Factors associated with early atrial fibrillation after ablation of common atrial flutter. A single centre prospective study.

BACKGROUND: The occurrence of early atrial fibrillation (< or = 6 months) after ablation of common atrial flutter is of clinical significance. Variables predicting this evolution in ablated patients without a previous atrial fibrillation history have not been fully investigated.

OBJECTIVES: The aim of the present study was: (1) to identify predictive factors of early atrial fibrillation (< or = 6 months) in the overall population following atrial flutter catheter ablation; (2) to identify predictive variables of early atrial fibrillation following (< or = 6 months) atrial flutter catheter ablation within a subgroup of patients without documented prior atrial fibrillation.

METHODS: This study prospectively included 96 consecutive patients (age 65 +/- 13 years; 18 women) over a 12-month period. Their counterclockwise flutter was ablated by radiofrequency, by the same operator, with an 8-mm-tip catheter. Clinical, electrophysiological and echocardiographic data were collected and 27 variables were retained for analysis: age; gender; type of atrial flutter (permanent vs paroxysmal); symptom duration (months +/- SD); pre-ablation history of atrial fibrillation; structural heart disease; left ventricular ejection fraction (%); left atrial size (mm); cava--tricuspid isthmus dimension; septal isthmus dimension; systolic pulmonary pressure > or < or = 30 mmHg; right atrial area; left atrial area; isthmus block; number of radiofrequency applications (+/- SD); antiarrhythmic drugs at discharge; left ventricular diastolic diameter; left ventricular systolic diameter; left ventricular telediastolic volume; left ventricular telesystolic volume; A-wave velocity (cm . s(-1)); E-wave velocity (cm . s(-1)); E/A; isovolumetric relaxation time; E-wave deceleration time; significant mitral regurgitation and flutter cycle length (ms).

RESULTS: Of the 96 consecutive ablated patients, early atrial fibrillation was documented in 16 patients (17%). Atrial fibrillation occurred 30 +/- 46 days (range 1 to 171 days) after ablation. Univariate analysis associated an early occurrence of atrial fibrillation with: atrial fibrillation history, left ventricular ejection fraction, left atrial size, left ventricular telesystolic volume, A-wave velocity, significant mitral regurgitation and flutter cycle length. Multivariate analysis using a Cox model found that the only independent predictors of early atrial fibrillation were left ventricular ejection fraction and pre-ablation history of atrial fibrillation. In the subgroup without prior atrial fibrillation history (n=63; 66%), the only independent predictor of early atrial fibrillation was the presence of a significant mitral regurgitation.

CONCLUSIONS: In a subgroup of patients without atrial fibrillation history, 8% of patients revealed an early atrial fibrillation. Mitral regurgitation is a strong predictive factor of early atrial fibrillation occurrence with 80% sensitivity, 78% specificity and 98% negative predictive value. These data should be considered in post-ablation management.