RESUMEN
This article describes: 1) situations that can cause angina pectoris in the absence of formal atherosclerotic obstructive lesions: a) those that cause non-atherosclerotic coronary obstructions and b) those with normal coronary angiography, among them cardiac syndrome X (CSX); 2) the various definitions of CSX, particularly the definition of true CSX by Bertrand et al.: effort anginal pain plus positive exercise test, plus a second demonstration of myocardial ischemia (e.g. abnormal myocardial scintigraphy), plus normal coronary angiography; 3) the different pathogenic mechanisms that have been proposed for CSX, which suggest that the problem is mainly at the microvascular level; 4) the excellent survival prognosis of CSX; 5) the lack of any standard therapeutic protocol.