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Mr Punjabi Prakash
Mr Nawaz M Asghar
Minimally invasive surgical techniques replicating the surgical maze for treatment of lone atrial fibrillation (LAF) - atrial fibrillation in the absence of heart disease, allow quick, effective intervention on a beating heart, superior to catheter intervention in creating transmural lesions.
Atrial fibrillation (AF) is the most common supraventricular tachyarrhythmia. It holds a five-fold risk of stroke and has important associated costs (1). Atrial fibrillation affects 1-2% of the general population and escalates to almost 15% in the eighth decade of life. Lone atrial fibrillation is AF in the absence of heart disease (while lone atrial fibrillation in the absence of any disease is termed "idiopathic"). Lone atrial fibrillation is more prevalent in younger males and is either paroxysmal, persistent or permanent. Its natural history still remains uncertain, so it is a diagnosis of exclusion, which should only be made after vigilant clinical assessment complete with ECG, Echocardiogram (echo) and TFTs (thyroid function tests) results. In LAF and idiopathic AF, atrial foci functioning as triggers are generally localised in the pulmonary veins (PVs). Various factors are involved in the onset, perpetuation and relapse of LAF. Autonomic disturbances hold the most profound links to lone atrial fibrillations, and trigger factors include hyperthyroidism, diabetes, genetic predisposition, obesity, sleep apnea, metabolic disturbances, alcoholism and mood disorder (2). Treatment is aimed at symptom relief and prevention of thromboembolic complications. A trial of medical therapy and/or percutaneous ablation may be offered prior to surgical intervention. Regular follow up with evaluation of cardiovascular risk factors is necessary in all lone atrial fibrillation patients.
Surgical treatment modality is contingent on a number of individual factors: type and duration of AF, LA size and degree of atrial remodeling. These factors will help to determine the suitability and success of the intervention. A summary of the main indications for surgical intervention in LAF are as follows.
Altogether, surgery is the mainstay for LAF refractory to medical therapy and/or failed catheter based intervention(s). Although standalone surgical intervention has not yet become a standard practice, it is progressively increasing in numbers. Indeed, surgery:
The original cut and sew Maze procedure is very difficult and time consuming. In order to make the procedure simpler, easier to perform and with advent of technology, investigators developed modifications. Kress et al have endorsed one such left atrial lesion set for the treatment of atrial fibrillation (7) as shown below. Fig. 1. LA Maze procedure: The broken lines represent ablative lesions made by an alternative energy source The exceptional results of Cox-Maze procedure mark it the gold standard, amid 75-95% success rate and freedom from AF up to 15 years. Mokadam et al in their multicenter trial of the Cox-Maze IV procedure revealed comparable outcomes as 96% of patients were free of AF at 6 months alongside zero operative mortality (8).
Niv Ad et al demonstrated a near 15% improvement in left ventricular (LV) function within 6 weeks following surgical restoration to SR in patients with poor pre operative LV function (i.e. ejection fraction (EF) <40%). Physical functioning health related quality of life scores improved with no stroke at 12 months with 19% of subjects having undergone stand-alone Cox-Maze for LAF (9). Video-assisted interventions Video-assisted interventions have been shown to result in a higher rate of conversion to SR and lower operative risks (10). Numerous studies have confirmed the safety and efficacy of bilateral, video-assisted, thoracoscopic pulmonary vein (PV) isolation with excision of the LAA (11). Sagbas et al evaluated the feasibility of a new off-pump technique of bilateral thoracoscopic pulmonary vein (PV) isolation for LAF, finding it safe and 100% effective for paroxysmal LAF (12).
Post operative antiarrhythmic and anticoagulants are continued for at least 3 months and up to 12 months./ They are subsequently withdrawn on maintenance of SR based on clinical, ECG, and echocardiographic assessment at 3, 6 and 12-month follow-ups (1). The surgical approach may, in some cases be ineffective as certain patients with post-operative residual or recurrent LAF may need antiarrythmics for rate control or maintenance of sinus rhythm beyond the initial post operative period. In the absence of prospective, randomised controlled trials in patients with LAF, definitive guidelines are still being developed.
(1). A. J. Cam et al., Guidelines for the management of atrial fibrillation. European Society of Cardiology, Eur Heart J 2010;31:2369-2429. (2). A.S. Gami, D.O. Hodge and R.M. Herges et al., Obstructive sleep apnea, obesity, and the risk of incident atrial fibrillation, J Am Coll Cardiol 49 (2007), pp. 565–571. (3). Bleeding during antithrombotic therapy in patients with atrial fibrillation. TheStroke Prevention in Atrial Fibrillation Investigators. Arch Intern Med 1996; 156:409.(4). Khasnis A, Jongnarangsin K, Abela G, et al: Tachycardia-induced cardiomyopathy: A review of literature. Pacing Clin Electrophysiol 2005; 28:710 (5). Prasad SM, Maniar HS, Camillo CJ, et al: The Cox Maze III procedure for atrial fibrillation: Long-term efficacy in patients undergoing lone versus concomitant procedures. J Thorac Cardiovasc Surg 2003; 126:1822. (6). Kamohara K, Kiyatoka F, Gillinov AM. Stroke prevention by means of epicardial occlusion of the left atrial appendage J Thorac Surg 2006;132:208 (7). D.C. Kress, D. Krum, V. Chekanov, et al. Validation of a left atrial lesion pattern for intraoperative ablation of atrial fibrillation. Annals of Thoracic Surgery 2002; 73:1160-8 (8). Mokadam NA, McCarthy PM, Gillinov AM, et al: A prospective multicenter trial of bipolar radiofrequency ablation for atrial fibrillation: Early results. Ann Thorac Surg 2004; 78:1665. (9). Niv Ad, Linda Henry and Sharon Hunt, The impact of surgical ablation in patients with low ejection fraction, heart failure, and atrial fibrillation. Eur J Cardiothorac Surg 2011;40 (10). Cui Y, Li Y, Gao F et al., Video-assisted minimally invasive surgery for lone atrial fibrillation: A clinical report of 81 cases, J Thorac Cardiovasc Surg 2 (2010), pp 326-332 (11). J.-G. Wang, Y. Li, J.-H. Shi, J. Han, Y.-Q. Cui, T.-G. Luo, and X. Meng. Treatment of long-lasting persistent atrial fibrillation using minimally invasive surgery combined with irbesartan. Ann. Thorac. Surg., 2011; 91(4): 1183 - 1189.(1):70-76 (12). Sagbas E, Akpinar B, et al., Video-assisted bilateral epicardial pulmonary veinisolation for the treatment of lone atrial fibrillation, Ann thorac surg 5 (2007), pp 1724-1730.
M. Asghar Nawaz MRCS, FCPS, P. Punjabi MS, FRCS Cardiothoracic surgery, Imperial College NHS healthcare, Hammersmith Hospital London, UK The authors have no conflicting interests to declare.
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