Heart Failure: Definition and Epidemiology (Nursing)

00:00 Hi, I'm Professor Lawes.

00:03 Welcome to this video series on heart failure.

00:06 See, when we run, we walk, or even sleep, our body has metabolic needs, and those needs always have to be met.

00:13 Now, in order to do this, we require the help of a never resting worker inside our body named, you probably guessed that, the heart.

00:22 Now, it's very specific, you have to get the right amount of blood to meet our metabolic needs.

00:28 But sometimes, however, especially when we've been suffering from a chronic disease, like hypertension, that constantly makes our heart work harder, our pump starts failing and being less effective.

00:39 Well, this results in an inability to meet our metabolic needs, which will cause the patient to have some really nasty symptoms.

00:48 They'll have dyspnea, difficulty breathing.

00:51 They can have some weird arrhythmias, edema, and a few other things we'll talk about.

00:56 This condition is known as heart failure.

00:59 And it's the disease we're going to study today.

01:01 So come along with me as we unravel the mysteries behind this complex condition and I'll give you the tips you need to ace your upcoming exams.

01:10 First, let's take a look at the epidemiology.

01:14 Now, it's about a 1 - 2% prevalence in the United States.

01:17 Now, that may seem like a small thing to you.

01:20 But actually, it does impact quality of life.

01:23 Now, the prevalence in African Americans is 25% higher than in Caucasians.

01:28 Now, the incidence and prevalence also increase with age.

01:32 So the older you get, the higher the risk for developing heart failure.

01:37 I want to give you a quick recap of the cardiovascular system.

01:41 Have you seen this picture before? Yeah, I saw this in books a lot when I was a student.

01:46 And frankly, it just didn't make sense to me.

01:49 But I want to explain it to you.

01:50 So it will the next time you take a look at it.

01:53 Now, we've kind of taken the heart and stretched it out, so, you can really walk through it.

01:58 What I'd like you to do is put your finger on the screen, or your pen or pencil on the screen, and follow me through.

02:06 At the very bottom you see it says body.

02:09 And you've kind of got that mixing there anytime you see blue and red pinkish coming together, that means there's going to be a gas exchange.

02:16 But what I want you to do is start on the left hand side, the blue side.

02:20 Now, follow that all the way around.

02:23 Alright, now that dumps into a chamber of the heart.

02:27 That's actually the right side of your heart, just as it was in your chest wall.

02:31 So, the right atrium, goes down to the right ventricle, then trace it up, stay on the blue line, not the red line, trace it up through the blue line, it's going to go to the lungs.

02:44 Okay, in the lungs, it's going to pick up oxygen where those capillaries are. See those? Then keep following.

02:50 Now, the line becomes pink in color.

02:53 As you trace it back down with your finger, it's going to go into the left atrium, into the left ventricle.

03:01 Now, that you're in the left ventricle, trace it around.

03:04 Look at that, that's like the aorta, and it's going to go back out to the body.

03:08 It's going to serve as the body, dump all its oxygen, pick up the CO2, and complete the process.

03:14 That's what has to happen to have a cardiovascular system intact, complete, and functioning.

03:20 So, next time you see that I would love for you to pause even right now. Trace it through.

03:26 Teach your brain what you're looking at here, because what you want to understand is wow, what is coming up before the right side of the heart? What does the left side of the heart do? You remember if that left side of the heart is not functioning well, it's not going to be able to pump blood out to the rest of the body.

03:44 This is going to become critically important to you understanding when we talk about the differences between right sided and left sided failure.

03:52 Spend some time with this drawing, make sure you clearly understand it before you move on.

03:58 Now, when the heart is not able to supply the normal cardiac output needs to meet our metabolic needs, that means it isn't pushing out.

04:07 It can't move through the heart or the body an adequate amount of blood.

04:11 Now, you see we've got this aorta for you.

04:14 This is something really cool the artists did for you to help you understand.

04:18 In a normal heart, when everything is beating and pumping, and attack and strong.

04:23 You see there's a thick arrow that represents the stroke volume, okay? Stroke volume is the amount of blood the heart can push out with each beat or stroke.

04:35 So, the blood is pumped out because one, the integrity of the heart is a pump, right, and it's working well.

04:41 It's strong and effective.

04:43 And the second part is called adequate systemic resistance.

04:49 Okay, those are kind of weird words.

04:51 We don't use those in everyday language.

04:52 But in order for things to be functioning with a normal heart, the pump or the heart has to be strong and effective.

05:00 The second thing is adequate systemic resistance.

05:04 Now, what does that mean? Well, you don't want it too high or too low.

05:09 But systemic resistance is the work that the heart has to do to push that blood through.

05:15 If the vessels are tight and constricted, that systemic resistance is going to be really high in the heart is going to have to work extra hard.

05:23 So, you want to just small enough, that creates a little tension enough to push the blood through, but you don't want it so clamped down, that it causes the heart to be overworked.

05:34 So, there's the heart. Look at the arrow.

05:38 See, that's an appropriate amount of stroke volume in a healthy heart.

05:42 Two things you have to have in order for the system to be working well, is integrity of the heart as a pump, and adequate.

05:51 So not too much, not too little systemic resistance.

05:55 Now, when the heart is damaged, let's say let's take a look at this heart is experiencing congestive heart failure.

06:01 First thing I want you to look as, look at the difference and the size of the arrow.

06:07 Now, remember, that arrow represents stroke volume.

06:10 So, this heart is not as intact or doesn't have the integrity that a normal heart would.

06:17 And why is that? Well, look at that.

06:20 You've got, on the side of the heart, you have the blue vessels - inferior vena cava, superior vena cava, they all lead into the right atrium, the right ventricle, right? It goes over to the lungs.

06:33 It comes back into the left atrium and the left ventricle.

06:36 Why are we going over that so many times? Because this is critically important that you understand this, so you don't have to memorize things.

06:45 You'll understand why they are the way they are.

06:47 Now this patient has had a myocardial infarction.

06:51 See where that dead tissue is, it's much darker in the drawing? That's letting you know dead tissue is not really flexible.

07:00 It's stiff. It doesn't conduct electricity like the other tissues did.

07:03 So this heart is putting out far less volume.

07:08 The stroke volume is less. How can you tell that? Again, look at that size of the arrow.

07:13 If you want to, you can even back it up and look at the previous one.

07:17 So heart failure usually occurs because the pump is not able to pump.

07:22 The heart has suffered some damage, it's not functioning as efficiently as it used to.

07:27 Now, this heart has lost some structural integrity, that myocardial infarction, it could also have some valvular defects.

07:34 Now, you don't see that on this drawing.

07:36 But those are other reasons that someone can be in heart failure.

07:39 These will cause lower stroke volume.

07:44 Now, chronic hypertension.

07:46 You don't really see that as being a big deal. But it is.

07:49 So, with chronic hypertension and coronary artery disease, the heart works harder.

07:55 Can you think about why the heart works harder with chronic hypertension? Well, when hypertension, those vessels are clamped down, so that left ventricle is having to work extra hard to get those vessels right, to get blood through those vessels, because they're clamped down, and they're smaller.

08:12 Now, if I have chronic hypertension, and coronary artery disease.

08:17 The inside of my vessels is also going to be smaller, because it's going to be filled with plaque.

08:21 So a combination of vessels clamped down and smaller to begin with, that's going to cause my heart to be over worked.

08:29 So, when it gets to the point where it causes heart failure, the heart can no longer pump enough blood to meet our metabolic needs can't keep things in balance.

08:38 So, systemic resistance, that's what happens systemic vascular resistance is increased in patients who have chronic hypertension.

08:48 So it's not count hypertension, it happens for just a minute.

08:50 This is hypertension over time, chronic hypertension, or coronary artery disease.

08:56 That is what causes the increased resistance for the left ventricle to be pushing against.

09:03 So because it's having to work harder, the heart has to increase the contractility of the heart to try and overcome that resistance.

09:11 That's why the heart is working harder.

09:15 So, your job is to think, so why are we so worried about risk factors of chronic hypertension that isn't treated, or coronary artery disease? This is exactly why.

09:26 We don't want the patient to develop congestive heart failure.

09:29 Both of these conditions hypertension and coronary artery disease, make extra work for the heart.

09:37 And that's eventually going to cause some really bad changes into the heart.

09:42 Because eventually, this will cause hypertrophy.

09:45 Now that word means the heart just gets over enlarged.

09:49 Look at the picture now. Look at the wall of the ventricle, the left ventricle.

09:55 That's what ventricular hypertrophy will look like.

09:58 How did that happen? Well, remember that left ventricle is having to work extra hard because the coronary artery disease and that how chronic hypertension that wasn't controlled.

10:09 So this is what leads to heart failure because look at that wall.

10:14 Do you think a heart that looks like that can push out enough blood pump out enough blood to meet our metabolic needs? No, it really can't. And what reinforces that? What's going on in that drawing to remind you that the output is lower? Cool, size of the arrow.

10:32 Look how tiny it is, compared to the big thick one we had before.

10:36 So this is how you can remember things that put patients at risk for heart failure if you just think about how your heart is supposed to work.

10:46 Let's talk about the co-morbidities.

10:49 Things that if a patient has heart failure and these can both put them at increased risk, and can cause multiple complications.

10:56 So, hang on, I'm going to give you a list, but know that the patient has diabetes that has increased cardiovascular risk.

11:05 If they have metabolic syndrome, remember, that's a list of criteria and that means they're at an increased risk in metabolic syndrome.

11:12 If they smoke, if they have vascular disease, so it's going to be extra work for the heart.

11:19 They might have some structural defects, like a septal defect can have a massive infection or a huge inflammatory process, they may not be making wise choices with alcohol or with drug use.

11:32 But the last one is really a strange one. I mean, I didn't quite get it until I had a friend who had chemotherapy.

11:39 The chemotherapy was successful in treating the cancer, but she died of heart failure, because the chemotherapy medication was so difficult on her heart.