OBJECTIVES: In our study we examined the physical activity of patient suffering from heart failure with Actigraph GT3X+ movement sensor simultaneously with the implanted CRT device to validate the internal sensors, and estimate the result of the physical performance reached in the 6-minute walking test (6MWT) based on the Patient Activity% (PA%).

METHODS: Biotronik CRT-P or CRT-D was implanted in all patients with heart failure included in the study. The 6MWT and the physical activity data from CRT-P or CRT-D and Actigraph were collected. The patients wore the Actigraph for a week (29.09.2018-10.10.2019), and the Home Monitoring data collection covered a year (01.07.2018-01.07.2019). SPSS 23 statistical package and Excel program were used for data processing. We used descriptive statistics, correlation analysis, Bland–Altman test and linear regression to evaluate the findings.

RESULTS: The Bland-Altman plots showed furthermore that there is correlation between the mean and the difference, with higher means resulting in larger (negative) differences (R2=0.109; F=4.665; p=0.037; Beta=-0.362; p=0.037) between the Actigraph GT3X+ and the built-in device activity datas. Compared the physical activity time spent in a day’s % from the Actigraph versus the results of 6MWT, where a moderate significant correlation among the variables (r=0.338; 0.031) was found. The analysis of the 6MWT and the PA% data revealed correlation with a linear regression (F= 6.126; p= 0.018). With this regression equation the assessing distance of the 6MWT can be estimated.

CONCLUSIONS: Based on the statistical analysis we found negative correlation in mean differences between the accelerometer PA% and built-in device’s PA%, which supports the fact that the physical activity was slightly overestimated by the built-in PA%. Based on this fact, further investigation is required about the CRT device's accelerometer and that of the PA%. The PA% result is applicable in estimating the walking distance of 6MWT.