Direct effects of chronic beta-adrenergic receptor blockade on left ventricular and myocyte function in a model of tachycardia-induced congestive heart failure

Journal of Cardiac Failure
F G SpinaleB U Jones

Abstract

Chronic beta-receptor blockade (beta-blockade) has been reported to improve symptoms and increase survival in patients with congestive heart failure (CHF); however, whether the mechanisms for the effects of beta-blockade in CHF are due to modulating chronotropy, inotropy, or both remains unknown. To address this issue, left ventricular function and isolated myocyte function were examined with chronic beta-blockade in a rapid pacing model of CHF, thereby eliminating potential chronotropic effects of beta-blockade. Pigs were randomly assigned to three groups of six pigs each: supraventricular tachycardia (SVT): 3 weeks of atrial pacing at 240 beats/min; SVT/beta-blockade: 3 weeks of rapid pacing and beta-blockade (25 mg atenolol twice daily on days 14-21 of pacing); control group, sham control animals. This dosage schedule for beta-blockade was chosen because catecholamines are persistently elevated by day 14 in this model of CHF. Left ventricular fractional shortening and end-diastolic dimension were measured by echocardiography in the conscious state with a resting ambient heart rate. Isolated left ventricular myocyte function was examined using high-speed videomicroscopy. Supraventricular tachycardia caused left ventricular di...Continue Reading

References

May 1, 1992·Circulation·L A MulieriN R Alpert
Aug 1, 1980·British Heart Journal·K SwedbergI Wallentin
Sep 27, 1984·The New England Journal of Medicine·J N CohnT Rector
May 1, 1995·Journal of the American College of Cardiology·S L OlsenM R Bristow

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