Myocardial Energy Response to Glyceryl Trinitrate: Physiology Revisited.
Watson WD., Green PG., Valkovič L., Herring N., Neubauer S., Rider OJ.
Objective: Although intravenous nitrates are commonly used in clinical medicine, they have been shown to increase myocardial oxygen consumption and inhibit complex IV of the electron transport chain. As such we sought to measure whether myocardial energetics were impaired during glyceryl trinitrate (GTN) infusion. Methods: 10 healthy volunteers underwent cardiac magnetic resonance imaging to assess cardiac function and 31phosphorus magnetic resonance spectroscopy to measure Phosphocreatine/ATP (PCr/ATP) ratio and creatine kinase forward rate constant (CK kf ) before and during an intravenous infusion of GTN. Results: During GTN infusion, mean arterial pressure (78 ± 7 vs. 65 ± 6 mmHg, p