Relationship between left ventricular diastolic dysfunction and six minute walk test in patients with systemic sclerosis

Objective: The six minute walk test (6MWT) is used for the assessment of functional capacity in pulmonary and cardiovascular diseases. Left ventricular diastolic dysfunction (LVDD) is the most common cardiac abnormality in systemic sclerosis (SSc). The aim of this study was to define the effect of LVDD on 6MWT parameters in patients with SSc. Methods: We studied 45 (female : male 40 : 5) SSc patients. Patients with obvious conditions that can affect 6MWT distance (6MWD) were excluded. All subjects were evaluated by 6MWT. Additionally, 6MWD of the participants was calculated as the percentage of normal predicted values. LVDD was assessed by using echocardiographic findings and classified into three categories: impaired relaxation, pseudonormal or restrictive. Results: There were 12 (27%) patients with LVDD. SSc patients with LVDD were older than SSc patients without LVDD (50 +/- 12 years vs. 41 +/- 10 years; P = 0.017). In all, the mean 6MWD was 487.9 +/- 98.3 m. The 6MWD was shorter in SSc patients with LVDD as compared to those without LVDD (438.0 +/- 94.7 m vs. 506.0 +/- 94.5 m; P = 0.039). There was significant difference between the groups regarding the percentage of the predicted 6MWD (74.1 +/- 10.1% vs. 82.8 +/- 13.1%; P = 0.041). Conclusion: The presence of LVDD alters 6MWD in SSc patients. Reduction of 6MWD in a patient with SSc should prompt the investigation of LVDD.