Left ventricular diastolic function and exercise capacity in patients with Chagas cardiomyopathy

Parameters of diastolic function have been shown to correlate with exercise capacity (EC) in individuals with impaired left ventricular (LV) systolic function. However, the role of LV diastolic function in predicting EC in Chagas cardiomyopathy has not been reported.

This study aimed to determine the relationship between LV diastolic parameters assessed by echocardiography and EC in patients with Chagas cardiomyopathy.

We studied 40 patients (23 men; 49 + or - 8 years), with diagnosis of Chagas disease and dilated cardiomyopathy. Medical therapy was individually adjusted according to standardized guidelines. Methods of acquiring two-dimensional Doppler, tissue Doppler imaging (TDI), and their measurements were described. Exercise testing was performed by a Bruce protocol. Brain natriuretic peptide (BNP) levels were also determined.

Most patients (63%) were in NYHA functional class I. Mean peak oxygen consumption estimated (peakVO(2)) was 31.7 + or - 10.2 mL/kg per minute, and mean left ventricular ejection fraction (LVEF) was 36.3 + or - 7.8%. Univariate analysis showed that various echocardiographic parameters of diastolic function were correlated with peakVO(2). There was no correlation between BNP levels or LVEF and EC. Multivariate analysis, after adjustment for age and gender, revealed that E/E' ratio and left atrial volume (LAV), emerged as independent predictors of EC, as demonstrated in the model: peakVO(2)= 60.825 + (0.439 x LAV) - (1.620 x E/E' ratio) - (0.483 x age) - (4.821 x female gender). The R(2) of this model was 0.52.

Functional capacity assessed by peakVO(2) was related to increase LV filling pressures, independently on systolic function in patients with Chagas cardiomyopathy. (Echocardiography 2010;27:519-524).