Time course of left ventricular function after cardiac denervation in conscious dogs.

Abstract

The time course of left ventricular (LV) function was compared in normal (N) and cardiac-denervated (CD) dogs over an 8-week period after instrumentation with solid-state LV pressure gauges and three pairs of ultrasonic crystals to measure LV long and short axes and wall thickness. Baseline LV systolic, end-systolic, and end-diastolic pressures did not differ in N and CD dogs. Heart rate was higher (p less than 0.01) and LV dP/dt was lower (p less than 0.05) in CD dogs. LV short-axis shortening, shortening fraction, velocity of circumferential fiber shortening, and ejection fraction were consistently lower (p less than 0.01) in CD dogs. With angiotensin II to increase LV afterload, relations of LV short-axis shortening, shortening fraction, velocity of circumferential fiber shortening, and ejection fraction to average LV systolic wall stress were shifted downward (p less than 0.01) in CD dogs at 2, 4, and 8 weeks. Relations of LV short-axis shortening to LV end-diastolic wall stress also differed (p less than 0.01) in N and CD dogs. Ganglionic blockade abolished differences in LV function between N and CD dogs during elevated LV systolic wall stress with angiotensin II. Thus, in conscious dogs, cardiac denervation results in a sustained reduction of LV function over a wide range of ventricular loading conditions.