BACKGROUND: Chronic Chagas Cardiomyopathy (CCC) induces early severe cardiac dysautonomia, potentially causing derangements in the regulation of coronary vasomotion and leading to myocardial ischemia and fibrosis. We assessed the correlation between dysautonomia severity and coronary artery diameter and tonus. METHODS: Eighteen patients with CCC (55±9 yrs, 8 males) and 23 normal volunteers (37±11 yrs, 16 males) were investigated. Both groups underwent evaluation of baroreflex sensitivity (BRS) by means of invasive arterial pressure (AP) monitoring and transient increases of AP induced by intravenous phenilephrinefrin injections (50-150µg). Patients with CCC had cardiac catheterization and coronary angiography at baseline and 5 min. after administration of 5mg of isosorbidedinitrate (ISDN). Quantitative coronary analysis was performed off-line for both conditions (baseline and post-ISDN). Baseline coronary artery tonus was calculated by the percent diameter increase after ISDN. LVEF was calculated by Dodge biplane method from contrast ventriculography and 2D-echocardiogram was used for the measurement of LV diastolic diameter and mass. RESULTS: CCC patients showed severe reduction of the BRS (4.1 ± 1.7 ms/mmHg) as compared to controls (15.0 ± 1.5 ms/mmHg), p < 0.001. Mean coronary artery diameter was 2.2 ± 0.3 mm, and was significantly correlated with parameters of LV remodeling: LEFF (p = 0.017, R = 0.554), LVDD (p = 0.0036, R = 0.648) and LV mass (p = 0.022, R = 0.534). No significant correlation occurred between coronary diameter and the BRS (p = 0.457, R = 0.187). Baseline coronary tonus was 13 ± 17%, without correlation with any variables, including coronary diameter (p = 0.386, R = 0.218) and BRS (p = 0.822, R = 0.057). CONCLUSIONS: Cardiac parasympathetic impairment does not seem to determine coronary artery diameter and tonus in patients with CCC.
Chagas disease; Autonomic nervous system diseases; Vasomotor system; Coronary circulation
