Patients with Chagas' disease often have chestpain as a prominent symptom. The objective of this studywas to compare the results of intraesophageal balloondistension in chagasic and nonchagasic patients with chest pain not caused by coronaryobstruction. We studied 40 patients with chest pain andangiographically normal coronary arteries, 25 with apositive serologic test for Chagas' disease (Chagasgroup, 16 women, mean age 53 ± 10 years), and15 with a negative serologic test (control group, 11women, mean age 46 ± 10 years). All patients hadradiologic and endoscopic examinations of esophagus,stomach, and duodenum, esophageal manometry with theacid infusion test in the distal esophagus, andintraesophageal balloon distension. None of them hadesophageal dilation or any signs of cardiovasculardisease. A 25-mm-long latex balloon located 10 cm abovethe lower esophageal sphincter was inflated and deflatedover a period of 10 sec at 1-ml increments of air untilthe subjects reported chest pain or to a maximum volume of 20 ml. The test caused chest pain in14 subjects in the control group (93%) and in 12 in theChagas' disease group (48% , P < 0.05). The meanvolume of air that caused chest pain was 10 ± 3ml in the control group and 15 ± 4 ml in theChagas' disease group (mean ± SD, P < 0.05).The maximum intraesophageal pressure during theexamination was higher in Chagas' disease patients withchest pain during balloon distension (60 ± 21mm Hg) than in patients who did not have chest pain (37± 18 mm Hg, P < 0.05) and did not differ fromthe control group (48 ± 16 mm Hg, P > 0.05).With the other examinations there was no differencebetween groups or between patients with or without chestpain during the balloon distension test. Althoughesophagitis was observed in 47% of patients in the control group and in 40% of the Chagas' diseasegroup, the acid infusion test was positive in 27% ofpatients in the control group and in 4% of patients inthe Chagas' disease group. We conclude that, as compared to a group of patients with similarchest pain, chagasic patients are less sensitive toesophageal distension. Thus, it is unlikely that theirchest pain is related to esophagealmechanisms.