麻豆传媒

For paroxysmal atrial fibrillation (Afib), heading straight to cryoablation kept more patients in sinus rhythm at 1 year than trying rhythm control drugs first, two randomized trials showed.

In the , recurrence of at least 30 seconds of atrial tachyarrhythmia after day 90 occurred in 42.9% assigned to cryoballoon ablation versus 67.8% who got antiarrhythmic drugs as the initial treatment strategy (HR 0.48, 95% CI 0.35-0.66).

The number needed to treat was just four, Jason Andrade, MD, of Vancouver General Hospital, reported at the virtual American Heart Association meeting and in the .

In the , first-line ablation achieved 74.6% treatment success at 12 months without recurrence after day 90 compared with 45.0% in the group randomized to class I or III antiarrhythmic drugs (P<0.001), Oussama Wazni, MD, of the Cleveland Clinic, and colleagues in the same journal. Their results had been initially presented at the virtual European Society of Cardiology meeting in August.

Neither trial was powered for clinical cardiovascular outcomes, such as stroke. However, quality of life was improved significantly in both without an increase in serious or overall adverse events in either trial.

While the two trials "rigorously demonstrated the superiority" of Afib ablation in first-line therapy, "larger scale and longer term studies would be needed to determine whether these benefits might translate into improved cardiovascular outcomes," noted AHA session discussant for the EARLY AF trial, Christine Albert, MD, MPH, of Cedars-Sinai Medical Center in Los Angeles.

Rhythm control early after Afib diagnosis improved cardiovascular outcomes in the EAST-AFNET 4 trial.

Achieving the same thing with ablation might also decrease progression to the more difficult to manage persistent type of Afib, Wazni's group noted, but radiofrequency ablation has proven only modestly effective in early Afib at the cost of more serious adverse events and a high rate of repeat procedures.

Thus, ablation has had a class IIa recommendation for first-line treatment in guidelines.

"To patients, the important outcome is symptomatic recurrences," argued Andrade. "If we apply the same standard to the interpretation of the evidence, I think we can confidently say that first-line ablation is a reasonable treatment strategy for appropriate patients."

In his trial of 303 patients with symptomatic, paroxysmal, untreated Afib, cryoablation reduced symptomatic recurrences by an absolute 16% (11.0% vs 26.2%, HR 0.39, 95% CI 0.22-0.68) along with the significantly better quality of life.

"I don't think we need a hard outcome study to consider ablation as a first-line therapy, as the intent of ablation is symptomatic improvement," he told 麻豆传媒. "However, a hard outcome study would help evaluate the cost-effectiveness of a first-line ablation approach and determine if this is an acceptable strategy for payers."

Albert agreed that quality of life is often the reason for doing ablation, noting the CABANA trial, which didn't show improvement in death, disabling stroke, serious bleeding, or cardiac arrest in the intent-to-treat analysis but did suggest a quality of life advantage in symptomatic patients.

Crossovers had been a problem in that trial, but were not in EARLY AF or STOP-AF First as repeat ablation or crossover from the drug-therapy arm to ablation was considered a primary endpoint event, including those during the 90-day blanking period.

EARLY AF used implantable loop recorders to monitor for atrial arrhythmia in both groups, who were enrolled a median of 1 year after diagnosis.

In STOP-AF First's 203 adults with paroxysmal Afib previously untreated with a rhythm control strategy, recurrence monitoring included ECG at each follow-up visit, patient-activated weekly telephone monitoring, and 24-hour ambulatory ECG at 6 and 12 months. It enrolled patients without marked left atrial enlargement at a mean of 1.3 years after Afib onset.

Wazni's group cautioned that their the sample size may not have been large enough to allow detection of uncommon adverse events.

Albert pointed to the relatively short duration of follow-up in both trials and small sample sizes as limitations. Also, generalizability to older populations and those with persistent Afib, treatment at lower volume centers, and other ablation technologies is unclear, she added.

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