This work explores correlations between genetic polymorphisms in apolipoprotein E (ApoE) and atrial fibrillation (AF). We detected polymorphisms in the APOE gene in 64 patients with AF and 49 non-AF volunteers at the Department of Cardiology of Lianyungang Second People's Hospital between July 2017 and July 2019. We found significant differences in age, body mass index, left atrial diameter, and left ventricular ejection fraction between the two groups. Six APOE genotypes were observed: ɛ2/ɛ2; ɛ2/ɛ3; ɛ2/ɛ4; ɛ3/ɛ3; ɛ3/ɛ4; and ɛ4/ɛ4. The ɛ3/ɛ3 genotype was significantly less frequent in the AF group than in the control group, while the ɛ3/ɛ4 and ɛ4/ɛ4 genotypes were significantly more frequent in the AF group than in the control group (p