pre-excitation (WPW)
- Prior inferior MI (Q-waves)
- LAFB
- LVH
- Hyperkalemia
- Elderly/obese patients
3
Q
DDx for ST elevation (16)
A
- 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
Q
Key acute causes of diffuse STE with differential indicators
A
- 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
Q
DDx for poor R-wave progression (r<3mm in V3) (the 6 Ls)
A
- LAFB
- LBBB
- LVH
- Low voltage
- Lead Misplacement
- Prior AS MI
6
Q
Criteria for “pathologic” Q-waves
A
- >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
Q
Signs of hypokalemia
A
- 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
Q
Describe Ashman phenomenon
A
- 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
Q
What are normal HR and QRSD for VTach?
A
- HR >120-130
- QRSD<200ms
- Unusually slow/wide VTach may indicate severe hyperkalemia!
10
Q
ECG features of Na+-channel blockade (TCA OD, Class I antiarrhythmic OD)
A
- 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
Q
Criteria for differentiating between acute pericarditis and STEMI
A
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
Q
Universal criteria for STEMI
A
- 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
Q
Indicators for BER
A
- 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