Question

When the sinus node slows down or fails to initiate depolarization, and a lower pacemaker spontaneously fires, it is called:

a. Ectopic focus
b. Escape rhythm
c. Atrial flutter
d. Supraventricular tachycardia

Answer 1

When the sinus node slows down or fails to initiate depolarization, and a lower pacemaker spontaneously fires, it is called an ectopic focus. An ectopic focus is an area of the heart other than the sinus node that initiates an electrical impulse.

Step-by-step explanation:

When the sinus node slows down or fails to initiate depolarization, and a lower pacemaker spontaneously fires, it is called an ectopic focus. An ectopic focus is an area of the heart other than the sinus node that initiates an electrical impulse.

This can occur due to various factors such as localized ischemia exposure to certain drugs, or disease conditions. If the ectopic focus becomes chronic, it can lead to arrhythmias or fibrillation.