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Effects Of β‐Adrenoceptor Stimulation On Pacing‐Induced Failure Of Dog Hypertrophic Hearts
Author(s) -
Huang Mark W,
Leone Richard J Leone,
Weiss Harvey R,
Tse James,
Scholz Peter M
Publication year - 2000
Publication title -
clinical and experimental pharmacology and physiology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.752
H-Index - 103
eISSN - 1440-1681
pISSN - 0305-1870
DOI - 10.1046/j.1440-1681.2000.03229.x
Subject(s) - medicine , heart failure , cardiology , stimulation , muscle hypertrophy , left ventricular hypertrophy , endocrinology , blood pressure
SUMMARY 1. We tested the hypothesis that the transition to pacing‐induced failure in hypertrophic hearts would result in reduced functional and metabolic responses to β‐adrenoceptor stimulation. 2. Isoproterenol (ISO; 0.1 μg/kg per min) was infused into a coronary artery in five anaesthetized open‐chest control, five aortic stenosis‐induced left ventricular hypertrophy (LVH) and five LVH pacing‐induced failure dogs. 3. In both control and LVH dogs, but not in failure dogs, ISO significantly increased local regional work (1923±665 vs 2656±715, 1185±286 vs 1906±562 and 835±106 vs 849± 216 g.mm/min, respectively), force (11.1±1.4 vs 16.9±2.6, 8.6±1.5 vs 13.7±2.3 and 12.2±1.1 vs 11.0±1.8 g, respectively) and myocardial O 2 consumption (7.3±2.0 vs 10.0±1.5, 8.2±1.6 vs 11.6±2.6 and 4.4±1.5 vs 5.5±1.8 mL O 2 /min per 100 g, respectively). 4. Isoproterenol also significantly increased cAMP in control and LVH dogs (474±67 vs 600±91 and 473±34 vs 619± 53 pmol/g, respectively). In heart failure, cAMP was significantly lower and there was no significant increase in cAMP in response to ISO (245±43 vs 314±40 pmol/g, respectively). 5. We conclude that there were no significant myocardial functional, O 2 consumption or cAMP responses to ISO after the transition from hypertrophy to cardiac failure.