PMID: 8606289Mar 1, 1996Paper

Altered inotropic and lusitropic responses to heart rate in conscious dogs with tachycardia-induced heart failure

Journal of the American College of Cardiology
H AsanoiS Sasayama

Abstract

The effects of increasing heart rate on left ventricular contraction and relaxation were examined in conscious dogs with tachycardia-induced heart failure under autonomically blocked conditions. Previous studies using isolated myocardium have shown attenuated positive inotropic responses to stimulation frequency in heart failure. However, these responses have not been well examined in intact preparations in the presence of heart failure with autonomic system blockade, where the intrinsic ventricular responses to increasing heart rate could be revealed. Seven dogs were instrumented with a micromanometer and a conductance volume catheter. After autonomic blockade to eliminate neural reflexes, left ventricular contractile properties were quantified by the slope of the end-systolic pressure-volume relation (ventricular elastance), and left ventricular relaxation was assessed by the time constant of isovolumetric ventricular pressure decay. Increasing the heart rate by 60 beats/min enhanced ventricular elastance by 71 +/- 18% (mean +/- SD) and decreased end-systolic volume by 6 +/- 5% in normal hearts. In failing hearts, ventricular elastance increased by only 21 +/- 20%, and end-systolic volume did not change appreciably. Although ...Continue Reading

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Citations

Sep 22, 2005·Clinical and Experimental Pharmacology & Physiology·Roberto CurielMiguel Cerrolaza
May 4, 2010·American Journal of Physiology. Heart and Circulatory Physiology·Xiaoxiao ChenDonal S O'Leary
Nov 3, 2010·Circulation Journal : Official Journal of the Japanese Circulation Society·Gerd Heusch
Mar 10, 2000·American Journal of Physiology. Heart and Circulatory Physiology·S E LitwinG D Pennock
Jan 15, 2002·American Journal of Physiology. Heart and Circulatory Physiology·Patrice ColinAlain Berdeaux
Jun 24, 2003·AACN Clinical Issues·Maureen A Turner

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