ABSTRACT
Elective cardioversion of atrial fibrillation may be complicated by systemic thromboembolic events presumably caused by embolization of pre-existing left atrial thrombi. Transe sophageal echocardiography [TEE] has proven to be a very sensitive tool of detecting left atrial thrombi and may therefore provide a mean of screening patients before cardioversion. Over a 10-months period, 41 patients underwent transesophageal echocardiography to exclude the presence of an LA thrombus before elective cardioversion for atrial fibrillation [n-38] or atrial flutter [n = 3] of nonvalvular origin. All patients were believed to have atrial fibrillation/flutter for a minimum of 2 days. The mean age of the patients was 59.8 +/- 13.22 years and 58% were men and 13 patients had history of embolization. All patients underwent transthoracic and transesophageal echocardiography. Transthoracic echocardiography detected thrombus in one patient only while TEE detected left atrial or left atrial appendage thrombus in 9 patients [21.9%] 3 of these were in the left atrial cavity and 6 were in the left atrial appendage. All of the patients with left atrial thrombi were in atrial fibrillation rather than in atrial flutter. Thirty three patients [80.5%] received heparin. Cardioversion was cancelled and anticoagulant therapy was begun in the 9 patients with left atrial thrombi. Cardioversion was successful in 25 out of 32 patients [15 spontaneous, 7 pharmacological and 3 electrical]. Four patients died during the period of follow-up due to other medical causes not related to complications of cardioversion. No one revealed evidence of thromboembolic event either immediately after cardioversion or at one month follow-up. Recurrence of atrial fibrillation occurred in 2 patients. There was transient atrial mechanical disjunction in 3 patients [7.3%] who received long-term anticoagulants for 4 weeks. The results of the present study are similar to preliminary information from other studies that have addressed this issue. In conclusion, our study revealed that if results are negative for thrombus, utilization of transesophageal echocardiography, lowers the embolic risk, provides some level of reassurance in patients with contraindication to anticoagulant therapy, and may obviate the need for anticoagulant therapy before cardioversion thus allowing cardioversion to be performed earlier