LAUSR

Several studies have shown autonomic dysfunction in early stages of Chagas disease (ChD). These alterations may be involved in the progression of the disease. The Valsalva Ratio (VR) is one of the most used tests to evaluate parasympathetic function, because it is easy and reproducible. On the other hand, the Higth Sensitive T troponin (HS-TnT) and the N-terminal pro B-type natriuretic peptide (NT-proBNP) are specific markers of myocardial damage and elevation of filling pressures, respectively. Both elevations are asociated with higher risk. The association between autonomic dysfunction and biomarker levels in ChD without evidence of structural heart affection, has been poorly studied. The aim of this study is to evaluate the presence of abnormal VR as an expression of disanutonomy in patients with Chagas without evidence of structural heart disease and its association with HS-TnT and NT-proBNP levels. A prospective study was performed, which included outpatients with positive serology for Chagas, with electrocardiogram, ergometry, holter and Doppler echocardiogram within normal parameters. The exclusion criteria were the following: history of ischemic heart disease, neurological diseases, chronic renal failure (clearence <30 ml/min), arterial hypertension and diabetes mellitus. All patients underwent a valsalva maneuver (VM), with continuous recording of the R-R interval by electrocardiogram. The VR was calculated dividing the longest RR interval after VM over the shortest RR interval during VM. Abnormal VR was considerated as a value <1.1. In addition, HS-TnT and NT-proBNP were measured in all patients. One hundred and forty four patients were included, with 45±8 years old, 44% fameles. The VR was 1.22±0.12, HS-TnT 6.44±3.8 ng/L and the NT-proBNP was 55±44 pg/ml. Abnormal VR was found in 29.1% of patients (n=42). The abnormal VR group showed a higher level of HS-TnT (8.11±3.8 versus 5.7±3.5 ng/L, p=0.0006) and higher level of NT-proBNP (78±54 versus 45±36 pg/ml, p<0.0001). In addition, the abnormal VR group presented a greater E/e'ratio (9.48±2.5 versus 7.1±1.8, p<0.0001) and greater s wave (0.08±0.02 versus 0.10±0.02 cm/sec, p=0.02). In the multivariate análisis, abnormal VR was asociated with higher HS-TnT (OR 1.22 (CI 95% 1.04–1.43), p=0.01) and higher E/e'ratio (OR 1.54 (CI95% 1.17–2.02), p=0.001), but not with NT-proBNP (p=0,09). About one third of patients with ChD without evidence of cardiopaty had autonomic dysfunction. The patients with abnormal VR had higher leves of HS-TnT and NT-proBNP, but in the multivariate analisys only the HS-TnT had associated with abnormal VR.