Learning how to calculate cardiac output is complex. Cardiac output is the blood pumped by the left ventricle. It is measured is by calculating what is called "stroke volume" and multiplying it by your heart rate. Cardiac output is one way to measure how efficient the heart is. High cardiac output is related to an increase in heart disease, heart failure and stroke. The harder the heart has to work when it is resting (i.e. not exercising), the less efficient it is. You can't measure cardiac output by yourself, you need specialized equipment and the assistance of a health care professional. Learn about the different ways to calculate cardiac output below.
- Electrical Cardiometry. This method of calculating cardiac output uses four electrodes (don't worry they are applied outside the body). The electrodes measure the electrical activity of the red blood cells moving through the aorta, called "bioimpedance." They calculation is a ratio of applied electrical current and corresponding output from the heart. This method is non-invasive and it can be performed by a Cardiologist or a Cardio Technician.
- Echocardiography. Echocardiography is a common method for calculating Cardiac Output. An echocardiogram is essentially an ultrasound of your heart. A technician, called a Sonographer applies a microphone to your chest which enables the sound waves to produce a picture of your heart. The Sonogrpher will record your cardiac output at different intervals and in different positions. The process can take anywhere from 30 to 45 minutes. Your doctor will then interpret the results of the Echocardiogram. People receive echocardiograms if there is a family history of heart problems or if you are having symptoms of a possible heart problem.
- Magnetic Resonance Imaging. Magagnetic Resonance Imaging(MRI) is frequently used to obtain images of tissue or bone. An MRI is like an X-Ray, but with significantly more detail. An MRI can be used to look at Cardiac Output by examining the heart structure and the function of the heart. A Cardiac MRI allows doctors to see detailed pictures of the heart's vessels, valves and any blockage that could be occurring. Cardiac output is measured by looking at blood flow generated by the pictures from the magnetic current. This technology is non-invasive and painless; however, while you are having an MRI performed, you cannot wear any metal. Because you are essentially in a huge magnet, the metal will be pulled out of you from the strong current.