Successful catheter ablation may reduce total mortality

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Yenn-Jiang Lin, Division of Cardiology, Department of Medicine, Taipei Veterans General Hospital, Taipei, Taiwan, and others reported in EP Europace that successful catheter ablation of atrial fibrillation may reduce the risk of total mortality, cardiovascular mortality and total vascular events in patients with an increased risk of stroke.

Lin et al wrote that although it is unknown whether or not successful atrial fibrillation ablation improves long-term outcomes, studies have shown that patients with symptom-free atrial fibrillation may have better cardiovascular outcomes than those treated with antiarrhythmic medication. They stated that their hypothesis was that “the incidence of cardiovascular events may be lower after a successful atrial fibrillation ablation and without recurrence of any atrial arrhythmias.” To confirm their theory, after adjusting for cofounding variables, they investigated the long-term cardiovascular outcomes and mortality in high-risk patients with atrial fibrillation who received catheter ablation compared with patients who received antiarrhythmic medications.

The study population were patients with atrial fibrillation who had been referred to the authors’ electrophysiology unit between January 2003 and December 2009. Of 1,262 patients referred, 953 high-risk patients were identified (CHA2DS2-VASc score of ≥1). The patient or the treating electrophysiologist chose the method of atrial fibrillation treatment (catheter ablation or antiarrhythmic medication). Patients were followed up every three months for at least one year and thereafter, every six months. They were assessed for recurrence of atrial fibrillation and the incidence of the combined occurrence of major adverse events (MACEs). Overall, 383 patients received catheter ablation and 174 were matched with individuals who received antiarrhythmic medications.

After a mean follow-up of 47±23 months, sinus rhythm was observed in 39.7% of patients on antiarrhythmic medication (group one) and 90.2% of patients who received catheter ablation (group two). Lin et al reported: “A Kaplan-Meier survival analysis indicated that the group one patients had a high cumulative incidence of MACEs compared with the group two patients.”

They added that the rates of total cardiovascular mortality and total mortality were higher in the group one patients than in the group two patients, but stated that these rates were not increased in patients who experienced atrial fibrillation recurrence after ablation (group three) compared with group two patients. Lin et al wrote: “The results of this study suggest that there is a potential increased survival rate in patients with rhythm control achieved using an ablation strategy, irrespective of atrial fibrillation recurrence, indicating the potential benefits of decreasing atrial fibrillation burden, because the documented atrial fibrillation duration was at least one minute in this study.”

Although atrial fibrillation recurrence did not appear to increase the risk of total mortality or cardiovascular mortality, it did to seem increase the risk of vascular events. The authors commented: “A Kaplan-Meier survival analysis demonstrated that the ablation-treated patients without an atrial fibrillation recurrence had lower incidences of total vascular events (p=0.004) and ischaemic strokes/transient ischaemic attacks (p=0.015) compared with the patients with an atrial fibrillation recurrence or medical treated patients.”

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