CHF Systolic Heart Dysfunction
Channel: EmpoweRN
Date: 23/08/2016

Congestive Heart Failure - Systolic Heart Dysfunction
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One in every 5 Americans will develop heart failure. During your time in the hospital, this is a disease that you will see no matter where you work.
Heart failure is categorized into 2 main categories:
Systolic and Diastolic Heart failure - Diastolic heart failure is known as heart failure with preserved ejection fraction.
In this video we will be focusing on systolic heart failure
When examining systolic heart failure, about 70% are ischemic and about 30% are non-ischemic.
Remember - the word Ischemic means inadequate blood supply which results in inadequate oxygen supply and therefore tissue death.
Now let's look at the pathophysiology of systolic heart dysfunction:
First you look at the normal functioning of the heart, as it relates to cardiac output.
Cardiac Output means the amount of blood that is being pumped by the heart
Normal Heart - This reflects the normal cardiac output of the heart
When there is an ischemic injury this is also known as a myocardial infarction the cardiac tissue will be weakened, which results in a decrease in contractility of the myocardium and therefore the cardiac output (or amount of blood being pumped by the heart) will be decreased.
We can look closer at this by looking at the
Frank starling's relationship = which shows us the relationship from stroke volume to preload
You usually see it in a graph like this:
On the right you see the words “stroke volume” = which represents the volume of blood pumped by the Left Ventricle per beat.
Then on the bottom you see the word Preload = which represents the initial stretching of the cardiac tissue prior to contraction. 
I like to think of preload as stretch and afterload as squeeze…. This helps me remember 
Preload = is the end diastolic volume which you may see abbreviated as EDV, 
Afterload = is the pressure in the wall of the left ventricle during ejection. 
Cardiac Output = the amount of blood volume ejected over a period of time.
The greater the contractility 
First let's look at a chart… then we will see a visual demonstration:
Here you see a normal functioning heart = this heart has a normal preload and stroke volume.
If the heart has injury, you will see something like this a decrease in preload and stroke volume.
In this visual demonstration of the heart this part is demonstrating preload and this is the stroke volume.
You can see that the stroke volume of the heart increases in response to an increase in the volume of blood filling the heart (preload) ( which is aka the end diastolic volume) 
For cardiac output the other factor you need to know is the heart rate. 
Basically Cardiac Output is the stroke volume per heart rate.
It looks like this:
CO = SV/HR
So think about it like this contractility is pumping.
But the pump needs liquid to “pump” = which is volume.
So what ever is pumped out is the output aka (also known as) afterload.
This shows the stroke volume which is the blood volume ejected over time.
The relationship here is direct 
The blood pressure is the peripheral BP = directly affected by blood viscosity and arterial diameter. 
All of this is dependent on the blood volume and the heart rate.
 (referring back to Frank’s chart) Here you can see a normal person’s heart functioning with a healthy preload and stroke  volume = this will equal a good cardiac output:
When the heart is injured, and the preload is high, the greater the stretch and therefore greater the squeeze and resistance the heart must overcome to push the blood out into systemic circulation. 
So if the preload is high, the afterload will be high AND the cardiac output will be high as well. 
 ↑Preload ↑Afterload = ↑ Cardiac Output
On  the other hand,  when the heart is injured the preload will be low, the stroke volume will be low AND the cardiac output will be low as well.
↓Preload ↓Afterload  = ↓ Cardiac Output
The lower cardiac output results in Activation of the  1 (ONE). Sympathetic Nervous System and is also results in 2 (TWO). decreased renal blood flow.
So let’s take a look at both of these:
So first let’s look at the activation of the Sympathetic Nervous System= 
which activates the Alpha and Beta receptors by the decrease in cardiac output. 
The Alpha and Beta  receptors are sensors located in the blood vessels. They sense the blood pressure and relay the information to the brain, so that a proper blood pressure can be maintained.  
Alpha receptors=  (equals) constriction which will bring more blood to the brain.
And Beta receptors = Dilation which will circulate blood to all the organs.
Here is an easy tool to help you remember this:
ABCD
Alpha Constricts and Beta Dilates.  
Once the Sympathetic Nervous System is activated, it has 3 main effects: