Low cardiovascular event rate and high atrial fibrillation recurrence rate one year after electrical cardioversion

Background: Electrical cardioversion is widely used to restore sinus rhythm in patients with atrial fibrillation. However, the long term clinical event and sinus rhythm maintenance rates following electrical cardioversion still remains unclear. This study evaluated one year incidence and risk factors for cardiovascular events and atrial fibrillation recurrence in a single center clinical practice. Methods: In a prospective study 188 patients with atrial fibrillation who underwent electrical cardioversion were enrolled. Patients and their primary care physicians were followed up one year after cardioversion and patient clinical and arrhythmic event rate was evaluated. Data obtained from patients and general practitioners were combined and the results were analyzed with PSPP 0.8.5 software. Results: Electrical cardioversion success rate was 90.4%. Within a year after cardioversion one patient (0.6%) suffered myocardial infarction, three patients (1.9%) had a stroke/transitory ischemic attack (TIA), three patients (1.6%) died and three patients (1.9%) had a bleeding event that required hospitalization. The presence of diabetes mellitus was the only factor with a tendency to increase the risk of combined event of myocardial infarction, stroke/TIA and bleeding (P = 0.096). At follow up 30.0% of patients reported having atrial fibrillation and within a year 62.2% had suffered at least one atrial fibrillation paroxysm. The proportion of patients who underwent additional cardioversions after the initial hospitalization was 32.5%. The factors that significantly increased the risk of atrial fibrillation recurrence were history of stroke/TIA (P = 0.014) and increased left atrial volume index on echocardiography (P = 0.039). Greater left atrial diameter had a tendency toward an increased risk (P = 0.087). Conclusions: Cardiovascular event rate one year after electrical cardioversion was low. Electrical cardioversion had a high immediate success rate, however, maintenance of stable sinus rhythm in the long term was low.