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Figure 1 Cinearteriogram frames and coronary diameter measurements in a 65-year-old man with ECG ischemic changes (from group 1 without pretreatment with an alpha₁ blocker). Coronary vasoconstriction was noted during urinary bladder distention at the stenotic segment (arrowhead), which was relieved after intracoronary nitroglycerin administration. A, Baseline. B, During bladder distention with an intravesical pressure of 20 mm Hg. C, After intracoronary injection of nitroglycerin (200 µg) with an intravesical pressure 20 mm Hg.