Dynamic regulation of atrial coronary blood flow in healthy adult pigs.

Autor:	van Bragt KA; Department of Physiology, Faculty of Medicine, Maastricht University, The Netherlands., Nasrallah HM; Department of Physiology, Faculty of Medicine, Maastricht University, The Netherlands., Kuiper M; Department of Physiology, Faculty of Medicine, Maastricht University, The Netherlands., van Hunnik A; Department of Physiology, Faculty of Medicine, Maastricht University, The Netherlands., Kuijpers NH; Department of Physiology, Faculty of Medicine, Maastricht University, The Netherlands., Schotten U; Department of Physiology, Faculty of Medicine, Maastricht University, The Netherlands., Verheule S; Department of Physiology, Faculty of Medicine, Maastricht University, The Netherlands. Electronic address: s.verheule@maastrichtuniversity.nl.
Jazyk:	angličtina
Zdroj:	Heart rhythm [Heart Rhythm] 2015 May; Vol. 12 (5), pp. 991-1000. Date of Electronic Publication: 2015 Jan 13.
DOI:	10.1016/j.hrthm.2015.01.016
Abstrakt:	Background: There are several indications for a mismatch between atrial oxygen supply and demand during atrial fibrillation (AF), but atrial coronary flow regulation has not been investigated extensively. Objective: The purpose of this study was to characterize the dynamic regulation of atrial coronary flow in pigs. Methods: In anesthetized open-chest pigs, Doppler flow probes were placed around left atrial (LA) and left ventricular (LV) branches of the circumflex artery. Pressures and work indices were measured simultaneously. Systolic and diastolic flow contribution, flow response kinetics, and relationship between pressures, work, and flow were investigated during sinus rhythm, atrial pacing, and acute AF. Results: During atrial systole, LA flow decreased. Only 2% of total LA flow occurred during atrial systole. Pacing with 2:1 AV block and infusion of acetylcholine revealed that atrial contraction itself impeded atrial coronary flow. The response to sudden changes in heart rate was slower in LA compared to LV. Both LA and LV vascular conductance were positively correlated with work. After the cessation of acute AF, the LA showed a more pronounced phase of supranormal vascular conductance than the LV, indicating a period of atrial reactive hyperemia. Conclusion: In healthy adult pigs, atrial coronary flow is impeded by atrial contraction. Although atrial coronary blood flow is positively correlated with atrial external work, it reacts more slowly to changes in rate than ventricular flow. The occurrence of a pronounced hyperemic phase after acute AF supports the notion of a significant supply-demand mismatch during AF. (Copyright © 2015 Heart Rhythm Society. Published by Elsevier Inc. All rights reserved.)
Databáze:	MEDLINE
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