The generic name of Betalucil is metoprolol tartrate, which can be used clinically for the treatment of arrhythmia, but not all arrhythmias can be treated with metoprolol. Metoprolol is a beta-blocker, which can selectively inhibit beta1 receptors and reduce heart rate and blood pressure. Clinically, it is mainly used in the treatment of hypertension, angina pectoris, myocardial infarction, and some arrhythmias. It should be noted that Metoprolol is prohibited for use in sick sinus node junction syndrome, 2nd degree, 3rd degree atrioventricular block, bradycardia with symptoms such as dizziness and fatigue or hypotension. When used in the treatment of supraventricular tachyarrhythmias, metoprolol should not be used in patients with a systolic blood pressure of less than 110 mmHg. Therefore, when using metoprolol to treat arrhythmia, it is important to use it under the guidance of a specialist and strictly grasp the contraindications to avoid adverse consequences.