Relationship between right ventricular wave speed and elastance in dogs.
Wave speed (c) must be known to separate forward- and backward-going waves during wave-intensity analysis, which measures the energy transported by the waves in the circulation. c is related to elastance; the present study was performed to measure right ventricular (RV) c during the cardiac cycle and to compare c with RV elastance. In 7 dogs, we measured right atrial, pulmonary arterial, pericardial and 2 RV pressures, and pulmonary arterial flow. A pulse generator was connected to the RV apex, and c was measured by determining the transit time between the 2 high-fidelity RV pressure transducers; the distance was measured roentgenographically. Eight sonomicrometry crystals were implanted in the RV endocardium to calculate RV volume and, thereby, elastance. RV c ranged from approximately 1 m/s during diastole to approximately 4 m/s during systole. Log-log plots of c vs. elastance were linear. These slopes represent the power relationships between c and elastance and ranged from 0.30 to 0.56; for the combined data, it was 0.31. Given knowledge of c, forward- and backward-going waves can be identified and their energy quantitated. In the canine RV, c is approximately proportional to 1/3 the power of elastance: log c = 0.31.log E - 2.05.
Sun
Yichun
Y
Department of Cardiac Sciences and Physiology, The Libin Cardiovascular Institute of Alberta, University of Calgary Health Sciences Centre, 3330 Hospital Drive NW, Calgary, Alberta T2N 4N1, Canada.
Wang
Jiun-Jr
JJ
Belenkie
Israel
I
Tyberg
John V
JV
D000818:Animals; D004285:Dogs; D008955:Models, Cardiovascular; D016278:Ventricular Function, Right / Q000502:physiology*; D017725:Ventricular Pressure / Q000502:physiology