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. Conclusion: An increase in coronary flow alters ventricular repolarisation through nitric oxide release from coronary endothelium.
|Number of pages||5|
|Journal||General Physiology and Biophysics|
|Publication status||Published - 2002|