Catecholaminergic polymorphic ventricular tachycardia
|Catecholaminergic polymorphic ventricular tachycardia|
|Classification and external resources|
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 of 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 prevents the heart from pumping blood appropriately. The most common symptom is dizziness or syncope which often occurs during exercise or as a response to emotional stress. These symptoms typically start 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 is often not detected by the traditional methods of heart examination such as echocardiogram and resting electrocardiogram.
Signs and symptoms
|This section requires expansion. (February 2009)|
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 unless immediate cardiopulmonary resuscitation is applied. The majority of events occur during childhood with more than 60% of affected individuals having their first episode of syncope or cardiac arrest by age 20.
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.
- 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.
Mutation of RYR2 is inherited in an autosomal dominant fashion. The inheritance of the Calsequestrin-2 mutation is autosomal recessive.
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.[clarification needed]
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- Watanabe, Hiroshi; Nagesh Chopra, Derek Laver, Hyun Seok Hwang, Sean S. Davies, Daniel E. Roach, Henry J. Duff, Dan M. Roden, Arthur A. M. Wilde, Björn C. Knollmann (2009-04-01). "Flecainide prevents catecholaminergic polymorphic ventricular tachycardia in mice and humans". Nature Medicine 15 (4): 380–383. doi:10.1038/nm.1942. PMC 2904954. PMID 19330009. Retrieved 2009-05-04.
- Hughes, Sue (2008-05-07). "Denervation successfully treats catecholaminergic polymorphic ventricular tachycardia". HeartWire (WebMD). Retrieved 2008-12-17.
- Scott, P.A.; A.J. Sandilands, G.E. Morris, J.M. Morgan (October 2008). "Successful treatment of catecholaminergic polymorphic ventricular tachycardia with bilateral thoracoscopic sympathectomy". Heart Rhythm 5 (10): 1461–1463. doi:10.1016/j.hrthm.2008.07.007. PMID 18760972.
- 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. (March 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.
- 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
- Catecholaminergic Polymorphic Ventricular Tachycardia (CPVT) Information Sheet
- GeneReviews article
- The Hannah Wernke Memorial Foundation