EFFECT OF INCREASED CORONARY VENOUS-PRESSURE ON LEFT-VENTRICULAR FUNCTION IN SHEEP

We studied the effect of increased coronary venous pressure (Pcv) on l eft ventricular (LV) function in nine anesthetized open-chested sheep. Pcv was increased by inflating a balloon in the coronary sinus. LV fu nction was estimated by measuring maximum rate of change in LV pressur e (dP/dt max) and LV end-diastolic pressure (LVEDP). Left anterior des cending (LAD) coronary artery blood flow was measured with an electrom agnetic flow probe. A control group (n = 6) was studied similarly exce pt that Pcv was not elevated. After completion of the experiment, LV w et/dry weight ratios were measured to estimate LV myocardial water con tent. The balloon inflation increased Pcv from 8.6 +/- 1.1 to 23.8 +/- 1.7 mmHg (mean +/- SEM), which decreased dP/dt max from 1611 +/- 236 at baseline to 1041 +/- 210 after 120 min of increased Pcv (P < 0.05). The dP/dt max in the control group did not change significantly. Hear t rate, LAD flow, LVEDP, and aortic pressures were similar in two grou ps but the LV water content was significantly higher (P < 0.05) in the experimental group (76.2 +/- 1.0 vs. 79.1 +/- 0.5%). These data sugge st that acute increases in Pcv result in LV dysfunction and that coron ary vascular congestion and myocardial edema may, at least in part, be responsible for this finding. (C) 1998 Elsevier Science B.V. Al right s reserved.