Effects of edema on systolic and diastolic function in vivo.

Recent advances in the study of myocardial edema are reviewed. A rat model, developed for the study of diastolic properties, is differentiated from larger mammals by less myocardial water content in the control state, by less cardioplegia-induced edema, and by more rapid evolution of ischemic contracture. The model has proven useful in defining the time course of recovery from iatrogenic edema, which requires less than 15 minutes, and in defining the time course and determinants of changes in compliance during transplant rejection. In pigs, a new experimental model allows study of left ventricular (LV) mass variation and changes in systolic and diastolic properties during resolution of iatrogenic edema. Initial studies indicate that iatrogenic edema and related increases in LV stiffness resolve in less than 45 minutes in pigs, in the absence of substantial ischemic injury. No significant changes in systolic performance were demonstrable statistically, but contractility was depressed immediately after reperfusion, requiring inotropic and mechanical circulatory support. In patients, measured changes in intraoperative LV mass are small and require correction for effects of changes in LV volume to define significance.