Sinus tachycardia Inappropriate sinus tachycardia 2015-09-11T15:40:53Z UMLS:C1881170 Inappropriate sinus tachycardia is a nonparoxysmal tachyarrhythmia characterized by an increased resting heart rate (HR) and/or an exaggerated HR response to minimal exertion or a change in body posture. HR is constantly above the physiological range with no appropriate relation to metabolic or physiological demands. SNOMEDCT_US:425582007