| Abstract: | Measurement of left anterior descending coronary arterial pressure, phasic coronary flow, and intramyocardial pressure in an open-chest dog provided data, which when entered into the computer model of the coronary circulation, permitted calculation of coronary artery compliance and resistance during systole and diastole. Resting in vivo compliance averaged 0.21 x 10(-3) mL/mmHg (1 mmHg = 133.322 Pa) while systolic resistance averaged 4.05 mmHg X min-1 X mL-1 and during diastole 2.06 mmHg X min-1 X mL-1. Left stellate ganglion stimulation or vasodilation caused minimal changes in compliance but glutaraldehyde applied to arterial wall caused a decrease in compliance. Sympathetic stimulation and vasodilation decreased both diastolic and systolic resistance. Transmural distribution of coronary flow was not significantly altered by the experimental changes in compliance and resistance. |
