CARDIOVASCULAR JOURNAL OF AFRICA • Volume 33, No 2, March/April 2022 60 AFRICA Outcome of concomitant left atrial ablation during valvular heart surgery: an African perspective Dambuza Nyamande, Risenga F Chauke, Siphosenkosi M Mazibuko, Shere P Ramoroko Abstract Objectives: The aim of this study was to determine the success rates of left atrial radiofrequency cardiac ablation for atrial fibrillation during heart valve surgery. Methods: This was a three-year retrospective study of 53 patients who had valve surgery and cardio-ablation. Immediate and long-term overall outcomes were analysed at three, six, nine, 12 and 24 months. The results were tested for significance by comparing to a chance outcome (50:50 probability) using the Z-test for the normal approximation of the binomial distribution. Results: A total of 56.9% of patients converted immediately to sinus rhythm, with that number increasing over time. Pre-operative poor ejection fraction was the only predictor of low success rates following ablation. Long-term rhythm was determined by the patient’s rhythm between three and six months. Conclusions: Concomitant left atrial ablation during valve surgery is effective in treating atrial fibrillation. Routine use of anti-arrhythmic medication after surgical ablation is not recommended. Keywords: atrial fibrillation, cardio-ablation Submitted 9/5/20, accepted 15/7/21 Published online 13/9/21 Cardiovasc J Afr 2022; 33: 60–64 www.cvja.co.za DOI: 10.5830/CVJA-2021-038 Atrial fibrillation is a global heart rhythm disorder, with prevalence rates in 2010 of 596.2 and 373.1 per million population for men and women, respectively.1 Of those presenting in atrial fibrillation in emergency rooms, about 2.2% in North America and 21.5% in Africa had valvular heart disease as a predisposing pathology.1 In the South African urban black population, an estimated 13% of valvular heart disease patients are complicated by atrial fibrillation.2 Cardiac ablation is a non-pharmacological treatment modality for atrial fibrillation, which is commonly done by cardiologists using catheter techniques. However, in patients with atrial fibrillation undergoing valvular heart surgery, concomitant cardiac ablation is a class IIA recommendation (American Heart Association/American College of Cardiology guidelines, 2014).3 Radiofrequency cardio-ablation during heart surgery is a commonly used modality. Since the description of the classical maze procedure in 1987 by Cox, the procedure has evolved through modifications up to the Cox IV procedure. This modification uses radiofrequency energy instead of the original cut-and-sew method. Despite several modifications, the standard maze procedure has remained a bi-atrial procedure with ablation lines on both the left and right atria.4 Cox explains the importance of bi-atrial ablation in the treatment of atrial fibrillation and atrial flutter. An isolated leftsided cardio-ablation will not produce the same high success rates for atrial fibrillation, and the non-ablated right atrium may cause an atrial flutter rhythm, according to his experimental models.4 As a result, bi-atrial cardiac ablation is regarded as the gold-standard ablation modality for atrial fibrillation and atrial flutter.5 International guidelines on atrial fibrillation treatment during valve surgery recommend a full (bi-atrial) modified maze procedure to be done whenever possible, as opposed to the lesser ablation procedures.3 However, many cardiac surgeons still perform isolated left atrial cardiac ablation, backed by several publications showing outcomes that are not inferior to the bi-atrial procedure.6 Simplicity and shorter operation times make left atrial ablation an attractive option, despite controversial results.6 Most publications on the management of atrial fibrillation are from non-African countries. The available information on non-pharmacological treatment of atrial fibrillation in Africa is from cardiologists, and is only on catheter ablation for atrial fibrillation in non-valvular heart disease.7 For the subset of patients who present for valvular heart surgery complicated by atrial fibrillation in Africa, information is needed on the outcome of either unilateral or bilateral cardio-ablation. Unilateral left atrial cardiac ablation is the treatment modality offered at Dr George Mukhari Academic Hospital, Pretoria, South Africa. This research outlines the findings of isolated left atrial radiofrequency ablation in valvular heart surgery patients in an African setting. Methods We conducted a retrospective quantitative study on 53 atrial fibrillation patients who underwent concomitant left atrial cardio-ablation during heart valve surgery between March 2013 and April 2017. The study was conducted at Dr George Mukhari Academic Hospital in Pretoria, South Africa. Ethical clearance was obtained from Sefako Makgatho Health Sciences University Research Ethics Committee (SMUREC/M/81/2018:PG). Peri-operative and at least 24-month follow-up records were obtained from hospital records. Patients were eligible if they had had pre-operative atrial fibrillation and heart valve pathology as documented by a cardiologist, concomitant left atrial ablation done during heart valve replacement(s) and/or repair, if unipolar Department of Cardiothoracic Surgery, Sefako Makgatho Health Sciences University, Ga-Rankuwa, Pretoria, South Africa Dambuza Nyamande, MB ChB, drnyamande@yahoo.com Risenga F Chauke, MMed, FC Cardio Siphosenkosi M Mazibuko, MMed, FC Cardio Shere P Ramoroko, MMed
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