Hjärtminutvolym

Hjärtminutvolym, often abbreviated as CO (Cardiac Output), is a measure of the amount of blood the heart pumps per minute. It is a crucial indicator of the circulatory system's efficiency and the body's ability to deliver oxygen and nutrients to its tissues.

The calculation of hjärtminutvolym is straightforward. It is determined by multiplying the stroke volume (SV), which is the amount of blood ejected by the left ventricle with each beat, by the heart rate (HR), the number of heartbeats per minute. The formula is thus CO = SV x HR. For example, if a person's stroke volume is 70 milliliters per beat and their heart rate is 70 beats per minute, their hjärtminutvolym would be 4900 milliliters, or 4.9 liters per minute.

Hjärtminutvolym varies significantly based on physiological conditions. At rest, the average adult hjärtminutvolym is typically between 4 to 6 liters per minute. During physical activity or stress, the body's demand for oxygen increases, leading to a substantial rise in hjärtminutvolym. This increase is achieved through both an elevated heart rate and, to a lesser extent, an increased stroke volume. Conversely, in conditions such as heart failure, the hjärtminutvolym can be significantly reduced, leading to symptoms like fatigue and shortness of breath. Monitoring hjärtminutvolym is therefore essential in the assessment and management of various cardiovascular conditions.