Retrograde coronary perfusion: effects on iatrogenic edema and diastolic properties

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 (t). 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.

Myocardial damage after prolonged accidental hypothermia: a case report

INTRODUCTION

A case of cardiac toxicity due to prolonged hypothermia is reported.

CASE PRESENTATION

A 42-year-old woman of Caucasian origin presented with hypothermia after an accident. She developed atrial fibrillation and heart failure with minor electrocardiographic changes, which mimicked ischaemia. She recovered completely after one month of treatment for heart failure.

CONCLUSION

Prolonged hypothermia, which mimicks ischaemia, may cause arrhythmias and heart failure.

Reversal of iatrogenic myocardial edema and related abnormalities of diastolic properties in the pig left ventricle

OBJECTIVE

This study examines the resolution of iatrogenic edema and related changes in systolic and diastolic properties in the intact pig left ventricle.

METHODS

The coronary arteries were perfused for 50 to 60 seconds with diluted blood (hematocrit value 10% +/- 1%, edema group, n = 5) or whole blood (hematocrit value 28% +/- 1%, control group, n = 6) infused into the aortic root during aortic crossclamping in conditioned, anesthetized pigs. After whole blood reperfusion, preload reduction by vena caval occlusion was used to define systolic and diastolic properties at 15-minute intervals. Left ventricular pressure and conductance, aortic flow, and two-dimensional echocardiography were recorded.

RESULTS

Left ventricular mass (wall volume) in the edema group increased significantly compared with that in control pigs after crossclamp removal. Mass returned to preperfusion levels after 45 minutes. The ventricular stiffness constant (beta) increased significantly in the edema group versus the control group, returning to baseline by 30 minutes. The diastolic relaxation constant (tau) and base constant (alpha) did not differ between groups. There was no significant change in contractility.

CONCLUSION

Increases in left ventricular mass and diastolic stiffness induced by coronary perfusion with hemodiluted blood resolve after 45 minutes of whole blood perfusion in pigs. This study defines physiologic effects of edema in the normal heart while eliminating most common confounding experimental errors.