Efficacy of transesophageal echocardiography as a perioperative monitor in patients undergoing cardiovascular surgery. Analysis of 149 consecutive studies. To evaluate the usefulness of transesophageal echocardiography as a perioperative monitor in patients undergoing cardiovascular surgery, 149 consecutive patients were studied since 1985. Left ventricular function was assessed by measurement of left ventricular dimension and ejection fraction in patients with valvular disease. This monitoring was useful in detecting the changes in left ventricular performance in patients with volume overload and in managing patients in the early postoperative period. Cardiac tamponade was clearly demonstrated before changes in electrocardiogram and hemodynamic data. In 27 patients, transesophageal color Doppler echocardiography was used to confirm that there was no residual regurgitation immediately after valvular reconstructive surgery. Transesophageal color Doppler echocardiography was also useful in detecting the entry of false lumen before surgery in 7 patients with dissecting aortic aneurysm. There were no unsuccessful introductions, no traumatic or thermal injuries, 18 patients (12.1%) with hoarseness and 5 patients (3.4%) with transient arrhythmia. In conclusion, transesophageal echocardiography provides a good imaging window to the heart and great vessels perioperatively. This expedient, safe informative imaging method can be used more routinely in patients during surgery. 