Patients who were candidates for
cardioversion were eligible for inclusion if they had
atrial fibrillation or
atrial flutter lasting longer than 2 days or of unknown duration. Patients received short-term anticoagulation with
warfarin or
heparin and underwent transthoracic echocardiography followed by transoesophageal echocardiography. Early
cardioversion was performed if no
thrombus was seen on the transoesophageal study.
Warfarin was maintained for 1 month after
cardioversion. In patients with atrial thrombi,
cardioversion was deferred and prolonged anticoagulation was prescribed. The study population included 183 patients. One hundred and sixty nine patients without atrial thrombi underwent early
cardioversion. Fourteen patients with atrial thrombi (7.6%) underwent a second transoesophageal echocardiogram after a median of 4 weeks of oral
warfarin, and
cardioversion was performed if clot regression was documented. No patient in our study population had a clinical thromboembolic event at 1 month follow-up (95% C.I. 0-0.016). The immediate success rate of
cardioversion was better among patients with
atrial fibrillation < 4 weeks duration compared with patients with
atrial fibrillation of longer or of unknown duration: 96.6% vs 85%, respectively (P = 0.014). At 1 month follow-up, the percentage of
arrhythmia relapses in patients with initially successful
cardioversion was similar in the two groups (29% vs 26%, P = ns); thus the initial better outcome in patients with recent-onset
arrhythmia was not lost.
CONCLUSION: Transoesophageal echocardiography-guided early
cardioversion in concert with short-term anticoagulation is safe. This approach permits abbreviation of the overall duration of
atrial fibrillation and has a better impact on the maintenance of sinus rhythm for patients in whom the duration of
atrial fibrillation is < 4 weeks.