The document discusses factors that regulate cardiac output, including preload, contractility, and afterload. It describes how the respiratory pump, cardiac pump, and muscle pump influence venous return and end-diastolic volume. The role of the sympathetic nervous system in increasing heart rate and contractility is explained. Methods for measuring cardiac output are outlined, including the Fick principle using oxygen consumption, indicator dilution techniques, thermodilution, and non-invasive methods like Doppler echocardiography and impedance cardiography. Disease states that increase or decrease cardiac output are briefly mentioned.