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Catecholaminergic polymorphic ventricular tachycardia
Classification and external resources
OMIM 604772 611938
DiseasesDB 33816

Catecholaminergic Polymorphic Ventricular Tachycardia (CPVT) is an electrophysiological disorder of the heart that occurs in genetically predisposed individuals. 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, the voltage gated ion channel mutation intermittently causes the heart to enter a life threatening state of arrhythmia as response to the natural release of catecholamines. The most common symptom is syncope, which most commonly appears 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.[1][2][3][4]

Contents

Signs and symptoms

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Syncopal

CPVT may cause exercise-induced ventricular arrhythmias and/or syncope occurring during physical activity or acute emotion, but demonstrates 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 ventricular arrhythmias during 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.[5]

Electrophysiology

The resting electrocardiogram is usually unremarkable but can show sinus bradycardia and a prominent U wave.[6]

Genetic testing

Genetic testing is clinically available and is useful for helping confirm a diagnosis in an individual suspected of having CPVT, as well as making a presymptomatic diagnosis of related individuals (Overview of CPVT Genetic Testing).[7]

Pathophysiology

Catecholamines

Genetics

CPVT has an autosomal dominant inheritance pattern. There are two genes currently associated with CPVT: RYR2 (majority) and CASQ2 (though this gene has a recessive inheritance pattern) (1-2%).[8]

  • The Ryanodine receptor (RYR2) is involved in intracardiac Ca2+ handling; Ca2+ overload triggers abnormal cardiac activity.[9]
  • Calsequestrin (CASQ2) is a calcium buffering protein of the sarcoplasmic reticulum.

Inheritance

Treatment

Medication

Medications to treat CPVT include beta blockers and verapamil.[10]

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.[11]

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.[3][12][13]

See also

References

  1. ^ Iyer, Vivek; Antonis A. Armoundas. "Unraveling the Mechanisms of Catecholaminergic Polymorphic Ventricular Tachycardia". Proc. IEEE Eng Med Biol Soc.. Cardiovascular Research Center, Massachusetts General Hospital: IEEE. PMID 17959506. http://embc2006.njit.edu/pdf/279918_Iyer.pdf. Retrieved 2008-12-02.  
  2. ^ Liu, N; Ruan Y, Priori SG (July-August 2008). "Catecholaminergic polymorphic ventricular tachycardia". Progress in Cardiovascular Diseases 51 (1): 23–30. doi:10.1016/j.pcad.2007.10.005. PMID 18634915.  
  3. ^ a b Wilde, Arthur; Zahurul A. Bhuiyan, Lia Crotti, Mario Facchini, Gaetano M. De Ferrari, Thomas Paul, Chiara Ferrandi, Dave R. Koolbergen, Attilio Odero, Peter J. Schwartz (2008-05-08). "Left cardiac sympathetic denervation for catecholaminergic polymorphic ventricular tachycardia". New England Journal of Medicine 358 (19): 2024–9. doi:10.1056/NEJMoa0708006. PMID 18463378. http://content.nejm.org/cgi/content/full/358/19/2024. Retrieved 2008-12-17.  
  4. ^ "Interview with Michael J. Ackerman, M.D., Ph.D." (PDF). Hannah Wernke Memorial Foundation. http://www.hannahwernkememorialfoundation.com/Intv-Dr.Ackerman-CPVT.030507.pdf. Retrieved 2009-02-09.  
  5. ^ Napolitano, Carlo; Silvia G. Priori (May 2007). "Diagnosis and treatment of catecholaminergic polymorphic ventricular tachycardia". Heart Rhythm 4 (5). PMID 17467641 doi:10.1016/j.hrthm.2006.12.048
  6. ^ Aizawa Y, Komura S, Okada S, et al. (May 2006). "Distinct U wave changes in patients with catecholaminergic polymorphic ventricular tachycardia (CPVT)". Int Heart J 47 (3): 381–9. doi:10.1536/ihj.47.381. PMID 16823244. http://www.jstage.jst.go.jp/article/ihj/47/3/47_381/_article.  
  7. ^ "Mayo Clinic Research Shows 35 Percent of 49 Young People Who Died Suddenly and Inexplicably Had Genetic Heart Defects". Mayo Clinic. 2007-01-30. http://www.mayoclinic.org/news2007-rst/3902.html. Retrieved 2008-12-23.  
  8. ^ "Catecholaminergic polymorphic ventricular tachycardia: Recent mechanistic insights". Cardiovascular Research 67 (3): 379–387. 2005-08-15. doi:10.1016/j.cardiores.2005.04.027. PMID 15913575 doi:10.1016/j.cardiores.2005.04.027. http://cardiovascres.oxfordjournals.org/cgi/content/full/67/3/379. Retrieved 2009-02-09.  . http://cardiovascres.oxfordjournals.org/cgi/content/full/67/3/379. Retrieved 2009-02-09.  
  9. ^ Wehrens XH, Marks AR (November 2004). "Sudden unexplained death caused by cardiac ryanodine receptor (RyR2) mutations" (). Mayo Clin. Proc. 79 (11): 1367–71. doi:10.4065/79.11.1367. PMID 15544013. http://www.mayoclinicproceedings.com/inside.asp?AID=711&UID=.  
  10. ^ Sumitomo, Naokata; Harada K, Nagashima M, Yasuda T, Nakamura Y, Aragaki Y, Saito A, Kurosaki K, Jouo K, Koujiro M, Konishi S, Matsuoka S, Oono T, Hayakawa S, Miura M, Ushinohama H, Shibata T, Niimura I (January 2003). "Catecholaminergic polymorphic ventricular tachycardia: electrocardiographic characteristics and optimal therapeutic strategies to prevent sudden death". Heart 89 (1): 66–70. doi:10.1136/heart.89.1.66. PMID 12482795. http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pubmed&pubmedid=12482795. Retrieved 2008-12-17.  
  11. ^ 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. PMID 19330009 doi:10.1038/nm.1942. http://www.nature.com/nm/journal/v15/n4/abs/nm.1942.html. Retrieved 2009-05-04.  
  12. ^ Hughes, Sue (2008-05-07). "Denervation successfully treats catecholaminergic polymorphic ventricular tachycardia". HeartWire (WebMD). http://www.theheart.org/editorial-program/862045.do. Retrieved 2008-12-17.  
  13. ^ 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.  

Further reading

External links


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