• Coronary Vessels
• Echocardiography

A clinical diagnosis of suspected angina that is accompanied by non-obstructive epicardial coronary artery disease is not uncommon, as evidenced by results from contemporary registries and trials of anatomical testing in chest pain. The basket labelled as angina with non-obstructive coronary artery disease (ANOCA—the clinical syndrome that may or may not accompany ischaemia with non-obstructive coronary artery disease (INOCA)) contains heterogeneous pathophysiological entities which vary in clinical presentation and adjunctive investigation findings.1 One distinct entry in this field is vasospastic angina, a dynamic phenomenon with characteristic symptoms that differ from those induced by fixed epicardial coronary artery stenoses. Although the seminal case series which provided the eponymous nomenclature for this clinical syndrome was published well before many (probably most) readers of Heart were born, attempts to codify and standardise definitions for vasospastic angina have only recently been promulgated.2 The syndrome is seen in only a small proportion of patients with chest pain, with correspondingly limited sections in current guidelines. 3 4 The diagnostic process can be difficult and the clinical course uncertain. The latter is salient, since, although long-term prognosis is thought to be favourable, there is of course a subset of patients who accrue future adverse events.5

The pathophysiology of coronary vasospasm is still somewhat opaque, but proposed mechanisms, which are unlikely to be discrete and independent, include vascular smooth muscle cell hypercontractility, endothelial dysfunction, low-grade inflammation, oxidative stress, …