Postoperative atrial fibrillation: The role of the inflammatory response

OBJECTIVE: Abnormal atrial conduction has been shown to be a substrate for postoperative atrial fibrillation (POAF). This study aimed to determine the relationship between the location of the atrial reentry responsible for POAF, and degree of atrial inflammation. METHODS: Normal mongrel dogs (n = 18) were divided into 3 groups: anesthesia alone (anesthesia), lateral right atriotomy (atriotomy), and lateral right atriotomy with anti-inflammatory therapy (steroid). Conduction properties of the right and left atria (RA and LA) were examined 3 days postoperatively by mapping. Activation was observed during burst pacing-induced AF. The RA and LA myeloperoxidase activity was measured to quantitate the degree of inflammation. RESULTS: Sustained AF (\u3e2 minutes) was induced in 5 of 6 animals in the atriotomy group, but in none in the anesthesia or steroid groups. All sustained AF originated from around the RA incision. Three of these animals had an incisional reentrant tachycardia around the right atriotomy and 2 had a focal activation arising from the RA during AF. The LA activations in these animals were passive from the RA activation. The RA activation of the atriotomy group was more inhomogeneous than that of the anesthesia group (inhomogeneity index: 2.0 ± 0.2 vs 1.0 ± 0.1, P \u3c .01). Steroid therapy significantly normalized the RA activation after the atriotomy (1.2 ± 0.1, P \u3c .01). The inhomogeneity of the atrial conduction correlated with the myeloperoxidase activity (r = 0.774, P \u3c .001). CONCLUSIONS: Reentrant circuits responsible for POAF are dependent on the degree of inflammation and rotate around the atriotomy. Anti-inflammatory therapy decreased the risk of postoperative AF

The long-term outcome of patients with coronary disease and atrial fibrillation undergoing the cox maze procedure

AbstractBackgroundA significant number of patients presenting for coronary revascularization have chronic atrial fibrillation. Although the Cox maze III procedure is the gold standard for the surgical treatment of this arrhythmia, few of these patients undergo atrial fibrillation operations at the time of their coronary bypass grafting. This study examined the long-term outcome of patients with ischemic heart disease who underwent the Cox maze procedure at our institution.MethodsFrom 1990 to 2002, 47 patients undergoing operations for ischemic heart disease underwent a concomitant Cox maze III procedure. All patients underwent coronary bypass grafting, and 7 (15%) patients underwent coronary bypass grafting plus a mitral valve repair. Follow-up was performed by means of mail and telephone questionnaires with both the patients and their cardiologists. All patients who had any history of arrhythmia or who were taking medications had their rhythm documented by electrocardiogram.ResultsThe mean age of these patients was 62 ± 8 years, with a marked male predominance (45 men and 2 women). Twenty-eight (60%) of the patients had paroxysmal atrial fibrillation, and the remainder had persistent arrhythmias. The mean duration of atrial fibrillation was 7.6 ± 6.5 years. The operative mortality in this series was 2%. Nine (19%) patients required postoperative pacemakers. At last follow-up (mean of 5.7 ± 3.3 years), 98% of patients were free of atrial fibrillation.ConclusionThe Cox maze III procedure has a low operative mortality and excellent long-term efficacy in patients with ischemic heart disease. These data suggest a more widespread use of this procedure in these patients

Three-year outcomes of the postapproval study of the AtriCure Bipolar Radiofrequency Ablation of Permanent Atrial Fibrillation Trial.

OBJECTIVES: The Cox Maze IV operation is commonly performed concomitant with other cardiac operations and effectively reduces the burden of atrial fibrillation. Prospective randomized trials have reported outcomes early and at 12 months, but only single-center late durability results are available. As part of the postapproval process for a bipolar radiofrequency ablation system, we sought to determine early and midterm outcomes of patients undergoing the Cox Maze IV operation. METHODS: A prospective, multicenter, single-arm study of 363 patients (mean age, 70 years, 82% valve surgery) with nonparoxysmal atrial fibrillation (mean duration, 60 months, 94% Congestive heart failure, Hypertension, Age ≥ 75, Diabetes, Stroke, VAScular disease, Age 65-74, Sex category ≥2) undergoing concomitant Maze IV atrial fibrillation ablation at 40 sites with 70 surgeons was performed between June 2010 and October 2014. Compliance with the study lesion set was 94.5%, and 99% had left atrial appendage closure. Freedom from atrial fibrillation was determined by extended monitoring, with a 48-hour Holter monitor minimum. RESULTS: There were no device-related complications. Freedom from atrial fibrillation off antiarrhythmic medications at 1, 2, and 3 years was 66%, 65%, and 64%, respectively, and including those using antiarrhythmics was 80%, 78%, and 76%, respectively. Warfarin was used in 49%, 44%, and 40%, respectively. CONCLUSIONS: In patients with nonparoxysmal atrial fibrillation, compliance with the protocol was high, and freedom from atrial fibrillation off antiarrhythmics was high and sustained to 3 years. The safety and effectiveness of the system and Cox Maze IV procedure support the Class I guideline recommendation for concomitant atrial fibrillation ablation in patients undergoing cardiac surgery