Application and perspectives of transesophageal stress echocardiography using monoplane and biplane instruments

Transesophageal stress echocardiography has been reported to have a high sensitivity and specificity for noninvasive identification and assessment of coronary artery disease. Its advantage is the virtually never obstructed acoustic window on the heart yielding superior image quality in almost all patients. Pharmacological stress as well as simultaneous atrial pacing--attaching electrodes to the echoscope--have been applied as stress modalities. Both transesophageal stress echocardiography modalities have been shown to be well tolerated, safe, and feasible in most patients. These promising initial experiences led to clinical application of this method for preoperative risk evaluation, for detection of restenosis after PTCA, and for evaluation of hibernating myocardium. This technique was also successful for evaluation of stress induced changes of transmitral and pulmonary venous flow in patients with left ventricular hypertrophy and coronary artery disease. Although all studies published so far were performed with monoplane technique, the sensitivity for detection of one-vessel and, even more so, multivessel disease was high. However, apical and basal wall-motion abnormalities may go undetected using monoplane equipment. The advent of biplane transesophageal imaging enables the visualization of more ventricular segments. Future studies will show to which degree biplane transesophageal stress echocardiography improves the diagnostic accuracy.