Table 3. Inter-observer variability.

	Pearson correlation		Intra-class coefficient		Bland-Altman
	r (95% CI)	p	ICC (95% CI)	p	Mean difference (ms)	Limits of agreement (ms)
QTobs1 vs. QTobs2	0.947 (0.935–0.957)	< 0.001	0.939 (0.908–0.958)	< 0.001	6.28	-24.67: 37.23
QTobs1 vs. QTobs3	0.964 (0.955–0.970)	< 0.001	0.958 (0.932–0.972)	< 0.001	5.54	-20.41: 31.49
QTobs2 vs. QTobs3	0.945 (0.934–0.956)	< 0.001	0.946 (0.934–0.956)	< 0.001	-0.74	-31.06: 29.58

95% CI = 95% confidence interval, obs = observer(s), r = Pearson’s r, p = p-value, ICC = intra-class coefficient, ms = milliseconds.