Objectives

To assess the effect of surgical ablation, as well as the effects of two different ablation procedures, on the recurrence of atrial fibrillation in participants with persistent or long-standing persistent atrial fibrillation who were undergoing mitral-valve surgery.

Background

Atrial fibrillation (AF), which is associated with reduced survival and increased risk of stroke, is present in 30 to 50% of patients presenting for mitral-valve surgery. The development of open surgical procedures for the ablation of AF has led to their widespread application during cardiac operations, but their effectiveness and safety have not been rigorously established. Moreover, although the pulmonary-vein isolation procedure is used more frequently than the biatrial maze procedure, data on the comparative effectiveness of the two ablation procedures are also limited.

The CTSN-AFB trial sought to determine the effect of surgical ablation on the recurrence of AF in the first year after surgery and to explore the effects of two different ablation procedures (pulmonary-vein isolation or biatrial maze procedure) on freedom from AF during the same period in patients with persistent or long-standing persistent AF who were undergoing mitral-valve surgery.

Participants

Eligible participants were adults with persistent or long-standing persistent AF who also had mitral-valve disease requiring surgical intervention. Persistent AF was defined as non–self-terminating AF lasting more than 7 days, or less than 7 days if cardioversion was required. Long-standing persistent AF was defined as continuous AF for more than 12 months. This definition applied only to AF episodes that were of at least 30 seconds’ duration and did not have a reversible cause such as acute pulmonary disease or hyperthyroidism.

A total of 260 participants underwent randomization, with 133 randomly assigned to mitral-valve surgery with ablation and 127 randomly assigned to mitral-valve surgery alone. In the ablation group, 67 participants were randomly assigned to pulmonary-vein isolation and 66 to the biatrial maze procedure.

Design

The CTSN-AFB study was performed at 20 centers in the Cardiothoracic Surgical Trials Network. Eligible participants were randomly assigned in a 1:1 ratio to undergo either surgical ablation or no ablation (control group) during the mitral-valve operation. Participants in the ablation group underwent further randomization to one of two lesion sets: pulmonary-vein isolation or biatrial maze. All participants also underwent closure of the left atrial appendage to reduce the risk of formation of a left atrial thrombus. Unless contraindicated, all participants received Class I or III anti-arrhythmic drugs within 24 hours of surgery, which were discontinued at three months.

Follow-up assessments were conducted by telephone interview at 3, 6, and 9 months and in person at 12 months. The primary end point was freedom from AF at both 6 months and 12 months after surgery, as assessed by means of 3-day continuous Holter monitoring. Secondary end points included major cardiac or cerebrovascular adverse events (death, stroke, hospitalization for heart failure, worsening heart failure [as defined by an increase of one or more classes in the New York Heart Association classification], or mitral-valve reintervention), mortality, the need for rhythm-related interventions, quality of life, and rehospitalization.

Conclusions

In participants with persistent or long-standing persistent atrial fibrillation, the addition of surgical ablation at the time of mitral-valve surgery significantly increased the rate of freedom from atrial fibrillation at one year.

Gillinov AM, Gelijns AC, Parides MK, et al. Surgical ablation of atrial fibrillation during mitral-valve surgery. N Engl J Med. 2015;372(15):1399-1409. doi:10.1056/NEJMoa1500528

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