highly significantp < 0.001
The ACs measured by the two observers showed a highly significant Spearman’s rank correlation with a coefficient of 0.74 (95%-CI 0.48 to 0.88, p < 0.001) and a very good ICC of 0.92. 2) Inter-Observer Agreement of the HRI In healthy individuals, the mean difference of calculated HRI-values was 0.17 (95%-CI 0.11-0.22), which is 14% of the mean (95%-CI 10-18.7%).