Intraoperative transesophageal echocardiography for detection of myocardial ischemia.

Preoperative myocardial ischemia seems to be a predictor of poor outcome when detected by electrocardiography, pulmonary capillary wedge/pressure measurement and echocardiography. It could be demonstrated, that regional wall motion abnormalities appear earlier and are more sensitive signs of myocardial ischemia than the ECG. Using intraoperative epicardial and transesophageal echocardiography, high quality 2-d echocardiographic images of the heart can be recorded. For monitoring of left ventricular function and wall motion the transesophageal approach is most often used. By the transesophageal approach the left ventricle can be scanned in the long axis and by the transgastric approach in cross sections. They correspond to the apical four-chamber and left parasternal cross sectional imaging of the heart. Using the transgastric approach in the papillary short axis view all segments representing the three coronary arteries can be imaged. Recording in this position have been found to be highly reproducible. Only localized ischemia of the apex of the ventricle may be missed. Methologically the rotation and translocation of the heart remain a problem using the cross section images of the heart. But the left ventricular papillary muscles and the septal-right ventricular boarders can be used as land marks. Wall motion is scored in five grades. In addition to the semiquantitative analysis also a quantitative calculation using computers is possible. Using the midd papillary short axis view in nearly 120 intraoperative transesophageal echocardiograms since 1989 analysis of the systolic wall thickening was possible in 73% of the patients. According to the literature review 87% of the patients undergoing coronary bypass surgery or non-cardiac surgery have signs of preoperative ischemia.(ABSTRACT TRUNCATED AT 250 WORDS)