IngentaConnect Post-Operative Atrial Fibrillation Is Influenced by Beta-Blocker ...

Authors: WORKMAN, ANTONY J.¹; PAU, DAVIDE¹; REDPATH, CALUM J.¹; MARSHALL, GILLIAN E.¹; RUSSELL, JULIE A.¹; KANE, KATHLEEN A.²; NORRIE, JOHN³; RANKIN, ANDREW C.¹

Source: Journal of Cardiovascular Electrophysiology, Volume 17, Number 11, November 2006 , pp. 1230-1238(9)

Publisher: Blackwell Publishing

Abstract:

Post-Operative AF, Beta-Blockade, and Atrial Electrophysiology.

Introduction: 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.

Methods and Results: 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.

Conclusion: 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.

(J Cardiovasc Electrophysiol, Vol. 17, pp. 1230-1238, November 2006)

Keywords: atrial fibrillation/atrial arrhythmias; cellular electrophysiology/electropharmacology; ion channels; membrane transporters

Document Type: Research article

DOI: 10.1111/j.1540-8167.2006.00592.x

Affiliations: 1: BHF Glasgow Cardiovascular Research Centre, University of Glasgow, Glasgow, UK 2: Department of Physiology and Pharmacology, University of Strathclyde, Glasgow, UK 3: Centre for Healthcare Randomised Trials, University of Aberdeen, Aberdeen, UK

The full text electronic article is available for purchase. You will be able to download the full text electronic article after payment.

$50.39 plus tax

Post-Operative Atrial Fibrillation Is Influenced by Beta-Blocker Therapy But Not by Pre-Operative Atrial Cellular Electrophysiology