Adenosine provokes myocardial ischaemia in patients with ischaemic heart disease without increasing cardiac work.

Abstract

Intravenous infusion of adenosine in patients with ischaemic heart disease (IHD) has been shown to induce chest pain and ST-depression. The aim of this study was to determine whether such myocardial ischaemia could be due to an increase in myocardial work. Thus patients with stable angina pectoris (n = 8) were randomly allocated to exercise or adenosine infusion, with a 1-h rest period before the second test. The maximal tolerable work load was 120 +/- 13 W, where all patients but one experienced typical angina pectoris. ECG revealed ST-depressions in all patients. The maximal tolerable dose of adenosine was 108 +/- 6 micrograms kg-1 min-1. All patients experienced chest pain typical of habitual angina pectoris, and all but one developed ST-depressions. During exercise there was a gradual and marked increase in the rate pressure product (RPP), in parallel with the development of ST-depression. By contrast, during infusion of adenosine there was only a minor increase in RPP (P = 0.0001). In conclusion, infusion of adenosine provokes signs and symptoms of myocardial ischaemia in patients with IHD with only a minor increase in cardiac work compared to exercise. These results are consistent with the hypothesis of a myocardial steal.