Correlation of 6 minute walk test results and low intensity exercise test to evaluation of functional capacity in heart failure patients

Abstract

Heart failure is one of the main causes of mortality of different human societies, that based on the cause of the disease to be divided into two major groups of ischemic and non-ischemic. Patients are included under investigation of functional capacity with different types of exercise test protocols for evaluation of response to receiving treatment, reviewing the quality of life and the future prospects of the disease. In this study, the results of the 6–minute walk test are compared with results of the low intensity exercise test in heart failure patients.

Methods and Materials: Seventy patients with ischemic and non-ischemic heart failure who were referred to Shahid Madani hospital in Tabriz, were selected and they were evaluated with 6-minute walk test and low intensity exercise test (Naughton protocol) and the results were recorded and analyzed by SPSS software.

Findings: At the end of this study, information of 70 patients with systolic heart failure (HFrEF) was collected, 35 patients (50%) were in NYHA functional class I and 35 patients (50%) were in NYHA functional class II. 38 patients (54.3%) were men and 32 patients (45.7%) were women. The age of patients ranged from 34 to 72 years with an average of 54.4±11.4 years. The cause of heart failure was ischemia in 40 patients (57.1%) and was non-ischemia in 30 patients (42.9%). Ejection fraction of the patients ranged from 15 to 45 % with an average of 30.2 ± 8%. The average of patients heart rate at the end of the 6-minute walk test was 119.3±11 per minute, and at the end of the low intensity exercise test was 123.4±7.9 per minute and the correlation rate of the heart rate at the end of 2 tests was r=0.81. The mean arterial pressure at the end of the 6-minute walk test was 102±14 mmhg and at the end of the low intensity exercise test was 105±8 mmhg and the correlation rate of the mean arterial pressure at the end of 2 tests was r=0.78. The arterial oxygen saturation at the end of the 6-minute walk test was 90±3.6 percent and at the end of the exercise test was 88±3 percent, and the correlation rate of the oxygen saturation at the end of 2 tests was r=0.81. The Borg Scale averaged 4.7±1.4 at the end of the 6-minute walk test and 5.5 ± 1.6 at the end of the exercise test, which was correlated with r=0.59. The average distance walked in the 6-minute walk test was 367.59±66.7 meters and the average METs that obtained in exercise test was 4.7±1.2. Finally the results obtained were related with a correlation coefficient of r=0.76.