Cryoballoon Ablation as Initial Therapy for Atrial Fibrillation

For decades, patients with early stage atrial fibrillation, termed paroxysmal atrial fibrillation, were required to fail specialized medications to meet eligibility for an afib ablation. The STOP AF First trial showed that a first-line strategy of cryoballoon ablation was superior to antiarrhythmic drug therapy. The trial was led by Dr. Oussama Wazni at the Cleveland Clinic Hospital. Dr. Makati was among the co-authors of the research trial now published in the New England Journal of Medicine (

Patients in the trial were randomized to either antiarrhythmic drugs (medications designed to suppress abnormalities involving the heart’s electrical system) or to cryoballoon ablation. Antiarrhythmic drugs are powerful medications with the ability to suppress atrial fibrillation. Unfortunately, their effectiveness ranges from 0-70%. Antiarrhythmic medications have known side effects; in some instances with FDA warnings highlighting the potential for dangerous electrical disturbances and the the possibility of increasing the likelihood of sudden cardiac death.

The study included over two hundred patients with newly diagnosed paroxysmal atrial fibrillation. Roughly half were assigned to the ablation arm, and the remainder assigned to take medications. At the end of 12 months, 75% of the cryoballoon ablation group remained in normal rhythm compared with only 45% of the drug therapy group.

The trial was also notable for the exceptionally low rate of procedural complications. In the past, afib ablation was always considered second line treatment as the procedure was felt to be effective, but with risk. This study confirms that afib ablation can be performed safely with a high degree of success, and now more effective when compared to the current standard of care using only medications.

In summary, among patients with paroxysmal atrial fibrillation, a first-line cryoballoon ablation strategy was superior to antiarrhythmic drug therapy. The strategy appeared to be safe with very few adverse events. The trial is a landmark study which will no doubt shape the practice of electrophysiology.