Ablation versus antiarrhythmics

BORDEAUX, FRANCE. There is continuing controversy as to which is the safest and most effective way of preventing afib occurrence – antiarrhythmics (AADs) or catheter ablation. Professor Haissaguerre and his group at the Hopital Cardiologique Haut-Leveque provide evidence that catheter ablation results in superior outcomes when compared to the use of AADs. Among the highlights from their recent article in the European Heart Journal are:

  • A re-analysis of AFFIRM trial data showed that maintenance of sinus rhythm with AADs is associated with a 47% increase in survival when compared with staying in afib. Unfortunately, the use of AADs is also associated with an increase in mortality of 49%. Conclusion – “Although evidence (from the AFFIRM trial) suggested an advantage of sinus rhythm over AF, this beneficial effect seemed to be mitigated by the adverse effects of the drugs used to achieve and maintain it.”

  • Several studies have compared the efficacy of AADs to that of ablation. One study involving 763 patients concluded that AADs prevented afib recurrence in 32% of participants, while catheter ablation was successful in 79% of cases. In studies involving only patients with paroxysmal (intermittent) afib, ablation success rate was 81% as compared to 29% in the AAD group. In patients with persistent afib only, normal sinus rhythm was maintained in 75% (at 1 year) in the ablation group with 27% needing more than one procedure. In comparison, only 55% in the AAD group had a favourable outcome.

  • Current guidelines recommend that all patients undergoing catheter ablation for AF have at least electrical isolation of all four pulmonary veins. This is usually sufficient to restore durable sinus rhythm in patients with paroxysmal AF and short arrhythmia episodes, whereas patients with longstanding persistent AF or with permanent AF often need extensive ablation, including complete lines, to achieve a satisfactory outcome. Others should have an intermediate approach to target AF substrate in trying to avoid excessive ablation potentially leading to left atrial flutters or complications.

  • In the AFFIRM trial use of AADs was associated with a 49% increase in mortality. (NOTE: The AFFIRM trial involved patients with heart disease. There is no evidence that the 49% mortality rate applies to lone afibbers.) AADs are also associated with the possibility of significant side effects. The one-year incidence of adverse events attributable to amiodarone was 6% for hypothyroidism, 1% for pulmonary toxicity, 0.9% for hyperthyroidism, 0.6% for liver toxicity, and 0.3% for peripheral neuropathy.

  • The procedure-related mortality associated with catheter ablation is 0.1%. Overall complication rate (2005) is about 6% including a 1.2% risk of tamponade (piercing of the heart wall), a 1% risk of stroke or TIA (transient ischemic attack), 0.6% risk of developing symptomatic pulmonary vein stenosis, and a 0.01% risk of incurring an atrio-esophageal fistula.

  • It is estimated that the cost of medical therapy over a 2 to 5 year period equals that of a catheter ablation.

The authors conclude that, “It should, therefore, be emphasized that there is consensus in the current practice guidelines to consider catheter ablation as a second line treatment for AF, after failure of medical therapy, and to reserve it for patients who are symptomatic. The future may hold a greater role for ablation, as we achieve better understanding of AF physiopathology, improve tools allowing faster, more efficient, and safer procedures, and as ongoing studies are conducted to assess whether there is a survival advantage with the ablative treatment of AF.”

Nault, I, et al. Drugs vs. ablation for the treatment of atrial fibrillation: the evidence supporting catheter ablation. European Heart Journal, March 23, 2010 [Epub ahead of print]

Editors’ comment: The authors point out that most data on catheter ablation of AF in the literature stem from a few high-volume centers which are over-presented and may not reflect results obtained in smaller centers. This is indeed the case as confirmed in our ablation/maze surveys. The 2008 survey of 950 procedure outcomes found the following final complete success rates (no afib, no AADs) for 600 patients:

  • Top-ranked institutions - Complete success, 65% - Repeat rate, 30%
  • Other institutions - Complete success, 32% - Repeat rate, 44%

Thus, it is likely that undergoing catheter ablation at a less than top-ranked institution will be no more effective than continuing on AADs.