Echocardiography and 6-minute walk test in left ventricular systolic dysfunction

Abstract

Background: Chronic heart failure is a major cardiovascular disorder.

Objective: The aim of this study was to prospectively examine whether a 6-min walk test (6-MWT) result correlates with echocardiographic variables in patients with left ventricular systolic dysfunction and stable chronic heart failure.

Methods: We prospectively studied 52 patients (65% male; mean age 60+/-11 years) who had chronic heart failure secondary to ischemic heart disease or idiopathic cardiomyopathy. All patients had left ventricular systolic dysfunction (ejection fraction <or= 0.45), and were in stable NYHA class II or III heart failure. An echo-Doppler study and a 6-MWT were performed on the same day.

Results: 6-MWT had moderate, but statistically significant correlation with end-systolic diameter (ESD) (r=-0.46; p=0.0006), with shortening fraction-SF (r=0.52; p=0.0001), and with ejection fraction-EF (r=0.5; p=0.0001), whereas it had poor, but statistically significant correlation with myocardial performance index-MPI (r=-0.39; p=0.0046), E/A(tricuspid) ratio (r=-0.333; p=0.016), pulmonary acceleration time (r=0.328; p=0.018), and lateral long axis amplitude (r=0.283; p=0.04). Linear regression model demonstrated that age (chi2=-0.59, p=<0.001), restrictive transmitral filling pattern (chi2=-0.44, p=0.004) and left ventricular end-systolic dimension (chi2=-0.34, p=0.012) were independent factors that influenced the 6-MWT.

Conclusion: In patients with heart failure due to left ventricular systolic dysfunction, the 6-MWT as a clinical assessment tool of the functional capacity has a significant correlation with the most important global LV systolic function parameters, as well as with LV MPI. In patients with LV systolic dysfunction, age, restrictive transmitral filling pattern, and left ventricular systolic dimension, were independently associated with the 6-MWT.