SLC22A4 acted as a risk factor for AF (OR = 1.08; 95% CI, 1.002–1.16; Pfdr = 0.043) and increased the risk of dissection of the aorta (OR = 1.58; 95% CI, 1.12–2.23; Pfdr = 0.029), but MR‒Egger (OR = 0.78) showed a different effect. Here, SLC22A4 is linked to atrial fibrillation.