Vasospastic angina (Prinzmetal or variant angina) is caused by transient, severe coronary artery spasm producing transmural ischemia, typically occurring at rest (often between midnight and early morning) rather than with exertion. The spasm occurs in focal segments of epicardial coronary arteries at sites of endothelial dysfunction, involving vascular smooth muscle hyperreactivity to vasoconstrictive stimuli. During spasm, the coronary artery lumen can narrow by greater than 75%, producing transmural ischemia with ST elevation on ECG (distinguishing it from typical stable angina which causes ST depression). Risk factors include cigarette smoking (endothelial damage), cocaine use (sympathomimetic vasoconstriction), and medications that promote vasoconstriction (triptans, ergot alkaloids, beta-blockers which leave alpha-mediated vasoconstriction unopposed). Complications include acute MI (if spasm is prolonged), ventricular arrhythmias, and sudden cardiac death. The nurse recognizes the atypical presentation (chest pain at rest, often nocturnal, with ST elevation that resolves with nitroglycerin), administers sublingual nitroglycerin for acute episodes, administers calcium channel blockers (first-line prevention -- diltiazem, amlodipine) and long-acting nitrates as prescribed, avoids beta-blockers (can worsen spasm by leaving alpha-mediated coronary vasoconstriction unopposed), educates about smoking cessation and avoidance of...