sinus node dysfunction

Introduction

Also see more specific term

Etiology

• degenerative fibrosis of the sinoatrial node
• beta-blockers & parasympathomimetics (donepezil, neostigmine, pyridostigmine) are the most common reversible cause of sinus node dysfunction

Pathology

• near-syncope, syncope, or confusion are manifestations of hypoperfusion

Clinical manifestations

• sinus bradycardia
• lightheadedness

Complications

• ectopic atrial bradycardia (rate <50/min)
• sinoatrial exit block
• sinus pause (>3 seconds)
• sinus node arrest
• tachycardia-bradycardia syndrome
• chronotropic incompetence
• isorhythmic dissociation

Management

• correct reversible cause(s)
• permanent pacemaker implantation for symptomatic sinus node dysfunction not due to reversible cause

More specific terms

• sick sinus syndrome; atrial fibrillation with bradyarrhythmia; tachycardia-bradycardia syndrome
• sinoatrial exit block
• sinus arrest/pause
• sinus arrhythmia
• sinus bradycardia