Sinus tachycardia history and symptoms

Sinus tachycardia is often asymptomatic. If the heart rate is too high, cardiac output may fall due to the markedly reduced ventricular filling time. Rapid rates, though they may be compensating for ischemia elsewhere, increase myocardial oxygen demand and reduce coronary blood flow, thus precipitating ischemia or valvular disease. Sinus tachycardia accompanying a myocardial infarction may be indicative of cardiogenic shock.