catecholaminergic polymorphic ventricular tachycardia

catecholaminergic polymorphic ventricular tachycardia

An inherited cardiac conduction disorder of early onset (age 7 to 9), which is characterised by episodic syncope occurring during exercise or acute emotion, which triggers ventricular tachycardia, usually followed by spontaneous recovery or less commonly by ventricular fibrillation and sudden death without CPR.

Diagnosis
Reproducible ventricular arrhythmias during exercise stress testing.

EKG
Alternating 180-degree-QRS axis on a beat-to-beat basis, so-called bidirectional VT, and irregular polymorphic VT without a "stable" QRS vector alternans.

Management 
Beta-blockers, even in absence of clinical disease; implantable cardioverter-defibrillator for recurrent cardiac arrest, anticoagulation as needed.

Prevent secondary complications 
Avoid exacerbating asthma, cardiac-specific beta-blocker: metoprolol is preferred. Follow-up visits with a cardiologist every 6–12 months to monitor therapy.
Avoid competitive sport and strenuous exercise.
Test blood relatives at risk with resting EKG, Holter monitoring, and exercise stress testing.

Genetic counselling
(1) RYR2-related CPVT is autosomal dominant—i.e., each child has a 50% chance of inheriting the mutation.
(2) CASQ2-related CPVT is autosomal recessive—i.e., each parent of an affected child is a carrier.

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