title: A novel sheep model to study the effect of high rate intracoronary perfusion on cardiac electrophysiology.
abstract: An increase in coronary flow is known to enhance myocardial metabolism and contractility (the Gregg effect) but the effect on cardiac electrophysiology is unclear. In 5 pentobarbital-anesthetised open-chest sheep, left circumflex coronary artery was perfused with fresh arterial blood at 6 and 10 ml/min respectively in the presence of normal coronary flow. The perfusion was repeated in these animals after treatment with nitro-L-arginine, a nitric oxide synthase inhibitor. The high rate intracoronary perfusion caused a flow-dependent T wave inversion on body surface ECG in all animals (p < 0.01). Pre-treatment with nitro-L-arginine abolished T wave inversion during 6 ml/min perfusion, and diminished the T inversion during 10 ml/min perfusion.
  
  
  CONCLUSIONS
  An increase in coronary flow alters ventricular repolarisation through nitric oxide release from coronary endothelium.
authors.affiliation: School of Biomedical Sciences, Charles Sturt University, Wagga Wagga, NSW, Australia. lwang@csu.edu.au
authors.forename: L
authors.initials: L
authors.lastname: Wang
mesh_terms: D000818:Animals; D003326:Coronary Circulation / Q000187:drug effects / Q000502:physiology*; D004562:Electrocardiography; D004594:Electrophysiology / Q000379:methods*; D005260:Female; D006321:Heart / Q000187:drug effects / Q000502:physiology; D006352:Heart Ventricles / Q000187:drug effects; D007275:Injections, Intravenous; D008297:Male; D023421:Models, Animal; D009569:Nitric Oxide / Q000378:metabolism; D019335:Nitroarginine / Q000008:administration & dosage; D010477:Perfusion / Q000379:methods; D016276:Ventricular Function
chemical_list: D019335:Nitroarginine; D009569:Nitric Oxide