Sinus Node Dysfunction

Sinus node dysfunction is historically referred to as sick sinus syndrome. It is due to age-related fibrotic degeneration of the sinus node resulting in impaired signal generation and propagation which manifests as sinus pauses, and occasionally episodes of atrial arrhythmias alternating with bradycardia (tachy-brady syndrome). With tachy-brady syndrome, episodes of bradycardia often alternate with atrial fibrillation.



  1. Kusumoto FM, Schoenfeld MH, Barrett C, et al. 2018 ACC/AHA/HRS Guideline on the Evaluation and Management of Patients With Bradycardia and Cardiac Conduction Delay: A Report of the American College of Cardiology/American Heart Association Task Force on Clinical Practice Guidelines and the Heart Rhyth. Circulation. 2019;140(8):e382-e482.