e323 Correspondence To the Editor:

Ong and coworkers1 reported that epicardial and microvascu-lar spasm were frequent in white patients with unobstructed coro-nary arteries and that epicardial spasm was most often diffuse and located in the distal coronary segments. They combine epicardial and microvascular spasm together as coronary spasm and speculated that epicardial spasm is probably a sign of concomitant microvascular disease.1 Their findings are interesting and in agreement with those of previous studies regarding epicardial spasm or coronary spasm.2 However, we take issue with them when they combine epicardial and microvascular spasm together as coronary spasm for the following reasons: 1. Patients with epicardial spasm or coronary spastic angina (CSA) may have preserved coronary microvascular function.3 2. Responses to Ca-channel blockers, nitrates, and β-blockers as well as risk and precipitating factors1 differ, and treatmen