Journal article

EFFECT OF HEART-RATE ON INDEXES OF MYOCARDIAL-CONTRACTILITY IN DOG

DR RICHMOND, JA ANGUS, AH GOODMAN, LB COBBIN

CLINICAL AND EXPERIMENTAL PHARMACOLOGY AND PHYSIOLOGY | BLACKWELL SCIENCE | Published : 1975

Abstract

1. Changes in heart rate were evoked by atrial pacing in anaesthetized dogs with no pretreatment and in dogs given reserpine or guanethidine for 72 h. The effect of alterations in heart rate were related to two indices of myocardial contractility: the maximal rate of change of left ventricular pressure (dp/dt), and an index which was independent of initial fibre length (dp/dt)/IIT, where IIT is integrated isometric tension. 2. An increase in heart rate in control dogs was accompanied by a rise in both dp/dt and (dp/dt)/IIT confirming that the Bowditch staircase does exist in the intact ventricle. The regression line relating heart rate to (dp/dt)/IIT was significantly steeper than that relat..

View full abstract

University of Melbourne Researchers