Cardiac output. This is a product of stroke volume or cc's of blood per beat times the heart rate so cardiac output increases with either an increase in stroke volume or heart rate or both.
Two ways. Either by pumping out more blood with each beat (by squeezing harder) or by beating faster. The output is the heart rate times the stroke volume. (the amount of blood pumped out with each beat).
What happens to cardiac output and after load when when heart rate is low? Does it increase because high heart rate causes decrease in CO
Varies. BUT in a young healthy person, generally the heart rate is low because the heart is efficiently pumping and the cardiac output is good. Generally, (in normals), increasing the heart rate increases pumping and cardiac output.
What to do if a transplanted heart has no nerve supply, how does the cardiac output of a transplanted heart increase and adapt to physiological changes?
Hormonal +/- nervous. The transplanted heart responds to hormonal changes. There is also some evidence that the transplanted heart may have some sympathetic re-innervation and possibly conduction of signals from the old sinus node to the new heart.
Can congenital heart defects or certain drugs result in increased cardiac output? What else causes it? Mine is 7.2lmin squared.
Yes. Medications and certain medical conditions can raise your cardiac output. But before going further, we need to know how you had your cardiac output measured, since the technique itself can give us some answers.
CO = HR x SV. Cardiac output (co) is the volume of blood pumped per minute, and related to heart rate (hr) and stroke volume (sv) (volume per heart beat). It can be affected by many bodily activities. An increase in either hr or sv can result in inceased co. So any drug that increases hr (caffeine, etc) can result in incresed co. Certain congenital heart defects (such as septal defects) can alter co.
About 4% About 4% of the cardiac output goes to the heart muscle itself. That is the same either at rest or with exercise.
Cardiac output. The major organs get about 80% of the total co. The percent each gets varies depending on the dynamics going on. As the heart can vary its resistance markedly coronary blood flow can vary by a factor of 5 depending on heart rate and resistance so it isn't a constant percent of co.
SVxHR=CO. You can count your heart rate by taking your pulse. That's the easy part. To get SV, you can do an echo to estimate it or do a right heart catheterization and perform a thermodilution and Fick measurements. (That's how cardiologists obtain it),
I was wondering what would the cardiac output of a patient be, if his heart was beating 80 times per minute while pumping 70 m?
Not with that data. Cardiac output is the product of heart rate by stroke volume (amount of blood the heart sends to the body with each heart beat). You do not have that info.
Cardiac Output. Cardiac output equals stroke volume x heart rate. That means if the heart rate goes up the cardiac output will go up. The stroke volume is how much the heart pumps out with each contraction. That can go down if the heart rhythm is off like in atrial fibrillation.
Echo. Echo is the simplest, easiest, cheapest, fastest way to determine the heart's strength ("ejection fraction"). Cardiac output, which is the product of heart rate and stroke volume (the amt of blood ejected per beat) can be calculated. Mri is more accurate but far more expensive and takes longer. Cardiac catheterization is the oldest way & still works fine for both but is invasive & more expensive.
Echocardiography. There are other modalities that can calculate "heart strength" (how well is the heart pumping blood) and cardiac output (how many liters of blood are pumped per minute) but the most accessible and non-invasive is an echo. By measuring the heart when full of blood and then when fully contracted you can estimate the effectiveness of the "squeeze" as well as the volume pumped.
All increase. Exercise causes an increased demand for blood flow to provide oxygen to the muscles doing the work. This is accomplished by increase in heart rate and stoke volume. Since cardiac output is determined by heart rate and stroke volume, it also goes up. Blood pressure also typically increases with strenuous exercise.