Which condition could result in a pulse rate less than 60 in a patient?

A pulse rate of less than 60 beats per minute is known as bradycardia. Second-degree A-V (atrioventricular) block is a condition that disrupts the conduction system of the heart, leading to a slowed or missed heartbeat. In this condition, there is a failure of electrical impulses to properly conduct through the A-V node to the ventricles, which can result in missed beats and, consequently, a slower overall heart rate.

In some types of second-degree A-V block, particularly type II, there can be intermittent blockages leading to a significant drop in heart rate. The result is that patients can experience a pulse rate that falls below 60 beats per minute, causing bradycardia. This condition is clinically significant as it can lead to inadequate blood circulation and symptoms such as dizziness, fatigue, or syncope (fainting).

In contrast, the other conditions listed, such as atrial flutter, sinus arrhythmia, and atrial fibrillation, typically result in a pulse rate that is either normal or tachycardic (greater than 100 beats per minute). Sinus arrhythmia, while it can exhibit a rate that dips lower during expiration, generally does not lead to sustained bradycard