Variant angina is angina pectoris secondary to epicardial coronary artery spasm. Symptoms include angina at rest and rarely with exertion. Diagnosis is by ECG and provocative testing with ergonovine or acetylcholine. Treatment is with calcium channel blockers and sublingual nitroglycerin.
(See also Overview of Coronary Artery Disease.)
Most patients with variant angina have significant fixed proximal obstruction of at least one major coronary artery. Spasm usually occurs within 1 cm of the obstruction (often accompanied by ventricular arrhythmia).
Diagnosis is suspected if ST-segment elevation occurs during the attack. Between anginal attacks, the ECG may be normal or show a stable abnormal pattern. Confirmation is by provocative testing with ergonovine or acetylcholine, which may precipitate coronary artery spasm. Coronary artery spasm is identified by significant ST-segment elevation or by observation of a reversible spasm during cardiac catheterization. Testing is done most commonly in a cardiac catheterization laboratory and occasionally in a coronary care unit.
Average survival at 5 yr is 89 to 97%, but mortality risk is greater for patients with both variant angina and atherosclerotic coronary artery obstruction. Usually, sublingual nitroglycerin promptly relieves variant angina. Calcium channel blockers may effectively prevent symptoms. Theoretically, beta-blockers may exacerbate spasm by allowing unopposed alpha-adrenergic vasoconstriction, but this effect has not been proved clinically.
Oral drugs most commonly used are calcium channel blockers:
In refractory cases, amiodarone may be useful. Although these drugs relieve symptoms, they do not appear to alter prognosis.