A comparative study of combined radiofrequency and cryoablation versus cryoablation only in concomitant Maze IV procedure for non-paroxysmal atrial fibrillation

B. Tharoev¹, R. Sharifulin¹, S. Khrushchev², S. Zheleznev¹, M. Murtazaliev¹, D. Lovtsova¹, M. Mustaev³, A. Bogachev-Prokophiev^1
1E. Meshalkin National Medical Research Center, Novosibirsk, Novosibirsk ²Sobolev Institute of Mathematics, Novosibirsk, Novosibirsk ³Guy's and St Thomas' NHS Foundation Trust, London, England

Purpose: Concomitant Maze IV procedure is an effective surgical treatment for atrial fibrillation. However, comparative data on efficacy of the energy sources is lacking. The study objective was to compare the efficacy of combined energy ablation with cryoablation only in the setting of concomitant Maze IV procedure for non-paroxysmal atrial fibrillation.

Methods: This is a retrospective analysis of 388 patients with non-paroxysmal atrial fibrillation who underwent concomitant Maze IV procedure during routine cardiac surgery using either combined energy ablation or cryoablation only from January 2008 to December 2020. The mean age of patients was 56 years (IQR 48, 62), 60% were male, 83% of patients were in NYHA III class, median duration of atrial fibrillation was 2 years (IQR 1, 5), 6.3% had previous stroke events, 41% had hypertension, and coronary artery disease was identified in 25% of patients. There was no difference in baseline characteristics between the two groups. Mixed effect logistic regression was used to analyze the recurrence of atrial arrhythmias. Recurrent event analysis was used to analyze the rate of hospital readmissions due to rhythm disruption and to analyze the rate of strokes. Kaplan-Meier method was used to analyze survival and freedom from permanent pacemaker implantation.

Results: It was found that the odds of atrial arrhythmia recurrence in patients with non-paroxysmal atrial fibrillation increased each year after operation by 55% (OR = 1.55 [1.42; 1.68], p < 0.001) if cryoablation only modality was used. However, if combined energy source was implemented the odds then decreased by 90% (OR = 0.10 [0.037; 0.27], p < 0.001. Significantly lower rate of hospital readmissions due to rhythm disruption was observed when combined radiofrequency and cryoablation was used compared to cryoablation only (RR = 0.27, p < 0.001). No significant difference in survival, freedom from strokes, or permanent pacemaker implantation between the two groups was observed.

Conclusion: In the setting of concomitant Maze IV procedure for non-paroxysmal atrial fibrillation, combined radiofrequency and cryoablation appears to be a superior treatment modality compared to cryoablation only in achieving long-term freedom from atrial arrhythmias and in reducing arrhythmia-related hospital readmissions. However, there was no difference in survival, freedom from strokes, or permanent pacemaker implantation in the studied population.

Identify the source of the funding for this research project: None