Genotypic and allelic distributions and frequencies of IL12A-504 G/T, IL18-607 C/A, and IFNGR1-611 A/G SNPs, values of Odds Ratio (OR) and 95% Confidence Interval (95% CI) adjusted for sex and race by unconditional logistic regression analysis among the groups of patients with Acute (AF, n = 39), Multifocal Chronic (MC, n = 93) and Unifocal Chronic (UC, n = 17) forms of PCM. This evidence concerns the gene IFNGR1 and atrial fibrillation.