title: Locations of ectopic beats coincide with spatial gradients of NADH in a regional model of low-flow reperfusion.
abstract: We studied the origins of ectopic beats during low-flow reperfusion after acute regional ischemia in excised rat hearts. The left anterior descending coronary artery was cannulated. Perfusate was delivered to the cannula using an high-performance liquid chromatography pump. This provided not only precise control of flow rate but also avoided mechanical artifacts associated with vessel occlusion and deocclusion. Optical mapping of epicardial transmembrane potential served to identify activation wavefronts. Imaging of NADH fluorescence was used to quantify local ischemia. Our experiments suggest that low-flow reperfusion of ischemic myocardium leads to a highly heterogeneous ischemic substrate and that the degree of ischemia between adjacent patches of tissue changes in time. In contrast to transient ectopic activity observed during full-flow reperfusion, persistent ectopic arrhythmias were observed during low-flow reperfusion. The origins of ectopic beats were traceable to areas of high spatial gradients of changes in NADH fluorescence caused by low-flow reperfusion.
authors.affiliation: Department of Pharmacology and Physiology, George Washington University, 2300 Eye Street NW, Washington, DC 20037, USA.
authors.forename: Matthew
authors.initials: M
authors.lastname: Kay
authors.forename: Luther
authors.initials: L
authors.lastname: Swift
authors.forename: Brian
authors.initials: B
authors.lastname: Martell
authors.forename: Ara
authors.initials: A
authors.lastname: Arutunyan
authors.forename: Narine
authors.initials: N
authors.lastname: Sarvazyan
mesh_terms: D000818:Animals; D018780:Body Surface Potential Mapping / Q000379:methods; D005117:Cardiac Complexes, Premature / Q000209:etiology* / Q000401:mortality / Q000503:physiopathology; D002851:Chromatography, High Pressure Liquid / Q000295:instrumentation; D003326:Coronary Circulation; D004195:Disease Models, Animal; D005453:Fluorescence; D006339:Heart Rate; D008297:Male; D008564:Membrane Potentials; D017202:Myocardial Ischemia / Q000150:complications / Q000378:metabolism / Q000503:physiopathology*; D009206:Myocardium / Q000378:metabolism*; D009243:NAD / Q000378:metabolism*; D010477:Perfusion / Q000295:instrumentation; D010496:Pericardium / Q000503:physiopathology; D051381:Rats; D017207:Rats, Sprague-Dawley; D012107:Research Design; D013997:Time Factors
chemical_list: D009243:NAD