Effect of novel modified bipolar radiofrequency ablation for preoperative atrial fibrillation combined with off-pump coronary artery bypass grafting surgery

Atrial fibrillation in patients with coronary heart disease: current state of the problem

Atrial fibrillation is one of the most common types of cardiac arrhythmia observed in clinical practice. Despite advances in the diagnosis and treatment, atrial fibrillation remains one of the leading causes of cardiovascular mortality and morbidity. In addition, atrial fibrillation is quite often combined with other pathologies of the cardiovascular system and is a marker of an unfavorable outcome. Several previous studies have demonstrated reduced survival in patients with coronary artery disease and atrial fibrillation who have not undergone surgery for arrhythmia. According to other data, the presence of preoperative atrial fibrillation among patients undergoing isolated coronary artery bypass grafting was associated with significantly higher rates of major postoperative complications. Nowadays, no one doubts the fact that atrial fibrillation during a coronary artery bypass surgery is a risk factor for increased hospital mortality, postoperative morbidity and leads to a decrease in the long-term survival. The studies confirm the necessity of surgical ablation for atrial fibrillation during coronary revascularization to reduce both short-term and long-term postoperative mortality and late complications.

The Mei mini-maze procedure

Atrial fibrillation is a common clinical arrhythmia with high morbidity and a risk of stroke. The Cox-maze IV procedure that uses radiofrequency energy for ablation is established as an effective way to eliminate atrial fibrillation. Compared to the Cox-maze IV procedure, the video-assisted Wolf mini-maze procedure is associated with reduced surgical trauma, but still requires bilateral thoracotomies, and the ablation line connecting the right and left pulmonary vein isolations cannot be created with a bipolar ablation clamp. We have developed a novel video-assisted mini-maze technique that uses a unilateral (left chest) thoracoscopic approach (the Mei mini-maze procedure).

Management of Atrial Fibrillation in Patients Undergoing Coronary Artery Bypass Grafting: Review of the Literature

Untreated atrial fibrillation is associated with an increased risk of all-cause mortality and morbidity. Despite the current guidelines recommending surgical ablation of atrial fibrillation at the time of coronary artery bypass surgery, most patients with concomitant atrial fibrillation and coronary artery disease do not receive surgical ablation for their atrial fibrillation. This review reports the efficacy of different surgical ablation techniques used for the treatment of atrial fibrillation during coronary artery bypass. PubMed was systematically searched for studies reporting outcomes of concomitant surgical ablation in coronary artery bypass patients between January 2002 and March 2018. Data were independently extracted and analyzed by two investigators. Twenty-four studies were included. Twelve studies exclusively reported outcomes of surgical ablation in patients undergoing coronary artery bypass, whereas the remaining 12 reported outcomes of concomitant cardiac surgery with subgroup analysis. Only four studies performed the concomitant Cox-Maze procedure. Freedom from atrial tachyarrhythmia was reported as high as 98% at 1 year and 76% at 5 years with Cox-Maze procedure, whereas lesser lesion sets had more variable outcomes, ranging from 35% to 93%. In most studies, the addition of surgical ablation was not associated with increased morbidity and mortality. Although the Cox-Maze procedure had the greatest short- and long-term success rates, most studies comprising the evidence documenting the safety and efficacy of adding surgical ablation were of low or moderate quality. There was a great deal of heterogeneity among study populations, follow-up times, methods, and definition of failure. To establish a consensus regarding a surgical ablation technique for atrial fibrillation in coronary artery bypass population, larger multicenter randomized controlled studies need to be designed.

Right minithoracotomy versus conventional median sternotomy for patients undergoing mitral valve surgery and Cox-maze IV ablation with entirely bipolar radiofrequency clamp

Cox-maze IV ablation by bipolar radiofrequency clamp was considered to be only performed through median sternotomy (MS), but impossible through right minithoracotomy (RM). Now, we developed a novel technique of performing Cox-maze IV ablation entirely by bipolar clamp through RM. To compare the outcomes of RM or MS for patients undergoing mitral valve surgery and concomitant Cox-maze IV ablation with entirely bipolar clamp. All 152 patients underwent mitral valve surgery and concomitant Cox-maze IV ablation with bipolar clamp through RM (n = 69) or MS (n = 83) were analyzed for outcome differences. The etiology of mitral valve disease was rheumatic (n = 97) and degenerative (n = 55). All patients had long-standing persistent atrial fibrillation (AF). Diameter of left atrium ranged from 42 to 60 mm. All patients successfully underwent Cox-maze IV ablation by bipolar clamp. RM group had longer cardiopulmonary bypass time (130.3 ± 17.7 vs 115.3 ± 14.4 min; P < 0.001) and aortic cross-clamp time (91.8 ± 12.7 vs 74.6 ± 9.3 min; P < 0.001). But mechanical ventilation time (14.2 ± 6.6 vs 21.3 ± 9.0 h; P < 0.001) and hospital length of stay (9.3 ± 2.6 vs 11.7 ± 3.0 days; P < 0.001) were shorter in RM group. At discharge, the maintenance of normal sinus rhythm (NSR) was 94.2% in RM group and 95.1% in MS group (P = 1.000). Cumulative maintenance of NSR at 2 years postoperatively was 85.1 ± 5.8% in RM group and 88.6 ± 3.6% in MS group (P = 0.767). RM can achieve similar therapeutic effect to MS for patients undergoing mitral valve surgery and concomitant Cox-maze IV ablation with entirely bipolar clamp. In addition, patients through RM had faster recovery.