Congestive Heart Failure (CHF): Overview (Nursing)

00:01 Hi, this is Prof. Lawes with an update on the nomenclature for congestive heart failure or as it's now called, heart failure. So you'll see the term congestive heart failure in the literature, but there's movement towards just calling it heart failure or HF. In addition, systolic and diastolic heart failure are heart failure with reduced ejection fraction. You'll see that written as HF, that little "r" and "EF" for reduced ejection fraction. Heart failure with preserved ejection fraction will be named HF, that small "p" for preserved and the letters "EF", respectively.

00:43 So now let's look at what happens when things go wrong.

00:47 So congestive heart failure is a progressive condition in which the cardiac output is so low that you do not have adequate blood circulation to your tissues and this is gonna lead to to further dysfunction in the rest of the body.

01:07 Congestive heart failure is a reflection of a weakened myocardium.

01:13 This can be caused by different factors.

01:16 First, it can be caused by coronary atherosclerosis.

01:21 In this, you have clogged arteries because of build up of fat in your arteries.

01:27 This in turn is going to impair oxygen delivery to those cardiac cells and when this happens, the heart becomes hypoxic and that causes contraction to occur inefficiently.

01:43 Because remember, the heart has an absolute dependence on oxygen, so any blocking of oxygen to the heart is gonna have major effects on the heart's ability to do work.

01:59 Another factor that can lead to this weakened myocardium and thus to congestive heart failure is a persistent high blood pressure.

02:08 So if your aortic pressure is always greater than about 90 mmHg, this can cause the myocardium to exert more force and thus if this is chronic, this increases your end systolic volume and causes the myocardium to hypertrophy or kind of get bigger but it's getting bigger but it's also getting weaker, so this is not a good thing when it's hypertrophy-ing.

02:38 Another thing that can lead to a weakened myocardial as going to be multiple myocardial infarcts or heart attacks.

02:46 Each heart attack causes the heart to become weak as your contractile cells start to be replaced with scar tissue instead of other contractile cells.

02:57 So now, your heart is losing its contractility because we now have a build up of scarred tissue in place of those contractile cells that we need for the pumping of the heart.

03:11 And then finally, we have dilated cardiomyopathy.

03:16 This is when the ventricle stretch and become flabby and the myocardium begins to deteriorate.

03:23 This is usually caused by drug toxicity or by chronic inflammation.

03:32 So with congestive heart failure, either side of the heart can be affected.

03:38 If the left side of the heart fails, this is going to resolve in pulmonary congestion and blood being backed up in the lungs.

03:47 Because remember, the lungs feed the left side of the heart so if there's a failure here, then the the blood has nowhere to go and so kind of sits in the lungs.

03:59 If the right side of the heart fails, this will result in what's known as peripheral congestion where the blood will now pool in your body's organs causing edema or swelling.

04:13 Failure of either side is ultimately gonna weaken the other side and this is because the other side is gonna be decompensated and thus so seriously weakened.

04:25 And so the way we treat this is by removal of fluid and drugs that reduce our afterload and increase the contractility of our cardiac muscle cells so that we can maintain a healthy heart that's able to pump blood efficiently.