Cardiac Medicine Certification (CMC) Practice Exam

What characterizes Wolff-Parkinson-White Syndrome (WPW)?

1. It involves a delay in electrical conduction through the heart.

2. It occurs due to an extra electrical conduction pathway.

3. It is only symptomatic during physical exertion.

4. It primarily affects the pacemaker cells.

The correct answer is: It occurs due to an extra electrical conduction pathway.

Wolff-Parkinson-White Syndrome is characterized by the presence of an extra electrical conduction pathway in the heart. This additional pathway, known as an accessory pathway, can lead to episodes of rapid heart rate (tachycardia) due to pre-excitation of the ventricles before the normal conduction system can propagate the impulse. As a result, the heart can potentially experience dangerous arrhythmias. This condition contrasts with typical conduction delays, as seen in other cardiac disorders, where the conduction through the AV node or within the ventricles is slowed rather than having alternate routes for conduction. The extra pathway allows impulses to bypass the normal route through the AV node, which can cause a circular electrical conduction pattern, leading to episodes of supraventricular tachycardia. Thus, the defining characteristic of WPW is indeed this abnormal accessory pathway, which distinguishes it from other conditions affecting cardiac conduction.