The Importance of the Double Product in the Six-Minute Walk Test to Predict Myocardial Function

Abstract

Introduction. The Six-Minute Walk Test (6MWT) is a widely used test to measure the physical performance of patients to assess the effectiveness of treatment, to qualify for rehabilitation, and to evaluate its effects. Aim. This paper focuses on the assessment of the growth of a double product (DP) during the 6MWT and its diagnostic value in the assessment of patients with heart failure. Material and Methods. The paper has retrospective character. We analyzed medical records of 412 patients hospitalized for cardiac reasons, in whom a 6MWT was performed. The patients were divided into two groups: one with diagnosed heart failure and a control group. Results. The patients with diagnosed heart failure, compared to the control group, were characterized by a shorter walking distance and greater DP increase at equal walking intervals. After distinguishing the group with the preserved and decreased left ventricle ejection fraction, the value of the DP increase was still higher compared to the control group. The mean DP increase corresponding to one meter of walk was the only one that correlated negatively with the left ventricular ejection fraction. Conclusion. The assessment of the increase of the DP during the march test seems to be a better parameter reflecting the efficiency of the myocardium from the distance of the march.