Sinus tachycardia

Definition

A sinus rhythm at a rate above 100 bpm. Impulses arise normally from the sinoatrial node, with a normal P wave (upright in leads I, II and aVF) before each QRS, but at an accelerated rate that is usually a physiologic response to demand, such as exertion, emotion, fever, pain, dehydration or anemia.

Clinical noteUsually a secondary, physiologic response to a trigger such as exertion, anxiety, pain, fever, anemia, low blood volume or hypoxia, rather than a primary rhythm disorder.