Is autonomic function associated with left ventricular systolic function in Chagas heart disease patients undergoing treatment for heart failure?

Introduction: The association between cardiac autonomic and left ventricular (LV) dysfunction in Chagas disease (ChD) is controversial. Methods: A standardized protocol that includes the Valsalva maneuver, a respiratory sinus arrhythmia (RSA) test, and an echocardiographic examination was used. Spearman correlation coefficients (rho) were used to investigate associations. Results: The study population consisted of 118 ChD patients undergoing current medical treatment, with an average LV ejection fraction of 51.4 +/- 2.6%. The LV ejection fraction and diastolic dimension were correlated with the Valsalva index (rho=0.358, p<0.001 and rho=-0.266, p=0.004, respectively) and the RSA (rho=0.391, p<0.001 and rho=-0.311, p<0.001, respectively). Conclusions: The impairment of LV function is directly associated with a reduction of cardiac autonomic modulation in ChD.