Introduction
Atrial fibrillation (AF) is linked to a lower chance of survival and a higher chance of having a stroke. Patients seeking mitral valve surgery have an incidence rate of 30–50%. After mitral valve surgery, only 10% of individuals get spontaneous sinus rhythm return. The current gold standard treatment for AF control is Cox-Maze III, but its degree of intricacy prevents it from being used widely. The advent of innovative tissue-ablation methods [such as radiofrequency (RF) ablation and cryoablation] and newer insights into the pathophysiological processes of AF have prompted repeated attempts to ablate AF during cardiac surgery. Both unipolar and bipolar energy sources have been used to introduce more straightforward techniques. Each of them has a unique set of benefits and disadvantages. Some of the drawbacks of unipolar RF ablation may be solved by bipolar RF ablation. In patients with paroxysmal, persistent, or permanently AF and mitral valve disease who needed surgical treatment, this study attempted to assess the clinical outcomes of adding RF modified-Maze surgery (using the Medtronic Cardioblate Surgical Ablation System) to the standard surgical care.
Patients and methods
A total of 38 patients with mostly rheumatic pathology were included in a prospective, multicenter, 6-month follow-up cohort research between November 2016 and November 2019. Only two patients had mitral valve repairs. The majority of patients (94%) required mitral valve replacement, either alone or in conjunction with other valve or coronary artery bypass surgeries. All patients had a modified-Maze technique employing a bipolar RF ablation device. The equipment was the Cardioblate BP2 irrigated RF surgical ablation system from Medtronic. The RF radiation was applied following the manufacturer’s instructions. A single burn was defined as the application of RF energy to tissue up to the energy generator showed the creation of a lesion (a ‘transmural’ indication light/label appeared on the generator display). Before administering a burn, the clamp irrigation was evaluated in accordance with manufacturer recommendations. Before continuing with additional ablation, the ablation clamp jaws were cleaned of char and blood residue after each lesion. To ensure transmurality, the same spot received two applications of the clamp. For the purpose of restoring sinus rhythm, patients were monitored.
Results
In our study, the use of this technique resulted in sinus rhythm restoration in 60.5% during the early postoperative period, whereas 34.2% had episodes of paroxysmal AF and 18.4% showed restoration of sinus rhythm later on during the follow-up period of 24 ± 2 weeks, including two (5.3%) patients with permanent pacemaker with atrial capturing and those who received cardioversions after recorded arrhythmias during follow-up with a total number of 30 (78.9%) patients who showed restoration of sinus rhythm.
Conclusion
Despite Cox-Maze procedure being the gold standard for AF ablation, left-sided RF Maze procedure is potentially an easier, practical, and promising procedure with comparable results. However, while performing this surgery, care must be exercised with patients who have left atrial hypertrophy and protracted AF. No clear cut-off numbers can be set yet owing to the small sample size in this study. Modification of the lesion sets and techniques are yet to be investigated to arrive at the best technique for ablation with reproducible results. With the current technological advances, devices that would ensure transmural lesions and simple techniques are needed.