Impact of acute myocardial edema on left ventricular function

Studies of the impact of myocardial edema on left ventricular (LV) systolic function show conflicting results. We sought to evaluate the impact of increased myocardial water content (MWC) on LV systolic and diastolic function. Anesthetized dogs ( n = 12) were instrumented with myocardial ultrasonic crystals and an LV micromanometer. Systolic function was measured by preload recruitable stroke work (PRSW) and dP/dt(max). Diastolic function was measured by -dP/dt(max) and the isovolumic relaxation constant tau (tau). Myocardial water content ( MWC) was determined using microgravimetry. In six dogs ( coronary sinus hypertension, CSH group) we produced myocardial edema by inflating a coronary sinus balloon for 2 h ( 30 - 40 mm Hg). In six other dogs ( Plegisol, PLEG group) cardiopulmonary bypass (CPB) was initiated (12.3 +/- 0.8 min), the aorta was cross-clamped ( 117 +/- 19 s), and 700 mL 4 degrees C crystalloid, hyperkalemic cardioplegic solution ( Plegisol) was administered into the aortic root ( 62 +/- 4 mm Hg). After declamping and reperfusion (7.2 +/- 1.0 min), the dogs were separated from CPB. Myocardial function parameters and MWC were measured for 2 h after edema generation. In the CSH group, MWC significantly increased from 75.9 +/- 0.3% to 77.6 +/- 0.3% ( p <.05). In the PLEG group, MWC increased from 75.8 +/- 0.3% to 77.7 +/- 0.3% (p <.05). PRSW and dP/dt(max) did not decrease in either group. Diastolic parameters did not change significantly. We conclude that acute myocardial edema without myocardial injury does not impair LV function.