A disorder characterized by a dysrhythmia with a heart rate greater than 100 beats per minute that originates in the sinus node. [CTCAE] Simple rapid heartbeats caused by rapid discharge of impulses from the SINOATRIAL NODE, usually between 100 and 180 beats/min in adults. It is characterized by a gradual onset and termination. Sinus tachycardia is common in infants, young children, and adults during strenuous physical activities. [MeSH]