ABSTRACT
Sinus Node Dysfunction Sinus node dysfunction, also called sick sinus syndrome, includes sinus bradycardia, sinus pauses, tachycardia-bradycardia syndrome (Figure 3-20), sinus arrest, and chronotropic incompetence. The diagnosis is made from the medical history and results of electrocardiographic (ECG) and Holter monitoring, which are the most useful diagnostic tests. Electrophysiologic testing generally is not helpful for evaluating patients with a history consistent with sinus node disease because it has low sensitivity. In some cases, prolonged monitoring with an event recorder may be required to correlate symptoms with bradycardia. If a patient is able to exercise, a treadmill test is useful for determining whether the sinus node rate can increase appropriately to meet metabolic need.
