Post-operative atrial fibrillation is influenced by beta-blocker therapy but not by pre-operative atrial cellular electrophysiology

Workman, A.J., Pau, D., Redpath, C.J., Marshall, G.E., Russell, J.A., Kane, K.A., Norrie, J. and Rankin, A.C. (2006) Post-operative atrial fibrillation is influenced by beta-blocker therapy but not by pre-operative atrial cellular electrophysiology. Journal of Cardiovascular Electrophysiology, 17(11), pp. 1230-1238. (doi: 10.1111/j.1540-8167.2006.00592.x)

Abstract

<b>Introduction:</b> We investigated whether post-cardiac surgery (CS) new-onset atrial fibrillation (AF) is predicted by pre-CS atrial cellular electrophysiology, and whether the antiarrhythmic effect of beta-blocker therapy may involve pre-CS pharmacological remodeling. <b>Methods and Results:</b> Atrial myocytes were obtained from consenting patients in sinus rhythm, just prior to CS. Action potentials and ion currents were recorded using whole-cell patch-clamp technique. Post-CS AF occurred in 53 of 212 patients (25%). Those with post-CS AF were older than those without (67 ± 2 vs 62 ± 1 years, P = 0.005). In cells from patients with post-CS AF, the action potential duration at 50% and 90% repolarization, maximum upstroke velocity, and effective refractory period (ERP) were 13 ± 4 ms, 217 ± 16 ms, 185 ± 10 V/s, and 216 ± 14 ms, respectively (n = 30 cells, 11 patients). Peak L-type Ca²⁺ current, transient outward and inward rectifier K⁺ currents, and the sustained outward current were −5.0 ± 0.5, 12.9 ± 2.4, −4.1 ± 0.4, and 9.7 ± 1.0 pA/pF, respectively (13-62 cells, 7-19 patients). None of these values were significantly different in cells from patients without post-CS AF (P > 0.05 for each, 60-279 cells, 29-86 patients), confirmed by multiple and logistic regression. In patients treated >7 days with a beta-blocker pre-CS, the incidence of post-CS AF was lower than in non-beta-blocked patients (13% vs 27%, P = 0.038). Pre-CS beta-blockade was associated with a prolonged pre-CS atrial cellular ERP (P = 0.001), by a similar degree (~20%) in those with and without post-CS AF. <b>Conclusion:</b> Pre-CS human atrial cellular electrophysiology does not predict post-CS AF. Chronic beta-blocker therapy is associated with a reduced incidence of post-CS AF, unrelated to a pre-CS ERP-prolonging effect of this treatment.

• Item Type: Articles
• Keywords: Atrial fibrillation/atrial arrhythmias; cellular electrophysiology/electropharmacology; ion channels; membrane transporters
• Status: Published
• Refereed: Yes
• Glasgow Author(s) Enlighten ID: Rankin, Professor Andrew and Workman, Dr Antony and Pau, Dr Davide
• Authors: Workman, A.J., Pau, D., Redpath, C.J., Marshall, G.E., Russell, J.A., Kane, K.A., Norrie, J., and Rankin, A.C.
• Subjects: Q Science > QP Physiology
• College/School: College of Medical Veterinary and Life Sciences > School of Cardiovascular & Metabolic Health; College of Medical Veterinary and Life Sciences > School of Medicine, Dentistry & Nursing > Clinical Specialities
• Journal Name: Journal of Cardiovascular Electrophysiology
• Publisher: Blackwell
• ISSN: 1540-8167
• Copyright Holders: Copyright © 2006 Blackwell
• First Published: First published in Journal of Cardiovascular Electrophysiology 17(11):1230-1238
• Publisher Policy: Reproduced in accordance with the copyright policy of the publisher

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