Echocardiogram Network Fundamentals 2

Question 1

Which cardiac structure serves as the primary pacemaker of the heart?

Accepted Answer

Sinoatrial (SA) node

Answer

The sinoatrial (SA) node, located in the right atrium, is the heart's primary pacemaker, generating electrical impulses at 60–100 bpm.

Question 2

What is the intrinsic firing rate of the AV node when acting as a secondary pacemaker?

Accepted Answer

40–60 bpm

Answer

The AV node has an intrinsic rate of 40–60 bpm, slower than the SA node, making it a secondary pacemaker.

Question 3

On an echocardiogram, which finding would suggest AV conduction delay affecting mechanical function?

Accepted Answer

Simultaneous atrial and ventricular contraction

Answer

A very long PR interval can cause simultaneous atrial and ventricular contraction, visible on echo as an absent or truncated A-wave.

Question 4

The Bundle of His bifurcates into which two structures?

Accepted Answer

Right and left bundle branches

Answer

The Bundle of His divides into the right and left bundle branches, which carry impulses to the ventricular myocardium.

Question 5

In left bundle branch block (LBBB), how does septal motion typically appear on M-mode echocardiography?

Accepted Answer

Paradoxical (posterior) septal motion

Answer

LBBB causes paradoxical posterior septal motion on M-mode due to abnormal electrical activation sequence of the left ventricle.

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