Electrophysiological Abnormalities in Cardiac Hypertrophy
The myocardial cell hypertrophies as an adaptive response to a mechanical overload. However, cardiac hypertrophy induced by chronic pressure overload results in a variety of structural and functional changes. These include alterations in morphology, metabolism, hemodynamics, contraction, and electrophysiology. Despite these adaptations, or because of these alterations, patients with left ventricular hypertrophy have high risk of cardiovascular morbidity and mortality. Electrophysiological abnormalities may be partly responsible for the increased mortality rate with left ventricular hypertrophy. Several recent clinical studies have demonstrated an increased incidence of ventricular arrhythmias and sudden cardiac death presumably due to ventricular fibrillation or tachycardia in association with left ventricular hypertrophy (1–3). In addition, superimposition of ischemia enhances arrhythmogenesis in hypertrophied hearts. Experimentally, it has been demonstrated that the incidence of ischemia- and reperfusion-induced ventricular fibrillation and sudden death are significantly higher in rats and dogs with left ventricular hypertrophy (4–6). However, the precise mechanisms of electrophysiological abnormalities and enhanced arrhythmogenesis in cardiac hypertrophy remain unsettled.
KeywordsLeft Ventricular Hypertrophy Ventricular Fibrillation Cardiac Hypertrophy Action Potential Duration Hypertrophied Cell
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- 13.Cameron JS, Linda SM, Kimura S, Kaiser CJ, Campbell DR, Kozlovskis PL, Gaide MS, Myerburg RJ, Bassett AL (1986) Systemic hypertension induces disparate localized left ventricular action potential lengthening and altered sensitivity to verapamil in left ventricular myocardium. J Mol Cell Cardiol 18: 169–175PubMedCrossRefGoogle Scholar
- 14.Ten Eick RE, Bassett AL, Robertson LL (1983) Possible electrophysiological basis for decreased contractility associated with myocardial hypertrophy in the cats: a voltage clamp approach. In: Perspectives in Cardiovascular Research. Myocardial Hypertrophy and Failure, edited by Alpert NR. New York, Raven, vol. 7, p. 245–259Google Scholar
- 18.Scamps F, Mayoux E, Charlemagne D, Vassort G (1991) Calcium current in single cells isolated from normal and hypertrophied rat heart: Effects of β-adrenergic stimulation. Circ Res 67: 199–208Google Scholar