Aim: to compare clinical results of linear ablation vs. PVI approach in patients with paroxysmal AF and to estimate theoretical probability of 4-waves re-entry to eliminate as a results of the both ablative techniques formatting by means left atrial geometry two-dimensional mathematical modeling.
Material and methods: Clinical phase. Study was conducted on 20 pts (6 women, 51,4±13,6 years of age) with paroxysmal AF underwent index RFA. All pts were divided into two age-sex-arrhythmia history duration-antiarrhythmic drugs (AAD)-matched groups. The first group consisted of 10 pts (3 women, mean age - 51,1±11,9, history of arrhythmia - 3,2±1,2 years) in whom ablation strategy consisted of PVI using LASSO technique. The second group concluded of 10 pts (3 women, mean age - 51,1±12,9, history of arrhythmia- 3,1±1,1 years) in whom ablation strategy consisted of wide-area circumferential lines application around pulmonary veins, combined to roof line and mitral isthmus RFA using three-dimensional mapping system. Mathematical phase. As the first step numeric reconstruction of the autowave process in excitable tissues of the left atrium and the simulation of AF was performed. Fitzhugh-Nagumo equation was used for simulation to enabled us to take into account the electrical inhomogeneity of the atria (pulmonary vein ostia). A special scanning method was used for calculating characteristics of autowave processes in a two-dimensional mathematical model of the atrium. As the second step simulation of circular (corresponding to LASSO approach) and linear ablation (corresponding to 3D approach) was performed.
Results: Clinical phase. There were no complications associated with RFA. 7 pts of the first group vs 4 pts of the second subgroup had early recurrences of arrhythmia. AAD free sinus rhythm incidence in the first/second groups was 80%/20% at 12 months respectively (p=0,003). Mathematical phase. While circular LASSO-like ablation pattern was used, there was no elimination of 4-waves re-entry turning around the pulmonary veins ostia and vortex waves caused by them in a distributed two-dimensional atrial medium after time period equal to the re-entry period. Thus, the circular ablation formatting does not affect peripulmonary veins re-entry and, therefore, does not suppress AF. In contrast, linear ablation patterns suppress arrhythmias caused by 4-waves re-entry in two-dimensional mathematical modeling of the left atrium.
Conclusion: Mathematical approach using linear ablation to simulate suppressed 4-waves re-entry more effectively comparing to PVI only. Clinical results are consistent with ablation formatting data obtained by means of 4-waves re-entry simulation in a two-dimensional mathematical modeling of the left atrium.