Cardiac question

[koko2002]

Hey everyone,

I'm doing cardiac stuff now and this isn't coming easy like some other systems.

So, in heart failure, you have more volume of blood in the ventricles at the end of diastole but less cardiac output? Can someone explain why this is?

Also, do all the cardiac drugs that someone would take for heart failure cause a decrease in the afterload, preload and cardiac output?

Thanks for you help!

[Jonathank]

In left sided heart failure, blood will become backed up in the pulmonary circulation before it gets to the left side of the heart. In right sided heart failure, blood will get backed up in the systemic circulation before it gets to the right side. The affected side can't generate enough contractile force to keep the blood moving, but the unaffected side will still keep trying to circulate the blood it gets.

[illuminati88]

Heart failure is usually described as systolic and diastolic. To answer your first question, Diastolic heart failure is when the ability of the ventricles to relax and fill during diastole is impaired. When this is impaired, it results high filling pressures and decreased ventricular filling. when the ventricles are not being filled to optimal levels it affects stroke volume and cardiac output. The ventricles aren't relaxing in the way they should be and are not being filled appropriately which ends up in decreased CO and blood starts to back up.

Not ALL cardiac drugs have the same therapeutic effects, of course. But for drug therapy and Heart failure, look into Diuretics, vasodilators, B-adrenergic blockers, positive inotropic agents, antihypertensive drugs(afterload).

[ImThatGuy, BSN, RN]

Hey everyone,

I'm doing cardiac stuff now and this isn't coming easy like some other systems.

So, in heart failure, you have more volume of blood in the ventricles at the end of diastole but less cardiac output? Can someone explain why this is?

Also, do all the cardiac drugs that someone would take for heart failure cause a decrease in the afterload, preload and cardiac output?

Thanks for you help!

To make the story short, while I'm eating pizza, the heart just gets kind of weak and stretched out. Think of it like a Slinky. Do they still make the Slinky? You can stretch it and it goes back. Stretch it and it goes back. Eventually, the more you stretch it the less it goes back. Once the old ventricle is big and stretched out it just won't go back and squirt as much blood back out.

If you took a small balloon and put a few ounces of water in it and squeezed you're likely going to squirt it all out like a good, healthy ventricle. For the purposes of demonstration (pretend a bigger balloon is actually the small one but old and stretched out) if you took a bigger balloon and put the same amount of water in it and squeezed it you're likely to squirt a little less out like an old, sick ventricle.

The left one gets weak and blood backs up in the pulmonary circuit and you get some pulmonary edema. The right one gets weak and blood backs up in the venous system. Eventually, no matter what side fails, the other side is going to get involved.

Your stroke volume (the amt. ejected in a contraction) is less because the ventricle is weaker and probably larger thus with a reduced stroke volume your cardiac output is reduced because heart rate in a minute x stroke volume = cardiac output.

To answer your drug question.....pretty much. Digoxin is a staple. If you look at a lot of HF drugs you'll see they can be used for blood pressure regulation as well indicating the similarity in volume/container (fluid/vessel) management.

Hope that helps.