CYP1A1 and atrial fibrillation: On the CYP1A1 gene, we identified that the rs4646422 which comprised of the CYP1A1*13 allele with AF of 7.4%, and the rs180744198 with AF of 1.0% in the Vietnamese population could have effects on the biological activity of such metabolizer, resulting in the changes in bioavailability and eventually effectiveness of fluvoxamine, haloperidol, clozapine, melatonin, and amiodarone.