Catecholaminergic polymorphic ventricular tachycardia (CPVT) is an inherited 
heart rhythm disorder characterized by the occurrence of potentially 
life-threatening polymorphic ventricular tachyarrhythmias in conditions of 
physical or emotional stress. The underlying cause is a dysregulation in 
intracellular Ca handling due to mutations in the sarcoplasmic reticulum Ca 
release unit. Recent experimental work suggests that sinus bradycardia, which is 
sometimes observed in CPVT patients, may be another primary defect caused by 
CPVT mutations. Herein, we review the pathophysiology of CPVT and discuss the 
role of sinus node dysfunction as a modulator of arrhythmia risk and potential 
therapeutic target.