CATECHOLAMINERGIC POLYMORPHIC VENTRICULAR TACHYCARDIA (CPVT)

Catecholaminergic polymorphic ventricular tachycardia (CPVT) is an autosomal dominant inherited disease of the healthy cardiac muscle with an incidence of approximately 1:10,000. The arrythmias are adrenergically induced and manifest on average at the age of 8 years. Bi‑directional or polymorphic ventricular tachycardias are typical.

If left untreated, CPVT leads to syncope before the age of 40 in 60% of cases and to sudden cardiac death before the age of 30 in 30-50% of cases. The resting EKG seems normal. The earlier syncope occurs, the worse the prognosis, and the risk of cardiac events is about four times higher in men. The treatment is beta blockers. However, about 30% of patients remain symptomatic and may need an implanted defibrillator.

Pathogenic variants in the RYR2 gene (ryanodine type 2 receptor) can be identified in 40-70% of CPVT patients. This cardiac ryanodine receptor is the most important Ca²⁺releasing channel of the sarcoplasmic reticulum (SR) and plays a central role in the activation of cardiomyocytes. Rare variants in the CASQ2 (calsequestrin) and TECRL (trans-2,3-enoyl-CoA reductase-like) genes are detectable in about 3-5% of patients and lead to an autosomal recessive inherited form of CPVT. Variants in these 3 genes can cause a Ca²⁺ leakage current from the SR.

References

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