CMC CMC Cardiac Diagnostics & Imaging

Question 1

What does the PR interval on an ECG represent?

Accepted Answer

Conduction time from atrial depolarization through the AV node to ventricular activation

Answer

Ventricular depolarization duration

Answer

Ventricular repolarization

Answer

Atrial repolarization only

Question 2

ST elevation in ECG leads II, III, and aVF is most consistent with infarction of which cardiac territory?

Accepted Answer

Inferior wall (RCA territory)

Answer

Anterior wall (LAD territory)

Answer

Lateral wall (circumflex territory)

Answer

Posterior wall

Question 3

A corrected QT interval (QTc) greater than 500ms on ECG significantly increases the risk of which arrhythmia?

Accepted Answer

Torsades de Pointes

Answer

Complete heart block

Answer

Wolff-Parkinson-White pre-excitation

Answer

Atrial flutter

Question 4

Which ECG change is one of the earliest and most characteristic findings in hyperkalemia?

Accepted Answer

Peaked, tall, narrow T waves

Answer

Prominent U waves

Answer

Short QT interval

Answer

Delta waves

Question 5

Why is new left bundle branch block (LBBB) in a patient with chest pain clinically significant?

Accepted Answer

New LBBB may be a STEMI equivalent requiring emergent catheterization

Answer

It is always a normal variant in adults

Answer

It indicates only benign vagal tone

Answer

It confirms pulmonary embolism

Question 6

Which arrhythmia produces characteristic 'sawtooth' flutter waves at approximately 300 beats per minute on ECG?

Accepted Answer

Atrial flutter

Answer

Atrial fibrillation

Answer

Ventricular tachycardia

Answer

Junctional tachycardia