Why do people with heart failure have low cardiac output?

---

They are going to be tachycardic and have diaphoresis. Doesn't the tachycardia mean they have incxreased cardiac output?
Also, are diuretics used for diastolic failure
In general patients with heart failure have hearts which are severely weakened and often quite dilated. Cardiac output is stroke volume times heart rate. Stroke volume is determined by the amount of filling of the heart before it beats minus the amount of blood in the ventricle after it beats. Poor hearts have less than 30% ejection fraction(normal being around 70%). If you have tachycardia than you are also decreasing the amount of filling time(diastole), so you will be decreasing your stroke volume even further and decrease your cardiac output. That is a very general description, hope it helps.  (+ info)

what isdifference between low and high cardiac output hypotensions?

---

The arterial pressure (or our blood pressure ) is determined by cardiac output, venous pressure and systemic vascular resistance ( the muscle tone of the peripheral blood vessels ). When any of the following is reduced, hypotension can occur. Cardiac output is just one of the factors here.

When the heart is diseased, the hypotension is most probably caused by low cardiac output. Meaning, the heart cannot pump out a good volume of blood to the other systems.

In other instances when there is a good cardiac output in a good functioning heart, but the blood vessels in the extremities are dilated, the blood pressure might still be low. This is a clear example of a high cardiac output hypotension.  (+ info)

Cardiac output?

---

Can anyone explains what is cardiac output and how cardiac output depends on factors.
This is a pretty complex question, but I'll try to keep the answer somewhat straightforward. Cardiac output is the volume of blood being pumped by the heart, in particular by a ventricle in a minute. The primary function of the heart is to impart energy to blood in order to generate and sustain an arterial blood pressure necessary to provide adequate perfusion of organs. The heart achieves this by contracting its muscular walls around a closed chamber to generate sufficient pressure to propel blood from the cardiac chamber (e.g., left ventricle), through the aortic valve and into the aorta.

Each time the heart beats, a volume of blood is ejected. This stroke volume (SV), times the number of beats per minute (heart rate, HR), equals the cardiac output (CO).

Some important terms to know in discussion of cardiac output:

Circulatory System: The circulatory system consists of the heart, the blood vessels, (arteries, arterioles, and blood) and its purpose is to carry oxygen and nutrients to tissues in the body, and to carry away the byproducts of metabolism.

Contractility: Contractility is the intrinsic ability of cardiac muscle to develop force for a given muscle length. It is also referred to as inotropism.

Preload: Preload is the muscle length prior to contractility, and it is dependent of ventricular filling (or end diastolic volume.) This value is related to right atrial pressure. The most important determining factor for preload is venous return.

Afterload: Afterload is the tension (or the arterial pressure) against which the ventricle must contract. If arterial pressure increases, afterload also increases. Afterload for the left ventricle is determined by aortic pressure, afterload for the right ventricle is determined by pulmonary artery pressure.

Determinants of Cardiac Performance:

When we discuss ventricular dysfunction, it is most often in reference to the left ventricle, however it is important to understand that the same basic principles apply to the right ventricle. The left and right sides of the heart exist in a series, and are therefore interdependent; in normal physiology, the right and left ventricle will have the same output. There are 2 main determinants in cardiac performance:

1. Heart Rate (HR)

Heart rate is directly proportional to cardiac output; an adult HR is normally 80-100 beats per minute (bpm.) Heart rate is an intrinsic factor if the SA (pacemaker) node in the heart, and it is modified by autonomic, humoral, and local factors. For example:

An increase in vagal activity via M2 cholinergic receptors in the heart will decrease the heart rate.
An increase in sympathetic activity via B1 and B2 adrenergic receptors throughout the heart will increase the heart rate.


2. Stroke Volume (SV)

Stroke Volume is determined by three factors: preload, afterload, and contractility. The preload gives the volume of blood that the ventricle has available to pump, as well as the end diastolic length of the muscle. The contractility is the force that the muscle can create at the given length, and the afterload is the arterial pressure against which the muscle will contract. These factors establish the volume of blood pumped with each heart beat. Valvular dysfunction and ventricular geometric form can also affect stroke volume, depending on the pathology of the valves or the ventricle.  (+ info)

What is the relation of hypertension and risk for decrease cardiac output?

---

I am doing my nursing care plan and I can't get the relation of hypertension and risk for cardiac output.
i'm not sure the exact form of the curve, but more hypertension there's more risk of low cardiac uotput.-
increasing the blood pressure increases the pressure the heart has to overpower to bomb the blood.-
there's a range where the compensatory mecanisms of the heart (frank-satrling and those) can mantain the output, but after they stop working the output start to decrease.-
hope you got this, i'm not very good with explanations.-
:)  (+ info)

How do you calculate this cardiac output equation?

---

Mrs. Jones has a heart rate of 85, a systolic pressure of 140 and diastolic pressure of 60, and an end diastolic volume of 110 and end systolic volume of 40. What is her cardiac output? Please help. Thanks
CO = Stroke volume x Heart rate
stroke volume = EDV - ESV
therefore 70 * 85
CO= 5950 ml/min  (+ info)

what is the connection between cardiac output and blood pressure?

---

If someone has decreased cardiac output, does that mean they have hypertension? Or hypoptension?
When your heart works hard, your blood pressure goes up. Your heart can be working hard because of exercise, clogged arteries, ageing, eating too much salt and lots of other things. When your heart doesn't have to work hard, your blood pressure is lower (but within a healthy range, never too low for a healthy heart). Things like dehydration, blood loss, tachycardia and other things can cause (too) low blood pressure.  (+ info)

How can decreased cardiac output be caused by increased fluid volume AND decreased fluid volume?

---

Why would a patient in renal failure have decreased cardiac output?
Check out starlings law.

Of course decreased fluid volume can decrease CO, but once fluid volume increases too much, the heart "stretches" too much and therefore contractility is affected. The heart muscle is sensitive to stretch- it's kinda like goldie locks and the three bears. Too little fluid= low CO, too much fluid= low CO (because the heart muscle is stretched so much that it can't squeeze effectively), just the right amount of fluid= perfect CO!  (+ info)

does anyone know about cardiac output and ejection fraction?

---

hello everybody,
i have a question about cardiac output and ejection fraction. i calculated my cardiac output and it came about to 2.5 L per min and a ejection fraction of 43 percent. i have a heart rate of 50 bpm and blood pressure 121/70. is that normal? i dont exercise and i eat poorly im about 5'6 165 pounds.
Your ejection fraction (Ef) is low.......it should be at least 55. Your heart is not beating as efficient as it should. You need to get daily exercise to improve your heart's output and lose some weight. Your BP is great.....yes, it's normal. Why do you eat poorly? Ask yourself. What did your cardiologist say to do about your Ef?  (+ info)

Where can I find more information on cardiac output and pre-eclampsia?

---

I am trying to find any research that is available for public consumption on the relationship between high cardiac output and pre-eclampsia. We will be monitored for cardiac output when we conceive but I would like to know what it entails, what the possible outcomes could be, etc.
You will find everything you need at the following website:
http://www.preeclampsia.org/  (+ info)

Define cardiac output. How is it calculated? ?

---

Define cardiac output. How is it calculated? What factors affect each component of cardiac output? Why does it need to be variable? How variable is it?
the cardiac output is the ammount of blood the heart pumps in one minute.-
heart rate * stroke volume = cardiac output.-
it's affected by 4 determinants: heart rate, preload, afterload and myocardic contractility.-
it needs to be variable to adjust to the organism needs.-
it's variability depends on the activity the person is doing.-  (+ info)

---

---

• Home
• Our method
• Usage examples
• Index

• Statistics
• Contact

---