CARDIOVASCULAR MEDICINE

Atrial fibrillation recurrence after internal cardioversion: prognostic importance of electrophysiological parameters

M Biffi, G Boriani, M Bartolotti, L Bacchi Reggiani, R Zannoli, A Branzi

Institute of Cardiology, University of Bologna, Bologna, Italy

Correspondence to:
Correspondence to:
Dr Mauro Biffi, Institute of Cardiology, University of Bologna, Via Massarenti 9, 40138 Bologna, Italy;
mbiffi{at}orsola-malpighi.med.unibo.it

Objective: To evaluate the clinical and electrophysiological determinants of arrhythmia recurrence in patients undergoing internal atrial cardioversion for chronic atrial fibrillation (AF).

Setting: Tertiary cardiac referral centre.

Methods: 101 consecutive patients with failed external cardioversion or AF 1 year underwent internal atrial cardioversion; once stable sinus rhythm (SR) was obtained, electrophysiological study was performed in 73 patients (72%) who gave informed consent. Patients were then followed on antiarrhythmic treatment.

Results: 101 consecutive patients underwent internal atrial cardioversion in the period 1996–1999 with 100% conversion to SR; prophylactic antiarrhythmic treatment was flecainide (52%), amiodarone (37%), and sotalol (11%). Average follow up at first AF recurrence was 18.4 (14.4) months (range 0.1–49.8 months); persistence of SR was observed in 72/101 (72%) patients. By logistic regression, AF duration (odds ratio (OR) 1.07, 95% confidence interval (CI) 1.01 to 1.13) and a lower sinus rate at discharge on antiarrhythmic drugs (OR 0.92, 95% CI 0.85 to 0.99) were independent predictors of AF recurrence, whereas age, New York Heart Association functional class, left atrial dimensions, and left ventricular ejection fraction were not predictive of arrhythmia recurrence. When electrophysiological parameters were added to the statistical model in 73 patients, a shorter atrial effective refractoriness (OR 1.04, 95% CI 1 to 1.08) and an abnormal relation of atrial effective refractoriness to cycle length (OR 31, 95% CI 3.7 to 266) were also independent predictors of AF recurrence at follow up, beyond AF duration and heart rate at discharge.

Conclusions: Patients with failed external cardioversion or long lasting AF may benefit from internal atrial cardioversion and antiarrhythmic treatment to keep SR at long term; electrophysiological study may identify patients at the highest risk of arrhythmia recurrence. Although preservation of SR seems unlikely for AF duration > 3 years, a consistent minority of this subgroup (38%) may benefit from this approach.

Keywords: atrial fibrillation; internal atrial cardioversion; electrophysiology; follow up

Abbreviations: AF, atrial fibrillation; BCL, basal cycle length; CI, confidence interval; CL, cycle length; EP, electrophysiological study; ERP, effective refractory period; NYHA, New York Heart Association; SR, sinus rhythm

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