Exercise capacity and quality of life (QOL) are important outcome predictors in
patients with systolic heart failure (HF), independent of left ventricular (LV)
ejection fraction (LVEF). LV diastolic function has been shown to be a better
predictor of aerobic exercise capacity in patients with systolic dysfunction and
a New York Heart Association (NYHA) classification ≥II. We hypothesized that the
currently used index of diastolic function E/e' is associated with exercise
capacity and QOL, even in optimally treated HF patients with reduced LVEF. This
prospective study included 44 consecutive patients aged 55±11 years (27 men and
17 women), with LVEF<0.50 and NYHA functional class I-III, receiving optimal
pharmacological treatment and in a stable clinical condition, as shown by the
absence of dyspnea exacerbation for at least 3 months. All patients had
conventional transthoracic echocardiography and answered the Minnesota Living
with HF Questionnaire, followed by the 6-min walk test (6MWT). In a
multivariable model with 6MWT as the dependent variable, age and E/e' explained
27% of the walked distance in 6MWT (P=0.002; multivariate regression analysis).
No association was found between walk distance and LVEF or mitral annulus
systolic velocity. Only normalized left atrium volume, a sensitive index of
diastolic function, was associated with decreased QOL. Despite the small number
of patients included, this study offers evidence that diastolic function is
associated with physical capacity and QOL and should be considered along with
ejection fraction in patients with compensated systolic HF.
OBJECTIVE:The effects of acute continuous positive airway pressure therapy on left ventricular diastolic function and functional capacity in patients with compensated systolic heart failure remain unclear.METHODS:This randomized, double-blind, placebo-controlled clinical trial included 43 patients with heart failure and a left ventricular ejection fraction <0.50 who were in functional classes I-III according to the New York Heart Association criteria. Twenty-three patients were assigned to continuous positive airway pressure therapy (10 cmH2O), while 20 patients received placebo with null pressure for 30 minutes. All patients underwent a 6-minute walk test (6MWT) and Doppler echocardiography before and immediately after intervention. Clinicaltrials.gov: NCT01088854.RESULTS:The groups had similar clinical and echocardiographic baseline variables. Variation in the diastolic function index (e′) after intervention was associated with differences in the distance walked in both groups. However, in the continuous positive airway pressure group, this difference was greater (continuous positive airway pressure group: Δ6MWT = 9.44+16.05×Δe′, p = 0.002; sham group: Δ6MWT = 7.49+5.38×Δe′; p = 0.015). There was a statistically significant interaction between e′ index variation and continuous positive airway pressure for the improvement of functional capacity (p = 0.020).CONCLUSIONS:Continuous positive airway pressure does not acurately change the echocardiographic indexes of left ventricle systolic or diastolic function in patients with compensated systolic heart failure. However, 30-minute continuous positive airway pressure therapy appears to have an effect on left ventricular diastolic function by increasing functional capacity.
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