Cardiac output changes depend on many factors. Changes in cardiac output may be a sign of response to an increase in the body's oxygen demand or are serious diseases affecting cardiac output.

Atrial flutter is a common supraventricular tachyarrhythmia. Atrial flutter is 2.5 times more common in men than in women and is more common in older patients. The disease often progresses spontaneously from asymptomatic to hemodynamically impaired, even to sudden death.