Transesophageal echocardiographic guidance of cardioversion in patients with atrial fibrillation

The role of TEE in the guidance of cardioversion of atrial fibrillation was studied. Thirty-seven (18 %) of 206 patients had left atrial thrombus. Cardioversion was attempted in 153 patients receiving no (n = 107) or <7 days (n = 46) of anticoagulation prophylaxis, in 27 patients after ≥3 weeks of anticoagulation, and was cancelled in 26 patients, primarily on the basis of TEE findings. Left atrial thrombus was observed in 37 (18%) of 206 patients. No embolic complications occurred over a 4-week follow-up period. In 7 (41 %) of 17 patients new left atrial appendage spontaneous echocardiographic contrast developed immediately after electric cardioversion. In this group, significant decreases occurred in the left atrial appendage maximal emptying shear rate (11.1 ± 11.1 sec−1 vs 5.0 ± 5.1 sec−1; p < 0.05), maximal filling shear rate (6.7 ± 5.9 sec−1 vs 3.7 ± 3.5 sec−1; p < 0.05), and peak emptying velocity (0.38 ± 0.29 cm/sec vs 0.19 ± 0.14 cm/sec; p < 0.05). In one patient a left atrial appendage thrombus formed after electric cardioversion. Left atrial thrombus resolved in 1(5 %) of 21 patients and became immobile in 0 (0%) of 16 patients after 3 to 5 weeks of anticoagulation but resolved (n = 9) or became immobile (n = 6) in 15 (71%) of 21 patients after ≥5 weeks of anticoagulation. TEE-guided cardioversion was safely done without or with <7 days of anticoagulation prophylaxis in selected patients, but the potential for left atrial thrombus to form after electric cardioversion makes anticoagulation advisable in all patients. The conventional recommendation of 3 to 4 weeks of anticoagulation prophylaxis before cardioversion is usually inadequate for left atrial thrombus to resolve or to become immobile.