Catheter ablation safe and effective for older afibbers

PHILADELPHIA, PENNSYLVANIA. As the proportion of elderly people grows in the US population so does the incidence and prevalence of atrial fibrillation (AF). Is catheter ablation (PVI) safe and effective in the geriatric population? This is the question that Dr. Marchlinski and colleagues at the University of Pennsylvania recently set out to answer.

Their study involved 1165 afibbers who underwent a total of 1506 ablations for AF (repeat rate of 29%) during the period 2000 to 2007. The patients were followed for an average of 2 years (minimum 1 year) to establish the safety and efficacy of the procedure in 3 different age groups – group A: less than 65 years old (mean age of 52), group B: aged between 65 and 74 years (mean age of 68), and group C: age 75 years or older (mean age of 77). The number of patients in each group was group A – 948 patients, group B – 185 patients, and group C – 32 patients. There were no statistically significant differences in clinical characteristics of the three groups except that the percentage of women in group C (56%) was significantly higher than in group A (20%), and group B (34%). Also, the incidence of hypertension and structural heart disease was significantly higher in group C than in groups A and B (88% vs 56% and 68%).

Thus, the prevalence of lone atrial fibrillation (LAF) was very low in group C (12%), but fairly high in group A (44%). The stroke risk in the 3 groups was also significantly different with 72% of group C afibbers having a CHADS2 score of 2 or more versus 12% in group A and 30% in group B. The prevalence of a left ventricular ejection fraction (LVEF) of less than 50% was 12% in group A, 7% in group B, and 16% in group C. There were no significant differences in left atrial diameter which averaged 4.4 cm.

All study participants underwent an ICE-guided segmental PVI procedure with additional lesions and right atrial flutter ablation as required. Repeat procedures were performed in 26% of patients in group A, 27% in group B, and 9% in group C. At the 1-year follow-up, 66% of group A members were afib-free without the use of drugs. Corresponding complete success rates for group B and group C were 53% and 50%. An additional 14% of group A members were free of afib, but still taking anti-arrhythmic drugs (sotalol or Class 1 – flecainide or propafenone). Corresponding numbers for groups B and C were 22% and 23%.

Thus, the combined complete and partial success rates were 80% for group B, 75% for group B, and 73% for group C. In addition, 9% of groups A and B had experienced a 95% or better reduction in their number of episodes or experienced 6 or fewer episodes during the 1-year follow-up. The corresponding percentage for group C was 14%. Overall, 89% of group A, 84% of group B, and 86% of group C benefited significantly from their procedure. The rate of major complications (stroke, TIA, symptomatic pulmonary vein stenosis, tamponade, atrioesophageal fistula or phrenic nerve injury) was low and similar in the 3 age groups – group A 1.6%, group B – 1.7%, and group C – 2.9%. NOTE: Differences not statistically significant.

The Philadelphia group concludes that elderly patients do well with catheter ablation of their AF with afib control achieved at a rate comparable to younger patients and no evidence of an increase in risk of adverse events. They also make the interesting observation that 5% of group A members remained on antiarrhythmics following a successful procedure even though there was no indication that they needed to do so. Corresponding numbers for groups B and C patients were 13% and 14% respectively.

Zado, E, et al. Long-term clinical efficacy and risk of catheter ablation for atrial fibrillation in the elderly. Journal of Cardiovascular Electrophysiology, Vol. 19, June 2008, pp. 621-26

Editor’s comment: This study adds to the evidence that age, as such, is not a detriment to undergoing a safe and effective PVI procedure. If this applies to a group in which 88% had structural heart disease or hypertension, it should doubly apply to lone afibbers.