Relation of recurrence of atrial fibrillation after successful cardioversion to renal function

Angiotensin II exerts proinflammatory effects leading to atrial fibrosis that is associated with persistence of atrial fibrillation (AF). Renal function plays a major role in activation of the renin-angiotensin-aldosterone system. We examined whether the level of impaired renal function, defined by glomerular filtration rate (GFR), would influence the maintenance of sinus rhythm after successful external electric cardioversion (ECV). One hundred two consecutive patients with persistent AF underwent successful ECV. Patients were prospectively followed for recurrence of AF by telephone interviews, Holter electrocardiograms, and electrocardiograms sent by primary care providers. Repeated GFR assays were performed before and 1 month after ECV. Patients were divided into 4 groups according to baseline GFR (I >90 ml/min, II 60 to 90 ml/min, III 30 to 59 ml/min, IV <30 ml/min). AF recurrence rate was significantly higher in patients with moderately or severely decreased renal function (GFR <60 ml/min, p = 0.003). Patients with moderately (GFR 30 to 59 ml/min, p = 0.02) or only mildly (GFR 60 to 90 ml/min, p = 0.01) decreased renal function showed an increase in GFR if sinus rhythm was maintained at 1 month follow-up. In conclusion, impaired renal function was associated with an increased risk of AF recurrence after successful ECV.