Relation between cardiomyopathy and exercise capacity multicenter trial

ABSTRACT

The six-minute walk test [6MW lest] is a safe and simple method to assess exercise capacity in patients with left ventricular [LV] dysfunction. Recent studies confirmed its prognostic significance. The aim of this Study Was to identify determinants of exercise capacity in patients with LV dysfunction as assessed by 6MW test. and 116 Patients with LV dysfunction caused by ischemic heart disease or idiopathic dilated cardiomyopathy [NYHA class l-IIl] underwent 6MW test, M-mode, two dimensional and Doppler transthoracic echocardiographic studies. 115 Patients were able to perform the 6MW test. The mean distance walked was 277 +/- 114m. Univariate analysis revealed that heart rate, systolic and diastolic arterial pressures, NYHA class, left atrial size, LV myocardial mass index, end-systolic and end-diastolic volume indices, ejection fraction, isovolumic relaxation time, peak early [PE] and peak atrial [PA] wave velocities of LV diastolic filling, PE/PA ratio and deceleration nine of early filling were all significantly related lo 6MW test distance [p<0.05]. Multivariate step-wise regression analysis showed that the only independent determinants of 6 MW test distance were PA wave velocity [F to enter 192.71, multiple r=0.79], PE/PA ratio [F to enter 115.22, multiple r=-0.37], and heart rate [F to enter 80.98, multiple r=-0.12]. Doppler-derived indices of LV diastolic function [PA wave velocity and PE/PA ratio] and heart rate are the main determinants of exercise capacity in patients with LV dysfunction as assessed by 6MW test