Cardiac Output: Pumped Out by Each Ventricle or Combinedly?

The cardiac output refers to the volume of blood that is pumped out by the heart in one minute. It is typically expressed in milliliters per minute (ml/min). The heart is composed of four chambers - two atria and two ventricles. The right atrium receives deoxygenated blood from the body, which then flows into the right ventricle. The right ventricle pumps this blood to the lungs for oxygenation. The oxygenated blood returns to the left atrium and then flows into the left ventricle. The left ventricle is responsible for pumping this oxygenated blood to the rest of the body.

1. Cardiac Output per Ventricle:
Each ventricle contributes to the overall cardiac output, but the left ventricle is responsible for the majority of the pumping. The left ventricle is larger and more muscular than the right ventricle because it needs to generate enough force to propel blood throughout the entire body. It is estimated that the left ventricle contributes approximately 70-80% of the total cardiac output, while the right ventricle contributes the remaining 20-30%.

2. Factors Affecting Cardiac Output:
Several factors influence the cardiac output. These include heart rate and stroke volume. Heart rate refers to the number of times the heart beats per minute, while stroke volume refers to the volume of blood pumped out by each ventricle with each heartbeat. To calculate the cardiac output, these two factors are multiplied together:
Cardiac Output = Heart Rate x Stroke Volume

3. Regulation of Cardiac Output:
The cardiac output is regulated by the autonomic nervous system, specifically through the sympathetic and parasympathetic divisions. The sympathetic nervous system increases heart rate and contractility, leading to an increase in cardiac output. On the other hand, the parasympathetic nervous system decreases heart rate and contractility, resulting in a decrease in cardiac output.

4. Clinical Significance:
The cardiac output is an important parameter in assessing cardiac function. It provides information about the overall efficiency of the heart in pumping blood to meet the body's demands. Various medical conditions can affect the cardiac output, such as heart failure, arrhythmias, and valve disorders. Monitoring and maintaining an adequate cardiac output is crucial for optimal cardiovascular health.

In conclusion, the cardiac output is the total volume of blood pumped out by both ventricles in one minute. While both ventricles contribute to the cardiac output, the left ventricle is responsible for the majority of the pumping. Factors such as heart rate and stroke volume influence the cardiac output, which is regulated by the autonomic nervous system. Monitoring and maintaining an adequate cardiac output are vital for overall cardiovascular health.

Cardiac output =Heart rate×Stroke volume and measured in Litre/mnt.For healthy adult weighing 70kg,Heart rate is 70beats/mnt, and Stroke volume 70mL,Cardic output will be calculated as 70 ×70=4900 ml/mnt,convert in litrs=4.9 L/m.