Myocardial perfusion and right ventricular function.
OBJECTIVE
Maximal right ventricular (RV) performance is influenced by left heart hemodynamics and hence coronary perfusion. We examined the role of myocardial perfusion of the right ventricle as potential determinant of maximal RV function.


METHODS
In 6 canine isovolumic right heart preparations, incremental volumes were introduced into a high compliance RV balloon until RV failure occurred. Maximal RV developed pressure (RVDP) and maximal positive RV dP/dt were determined at a constant controlled left ventricular (LV) output of 2 l/min and at controlled mean arterial pressures of 50, 80 and 120 mmHg. Right coronary artery (RCA) flow was measured.


RESULTS
Maximal RVDP increased significantly with increasing mean arterial pressures (44.8+/-11.2 vs 57.2+/-15.5 vs 75.4+/-2.5 mmHg for systemic pressures of 50, 80 and 120 mmHg respectively, p < 0. 05). With increasing mean arterial pressures RCA flow increased significantly (33.1+/-11.0 vs 46.1+/-20.4 vs 79.6+/-35.3 ml/min). At the onset of RV failure, RCA blood flow significantly decreased in all preparations compared to the maximal flow in the RCA (1.9+/-1.0 vs 33.1+/-11.0 ml/min at 50 mmHg; 13.6+/-10.2 vs 46.1+/-20.4 ml at 80 mmHg and 18.7+/-8.0 vs 79.6+/-35.3 ml/min at 120 mmHg; p < 0.05).


CONCLUSIONS
These results suggest that coronary perfusion is a major determinant of maximal RV function. The coronary artery driving pressure must be sufficient to avoid the onset of RV failure. Maintaining systemic pressure and hence RV myocardial blood flow may thus extend RV function.
Klima
U P
UP
Cardiothoracic and Vascular Surgery, Hannover Medical School, 30623 Hannover, Germany.
Guerrero
J L
JL
Vlahakes
G J
GJ
D000818:Animals; D001783:Blood Flow Velocity; D001794:Blood Pressure; D003326:Coronary Circulation; D004285:Dogs; D016278:Ventricular Function, Right; D017725:Ventricular Pressure