Statistical analyses
Continuous variables are expressed as mean ± standard deviation for normal distribution and as median and interquartile range in case of skewed distribution. Categorical data are expressed as number and percentages. To compare proportions of patients with at least 1 episode in the two periods of comparison (reference and lockdown periods) we used a test for categorical dependent samples (McNemar). To assess differences in numbers of events over the two periods of interest (reference and lockdown periods) we used a non-parametric paired samples test (Wilcoxon). A two-sided p-value of less than 0.05 was considered significant. Statistical analyses were undertaken using SPSS version 22 (IBM SPSS Statistics).
Observation time was divided in 3 periods: lockdown period (March 9 through May 4, 2020) with the corresponding reference period in 2019 (March 9 through May 4, 2019) with a global observation period of 16 months (January 1, 2019 to May 4, 2020). We compared cardiac arrhythmias rate during lockdown period (March 9 through May 4, 2020) to the corresponding reference period in 2019.