β-AR antagonists are used in the pharmacological treatment of patients with AF, primarily for controlling the associated rapid ventricular rates (rate control), but they may also be effective in suppressing AF (rhythm control) when adrenergic tone is elevated, e.g. β1-AR sub-type antagonists in patients with postoperative AF (bisoprolol, metoprolol) [8] or with heart failure (metoprolol) [37]. Here, ADRB1 is linked to atrial fibrillation.