Preexcitation occurs when an electrical impulse from the atria bypasses the normal conduction pathway through the AV node and instead uses an accessory pathway to reach the ventricles more quickly. This results in a short PR interval and a slurred beginning of the QRS complex, known as a delta wave, on an ECG.

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Preexcitation

Question 9

Multiple Choice

Preexcitation:

A) leads to a delayed depolarization of the ventricles.
B) occurs when an impulse arises from a supraventricular site and travels through the AV node to the ventricles more quickly than normal.
C) leads to a longer than normal PR interval.
D) produces a characteristically abnormal slurring at the onset of the QRS complex and a short PR interval.

Correct Answer: