Sinus rhythm refers to a heart rhythm in which the patient’s heart beats by the sinus node, which sends impulses that control the heart. The heart has multiple pacing points, including the sinus node, atrioventricular node or ventricular muscle, with the highest pacing point being in the sinus node. In a normal person, the sinus node is responsible for the impulses and control of the heart, and the rhythm formed by the sinus node controlling the heart is called sinus rhythm. Conversely, if the heart beats due to impulses from a pacing point other than the sinus node, this rhythm is called ectopic rhythm. Therefore, the presence of sinus rhythm means that the heart beat is controlled and completed by the sinus node, which is a normal heart rhythm.