CCS Cardiac Rhythm Interpretation & ECG Analysis 2

Question 1

Which ECG finding is most characteristic of a left bundle branch block (LBBB)?

Accepted Answer

QRS >0.12 s with broad monophasic R wave in V5–V6

Answer

QRS >0.12 s with RSR' pattern in V1

Answer

QRS >0.12 s with deep S wave in V5–V6

Answer

QRS >0.12 s with right axis deviation

Question 2

What ECG triad is associated with Wolff-Parkinson-White (WPW) syndrome?

Accepted Answer

Short PR interval, delta wave, and wide QRS complex

Answer

Prolonged PR interval, wide QRS, and ST elevation

Answer

Normal PR interval with intermittently dropped QRS complexes

Answer

Prolonged QT interval and biphasic T waves

Question 3

Atrial flutter typically presents with what atrial rate?

Accepted Answer

250–350 bpm

Answer

100–150 bpm

Answer

150–250 bpm

Answer

350–600 bpm

Question 4

Which ECG change is classically seen early in hyperkalemia?

Accepted Answer

Peaked narrow symmetrical T waves and QRS widening

Answer

Prolonged QT interval and prominent U waves

Answer

ST elevation and short QT interval

Answer

PR prolongation with delta waves

Question 5

Which ECG finding most strongly supports ventricular tachycardia (VT) over SVT with aberrancy?

Accepted Answer

Wide complex tachycardia with AV dissociation and QRS >0.14 seconds

Answer

Narrow complex tachycardia at 180 bpm with retrograde P waves

Answer

Irregularly irregular wide complex tachycardia

Answer

Regular narrow complex tachycardia terminating with vagal maneuvers

Question 6

ST elevation in leads V1–V4 most commonly indicates occlusion of which coronary artery?

Accepted Answer

Left anterior descending artery (LAD)

Answer

Right coronary artery (RCA)

Answer

Left circumflex artery (LCx)

Answer

Posterior descending artery (PDA)

Question 7

What is the defining ECG appearance of torsades de pointes?

Accepted Answer

Polymorphic ventricular tachycardia with QRS complexes that appear to twist around the isoelectric baseline

Answer

Regular monomorphic wide complex tachycardia at a constant rate

Answer

Narrow complex tachycardia with alternating QRS amplitude

Answer

Wide complex bradycardia with variable PR intervals