Role of transoesophageal echocardiography

Accepted for publication 29 April 1991 Abstract Objective-To determine the value of transoesophageal echocardiography in the assessment of selected patients at risk of cardiogenic embolism or after it. Design-Prospective comparison of the results of transoesophageal and transthoracic echocardiography. Transoesophageal echocardiography was performed with a 5 MHz single plane phased array transducer. Setting-University teaching hospital. Patients-100 patients referred for transoesophageal echocardiography after a cerebral ischaemic event or peripheral arterial embolism (n = 63), before percutaneous balloon dilatation of the mitral valve (n = 23), or before electrical cardioversion of atrial fibrillation (n = 14). Results-Transthoracic echocardiography showed potential sources of embolism in four patients including left ventricular thrombus in two patients (with one false positive), left atrial appendage thrombus (n = 1), and patent foramen ovale (n = 1). Transoesophageal echocardiography showed 59 potential embolic sources in 45 patients including left atrial spontaneous echo contrast (n = 33), left atrial appendage thrombus (n = 13), left ventricular thrombus (n = 5), patent foramen ovale (n = 3), left ventricular spontaneous echo contrast (n = 2), mitral valve prosthesis thrombus (n = 1), mitral valve prolapse (n = 1), and pronounced aortic atheroma (n = 1). Transoesophagal echocardiography showed potential embolic sources in 36/53 (68%) patients with atrial fibrillation compared with 9I47 (19%) patients in sinus rhythm. Percutaneous balloon dilatation of the mitral valve was performed without embolic complications in 18 patients without left atrial thrombi and in three patients with small fixed thrombi in the left atrial appendage. It was cancelled in two patients with large thrombi in the left atrial appendage. Cardioversion was performed without embolic complications in 14 patients without left atrial thrombi. Conclusions-Transoesophageal echocardiography detects potential sources of embolism better than transthoracic echocardiography in selected patients at risk of cardiogenic embolism or after it. Cardiogenic embolism accounts for 15% of ischaemic strokes and transient ischaemic attacks'2 and is an important cause of systemic arterial embolism.3 Cardiogenic embolism can also complicate therapeutic procedures, including percutaneous balloon dilatation of the mitral valve4 and cardioversion of atrial fibrillation.5 Transthoracic echocardiography has been used to detect intracardiac thrombi and other potential cardiac sources of embolism.67 Recently the use of transoesophageal echocardiography to detect left atrial thrombi and other cardiac sources of embolism has been reported."' This technique provides high quality imaging of the cardiac anatomy including the left atrial body and appendage, which are close to the oesophagus, without interference from the chest wall and lungs.'2 In a preliminary report in patients with a history of embolism, transoesophageal echocardiography was found to be more sensitive than transthoracic echocardiography for the detection of left atrial thrombi and also of left atrial spontaneous echo contrast.'0 The latter term refers to swirling, smoke-like echoes seen in the left atrial cavity in patients with relative stasis of left atrial blood,'3 and this feature was reported to be an independent predictor of thromboembolic risk in patients with mitral valve disease.'4 Furthermore, there is little information about the role of transoesophageal echocardiography in patients undergoing procedures with a risk of cardiogenic embolism, such as electrical cardioversion of atrial fibrillation and percutaneous balloon dilatation of the mitral valve. We prospectively assessed the overall role of transoesophageal echocardiography in the detection of potential cardiac sources of embolism by comparing the results of transoesophageal with those of transthoracic echocardiography both in patients referred after suspected cardiogenic embolism and in patients before procedures with a risk of cardiogenic embolism.