Cardiac Denervation in Conscious Dogs

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<0.01) and LV dP/dt was lower (p<0.05) in CD dogs. LV short-axis shortening, shortening fraction, velocity of circumferential fiber shortening, and ejection fraction were consistently lower (p<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<O.O1) in CD dogs at 2, 4, and 8 weeks. Relations of LV short-axis shortening to LV end-diastolic wall stress also diflered (p<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 ofLV function over a wide