Sick Sinus Syndrome

This is part of: Sinus node rhythms and arrhythmias

In sick sinus syndrome there is a malfunctioning sinus node. Several arrhythmias can result from this:

• Symptomatic slow sinus bradycardia in the absence of medication
• Sinus arrest or exit block
• Combinations of sinoatrial and atrioventricular conduction disturbances
• Brady-tachycardia syndrome; typically there is sinus bradycardia, sinus arrest or SA-block which is alternated by periods with fast or (ir)regular atrial arrhythmias (atrial fibrillation, atrial flutter, atrial tachycardia or sinus tachycardia).

ECG with Sick Sinus Syndrome. Rapid atrial fibrillation abruptly stops.

Usually a pacemaker is implanted to prevent bradycardia and tachycardias are 'topped off' with anti-arrhythmics, such as beta blockers.