A 58-year-old woman, referred to our hospital to undergo invasive assessment of mitral valve stenosis, demonstrated prolonged asymptomatic catheter-induced left anterior descending and right coronary artery spasm during coronary arteriography. Coronary spasms were not associated with ECG and arterial blood pressure changes. Intracoronary injection of nitroglycerin (300 and 600 micrograms bolus) did not resolve coronary spasm. Coronary angiography, repeated 24 hours later using the same procedure and materials, did not show any evidence of coronary artery spasm. The present clinical case is interesting for 3 reasons. First, the presence of prolonged proximal double-vessel coronary spasm not associated with symptoms or signs of acute myocardial ischemia; second, the incapacity of high dose of intracoronary nitroglycerin to resolve the coronary spasm; third, the dramatic changes in the sensitivity of coronary artery to mechanical stimulation in different days.