The most common indication for permanent pacing is:

D. Sick sinus syndrome.

DISCUSSION: Patients with sinus node dysfunction may develop a number of arrhythmias, such as inappropriate sinus bradycardia, chronotropic incompetence, sinoatrial exit block, and sinus arrest. This group of rhythm disorders typically occurs in older patients with or without underlying heart disease and is collectively known as the “sick sinus syndrome.” In addition, many patients with sick sinus syndrome have associated atrial tachyarrhythmias, particularly atrial fibrillation. This association of atrial tachyarrhythmias in patients with the sick sinus syndrome is called the tachycardia-bradycardia (or tachy-brady) syndrome. The most common indication for permanent pacing occurs in patients with the sick sinus syndrome.