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https://hdl.handle.net/2440/134730
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Type: | Journal article |
Title: | Autonomic Afferent Dysregulation in Atrial Fibrillation |
Author: | Malik, V. Elliott, A.D. Thomas, G. Mishima, R.S. Pitman, B. Middeldorp, M.E. Fitzgerald, J.L. Young, G.D. Roberts-Thomson, K.C. Arnolda, L.F. Lau, D.H. Sanders, P. |
Citation: | JACC: Clinical Electrophysiology, 2022; 8(2):152-164 |
Publisher: | Elsevier |
Issue Date: | 2022 |
ISSN: | 2405-500X 2405-5018 |
Statement of Responsibility: | Varun Malik, Adrian D. Elliott, Gijo Thomas, Ricardo S. Mishima, Bradley Pitman, Melissa E. Middeldorp, John L. Fitzgerald, Glenn D. Young, Kurt C. Roberts-Thomson, Leonard F. Arnolda, Dennis H. Lau, Prashanthan Sanders |
Abstract: | Objectives: This study sought to evaluate the role of cardiac afferent reflexes in atrial fibrillation (AF). Background: Efferent autonomic tone is not associated with atrial remodeling and AF persistence. However, the role of cardiac afferents is unknown. Methods: Individuals with nonpermanent AF (n ¼ 48) were prospectively studied (23 in the in-AF group and 25 in sinus rhythm [SR]) with 12 matched control subjects. We performed: 1) low-level lower body negative pressure (LBNP), which decreases cardiac volume, offloading predominantly cardiac afferent (volume-sensitive) low-pressure baroreceptors; 2) Valsalva reflex (predominantly arterial high-pressure baroreceptors); and 3) isometric handgrip reflex (both baroreceptors). We measured beat-to-beat mean arterial pressure (MAP) and heart rate (HR). LBNP elicits reflex vasoconstriction, estimated using venous occlusion plethysmography–derived forearm blood flow (f1/vascular resistance), maintaining MAP. To assess reversibility, we repeated LBNP (same day) after 1-hour low-level tragus stimulation (in n ¼ 5 in the in-AF group and n ¼ 10 in the in-SR group) and >6 weeks post-cardioversion (n ¼ 7). Results: The 3 groups were well matched for age (59 12 years, 83% male), body mass index, and risk factors (P ¼ NS). The in-AF group had higher left atrial volume (P < 0.001) and resting HR (P ¼ 0.01) but similar MAP (P ¼ 0.7). The normal LBNP vasoconstriction (-49 5%) maintaining MAP (control subjects) was attenuated in the in-SR group (-12 9%; P ¼ 0.005) and dysfunctional in the in-AF group (þ11 6%; P < 0.001), in which MAP decreased and HR was unchanged. Valsalva was normal throughout. Handgrip MAP response was lowest in the in-AF group (P ¼ 0.01). Interestingly, low-level tragus stimulation and cardioversion improved LBNP vasoconstriction (-48 15%; P ¼ 0.04; and -32 9%; P ¼ 0.02, respectively). Conclusions: Cardiac afferent (volume-sensitive) reflexes are abnormal in AF patients during SR and dysfunctional during AF. This could contribute to AF progression, thus explaining “AF begets AF.” |
Keywords: | atrial fibrillation; autonomic nervous system; isometric handgrip reflex; lower body negative pressure; low-level vagal nerve stimulation; Valsalva reflex |
Rights: | © 2022 Published by Elsevier on behalf of the American College of Cardiology Foundation. All rights reserved. |
DOI: | 10.1016/j.jacep.2021.10.010 |
Published version: | http://dx.doi.org/10.1016/j.jacep.2021.10.010 |
Appears in Collections: | Medicine publications |
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