Mechanisms of angina pectoris in syndrome X assessed by myocardial perfusion dynamics and heart rate variability

The fundamental abnormality in syndrome X (angina pectoris, ischaemia-like stress ECG despite angiographically normal coronary arteries) might be patchily distributed increased tone in pre-arteriolar coronary vessels with compensatory release of adenosine. The aim of this study was to confirm this hypothesis and to explore its relationships with autonomic system functioning. Using parametric positron emission tomography, myocardial perfusion was examined in 480 segments in 16 syndrome X patients and 16 age- and sex-matched healthy volunteers. Autonomic function was explored by Holier monitoring of time domain parameters of heart rate variability. Compared to volunteers, both mean perfusion (123 ± 55 vs 87±16mg. min−1. 100g−1; P