Transesophageal Echocardiography: Technique, Anatomy and Clinical Applications

Transesophageal echocardiography(TEE) is a new acoustic window to the cardiac structures and great vessels via retrocardiac esophagus. Because of the close relation between the esophagus and the heart, higher transducer frequencies can be applied, therefore leading to improved resolution and more accurate images than transthoracic echocardiography. We describe our experience with the first 353 awake patients. The procedure was well tolerated by the patients and associated with no major complications, within examination 10 to 20 minutes. Clinical diseases which appear to be suited for TEE includes 1) evaluation of native valve diseases, particulary mitral valve, pathologic valvular abnormalities and color Doppler regurgitant flows ; 2) assesment of prosthetic heart valves to better define malfunction and important pathologic associations ; 3) congenital heart disease, particularly atrial septal defect ; 4) endocarditis and detection of vegetations and complications ; 5) detection of thrombus and tumors, size, location, morphology, stalk ; and 6) aortic pathology including atherosclerosis, aneurysm and dissection. We conclude that transesophageal echocardiography is a new imaging technique that is rapidly evolving into a major tool for general cardiac imaging in a variety pathologic conditions and is a safe and useful tool in patients. Future advances in probe technology will continue to expand its applications.

Visualization of Coronary Arteries by Color-Coded Transesophageal Doppler Echocardiography

The visualization of coronary arteries by transthoracic two-dimensional echocardiography has been used for over 10 years. In many cases, the imaging quality is too poor to allow an anatomic evaluation. During the last few years, transesophageal echocardiography has been shown to provide optimal imaging quality in virtually all patients and of all cardiac structures including the coronary arteries. The purpose of this study was to test the ability of transesophageal echocardiography in the visualiation of the coronary arteries and assessment of coronary blood flow by transesophageal two-dimensional pulsed Doppler echocardiography. We Studied 285 patients, 91 men and 194 women, aged 16 to 81 year(mean 50.6 year men, mean 54.2 year women). We have been used a 5-MHz phased array transducer with incorporated color-coded Doppler. The left main coronary artery was visualized 95.1%, left circumflex artery 27.4, left anterior descending artery 21.4% and the main stem of the proximal right coronary artery 45.1%. The time-sequential left anterior descending artery flow pattern generally consisted of a small late systolic component and a large diastolic component. The peak flow velocity in the proximal left anterior descending artery during diastole was 40.8+/-8.0cm/sec(integrity 7.6+/-0.9) and during late systole was 18.5+/-5.5cm/sec(integrity 2.9+/-0.9). There were no complications during and after examination. This study suggests that transesophageal color-coded Doppler two-dimensional echocardiography appers to be a feasible noninvasive technique for imaging the proximal left coronary artery and the left anterior descending artery flow is detectable from the transesophageal approach.