Sick Sinus Syndrome

This is part of: Sinus node rhythms and arrhythmias

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

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).

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