Mendelian randomization analyses suggest that genetic proxies for antidiabetic drug targets—KCNJ11/ABCC8, SLC5A2, and RXRB—reduce the risk of paroxysmal tachycardia (PT), right bundle branch block (RBBB), and atrial fibrillation (AF), respectively. The gene discussed is ABCC8; the disease is atrial fibrillation.