Transesophageal echocardiography-guided cardioversion after cardiac operations.

Background: Transesophageal echocardiography (TEE) is often performed during cardiac operations. The need to repeat TEE to exclude left atrial or left atrial appendage thrombus before direct current cardioversion (DCCV) in patients with a recent intraoperative TEE showing no thrombus is unclear. We sought to determine the incidence of and risk factors for new thrombus in patients undergoing TEE-guided DCCV after cardiac operations.

Methods: We reviewed 817 patients referred for TEE-guided DCCV within 30 days of a cardiac operation and an intraoperative TEE. Patients were excluded if the intraoperative TEE showed thrombus or a surgical left atrial appendage intervention was performed. Univariate logistic regression identified risk factors for thrombus.

Results: The study included 362 patients (71% male) with a mean age of 69 years. Median time from the operation to DCCV was 6 days. Thrombus was present in 13 patients (3.6%) on TEE before cardioversion; DCCV was cancelled in these patients. Heart failure was associated with a significantly higher risk of new thrombus formation (7% vs 2%; odds ratio, 3.26; 95% confidence interval, 1.07 to 9.95). Preoperative atrial arrhythmias, duration of perioperative arrhythmias, level of anticoagulation, and time from operation to DCCV were not significantly associated with thrombus. Thrombus was not associated with 30-day mortality.

Conclusions: Development of new thrombus in patients with atrial arrhythmias early after cardiac operations is not uncommon, especially in patients with heart failure. Patients at high risk for thromboembolic events should undergo TEE before DCCV, even if a recent intraoperative TEE showed no thrombus.