Factors predicting success of circumferential PVI
GHENT, BELGIUM. The success rate for a single pulmonary vein isolation procedure carried out at a top-rated center now ranges between 70% and 90% in the case of healthy, paroxysmal afibbers. Researchers at University Hospital Ghent recently carried out a study to determine if there were any specific pre-procedure variables that could predict, more specifically, whether a PVI would be successful.

Their study involved 100 patients (average age of 54 years), 85% of whom were lone afibbers with paroxysmal (80%), or short-standing persistent (20%) afib. The patients had an average of 4 symptomatic episodes a week and had been diagnosed an average of 6.2 years ago. They had unsuccessfully tried an average of 2.6 antiarrhythmic drugs each. All participants underwent a circumferential PVI (CARTO-guided) procedure while in sinus rhythm. They remained on antiarrhythmics (sotalol or flecainide) and warfarin for at least 3 months following the procedure.

After an average follow-up of 28 months (15 – 59 months) Holter monitoring was performed. At this time, 71% of patients were free of afib without the use of antiarrhythmic drugs, while 5% experienced recurring asymptomatic episodes. An early occurrence (during the first month following the procedure) was not necessarily an indication of failure since 17 out of 25 patients (68%) experiencing recurrence were afib-free at the end of follow-up. The researchers found no evidence that age and gender influenced the outcome of the procedure; however, they did notice that patients who were ablated early in their "afib career" experienced a substantially better outcome (92% success if ablated within 1 year of diagnosis) than did those who waited. The researchers also found that a smaller left atrial volume (measured by 3D CARTO geometry) was associated with a substantially greater success. Thus, patients with a LA volume less than 80 mL had a success rate of 88% at end of follow-up, while those whose procedures failed had an average LA volume of 106 mL.

De Potter, T, et al. Predictors of success after a first circumferential pulmonary vein isolation for atrial fibrillation. Journal of Atrial Fibrillation, Vol. 1, No. 6, April 2009, pp. 311-20

Editor's comment: The above findings provide strong evidence that undergoing an ablation soon after diagnosis materially improves the chance of success. However, a decision to "jump right in" must be weighed against the currently unknown long-term effects of PVIs in general.