AT THE ESC CONGRESS 2017
BARCELONA (FRONTLINE MEDICAL NEWS) – Catheter ablation of symptomatic atrial fibrillation produced significantly better quality of life after 12 months than did continued treatment with antiarrhythmic drugs in a randomized, multicenter trial with 155 patients who had a history of failed drug treatment.
The trial was notable as the first prospective comparison of atrial fibrillation (AF) management by ablation with drug treatment to use quality of life as the primary efficacy endpoint. Such a quality of life–oriented assessment has been lacking “even though the main indication for ablation is symptom relief,” Carina Blomstr ö m-Lundqvist, MD , said at the annual congress of the European Society of Cardiology.
Clinicians have traditionally measured residual or recurrent AF after treatment with a periodic ECG to see whether patients experience AF episodes that last at least 30 seconds, but this is “hardly a measure of successful treatment,” said Dr. Blomström-Lundqvist, an electrophysiologist at the University Hospital in Uppsala, Sweden.
She and her associates placed an implanted cardiac monitor into each patient for continuous measurement of residual AF episodes. Twelve months after entry into the study, patients who underwent ablation had their AF burden decreased by an average of 20 percentage points compared with baseline, while the AF burden dropped by an average of 12 percentage points among patients maintained on antiarrhythmic drugs, a between-group difference that was not statistically significant.
Based on that finding, Dr. Blomström-Lundqvist inferred that the significantly better improvement in quality of life seen with ablation compared with drug treatment occurred because the ablated patients all came off antiarrhythmic drug treatment. The study protocol required patients randomized to the ablation regimen to be completely off antiarrhythmic drugs by 6 months after their ablation procedure.
Continued treatment with an antiarrhythmic drug in the drug-arm patients compared with no drug treatment in the ablated patients “is absolutely the explanation” for the observed difference in quality of life, she said. Patients randomized to the antiarrhythmic drug arm of the study received treatment with one of six eligible drugs: amiodarone, disopyramide, dronedarone, flecainide, propafenone, or sotalol. Patients could also be on a beta-blocker.
The Catheter Ablation Compared With Pharmacological Therapy for Atrial Fibrillation ( CAPTAF ) trial enrolled symptomatic patients with paroxysmal or persistent AF at four Swedish centers and at one center in Finland. All enrolled patients had to have a history of being refractory to or intolerant of a beta-blocker or an antiarrhythmic drug. Patients with paroxysmal AF had to have experienced an AF episode within the prior 2 months, while those with persistent AF had to have had at least two AF episodes within the prior year. The average age of the enrolled patients was 56 years. Nearly three-quarters had paroxysmal AF. Their average AF burden was about a quarter of the time, on average they had been diagnosed with AF for about 5 years, and 70%-80% of the patients had severe or disabling symptoms. At entry, about 90% of patients were on beta-blocker treatment and a bit more than a third were taking an antiarrhythmic drug.
The researchers measured quality of life using the 36-item Short Form Survey Instrument ( SF-36 ). At baseline, the average SF-36 score (measured on a 0-100 scale) was 63 in the 79 patients randomized to ablation and 62 in 76 patients randomized for drug therapy. Patients randomized to an ablation procedure underwent pulmonary vein isolation by whatever technique their attending cardiologists preferred.
The average SF-36 score 12 months after study entry was 73 for the ablation patients, an average gain from baseline of 11 points, and 65 in the drug-treated patients, an average gain of 3 points. The 8-point difference in SF-36 gain between the two groups was statistically significant.
Contributing to the overall superiority of ablation for improving quality of life were statistically significant advantages for ablation over drug treatment in the individual SF-36 domains of general health, physical function, mental health, role-emotional, role-physical, and vitality. The two treatment arms of the study showed no significant differences in the two remaining SF-36 domains of bodily pain and social functioning.
Nine of the 79 patients (11%) who underwent ablation had a procedure-related serious adverse event, including four patients with an infection or septicemia, two patients with tamponade or pericardial effusion, one patient with a transient ischemic attack, and two with a different vascular complication. Serious cardiovascular adverse events during the 12 month follow-up occurred in 14 of the ablated patients (18%) and in 18 of the drug-treated patients (24%), a between-group difference that did not undergo statistical analysis. Dr. Blomström-Lundqvist called the rates “comparable,” but cautioned that the study was not powered to compare serious adverse event rates in the two treatment arms.
H é ctor Bueno, MD , a cardiologist at the Spanish National Center for Cardiovascular Research in Madrid and a cochair of the session that included the CAPTAF report, voiced concern about the procedure-related serious adverse events among patients who underwent ablation.
“An 11% serious complication rate is not negligible,” he said. “Some of them were really serious complications.”
On Twitter @mitchelzoler