inherent rate, the frequency of impulse formation attributed to a given pacemaker location within the heart. The following rates are representative of the adult heart: sinus node, 60 to 100 beats/min; atrioventricular junction, 40 to 60 beats/min; ventricle, 15 to 40 beats/min. In adults a rate above 100 beats/min is normal during exercise, exertion, strong emotion, or pain. Most clinicians are alert to possible problems when the sinus rate is greater than 90 beats/min and are not concerned unless it drops to less than 50 beats/min. In children the normal sinus rate is higher, decreasing as the age of the child increases.
