Early changes in left ventricular diastolic function and left atrial function in chagas disease identified by tissue doppler and speckle tracking

Abstract

Purpose: Up to 20 to 30% of chronic Chagas' disease patients are expected to develop the cardiac form of the disease. The identification of left ventricular (LV) diastolic dysfunction or left atrial (LA) dysfunction may yield a strategy to recognize early cardiac involvement. Our aim was to analyze these parameters in Chagas' disease patients with normal LV systolic function using new echocardiographic techniques. Methods: Echocardiograms from 52 Chagas' disease patients with the indeterminate form, 29 patients at the stage A of the cardiac form (changes limited to the electrocardiogram) and 25 controls were consecutively acquired. LV diastolic function was analyzed by interrogation of the mitral inflow, pulmonary vein flow, color M-mode flow propagation velocity, LV untwist and tissue Doppler of the mitral annulus. LA function was analyzed by real-time 3 dimensional echocardiography and LA strain (ɛ) analysis including global peak positive LA ɛ (ɛ pos peak), peak negative LA ɛ and total LA ɛ. Results: All groups presented similar age, gender distribution, chamber diameters, LV mass and LV systolic function. Diastolic dysfunction was more prevalent in stage A patients. While all controls presented normal LV diastolic function, 11.5% of the patients with the indeterminate form presented delayed relaxation and 2% pseudo-normal LV diastolic function and 35.5% of the patients at the stage A of the cardiac form presented delayed relaxation and 13.5% pseudo-normal LV diastolic function (p=0.0001). Tissue Doppler was the best index to discriminate the presence of diastolic dysfunction. E/E' ratio was progressively higher (C: 5.8±1.6; indeterminate: 7.0±1.7; stage A: 8.0±2.9; p=0.0008) and E'/A' ratio was progressively lower (C: 1.5±0.3; indeterminate: 1.2±0.5; stage A: 1.0±0.3; p=0.0004) from controls towards stage A patients. LA volumes were higher in stage A patients than in controls, but LA emptying fractions did not differ among the groups. LA ɛ pos peak was lower in stage A patients (15.1±4.2%) than in patients with the indeterminate form (17.9±4.8%) and controls (17.8±4.3%; p=0.02), while the other LA ɛ parameters did not differ among the groups. Conclusions: Patients with Chagas' disease and normal LV systolic function present LV diastolic dysfunction, which is more prevalent in patients at the stage A of the cardiac form. Tissue Doppler was the best index to discriminate the presence of diastolic dysfunction and routine evaluation of E'/A' ratio may enable its early recognition. Depression of LA conduit function in stage A patients was observed only by LA strain analysis.