Heart Healthy Cardiac Physiology

Heart Healthy Cardiac Physiology


– Hi, my name’s Jenny Sprengler. I’m an RN
with the cardiology clinic at the St. Cloud VA. Today we’re going to talk about
cardiac physiology, or how your heart works. The heart is a muscle, it’s about the size
of your fist, and it sits in
the center of your chest and a little bit to the left. It’s essential for life. It receives blood
that needs oxygen and it pumps it to the lungs,
where it’s filled with oxygen, and it comes back into the heart and is pumped to
the rest of your body. The heart has four chambers. There’s two on the top
that are called the atrium, and two on the bottom
that are called the ventricle. The top two chambers are
a light blue on the screen, and the bottom two are
a darker blue on the screen. Blood comes in the heart
through the right side, through the superior
and inferior vena cava. It’s then pumped through
the pulmonary artery into the lungs, where it’s filled with oxygen, then returns to the heart
through the pulmonary veins, and it enters the left side
of the heart. The blood is then pumped through
a large vessel called the aorta, and it distributes oxygen-rich
blood to the rest of the body. As you can see
from the previous picture, there are four valves
in the heart. This picture gives us a little
close-up of those valves. There is a valve
on each side of the heart between the atrium,
or the upper chamber, and the ventricle,
the lower chamber. These valves help to
prevent blood from back-flowing. On the right side
we have the tricuspid valve, and on the left side
we have the mitral valve. When the blood goes to leave
the heart from the right side, it goes through
the pulmonary valve, and on the left side it leaves
through the aortic valve. How does the heart pump blood? The heart receives blood
while it is relaxed. This is called diastole. When the heart pumps,
it is called systole. This relates to
your blood pressure. The top blood pressure number is called your
systolic blood pressure. This is when
your heart contracts. The bottom number is called
your diastolic blood pressure. This is when
your heart is relaxed. This picture shows some of
the main vessels in your heart. The vessels in your heart fill
with blood during diastole, or while your heart is relaxed. These vessels deliver
oxygen-rich blood to the heart muscles. When a vessel is blocked– for example, when
someone has a heart attack– the blood to one area
of the heart is lost. This can affect
how your heart pumps. What causes heart attacks? Heart attacks happen when a heart vessel becomes
completely blocked. This prevents blood flow
to an area of your heart. The most common cause
of heart attacks is from plaque becoming unstable
and breaking open. In the picture, you can see
the yellow area is plaque. In the third picture over, that plaque is broken open. When that plaque breaks open,
it activates our body to release certain enzymes that produce
an inflammatory response. Blood vessels respond to this
and form a clot, which completely blocks the
blood flow through that vessel. So what can we do about that? There are many risk factors to prevent heart attacks
or coronary artery disease. We have non-modifiable
risk factors and modifiable, and these are just a few. Non-modifiable means
these are things you can’t do anything about,
things like… You already had a cardiac event
or a heart attack. You might have a family history and a parent or a sibling
of heart disease. Your age. We know as we get older, your
risk of heart disease increases. The highest rate
of hospitalization for heart attacks are in those
85 years of age and older. Your gender. Heart attacks occur
in both men and women. For women, heart disease tends
to happen about ten years later, and heart attacks happen about
20 years later than men. Diabetes is another risk factor. Modifiable risk factors
are things that you can change. Tobacco use. Cigarette smoking is the leading
avoidable cause of death in the United States. This is the most
single important modifiable risk factor. Lack of exercise. High blood pressure. High cholesterol. I put diabetes on both
non-modifiable and modifiable because there are many things
that you can do to control your diabetes. And stress is another modifiable
risk factor for heart disease. Our other presenters
will get into more things that you can do to reduce these risk factors. Here are some other
heart conditions: heart failure, cardiomyopathy, irregular heart rhythms, and congenital abnormalities. With heart failure, 49% of the cases are caused by
untreated hypertension. A common question I get is, “What does the EKG tell us?” First of all, an EKG or an ECG
are the same thing. They both mean
electrocardiogram. Besides a few squiggly lines
on the EKG, we can get information from this
about your heart. Above you’ll see a normal EKG. When we see changes on an EKG,
it might mean nothing, or it could indicate
blockage in a vessel or enlargement of the heart. The EKG assists us with
knowing what to explore further. This is a picture of
the electrical activity of your heart. This is what’s shown on the EKG. The electrical activity starts
at the top of your heart in the sinus node, and it moves its way all the way
through to the ventricles. In summary, we’ve talked about
the location of your heart, the chambers of your heart, your heart valves, blood flow through the heart, your heart vessels, risk factors for heart disease, and the electrical system
of your heart. So now that we’ve talked about
heart function, let’s talk about ways that you can reduce your risk
for heart disease.