Angina pectoris caused by coronary microvascular spasm.

Presents research which tested the hypothesis that primary hyperconstriction, or spasm, of coronary microvessels causes myocardial ischemia at rest. Microvascular angina occurring both at rest and during exercise; Role of reduced vasodilator capacity of coronary microvessels; Methods; Findings; Conclusion that coronary microvascular spasm and resultant myocardial ischemia may cause chest pain in some angina.