Sinus rhythm with a resting heart rate of >100bpm in adults, or above the normal range in children.
- In the vast majority of cases, a sinus tachycardia is a physiological response (via increased sympathetic innervation) e.g. during exercise, stress, infection, blood loss.
- It is also seen with alcohol and caffeine consumption
- The maximal heart rate for any individual can be calculated as 207-0.7×Age (years). More commonly, this is simplified to 220-Age.
- Pathophysiological causes include
- Hypoxia, hypercapnia, acidaemia
- Sepsis, pyrexia
- PE, heart failure
- Beta-agonists e.g. adrenaline, salbutamol, dobutamine
- Sympathomimetics e.g. amphetamine, cocaine
- Antimuscarinics e.g. antihistamines, TCAs, atropine
- Caffeine, theophylline, marijuana
- Patients can present with symtoms of the underlying cause. Other symptoms may include palpitations, pre-syncope, anxiety etc
- Management is almost always of the underlying cause; If the patient presents acutely (e.g. palpitations, SOB, syncope etc), manage as adult tachycardia (ABCDE) approach (see here)