Commonly referred to as Prinzmetal Angina or Variant Angina
Typically affects patients <50 yo
Associated with transient ST elevation in local distribution
Often occurs in early morning 
Mechanism is likely vagal withdrawal
Tobacco use a major risk factor (up to 75% of cases)
May be associated with migraines 
Vfib, tachycardia, and complete AV block may be associated with ischemic episodes
Coronary artery vasospasm
Acute coronary syndromes 
Anomalous coronary arteries
STEMI
Cocaine-associated chest pain
Non-STEMI
Digoxin toxicity
Unstable angina