CORONARY VASCULAR REACTIVITY IS ABNORMAL IN PATIENTS WITH CHAGAS HEART-DISEASE

Symptoms of myocardial ischemia, such as chest pain (sometimes with an ginal features), acute myocardial infarction, and segmental wall motio n abnormalities (including left ventricular apical aneurysm), frequent ly occur in patients with Chagas' heart disease, Because these clinica l findings occur in the presence of normal coronary arteries, it is po ssible that an abnormality of the coronary vascular reactivity could b e present in these patients. Therefore the current study was undertake n to determine whether endothelium-dependent coronary vasodilation is abnormal in Chagas' heart disease, Coronary endothelial function was a ssessed by infusing the endothelium-dependent vasodilator acetylcholin e (10(-8) to 10(-6) mol/L) and the endothelium-independent vasodilator adenosine (10(-4) mol/L) into the left anterior descending coronary a rtery of nine patients (age 43 +/- 4 years) with Chagas' heart disease , Coronary blood flow was measured with a Doppler flow velocity cathet er and by quantitative coronary cineangiography. The left ventricular ejection fraction was 39% +/- 5%; eight patients had a left ventricula r apical aneurysm; and one had an area of anteroapical hypokinesis, An impairment of the endothelium-dependent coronary vasodilation was dem onstrated by a reduction in coronary blood flow of 41.2% +/- 12.8% pro duced by the infusion of acetylcholine at 10(-6) mol/L and by a blunte d but preserved increase in coronary blood flow of 114.6% +/- 65.0% wi th the infusion of adenosine at 10(-4) mol/L (p = 0.03). In conclusion , patients with Chagas' heart disease have an abnormality of the coron ary endothelium-dependent vasodilation, and this abnormality may play a role in their chest pain syndrome and in the development of segmenta l wall motion abnormalities,