Usefulness of the evaluation of left ventricular diastolic function changes during stress echocardiography in predicting exercise capacity in patients with ischemic heart failure

Background: Diastolic dysfunction and elevated left ventricular (LV) filling pressure at rest are key factors of exercise intolerance in patients with heart failure (HF). There are few studies, however, that have addressed the issue of changes of LV diastolic function and filling pressure during exercise in patients with HF with severe systolic dysfunction. The ratio of early diastolic velocity of mitral inflow (E) and early myocardial diastolic velocity (E') strongly correlates with invasively obtained LV filling pressure. Objective: We sought to assess dynamic changes of diastolic function, including LV filling pressure using Doppler tissue imaging, during stress echocardiography and its impact on exercise capacity in patients with ischemic HF. Methods: We studied 50 adult patients (44 male and 6 female) with a mean age of 62.9 +/- 8.8 (46-79) years, mean New York Heart Association class of 1.97 +/- 0.86, and mean ejection fraction of 28.4 +/- 9.5 (10%-45%). The following conventional and tissue Doppler parameters were measured at baseline and peak exercise during semisupine stress echocardiography (20 W, 2-minute increments): peak early (E) and late (A) diastolic velocity of the mitral inflow, E/A ratio, peak early myocardial diastolic velocity (E'), and E/E' ratio. Diastolic Doppler tissue imaging indices were derived from septal, lateral, anterior, and inferior border of the mitral annulus in the apical 4- and 2-chamber views. Simultaneously during stress echocardiography peak oxygen uptake was measured. Patients were divided into two groups according to peak oxygen uptake value: group 1 with 23 patients (<14 mL/kg/min) and group 2 with 27 patients (>= 14 mL/kg/min). Results: There were significant differences in terms of E' and E/E' ratios both at rest and peak exercise between the two groups. The best correlation with exercise capacity was E/E' at peak stress (r = -0.75, P < .0001). The most useful parameter for identifying severe exercise intolerance, as indicated by peak oxygen uptake less than 14 mL/kg/min, was E/E' at peak stress with an area under receiver operating characteristic curve of 0.92. The cut-off of 18.2 for E/E' at peak stress showed a sensitivity of 85.2% with a specificity of 95.6%. Conclusions: The evaluation of hemodynamic response of diastolic function, including LV filling pressure, during exercise is feasible during stress echocardiography and provides valuable information in predicting exercise capacity in patients with ischemic HF.