SLC22A4 and atrial fibrillation: While exploring the safety of the medication, we found that SLC22A4 can increase the risk of AF; the results of a study in which 2 prospective nested case‒control studies were conducted showed that higher choline and betaine levels were associated with an increased risk of AF [63], which supports the conclusion in our study and emphasizes the role that carnitine, choline, etc. play in SLC22A4 affecting the disease.