Introduction
Atrial fibrillation (AF) is the most common sustained cardiac arrhythmia, with prevalence estimates increasing globally over the last decade.[1] Patients with AF have significant morbidity and mortality secondary to symptoms detrimental to quality-of-life, hemodynamic compromise, and embolic stroke.[1,2] Many treatment modalities have been used to reduce the global burden of this disease, including antiarrhythmic drugs (AADs), catheter-based ablation, and surgical ablation (SA).
While relatively ubiquitous in clinical practice, medical management with AADs has had poor efficacy and has been associated with significant adverse side effects.[3–6] Given advances in percutaneous interventional techniques, catheter-based ablations have been utilized more frequently, and have had excellent success rates, particularly in patients with paroxysmal AF.[6] However, even the best outcomes in published series have only shown 52% freedom from AF at 10 years.[7] In addition, these studies have shown that patients with long-standing persistent AF tend to have inferior freedom from recurrent atrial tachyarrhythmias (ATAs) when compared to those patients with paroxysmal AF.[6–10]
The Cox-Maze procedure was introduced in 1987, and was the first successful interventional treatment for AF.[11] Since then, a multitude of different surgical techniques have been developed, utilizing a variety of lesion sets and ablation technologies. However, the most-effective SA technique has remained the Cox-Maze procedure.[11] While initial “cut-and-sew” iterations of this technique were time-intensive and complex due to need to create multiple incisions in the atrial myocardium, the introduction of bipolar radiofrequency ablation and cryoablation has simplified the procedure significantly.[12] This has led to the development of the Cox-Maze IV procedure (CMP-IV).[13,14] The CMP-IV has excellent efficacy as shown by our group and others[15–17], with 77% freedom from ATAs at 10 years[18]. The late survival benefit associated with concomitant CMP-IV has also been well-established.[19] Most importantly, it has sharply reduced both operative times and complication rates, leading to more widespread adoption of surgical ablation, particularly in patients referred for concomitant cardiac surgery.[12,19,20]
While used most commonly in the setting of other concomitant cardiac surgery (e.g. mitral valve repair or replacement), the Cox-Maze IV has been shown to be efficacious and safe as a stand-alone procedure.[21,22] Our group has previously shown equal efficacy of the stand-alone CMP-IV in restoring sinus rhythm (SR) amongst patients with paroxysmal and non-paroxysmal AF at early follow-up. Few studies have described outcomes at late follow-up in sizable cohorts of patients.[21–23] This study examined our early-, mid-, and late-term outcomes of the stand-alone CMP-IV amongst 174 consecutive patients with long-standing persistent AF. This group was selected for analysis because it is recognized to be the most difficult to treat, and it is the most commonly referred for surgical ablation.[15]