1. Autonomic modulation impacts conduction velocity dynamics and wavefront propagation in the left atrium.
- Author
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Honarbakhsh S, Roney C, Horrach CV, Lambiase PD, and Hunter RJ
- Subjects
- Humans, Female, Male, Middle Aged, Aged, Action Potentials, Catheter Ablation, Atrial Remodeling, Heart Rate, Electrophysiologic Techniques, Cardiac, Autonomic Nervous System physiopathology, Atrial Function, Left, Isoproterenol pharmacology, Atropine pharmacology, Time Factors, Heart Conduction System physiopathology, Treatment Outcome, Atrial Fibrillation physiopathology, Atrial Fibrillation surgery, Heart Atria physiopathology, Heart Atria innervation, Fibrosis
- Abstract
Aims: Atrial fibrosis and autonomic remodelling are proposed pathophysiological mechanisms in atrial fibrillation (AF). Their impact on conduction velocity (CV) dynamics and wavefront propagation was evaluated., Methods and Results: Local activation times (LATs), voltage, and geometry data were obtained from patients undergoing ablation for persistent AF. LATs were obtained at three pacing intervals (PIs) in sinus rhythm (SR). LATs were used to determine CV dynamics and their relationship to local voltage amplitude. The impact of autonomic modulation- pharmacologically and with ganglionated plexi (GP) stimulation, on CV dynamics, wavefront propagation, and pivot points (change in wavefront propagation of ≥90°) was determined in SR. Fifty-four patients were included. Voltage impacted CV dynamics whereby at non-low voltage zones (LVZs) (≥0.5 mV) the CV restitution curves are steeper [0.03 ± 0.03 m/s ΔCV PI 600-400 ms (PI1), 0.54 ± 0.09 m/s ΔCV PI 400-250 ms (PI2)], broader at LVZ (0.2-0.49 mV) (0.17 ± 0.09 m/s ΔCV PI1, 0.25 ± 0.11 m/s ΔCV PI2), and flat at very LVZ (<0.2 mV) (0.03 ± 0.01 m/s ΔCV PI1, 0.04 ± 0.02 m/s ΔCV PI2). Atropine did not change CV dynamics, while isoprenaline and GP stimulation resulted in greater CV slowing with rate. Isoprenaline (2.7 ± 1.1 increase/patient) and GP stimulation (2.8 ± 1.3 increase/patient) promoted CV heterogeneity, i.e. rate-dependent CV (RDCV) slowing sites. Most pivot points co-located to RDCV slowing sites (80.2%). Isoprenaline (1.3 ± 1.1 pivot increase/patient) and GP stimulation (1.5 ± 1.1 increase/patient) also enhanced the number of pivot points identified., Conclusion: Atrial CV dynamics is affected by fibrosis burden and influenced by autonomic modulation which enhances CV heterogeneity and distribution of pivot points. This study provides further insight into the impact of autonomic remodelling in AF., Competing Interests: Conflict of interest: R.J.H. has received research grants, educational grants, and speaker’s fees from Biosense Webster, Medtronic, and Abbott. P.D.L. receives speaker fees and research grants from Medtronic, Abbott, and Boston Scientific. S.H. has received speaker’s fee from Abbott. S.H. and R.J.H. are shareholders in Rhythm AI Ltd. S.H. is a British Heart Foundation Clinical Intermediate Fellow and receives a grant from the British Heart Foundation., (© The Author(s) 2024. Published by Oxford University Press on behalf of the European Society of Cardiology.)
- Published
- 2024
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