Given the prevalence, high morbidity, mortality and impaired quality of life, ischemic heart disease (IHD) is a major medical challenge. The use of myocardial revascularization techniques and of antianginal and cardioprotective drugs had an outstanding positive therapeutic impact. However, under anatomic circumstances in some patients a complete revascularization may be impossible, for example, after previous interventions or in the presence of peripheral pathology. In some patients conventional antianginal drugs, such as β-blockers, calcium-channel blockers, nicorandil (a nitrate and K+- and ATP-channel agonist), molsidomine and ivabradine either exert reduce symptoms to an insufficient extent or the therapy induces limiting side effects. Last, up to 10% of all patients with angina pectoris (mostly women) have symptoms and cardiac ischemia in the absence of significant coronary artery disease, supposedly because of microcoronary dysfunction.