Ablation vs. drug therapy study

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Catheter ablation feasible as front-line approach for the treatment of

symptomatic AF

Jun 1, 2005 O'Riordan

Cleveland, OH - Pulmonary vein isolation with radiofrequency ablation

is associated with better clinical outcomes than drug therapy and

appears to be feasible as a front-line approach for the treatment of

symptomatic atrial fibrillation (AF). In one of the first studies

comparing catheter-based ablation of AF with standard antiarrhythmic

drug therapy, investigators showed that pulmonary vein isolation was

associated with less AF recurrence, improved quality of life, and a

lower hospitalization rate at one year [1].

In this multicenter, prospective, randomized pilot study, led by Dr

Oussama Wazni (Cleveland Clinic, OH) and published in the June 1, 2005

issue of the Journal of the American Medical Association,

investigators directly compared catheter-based ablation of AF with

standard antiarrhythmic drug therapy. Typically, pulmonary vein

isolation, although shown in preliminary reports to eliminate AF

completely, is considered only after drug therapy has failed, because

of the risks associated with the procedure, such as stroke and

pulmonary vein stenosis.

We are moving forward with performing the procedure more regularly,

performing it as a standard of care that can benefit the many patients

with AF.

" The standard of care for the treatment of atrial fibrillation has

been to first consider drug therapy, either to maintain sinus rhythm

or to achieve rate control, " senior investigator Dr Natale

(Cleveland Clinic) told heartwire. " The problem with these approaches

is that they are not very effective. Even in the best-case scenario,

over four or five years atrial fibrillation is under control in maybe

30% or 40% of patients. Catheter ablation of atrial fibrillation

really then becomes one of the few options that we have to cure it.

The therapy has evolved over the past five or six years, to a point

where we are able to cure a significant number of patients of their

atrial fibrillation. With one or two ablation procedures, we have been

able to eliminate their atrial fibrillation completely. "

Patients were included in the study if they experienced monthly

symptomatic AF episodes for at least three months and had not

previously been treated with antiarrhythmic drugs. There were no

differences in baseline patient characteristics, including age, left

atrial size, and duration and type of AF, among those randomized to

ablation (n=32) and those randomized to drug therapy (n=35). The

primary end point of the study was any recurrence of symptomatic AF or

asymptomatic AF lasting longer than 15 seconds during Holter or event

monitoring in the one-year follow-up period.

In the drug group, the physician providing patient care chose the

drug; it was recommended that the maximum tolerable dose of each agent

be used. The recommended medical regimen consisted of oral flecainide

(100-150 mg) twice daily, propafenone (225-300 mg) three times daily,

or sotalol (120-160 mg) twice daily. The end point of ablation was

complete electrical disconnection of the pulmonary vein antrum from

the left atrium.

After excluding events in the first two months after enrollment, 22

patients in the drug group compared with four patients in the ablation

group had at least one AF. Of these events, asymptomatic AF was

documented in 16% of the drug group and in 2% of the ablation group.

Asymptomatic mild or moderate pulmonary vein stenosis developed in two

patients randomized to ablation.

One-year follow-up results by treatment group

NOTE: TABLE OMMITTED

At six months, improvements in quality of life of patients in the

ablation arm were also significantly better than improvements in drug

group (as measured by the Short-Form 36 health survey).

Replicating the results in smaller centers critical

" This is a preliminary study and a preliminary result, but the

findings are encouraging, " said Natale. " The next step will involve

repeating the study in more centers, which have begun, mostly in North

America and a few European centers. This study will include

less-specialized, lower-volume centers so that we can prove that what

we achieved at these highly experienced hospitals can be the standard

of care for everybody else. "

Natale and colleagues point out that the technique for performing

pulmonary vein isolation is similar but not identical to other

catheter-based techniques for performing AF ablation. Although the

best technique for AF ablation remains a debated topic, they write

that ablation techniques continue to evolve as knowledge, experience,

and technology advance. Although the pilot study proved that

catheter-based ablation of AF is feasible, Natale told heartwire that

the procedure still requires experienced operators.

" This is an extremely complex procedure that has the potential for

serious complications, " he said. " But there are a large number of

physicians being trained in the ablation procedure and in the next few

years we are bound to see an increase in the number of

electrophysiologists capable of doing a good job. At this point, I

would not encourage clinicians with no experience to do the procedure,

but this study is certainly a start. We are moving forward with

performing the procedure more regularly, performing it as a standard

of care that can benefit the many patients with atrial fibrillation. "