- Atrial fibrillation (AF) ablation is increasing and is being offered to sicker patients
- Recurrence post-ablation still plagues the field
- Ballloon technologies promise to reduce procedure time
- Delayed-enhancement MRI could be a game changer
Writing on the wall
In a worldwide survey conducted between 2003 and 2006, Cappato et al found AF ablation to be effective in about 80 percent of patients after 1.3 procedures per patient, with about 70 percent of them not requiring further anti-arrhythmic drugs during intermediate follow-up (Circ Arrhythm Electrophysiol 2010;3:32-38). Noted observations included:
- Ablation is increasingly being offered to patients with AF and to sicker AF patients;
- Proportions of successful cases that are free of anti-arrhythmic drugs appear to increase with experience;
- The proportion of overall successes does not appear to have improved, as better results with catheter ablation only appear to be counterbalanced by poorer efficacy of previously ineffective anti-arrhythmic drugs; and
- Complication rates and incidence of iatrogenic atrial flutter do not appear to be decreased with experience.
“The primary driver for whether to ablate or not is symptoms,” says Edward P. Gerstenfeld, MD, from the division of cardiac electrophysiology at the Hospital of the University of Pennsylvania in Philadelphia, who was not associated with the above study. “Several studies, although not prospective, show a mortality benefit from keeping people in sinus rhythm rather than leaving them in atrial fibrillation, but there is controversy over this idea. One study showed people who stayed in sinus rhythm fared better, but it’s not clear if the improvement was because they were in sinus rhythm or if it was just a marker of being better.”
Interestingly, the approval of dabigatran (Pradaxa, Boehringer Ingelheim) in 2010 to reduce the risk of stroke could actually decrease the number of ablations, according to John D. Day, MD, director of Heart Rhythm Services at Intermountain Healthcare in Murray, Utah. “No one likes to use warfarin and to a certain degree, procedures are being driven by patients wanting to avoid this drug. Dabigatran may lessen the incredible drive to get off warfarin.”
Day also cautions that many patients are moving to higher deductable health plans and may not be able to afford the more effective ablation treatment because of the high out-of-pocket expenses.
Several factors play a role in ablation success including younger age, less duration time, paroxysmal versus persistent or permanent and fewer comorbidities. In a recent study, Leong-Sit and colleagues found that patients younger than 45 years had a lower major complication rate and a comparable efficacy rate, with a greater chance of being AF free without anti-arrhythmic drugs compared with older patients (Circ Arrhythm Electrophysiol 2010;3:452-457). Current U.S. and European guidelines and consensus documents indicate that ablation is a second-line therapy for all categories of patients or only in rare clinical situations. However, Gerstenfeld, a co-author of the study, says, “These findings suggest that it may be appropriate to consider ablation as a first-line therapy in this age group.”
There is currently momentum to make AF ablation a first-line therapy. Years ago, patients with supraventricular tachycardias had to have failed several medications before undergoing a three- to four-hour ablation procedure. Now, the procedure is offered as a preferred, first-line therapy, typically taking 90 minutes, says John M. Mandrola, an EP with Louisville Cardiology in Louisville, Ky. “Atrial fibrillation is not there yet. However, AF patients previously had to have failed two drugs and now it is one. For young people with paroxysmal AF, it’s not unreasonable to offer ablation as a first-line therapy, because you know the disease will remain and drugs are often poorly tolerated.”
With advances in technology, including imaging, mapping and catheters, physicians don’t need so much to ask “can I ablate this patient, but should I,” Mandrola notes. The decision to ablate or not is easier for the extreme cases of drug refractory, symptomatic patients, but the intermediate cases can be challenging to call, he says.
Generally, a successful first-time AF ablation is not a guarantee. Whereas simple arrhythmias carry a 98 percent initial success rate, that figure drops to 75 percent for AF. “The guidelines