Case nine, autosomal dominant catecholaminergic polymorphic ventricular tachycardia, or CPVT, is caused by mutations in the cardiac ryanidine receptor. Which of the following statements best describes the pathogenesis of arrhythmias in patients with CPVT? A, RYR2 mutations increase inward sacralemmal calcium currents, leading to calcium overload and arrhythmias through the electrogenic sodium calcium exchanger. B, ryanidine receptor mutations lead to early after depolarizations and triggered activity through reactivation of inward calcium currents. C, ryanidine receptor mutations lead to delayed after depolarization and triggered activity by causing abnormal calcium leak from the sacroplasmic reticulum associated with epsilon waves on the electrocardiogram. D, ryanidine receptor mutations lead to delayed after depolarizations and triggered activity by causing abnormal calcium leak from the sacroplasmic reticulum that leads to inward current through the electrogenic sodium calcium exchanger.

CPVT

RYR2 mutations

calcium overload

delayed after depolarizations

sodium calcium exchanger