Why the study?
Does increasing the frequency of contraction improve the left ventricular contractile state in normal conscious dogs compared to dogs with myocardial depression?
Population
10 mongrel dogs, weighing between 24 and 31 kg, instrumented with ultrasonic diameter gauges and miniature…
Comparison
Atrial pacing to increase the frequency of… vs Responses compared within the same dogs across…
Design
Preclinical
Authors
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Supports minor Bowditch role in conscious hearts; leaves open amplification in myocardial depression pending clinical data.
Does increasing the frequency of contraction improve the left ventricular contractile state in normal conscious dogs compared to dogs with myocardial depression?
The Bowditch staircase (positive inotropic effect of tachycardia) plays only a minor role in the normal conscious heart but is significantly amplified in the presence of myocardial depression.
Higgins et al. (1973) studied this question.