catecholaminergic polymorphic ventricular tachycardia

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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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References in periodicals archive ?
Using patient-specific iPSCs, CPVT type I models were also obtained [45-47].
iPSC-based model of CPVT type I was also created for a female patient carrying the p.
Thus, as in the case of LQT syndrome, patient-specific iPSC-derived cardiomyocytes adequately reproduce the disease in vitro and are a good tool for studying CPVT molecular mechanisms and drug searching (see Table 4).
Potentially lethal cardiac channelopathies (LQTS, CPVT, and BrS) and cardiomyopathies (HCM, DCM, and ACM) are heritable genetic disorders that often exhibit variable expressivity ranging from a lifelong asymptomatic course, to mild cardiac episodes (ie, palpitations or syncope), to sudden cardiac death as the first manifestation, even in a single pedigree.
Abbreviations: ACM, arrhythmogenic cardiomyopathy; BrS, Brugada syndrome; CPVT, catecholaminergic polymorphic ventricular tachycardia; DCM, dilated cardiomyopathy; HCM, hypertrophic cardiomyopathy; LQTS, long QT syndrome; NHLBI GO, National Heart, Lung, and Blood Institute Grand Opportunity; QT, interval between the start of the Q wave and end of the T wave in the cardiac electrical cycle as seen on an electrocardiogram; SNVs, single-nucleotide variants.
Patients with CPVT experience abnormally rapid heart rates (tachycardia), usually during exercise or stress, and are at risk for fainting and cardiac arrest.
The researchers developed a mouse model for CPVT (by eliminating the calsequestrin gene) and proposed using the model to study medications and interventions for the disorder.
In isolated heart cells, flecainide blocked the ryanodine receptor and the calcium "leak" (the underlying molecular defect in CPVT), and it completely prevented ventricular arrhythmias in the mouse model of CPVT.