Relation of regional sympathetic denervation and myocardial perfusion disturbance to wall motion impairment in Chagas' cardiomyopathy

Impairment of sinus node autonomic control and myocardial perfusion disturb ances have been described in patients with chronic Chagas' cardiomyopathy. However, it is not clear how these conditions contribute to myocardial dama ge. In this investigation, iodine-123 (I-123) meta-iodobenzylguanidine (MIB G) and thallium-201 myocardium segmental uptake were studied in correlation with the severity of left ventricular (LV) dysfunction detected in various phases of Chagas' heart disease. Group I consisted of 12 subjects (43 +/- 4 years, 7 men) with no symptoms and no cardiac involvement on electrocardi ogram (ECG) or echocardiography; group II consisted of 13 patients (48 +/- 3 years, 9 men) with abnormal resting ECG and/or echocardiographic segmenta l abnormalities, and LV election fraction of greater than or equal to0.5; g roup III was comprised of 12 patients (59 +/- 3 years, 10 men) with more se vere heart disease, LV dilation, and LV election fraction of <0.5. Eighteen control volunteers (38 +/- 3 years, 9 men) were also included in the study . I-123 MIBG single-photon emission computed tomographic (SPECT) segmental uptake defects were observed in group I (33%), group II (77%), and group II I (92%). Quantitative analysis showed mean areas of reduced LV I-123-MIBG u ptake: group I was 3.7 +/- 2.1%; group II was 8.3 +/- 2.3%; and group III w as 19.0 +/- 3.3%. The differences between group I and both groups II and II I were statistically significant (p <0.001, analysis of variance test). Myo cardial perfusion defects (reversible, fixed, and paradox) were observed in group I (83%), group II (69%), and group III (83%). A marked topographic a ssociation between perfusion, innervation, and wall motion abnormalities (a ssessed by gated-SPECT perfusion studies) was observed in all the groups. D efects predominated in the inferior, posterior lateral, and apical LV regio ns. Thus, extensive impairment of cardiac sympathetic function at the ventr icular level occured early in the course of Chagas' cardiomyopathy and was related to regional myocardial perfusion disturbances, before wall motion a bnormalities, Both conditions are associated with progression of ventricula r dysfunction. (C)2000 by Excerpta Medica, Inc.