Markus Rottmann
Karlsruhe Institute of Technology, Germany
Title: Dynamics of rotational and focal drivers in persistent atrial fibrillation at cardiac fibrosis -A clinical mapping and simulation study
Biography
Biography: Markus Rottmann
Abstract
Introduction: Persistent atrial fibrillation (AF) is associated with increased prevalence of atrial fibrosis. However, the role of fibrosis in arrhythmogenesis for AF is not well understood.
Methods: Clinical data of 18 patients with persistent AF and AF termination by ablation were analysed with regard to spatial relationship of AF termination sites and low voltage areas (LVA<0.5mV). For the first time, numerical simulations in 3D human atrial models assessed the impact of variable size and degree of myocardial fibrosis (DoF) on development and stability of focal and re-entrant sources in AF. Conduction velocity (CV), fiberorientation, pacing frequency and repetition of sources were analyzed.
Results: 14/18 (78%) of AF termination sites located to low voltage areas (0.5mV) and 4/18 (22%) to borderzones (<1cm distance to LVA). Simulations of persistent AF in a 3D-atrial model with regional fibrosis revealed stable (>20 AF cycles) anchoring of meandering rotational and focal sources within fibrosis (<5mm of borders). Rotational excitation wavefronts spread out from fibrosis area to healthy tissue, resulting in focal-like excitation patterns. However, the focal sources originated from variable locations around the fibrosis borders, potentially leading to beat-to-beat variabilities in the electrogram morphology. CV was 1 m/s within healthy tissue, 0.2 m/s at fibrosis > 40% and 0.4 m/s at fibrosis 30-40%. With increasing degree of fibrosis, electrogram amplitudes decreased but the cycle lengths, stability and consistency of sources increased.
Conclusions: Region of increased atrial fibrosis display low voltage amplitudes and harbour rotational and focal sources responsible
for AF.