Transoesophageal echocardiography-guided cardioversion of atrial fibrillation or flutter. Selection of a low-risk group for immediate cardioversion

Abstract

Aims Despite exclusion of left atrial thrombi by transoesophageal echocardiography, cardioversion-related thromboembolism has been reported in atrial fibrillation or flutter. To define a low-risk group for cardioversion without previous anticoagulation, patients were selected for immediate cardioversion if there were no thrombi, no echo spontaneous contrast and the outflow velocity of the left atrial appendage was greater than 0·25 m . s 1 on transoesophageal echocardiography. Methods and ResultsTwo hundred and forty-two consecutive patients referred for cardioversion of atrial fibrillation or flutter with a duration of more than 2 days and no anticoagulation therapy were examined with transoesophageal echocardiography. After the transoesophageal echocardiography examination, patients who were eligible for immediate cardioversion were anticoagulated with low molecular weight heparin (dalteparin) subcutaneously, together with warfarin prior to cardioversion. Dalteparin treatment was continued until the patient had reached therapeutic prothrombin values.Based on the transoesophageal echocardiographic findings the patients were divided into two groups: immediate cardioversion, group A, with a mean age of 62 13 years (n=162); or conventional warfarin treatment before cardioversion, group B, with a mean age of 67 10 years (P<0·05) (n=80). In group A, lone atrial fibrillation or flutter was more common (53%; 95% CI: 45-61) compared to group B (34%; 95% CI: 23-44, P<0·05), while heart disease was more common in group B (45%; 95% CI: 34-56) compared to group A (31%; 95% CI: 24-39, P<0·05). Echocardiography revealed thrombi in 5% (95% CI: 2·6-8) of the patients, left atrial size was larger, fractional shortening lower, and a higher proportion had impaired left ventricular function in group B. No thromboembolic event occurred at or after cardioversion in any of the patients; however, before planned cardioversion one transitory ischaemic attack, one lethal stroke and one cardiac death occurred in three of the patients with thrombi despite warfarin therapy. One-month follow-up maintenance of sinus rhythm was 75% in group A compared to 45% in group B (P<0·01).Conclusion After using our transoesophageal echocardiographic exclusion criteria (no thrombi, no spontaneous echo contrast and left atrial appendage outflow velocity d0·25 m . s 1 ) cardioversion can safely be performed in 2/3 of patients with atrial fibrillation or flutter without previous anticoagulation therapy. These patients maintained sinus rhythm significantly better after 1 month compared to patients with prolonged warfarin therapy before cardioversion.

Duration of warfarin sodium therapy prior to electrical cardioversion of atrial fibrillation

“…The treatment with warfarin sodium prior to electrical cardioversion was found to exceed the 4 weeks recommended in current guidelines, being approximately 12 weeks. Similar treatment duration with warfarin sodium was observed by Roijer et al [14]. Before start of treatment with warfarin sodium, the AF duration was <2 months for the majority (69%) of the patients.…”

“…An important question is whether the results from the present study can be generalized. The data are in agreement with another Swedish study [14], but as similar studies from other countries are lacking, this question cannot be fully resolved. In addition, to improve the logistics of the precardioversion period in this patient group, it also seems important to evaluate whether the present recommended treatment duration can be decreased.…”

Is Early Cardioversion for Atrial Fibrillation Safe in Patients with Spontaneous Echocardiographic Contrast?

“…Roijer 34 and Fonseca 35 attempted to identify a low-risk group of patients for immediate cardioversion. To be eligible, patients had to be free of LA or LAA thrombus and SEC and have an LAA outflow velocity >0.25 m.s −1 .…”

Safety and Efficacy of Enoxaparin Compared With Unfractionated Heparin and Oral Anticoagulants for Prevention of Thromboembolic Complications in Cardioversion of Nonvalvular Atrial Fibrillation

“…In one nonrandomized trial using dalteparin, the rate of embolic events in cardioversion of atrial fibrillation was also low. 15 However, the effectiveness for the reduction of thromboembolic events in the arterial bed has not been shown consistently for all LMWHs. 22 In this study, phenprocoumon, commonly prescribed in Germany, was used as the oral anticoagulant instead of warfarin, which is the most widely used oral anticoagulant worldwide.…”

“…13 Moreover, the use of LMWH in patients with atrial fibrillation has been reported to be safe in patients with contraindications to oral anticoagulants 14 and effective in nonrandomized studies of atrial fibrillation cardioversion. 15 The aim of the present study was to compare the efficacy and safety of subcutaneous enoxaparin with conventional anticoagulation using intravenous UFH followed by the oral anticoagulant phenprocoumon in the setting of cardioversion of nonvalvular atrial fibrillation.…”