Statistical analysis
The distribution of continuous variables was checked by visual
inspection of the histogram and by assessing skewness and kurtosis. As
all variables were normally distributed, they were presented as means (±
standard deviations (SD)) and compared using paired Student’s t-tests.
We used Bland Altmann plots to investigate differences in QTc between
limb and chest leads. A two-sided p-value <0.05 was considered
statistically significant. All statistical analyses were performed using
SAS 9.4 (SAS Corporation, Cary, North Carolina, USA).