Elicitation of myocardial ischemia by nifedipine in a case of coronary artery fistula.

A 63-year-old woman had chest pain that worsened when nifedipine was given. She was found to have a right coronary-to-thorax angioma/fistula. Acute nifedipine administration elicited precordial symptoms, associated with ischemic changes in the inferior ECG leads and an obvious vasodilatation of the fistulous tract, suggesting that a nifedipine-induced "steal" phenomenon might be responsible for the paradoxic clinical response.