Inappropriate sinus tachycardia (IST), a form of dysautonomia that is estimated to impact around 1.2% of the population. IST is characterized by unexpectedly fast heart rates at rest, with minimal physical activity, or both. Patients with IST range in presentation from asymptomatic to complaining of extremely debilitating symptoms such as palpitations, weakness, chest pain, shortness of breath fatigue, dizziness, or near syncope. IST is a diagnosis of exclusion. If IST is suspected, a thorough medical history review and physical examination should be performed, in order to rule out secondary causes for the tachycardia . The echocardiogram should reveal a structurally normal heart, and a treadmill exercise test (if used) should document an exaggerated tachycardic response to exercise. 

Keywords: Sinus Tachycardia; Inappropriate; Rate.