Genome-wide significant association findings for PR interval obtained at nine independent loci. In each locus at least one marker exceeds the genome-wide significant threshold of P<5 × 10-8. Betas estimate the difference in PR interval per one additional copy of the minor allele, adjusted for the covariates in the model. Column “Method” indicates whether a SNP was directly genotyped on one of the array platforms (G) or whether its genotype was imputed in all of the samples (I). The RSQR and the MAF are averages weighted by study size. RSQR (sometimes also termed OEvar) denotes the average of the observed by expected variance ratio of any SNP which indicates deviation from Hardy-Weinberg equilibrium and quality of imputation. All these SNPs met QC criteria in each study as outlined in Supplementary Tables 2 and 3. Effect size (beta) is reported in milliseconds (ms) per one copy of the minor allele. We observed no heterogeneity in effect size estimates between studies and report the I2-statistic results as the ratio of between-study to overall variance in betas.