Where does sinus tachycardia originate?

Sinus tachycardia originates in the sinoatrial (SA) node, which is located in the right atrium of the heart. The SA node is responsible for initiating electrical impulses that trigger the heartbeat. In sinus tachycardia, the heart rate exceeds 100 beats per minute due to increased automaticity or heightened sympathetic nervous system activity, often in response to factors such as exercise, stress, or fever.