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Titolo:
Genetic aspects in acquired long QT syndrome - a piece in the puzzle
Autore:
Schulze-Bahr, E; Haverkamp, W; Eckardt, L; Kirchhof, P; Wedekind, H; Breithardt, G;
Indirizzi:
Univ Munster Hosp, Dept Cardiol & Angiol, D-48129 Munster, Germany Univ Munster Hosp Munster Germany D-48129 giol, D-48129 Munster, Germany Univ Munster, Inst Arteriosclerosis Res, D-4400 Munster, Germany Univ Munster Munster Germany D-4400 lerosis Res, D-4400 Munster, Germany
Titolo Testata:
EUROPEAN HEART JOURNAL SUPPLEMENTS
fascicolo: K, volume: 3, anno: 2001,
pagine: K48 - K52
SICI:
1520-765X(200109)3:K<K48:GAIALQ>2.0.ZU;2-M
Fonte:
ISI
Lingua:
ENG
Soggetto:
TORSADES-DE-POINTES; LANGE-NIELSEN-SYNDROME; CARDIAC-ARRHYTHMIA; POTASSIUM CHANNEL; MISSENSE MUTATION; XENOPUS OOCYTES; MOLECULAR-BASIS; FEMALE GENDER; HEART-FAILURE; RISK FACTOR;
Keywords:
long QT syndrome; torsade de pointes; KCNQ1; HERG; ventricular repolarization; I-Kr; I-Ks;
Tipo documento:
Article
Natura:
Periodico
Settore Disciplinare:
Clinical Medicine
Citazioni:
47
Recensione:
Indirizzi per estratti:
Indirizzo: Schulze-Bahr, E Univ Munster Hosp, Dept Cardiol & Angiol, D-48129 Munster,Germany Univ Munster Hosp Munster Germany D-48129 nster, Germany
Citazione:
E. Schulze-Bahr et al., "Genetic aspects in acquired long QT syndrome - a piece in the puzzle", EUR H J SUP, 3(K), 2001, pp. K48-K52

Abstract

Torsade de pointes (TdP) is a serious complication which is induced by a large variety of cardiovascular and noncardiovascular drugs. Many clinical conditions and risk factors for the occurrence of UP during administration of drugs with a proarrhythmic potential have been identified. All such drugshave in common that they reversibly alter myocardial repolarization due tothe prolongation of the action potential (acquired QT interval prolongation) which is per se not arrhythmogenic. TdP is initiated (acquired long QT (LQT) syndrome) only when a threshold level is reached leading to early after-depolarizations (EADs) and triggered beats together with a marked dispersion in recovery of excitability. The underlying mechanisms of UP are not yet satisfactorily elucidated but, in general, alterations in cardiac ion currents which tune the normal action potential play a major role in arrhythmogenesis. Following recent advances in molecular biology and genetics, it has becomeclear that in some clinical instances (e.g. congestive heart failure or cardiac hypertrophy) ion channel genes become less expressed (down-regulated)and the consequent reduced ion currents (e.g. I-Kr) are likely to cause prolonged myocardial repolarization. In this setting, the use of drugs with action potential-prolonging properties could possibly be harmful and could not be compensated by the normal cardiac 'repolarization reserve'. In congenital LQT syndrome some of the same ion channel components were found to be genetically altered, suggesting that either quantitative or qualitative changes of ion currents may be involved in ventricular arrhythmogenesis through similar mechanisms ('final common pathway'). A variable clinical expressivity and, especially, an incomplete penetrance has been found in patients carrying the same LQT genotype, even when near-relatives, which raises the question on the frequency and importance of 'silent' (i.e. minor functional)ion channel gene mutations that may become functionally significant in presence of action potential prolonging drugs and other coexisting factors. The observation of adverse drug reactions in apparently healthy ('normal heart') individuals is suggestive of a genetic susceptibility for 'acquired' arrhythmias. This report reviews and summarizes the recent knowledge on unapparent ion channel gene mutations and preliminary concepts about 'acquired' arrhythmias. (Eur Heart J Supplements 2001; 3 (Suppl K): K48-K52) (C) 2001 The European Society of Cardiology.

ASDD Area Sistemi Dipartimentali e Documentali, Università di Bologna, Catalogo delle riviste ed altri periodici
Documento generato il 25/01/20 alle ore 16:25:40