A novel sheep model to study the effect of high rate intracoronary perfusion on cardiac electrophysiology.
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.
Wang
L
L
School of Biomedical Sciences, Charles Sturt University, Wagga Wagga, NSW, Australia. lwang@csu.edu.au
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
D019335:Nitroarginine; D009569:Nitric Oxide