title: Cardiac inotropic rebound effect after washout of acetylcholine is associated with electrophysiological heterogeneity in Langendorff-perfused rabbit heart.
abstract: Cardiac electrophysiological heterogeneity related to the washout of acetylcholine (ACh) remains incompletely characterized. The aim of this study was to examine whether positive cardiac inotropic action is associated with electrophysiological heterogeneity between the atrium and the ventricle after ACh perfusion and washout. Epicardial monophasic action potentials (MAPs) from the right ventricle and right atrium, as well as cardiac contractility, were recorded from isolated Langendorff-perfused rabbit hearts using MAP electrodes and a force transducer. The results indicated that rebound positive inotropic actions were induced by ACh washout with adrenaline preconditioning. This effect was accompanied by an increase in MAP amplitude (MAPA) in the right ventricle but not the right atrium. These findings indicate that cholinergic muscarinic stimulation may lead to positive cardiac inotropic action followed by changes in regional electrophysiological heterogeneity between the atrial and ventricular myocardium. Therefore, we hypothesize that electrophysiological heterogeneity is an underlying cause of arrhythmogenesis as well as hemodynamic disturbance elicited by sudden termination of vagus stimulation.
authors: Department of Physiology, Shihezi University School of Medicine, Shihezi, Xinjiang 832003, P.R. China ; Department of Cardiology, Wuxi People's Hospital Affiliated to Nanjing Medical University, Wuxi, Jiangsu 214023, P.R. China ; Institute of Cardiovascular Sciences, The University of Manchester, Manchester M13 9PL, UK.
authors: Haijian
authors: H
authors: Luo
authors: Department of Physiology, Shihezi University School of Medicine, Shihezi, Xinjiang 832003, P.R. China.
authors: Junqiang
authors: J
authors: Si
authors: Department of Physiology, Shihezi University School of Medicine, Shihezi, Xinjiang 832003, P.R. China.
authors: Fengjie
authors: F
authors: Zhang
authors: Department of Cardiology, Wuxi People's Hospital Affiliated to Nanjing Medical University, Wuxi, Jiangsu 214023, P.R. China.
authors: Zhenyu
authors: Z
authors: Yang
authors: Department of Cardiology, Wuxi People's Hospital Affiliated to Nanjing Medical University, Wuxi, Jiangsu 214023, P.R. China.
authors: Ruxing
authors: R
authors: Wang
keywords: acetylcholine; heterogeneity; rabbit heart; triggered activity; vagus nerve