Influence of glyceryl trinitrate during supine and upright exercise in patients with angina pectoris.

Abstract

SUMMARY The clinical, electrocardiographic, and circulatory effects of 0-6 mg sublingual glyceryl trinitrate were studied at rest and during treadmill and supine bicycle exercise in 16 patients with angina pectoris. Before glyceryl trinitrate, all patients experienced angina during both exercise periods. However, the heart rate and rate pressure product at angina were higher during treadmill than during supine bicycle exercise. This is considered to be the result of diminished left ventricular volume and oxygen requirements in the upright posture.At rest after glyceryl trinitrate, systolic blood pressure fell and heart rate rose in each posture, the effects being more pronounced in the standing position. During exercise, when the rate pressure product at the onset of angina before glyceryl trinitrate was compared with the rate pressure product at the same work load after glyceryl trinitrate, there was no significant difference in either position (treadmill, 192 ± 10 vs 203 ± 9; supine, 185 ± 9 vs 182 ± 8 mmHg/min x 10-2). However, in comparison with the control values before glyceryl trinitrate, exercise duration to angina after glyceryl trinitrate increased significantly in each posture. The rate pressure product at angina after glyceryl trinitrate increased significantly in comparison with the rate pressure product at angina during the control studies in each posture. The improvement in exercise tolerance and increase in rate pressure product after glyceryl trinitrate were similar during both upright and supine exercise. This could be interpreted as evidence for the predominant influence of glyceryl trinitrate on coronay perfusion but it is possible that similar changes in ventricular volume during exercise occurred in both positions.Patients with angina pectoris have better exercise tolerance and achieve higher rate pressure products in the upright than in the supine posture (Lecerof, 1971;Bygdeman and Wahren, 1974). This probably reflects reduced left ventricular volume with resultant decrease in wall tension and myocardial oxygen requirements for any given rate pressure product in the upright posture. This is supported by the observation that left ventricular filling pressures during exertional angina are lower during upright than during supine exercise (Thadani et al., 1977). Glyceryl trinitrate, by its venous and arteriolar effects (Mason and Braunwald, 1965), reduces left ventricular volume (Burggraf and Parker, 1974) which should be more pronounced in the upright position. Thus, one might expect that

Role of short-acting nitroglycerin in the management of ischemic heart disease

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Side effects of using nitrates to treat heart failure and the acute coronary syndromes, unstable angina and acute myocardial infarction

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A Randomized, Double-Blind, Placebo-Controlled, Crossover, Dose-Ranging Multicenter Study to Determine the Effect of Sublingual Nitroglycerin Spray on Exercise Capacity in Patients with Chronic Stable Angina

“…12 A number of placebo-controlled studies have shown that the sublingual application of nitroglycerin increases exercise duration in patients with stable angina. 13–17…”