Maximal functional capacity in patients with Chagas' cardiomyopathy without congestive heart failure.
BACKGROUND
Chagas' disease is a known dilated form of cardiomyopathy. However, a great number of patients, although showing electrocardiographic (ECG) well-recognized changes, maintain normal ventricular chamber dimensions and are asymptomatic. The aim of the present study was to objectively characterize functional capacity in asymptomatic patients with Chagas' disease and normal left ventricular function.


RESULTS
Eighteen asymptomatic male patients with Chagas' disease, aged 33+/-6 years, were selected for the study. All showed ECG changes typical of the disease, as well as left ventricular fractional shortening (LVFS) greater than 0.30 on M-mode 2-dimensionally guided echocardiography. Twenty sedentary normal male patients, aged 29+/-6 years, served as controls. Both groups were submitted to ergoespirometry testing for assessment of exercise functional capacity. Patients with Chagas' disease, when compared with controls, showed lower (P < .001) maximal O2 consumption (VO2max, 24.3+/-4.2 v 37.0+/-5.4 mL x kg(-1) x min(-1) respectively); O2 pulse rate (PO2max, 10.5+/-1.4 v 15.1+/-2.5 mL/beat, respectively); maximal ventilation (VEmax, 50.1+/-13.5 v 113.0+/-17.6 L x min(-1), respectively); anaerobic threshold of maximal O2 consumption (VO2-AT, 15.8+/-3.6 v 24.6+/-4.7 mL x kg(-1) x min(-1), respectively); and maximal heart rate (HRmax, 154+/-21 v 186+/-7 beat x min(-1), respectively).


CONCLUSIONS
Asymptomatic patients with Chagas' disease, although presenting normal left ventricular systolic function at rest, display a substantial impairment of exercise functional capacity.
Mady
C
C
Heart Institute, University of São Paulo Medical School, Brazil.
Ianni
B M
BM
Arteaga
E
E
Salemi
V M
VM
de Carvalho Frimm
C
C
D000328:Adult; D016022:Case-Control Studies; D002598:Chagas Cardiomyopathy / Q000503:physiopathology*; D004562:Electrocardiography; D016552:Ergometry; D017079:Exercise Tolerance; D006329:Heart Conduction System / Q000503:physiopathology*; D006333:Heart Failure / Q000503:physiopathology; D006339:Heart Rate; D006801:Humans; D008297:Male; D010101:Oxygen Consumption; D012720:Severity of Illness Index; D013147:Spirometry; D013599:Systole; D016277:Ventricular Function, Left