Catecholaminergic polymorphic ventricular tachycardia

"CPVT" redirects here. For the thermal power usage of concentrated photovoltaics, see Concentrated photovoltaics and thermal.

Catecholaminergic polymorphic ventricular tachycardia
Specialty	Cardiology

Catecholaminergic Polymorphic Ventricular Tachycardia (CPVT) is a rhythm disorder of the lower chambers of the heart, or ventricles that occurs in genetically predisposed individuals. Synonyms: Familial Polymorphic Ventricular Tachycardia (FPVT), Catecholamine-Induced Polymorphic Ventricular Tachycardia. Thought to affect as many as one in ten thousand people, it is estimated to cause 15% of all unexplained sudden cardiac deaths in young people.

First recognized in 1975, this condition, due to a mutation in a voltage gated ion channel which regulates the flow of ions in and out or cardiac cells and therefore their electrical stability may cause the heart to enter a life threatening state of arrhythmia as response to the natural release of catecholamines from nerve endings on the heart muscle and from the adrenal glands into the circulation. This rhythm disturbance prevent the heart from pumping blood appropriately. The most common symptom is dizziness or syncope occurring on exercise or due to emotional stress, symptoms which typically starts manifesting themselves during the first or second decade of life.

Because its symptoms are most prevalent when the body is subjected to intense emotional or physical stress, the condition can elude traditional methods of heart examination such as echocardiogram and resting electrocardiogram.

Signs and symptoms

Dizziness and Syncope

CPVT may cause exercise-induced ventricular arrhythmias with ensuing dizziness and/or syncope occurring during physical activity or acute emotional stress. Affected patients though demonstrate no structural problems of the heart. Ventricular tachycardia may self-terminate or degenerate into ventricular fibrillation, causing sudden death without immediate cardiopulmonary resuscitation. The majority of events occur during childhood and more than 60% of affected individuals will have a first episode of syncope or cardiac arrest by age 20.

Diagnosis

CPVT diagnosis is based on reproducing irregularly shaped ventricular arrhythmias during ECG exercise stress testing, syncope occurring during physical activity and acute emotion, and a history of exercise or emotion-related palpitations and dizziness with an absence of structural cardiac abnormalities.

Type	OMIM	Gene	Locus
CPVT1	Template:OMIM2	RYR2	1q42.1-q43
CPVT2	Template:OMIM2	CASQ2	1p13.3-p11

• The Ryanodine receptor (RYR2) is involved in intracardiac Ca²⁺ handling; Ca²⁺ overload triggers abnormal cardiac activity.
• Calsequestrin (CASQ2) is a calcium buffering protein of the sarcoplasmic reticulum.

Inheritance

Mutation of RYR2 is inherited in an autosomal dominant fashion. The inheritance of the Calsequestrin-2 mutation is autosomal recessive.

Treatment

Medication

Medications to treat CPVT include beta blockers and verapamil.

According to recent research published in Nature Medicine, flecainide inhibits the release of the cardiac ryanodine receptor–mediated Ca²⁺, and is therefore believed to medicate the underlying molecular cause of CPVT in both mice and humans.

Implantable cardioverter-defibrillator

Implantable cardioverter-defibrillators are used to prevent sudden death.

Sympathectomy

In recent reports, left cardiac sympathetic denervation and bilateral thoracoscopic sympathectomy have shown promising results in individuals whose symptoms cannot be controlled by beta blockers.

See also

• Brugada syndrome
• Cardiac arrhythmia
• Long QT syndrome
• Sick sinus syndrome
• Sudden cardiac death

Further reading

• Receptor defects cause inherited disorder CPVT
• Denervation successfully treats catecholaminergic polymorphic ventricular tachycardia
• Screening relatives of sudden-death victims provides likely cause of death and potentially saves lives
• Nakajima T, Kaneko Y, Taniguchi Y; et al. (1997). "The mechanism of catecholaminergic polymorphic ventricular tachycardia may be triggered activity due to delayed afterdepolarization". Eur Heart J. 18 (3): 530–1. PMID 9076398. {{cite journal}}: Explicit use of et al. in: |author= (help); Unknown parameter |month= ignored (help)CS1 maint: multiple names: authors list (link)
• Catecholaminergic Polymorphic Ventricular Tachycardia (CPVT) Information sheet - Auckland District Health Board's Cardiac Inherited Disease Registry
• Clinical Data's PGxHealth Division Launches CPVT Cardiac Channelopathy Test - Business Wire
• SADS UK - What is CPVT
• Arrhythmogenesis in CPVT: Lessons Learned from a CPVT Mouse Model

External links

• Catecholaminergic Polymorphic Ventricular Tachycardia (CPVT) Information Sheet
• GeneReviews article
• The Hannah Wernke Memorial Foundation