Sick Sinus Syndrome - Sick Sinus Syndrome Information
Sick sinus syndrome occurs most commonly in elderly patients. The pathologic changes are usually nonspecific, characterized by patchy fibrosis of the sinus node and cardiac conduction system. Sick sinus syndrome may be caused by other conditions, including sarcoidosis, amyloidosis, Chagas' disease, and various cardiomyopathies. Coronary disease is an uncommon cause.
Sick Sinus Syndrome Information
Most patients with electrocardiographic evidence of sick sinus syndrome are asymptomatic, but rare individuals may experience syncope, dizziness, confusion, palpitations, heart failure, or angina. Because these symptoms are either nonspecific or are due to other causes, it is essential that they be demonstrated to coincide temporally with arrhythmias. This may require prolonged ambulatory monitoring or the use of an event recorder. Pharmacologic therapy for sick sinus syndrome has been difficult, but recent studies have indicated that oral theophylline may be effective, especially when sinus bradycardia is the major manifestation.
Most symptomatic patients will require permanent pacing. Dual-chamber pacing is preferred because ventricular pacing is associated with a higher incidence of subsequent atrial fibrillation, and subsequent atrioventricular block occurs at a rate of 2% per year. Treatment of associated tachyarrhythmias is often difficult without first instituting pacing, since digoxin and other antiarrhythmic agents may exacerbate the bradycardia. Unfortunately, symptomatic relief following pacing has not been consistent, largely because of inadequate documentation of the etiologic role of bradyarrhythmias in producing the symptom. Furthermore, many of these patients may have associated ventricular arrhythmias that may require treatment; however, carefully selected patients may become asymptomatic with permanent pacing alone.