Regional myocardial blood flow in patients with chest pain syndromes and normal coronary arteriograms.

Abstract

To evaluate possible disorders of regional myocardial blood flow in patients with chest pain syndromes and normal coronary arteriograms, we studied 21 patients with intracoronary injections of Xenon-133.Thirteen patients were restudied during an intervention: 6 patients received glyceryl trinitrate and 7 patients had contrast agent-induced hyperaemia.Patients were divided into 3 clinical groups: 7 patients had classic angina, 7 patients had a mixture of typical and atypical chest pain, and 7 patients had entirely atypical pain.A wide range of normal values for regional myocardial blood flow at rest was noted (41 to 128 ml/min per 100 g, with an average regional myocardial blood flow of 77 ml/min per 100 g ± 7 (mean ± SEM)).There were no significant differences between the 3 groups.With contrast hyperaemia, regional myocardial blood flow increased 164 per cent, while with glyceryl trinitrate, it decreased 31 per cent.Again, there was no statistical difference among the groups.Regional abnormalities offlow (> 15% difference between distal quadrants) were noted in 3 of 34 measurements.Two patients had heterogeneity of flow at rest by quadrant analysis but no focal perfusion abnormalities detected by functional imaging.Interestingly, both patients had positive exercise tests.Another patient had regional differences only during contrast-induced hyperaemia.Our findings suggest that most pat- ients with chest pain syndromes and normal coronary arteriograms-even those with classic angina-do not have significant measurable myocardial perfusion abnormalities.The pathophysiology of angina pectoris is usually related to myocardial ischaemia secondary to significant luminal obstruction of the proximal coronary arteries (Zoll et al., 1951).Occasionally, however, patients will present with the typical or quasi-typical symptoms of angina, yet have entirely normal coronary arteriograms and no other recog- nised cause of myocardial ischaemia (valvular heart disease, hypertension, arteritides, etc.).Some patients with typical (and even atypical) angina may also have evidence of abnormal myocardial function compatible with ischaemia-such as myocardial lactate production with stress (Arbogast and Bourassa, 1972; Boudoulas et al., 1974) and electrocardiographic ST segment depres- sion on exercise testing (Dwyer et al., 1969; Kemp et al., 1973)-others show abnormal left ventricular performance-such as a rise in left 'Supported by USPHS Grants.