Among 545 participants with HF, 34% were not taking a beta-blocker, 39% were not taking an angiotensin-converting enzyme inhibitor/angiotensin receptor blocker/angiotensin receptor-neprilysin inhibitor, or hydralazine-isosorbide dinitrate, and 90% were not taking a mineralocorticoid receptor antagonist at admission; among participants with coronary artery disease, 36% were not taking an antiplatelet agent, and 38% were not taking a statin; and among participants with atrial fibrillation, 49% were not taking an anticoagulant. Here, ACE is linked to atrial fibrillation.