Optimization of Catheter Ablation of Atrial Fibrillation: Insights Gained from Clinically-Derived Computer Models

Abstract

Atrial fibrillation (AF) is the most common heart rhythm disturbance, and its treatment is an increasing economic burden on the health care system. Despite recent intense clinical, experimental and basic research activity, the treatment of AF with current antiarrhythmic drugs and catheter/surgical therapies remains limited. Radiofrequency catheter ablation (RFCA) is widely used to treat patients with AF. Current clinical ablation strategies are largely based on atrial anatomy and/or substrate detected using different approaches, and they vary from one clinical center to another. The nature of clinical ablation leads to ambiguity regarding the optimal patient personalization of the therapy partly due to the fact that each empirical configuration of ablation lines made in a patient is irreversible during one ablation procedure. To investigate optimized ablation lesion line sets, in silico experimentation is an ideal solution. 3D computer models give us a unique advantage to plan and assess the effectiveness of different ablation strategies before and during RFCA. Reliability of in silico assessment is ensured by inclusion of accurate 3D atrial geometry, realistic fiber orientation, accurate fibrosis distribution and cellular kinetics; however, most of this detailed information in the current computer models is extrapolated from animal models and not from the human heart. The predictive power of computer models will increase as they are validated with human experimental and clinical data. To make the most from a computer model, one needs to develop 3D computer models based on the same functionally and structurally mapped intact human atria with high spatial resolution. The purpose of this review paper is to summarize recent developments in clinically-derived computer models and the clinical insights they provide for catheter ablation.

Three‐dimensional Integrated Functional, Structural, and Computational Mapping to Define the Structural “Fingerprints” of Heart‐Specific Atrial Fibrillation Drivers in Human Heart Ex Vivo

“…Importantly, ablation lesion sets are not reversible, so the success of different procedures can never be compared for the same patient 13, 45. The computer modeling approach is currently the only way to compare a variety of ablation strategies on the same heart and can be used for ablation planning and guidance 14, 36.…”

Maintenance of Atrial Fibrillation

“…These heart-specific computer models would present the opportunity to test multiple targeted ablation strategies for the same AF driver, as in silico ablation is uniquely reversible compared to ex-vivo and in-vivo studies 45 .…”

Fibrosis and Atrial Fibrillation: Computerized and Optical Mapping

“…(58-60) One of these studies conducted by the Trayanova group using DE-MRI based 3D models demonstrated that reentrant AF drivers are perpetuated at fibrotics boundary zones. (60) These studies clearly delineate the crucial role of patient-specific fibrosis architecture in AF initiation and maintenance; however, there is still no consensus in the field as to how atrial fibrosis should be modelled.…”

“…(58,65) However, the in-vivo low resolution of DE-MRI may mean that voxels at or just above the fibrotic threshold represent an unknown mix of myocytes, fibroblasts, and connective tissue, making the most important assumptions of the computer models less robust. Thus, integration of ex-vivo functional and structural studies may provide the most accurate submillimeter high-resolution data on the human heart in order to improve current human atrial models.…”