cardiac output calculator - calculate your cardiac output


Cardiac output calculator

Each ventricle that pumps the blood into the body that called cardiac output. That refers to liters per minute. It's flowing in the systemic & pulmonary cycle.

Those formula calculated cardiac output that called cardiac output calculator.
So, this formula is,

Cardiac output = no. of heart rate / stroke volume.

CO = HR * SV

Heart rate means a no. of beats per minute.

Stroke volume means a blood volume is ejected by each ventricle with their every beat.

Understand cardiac output calculator for very easy ways like,

If ventricle heartbeat is 72 per minute & stroke volume (ejected blood through ventricles) are 60 ml, so calculate this way,

CARDIAC OUTPUT = 72 beats per min * 0.06 liter per beat = 4.32 liter per minute

The average blood volume in one minute is around 5.5 liter (resting condition). Also, a depends on the exercise it may be various. During the extreme exercise & some athletes, cardiac output is around a 35 liter per minute. Because heartbeats & stroke volume increases during the exercise.

Also, during exercise normal man cardiac output in exercise is 20-25 liter per minute.

Just two factors affect the cardiac output, 

➠ Heart rate
➠ Stroke volume

Please, keep in mind heart rate & stroke volume does not change in the same direction. For example, if any blood loss condition stroke volume decreases but heart rate increases. So, it can produce the opposite result.  

➣ Heart rate

The average heart rate in human is almost  72 to 75 beats per minute. That is not any hormonal & nervous influence. But any other condition this heart rate may be decreased or increase it depends on hormonal & nervous system.

The sympathetic neurons that cause heart rate increase, whereas, parasympathetic neurons that cause heart rate decrease. That called a chronotropic effect.  

It’s also a innervate other parts of the conducting system. Sympathetic is increase the conduction velocity through the cardiac conducting system and parasympathetic decrease the speed of excitation through AV & atria node. That’s called a dromotropic effect.

The normal resting-state more parasympathetic activity produce than sympathetic activity. So, that’s why the normal heart rate is 72 to 75 beats per minute. It’s well below the inherent rate of 100 beats per minute.

Sympathetic & parasympathetic are influence the SA node potential. Sympathetic are stimulate the pacemaker potential by the F – type of channel permeability. That the sodium current that enters in the cell. Cells are depolarized. That causes SA nodes are reached that threshold potential & increase the heart rate.

Parasympathetic are opposite to the sympathetic. It stimulates the hyperpolarize (negative ion increases in the cell) to the plasma membrane reduce the current & decrease the heart rate.

The plasma epinephrine is increasing the heart rate & norepinephrine are decrease the heart rate.

Cardiac nerve can also alter the heart rate. Epinephrine & norepinephrine are also affecting the heart rate. Other many factors that affect the heart rate like, body temperature, other hormonal changes, plasma electrolyte concentration or etc.

➣ Stroke volume

In cardiac output calculator stroke volume the second important variable. The volume of blood ejects during each cardiac breath that called a stroke volume. That is not completely empty during the concentration.

So, forcefully contraction is increasing the stroke volume & slow contraction are decreases the heart rate. So, various contraction is affecting the stoke volume.  

Three major factors that affect stroke volume.

The frank- starling mechanism (end diastolic movement)
Sympathetic nervous system

⇨ The frank – starling mechanism

In systole condition the ventricle are more forcefully contracts, in other words, stroke volume can be increased when end-diastolic volume increases.

This relationship called a frank – starling mechanism. Also, a called a staring law of the heart .
The greater the end-diastolic, the more stretch the skeletal muscle & more forcefully contraction are producing.

When the heart rate increases the flow of blood from veins to the heart also increases.
Automaticity of force increase in cardiac output by increasing its end-diastolic volume.  And also, an increase in the stroke volume.

cardiac output calculator


When stroke volume & heart rate increase in the above condition, definitely, the cardiac output is increase.

⇨ Sympathetic regulation

The sympathetic neurotransmitter of norepinephrine acts on the β adrenergic receptor to increase its ventricular contractility. Which is a process to generate to force of contraction. Epinephrine are acts on these receptors to also increase myocardial contractility.

So, that is increase the force of contraction & stroke volume that result also a sympathetic nerve stimulation. The frank starling mechanism still applied, during the sympathetic stimulation, stroke volume is also an increase.

Increase the contraction, more ejection produces.

Ejection fraction (EF) = stroke volume / end volume diastolic

In heart resting condition ejection fraction average is 50% & 75%. When increasing the contractility cause an increase in the ejection fraction.

Not only cause powerful contraction but also a contraction & relaxation of ventricles occur. As they increase the sympathetic activity of the heart also increases the heart rate. 

Heart rate increase, the diastolic filling time decrease. The parasympathetic the system has normally negligible, that directly affect the ventricular contractility.

⇨ Afterload

When the arterial pressure is increase tends to reduce the stroke volume. Because of the skeletal muscle lifting a weight, arterial pressure constitutes ‘LOAD’ that contraction of ventricular muscle.

The term afterload means how hard to heart must eject the blood.

When the load greater, less contracting muscle fibers.

In a normal heart, several inherent adjustments minimize its atrial pressure on the stroke volume.

Cardiac output measurement

In cardiac output calculator, cardiac output is measured by many techniques. Like, echocardiography. It obtains two- or three-dimensional images of the heart by the cardiac cycle. The ultrasonic waves that beamed on the heart & electrically images plot by computer.

Echocardiograph is detecting the abnormal functioning of contraction & relaxation of the cardiac wall as well as detect the abnormal function of the valve. Also, a detect the ejection fraction.  

The other technique is used cardiac angiography, in cardiac angiography that requires a temporary threading of thin, the flexible tube called as a catheter by artery or vein in the heart. 

The radiopaque contrast material is injected through a catheter during the high-speed X-ray videography. Cardiac angiography is useful in cardiac function as well as identify the narrow coronary arteries.


In this article, you find all details in deep about the cardiac output calculator. like heart rate, stroke volume, etc. I hope you will be like that. if you like to comment out. 

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