Potential Maintenance Mechanism in Atrial Fibrillation Patients Subject to Different Treatment Procedures: A Preliminary Study Based on a Human Atrial Model

Abstract

Two clinical ablation protocols, 2C3L and stepwise, have been routinely used in our group to treat atrial fibrillation (AF), but with a less than 60% long-term arrhythmia-free outcome achieved in patients. The goal of this study was to examine the underlying mechanism of low success in clinical outcome. MRI images from one patient were used to reconstruct a human atrial anatomical model, and fibrotic tissue was manually added to represent the arrhythmia substrate. AF was induced with standard protocols used in clinical practice. 2C3L and stepwise were then used to test the efficacy of arrhythmia termination in our model. The results showed that re-entries induced in our model could not be terminated by using either 2C3L or the stepwise protocol. Although some of the induced re-entries were terminated, others emerged in new areas. Ablation using only the 2C3L or stepwise method was not sufficient to terminate all re-entries in our model, which may partially explain the poor long-term arrhythmiafree outcomes in clinical practice. Our findings also suggest that computational heart modelling is an important tool to assist in the establishment of optimal ablation strategies.

Keywords

computational modelling / atrial fibrillation / atrial ablation / 2C3L / stepwise

References

[1] ChungMK. Current clinical issues in atrial fibrillation. Cleve Clin J Med, 2003, 70(3): S6-S11

[2] SavelievaI, CammAJ. Atrial pacing for the prevention and termination of atrial fibrillation. Am J Geriatr Cardiol, 2002, ll(6): 380-398

[3] GoAS, HylekEM, PhillipsKA, et al.. Prevalence of diagnosed atrial fibrillation in adults: national implications for rhythm management and stroke prevention: the Anticoagulation and Risk Factors in Atrial Fibrillation (ATRIA) Study. JAMA, 2001, 285(18): 2370-2375

[4] CalkinsH, HindricksG, CappatoR, et al.. 2017 HRS/ EHRA/ECAS/APHRS/SOLAECE expert consensus statement on catheter and surgical ablation of atrial fibrillation. Heart Rhythm, 2017, 14(10): e275-e444

[5] DongJZ, SangCH, YuRH, et al.. Prospective randomized comparison between a fixed '2C3L' approach vs. stepwise approach for catheter ablation of persistent atrial fibrillation. EP Europace, 2015, 17(12): 1798-1806

[6] RuchatP, DangL, ViragN, et al.. A biophysical model of atrial fibrillation to define the appropriate ablation pattern in modified maze. Eur J Cardiothorac Surg, 2007, 31(1): 65-69

[7] ReumannM, BohnertJ, SeemannG, et al.. Preventive ablation strategies in a biophysical model of atrial fibrillation based on realistic anatomical data. IEEE Trans Biomed Eng, 2008, 55: 399-406

[8] GongY, GaoY, LuZ, et al.. Preliminary simulation study of atrial fibrillation treatment procedure based on a detailed human atrial model. J Clin Trial Cardiol, 2015, 2(4): 1-9

[9] DengD, JiaoP, YeX, et al.. An image-based model of the whole human heart with detailed anatomical structure and fiber orientation. Comput Math Methods Med, 2012, 2012: 891070

[10] CourtemancheM, RamirezRJ, NattelS. Ionic mechanisms underlying human atrial action potential properties: insights from a mathematical model. Am J Physiol, 1998, 275: H301-H321

[11] GongY, XieF, SteinKM, et al.. Mechanism underlying initiation of paroxysmal atrial flutter/atrial fibrillation by ectopic foci: a simulation study. Circulation, 2007, 115(16): 2094-2102

[12] ZahidS, CochetH, BoylePM, et al.. Patient-derived models link re-entrant driver localization in atrial fibrillation to fibrosis spatial pattern. Cardiovasc Res, 2016, 110(3): 443-454

[13] WhiteleyJP. An efficient numerical technique for the solution of the monodomain and bidomain equations. IEEE Trans Biomed Eng, 2006, 53(11): 2139-2147