Catecholaminergic polymorphic ventricular tachycardia (CPVT) is an arrhythmogenic heart disease, which is characterized by the presence of polymorphic ventricular tachycardia induced by physical activity, stress or catecholamine infusion. It may degenerate into ventricular fibrillation.
Ventricular arrhythmias CPVT characteristics appear in the situations described above, not when patient is at rest. First, complexes appear as premature ventricular, bigeminy subsequently followed by polymorphic or bidirectional ventricular tachycardia. In the last stage ventricular fibrillation can occur.
It is imperative that individuals affected receive treatment. In cases where it was not, the patients had high rates of mortality, experiencing cardiac arrest in about 30%. 80% of individuals may experience one or more syncopal events (usually the first symptom detected).
Catecholaminergic polymorphic ventricular tachycardia is a disorder that has high genetic heterogeneity. Also, it may appear under a autosomal dominant or recessive inheritance, accompanied by a variable clinical penetrance. Specifically, mutations were detected associated with the disease in three different genes; RYR2 (1q43) CASQ2 (1p13.3-p11) and TRDN (6q22-q23). Alterations in RYR2 are the most common and are inherited in an autosomal dominant. The rest are autosomal recessive.
RYR2 encodes a cardiac ryanodine receptor, located on the sarcoplasmic reticulum that acts as a source of calcium required for the coupling of the processes of excitation-contraction of heart muscle. CASQ2 encodes calsequestrin cardiac isoform, a protein that acts like a fundamental reservoir of calcium ions in the sarcoplasmic reticulum of cardiac myocytes and it is part of a protein complex that contains the ryanodine receptor. TRDN encodes triadina, a protein that plays an active role in releasing calcium in the sarcoplasmic reticulum, besides having a structural role in anchoring calsequestrin and ryanodine.
As for treatment, beta blockers can be administered at maximum dose to the control of arrhythmias. Most reference centers are using nadolol or propranolol. However, flecainide (it acts by blocking the sodium channel) also exhibited good results. For the prevention of sudden death and cardiac arrests are using implantable cardioverter defibrillators, particularly in individuals with CPVT and recurrent syncope.