2. Cardiac imaging & CVS anatomy

Question 1

List the different imaging techniques that can be used to assess cardiac structure and functioning

Answer 1

1. X-rays
2. Nuclear imaging (e.g PET)
3. Cardiac MRI
4. CT scanning

Question 2

what is the CT pulmonary angiography?

Answer 2

This is an imaging technique that can be used to study the pulmonary arteries.
It can be used to identify blood clots or narrowing in the pulmonary arteries.

Question 3

describe the flow of blood through the chambers of the heart, including the valves it goes through

Answer 3

Deoxygenated blood from the cells of the body enter the right atrium of the heart through the inferior and superior vena cava. the blood then flows to the right ventricle through the tricuspid valve. when the right ventricle contracts, the blood flows into the pulmonary artery through the pulmonary valve and to the lungs.

Oxygenated blood from the lungs enters the left atrium via the pulmonary vein. it then flows into the left ventricle through the mitral valve and then to the aorta through the aortic valve and to the rest of the body.

Question 4

how many pulmonary veins are there?

Answer 4

4 - two from each lung

two on the right side and two on the left

Question 5

what is the main difference between the left and right ventricle?

Answer 5

left ventricle is much thicker as it has higher pressure

Question 6

describe the 3 layers of arteries

Answer 6

tunica intima - composed of an elastic membrane lining and smooth endothelium
tunica media - composed of smooth muscle and elastic fibres
tunica extern/adventitia - composed of collagen and elastic fibres(connective tissue)

Question 7

how does size of arteries affect its structure?

Answer 7

large arteries e.g. aorta have more elastic tissue which allows it to expand.
medium sized arteries are more muscular as they are the distributing arteries
small sized arteries are also muscular as they are resistance vessels and control blood pressure

Question 8

describe the structure of the aorta

Answer 8

The aorta is the largest artery in the body.The aorta is divided into four sections:
The ascending aorta, the aortic arch, the descending aorta and the abdominal aorta.

Question 9

describe the sections of the aorta

Answer 9

1. The ascending aorta begins at the opening of the aortic valve in the left ventricle of the heart. The coronary arteries branch off the ascending aorta to supply the heart with blood.
2. The aortic arch curves over the heart, giving rise to branches that bring blood to the head, neck, and arms.
3. The descending thoracic aorta travels down through the chest. Its small branches supply blood to the ribs and some chest structures.
4. The abdominal aorta begins at the diaphragm, splitting into smaller arteries in the lower abdomen. Most of the major organs receive blood from branches of the abdominal aorta.

Question 10

what is the function of the aorta?

Answer 10

The aorta is used to distribute oxygenated blood to all parts of the body.

Question 11

Give the equation for Cardiac output

Answer 11

CO= HR x SV

Question 12

Compare the HR, CO and SV in a 70kg under resting conditions and during exercise

Answer 12

At rest:
HR= 60-90bpm
SV= 55-83 ml/beat
CO= 5L/min

During exercise:
HR- 150-200bpm
SV= Up to 200ml/ beat
CO= 20-35L/ min

Question 13

what are the 3 layers of the heart?

Answer 13

Epicardium - serous membrane, smooth outer surface of heart. contains loose connective tissue and adipose tissue.
Myocardium - middle layer composed of cardiac muscle cell and responsible for heart contracting
Endocardium - smooth inner surface of heart chambers

Question 14

what are pectinate muscles?

Answer 14

muscular ridges in auricles and right atrial wall

Question 15

what are trabeculae carnae?

Answer 15

muscular ridges and columns on inside walls of ventricles

Question 16

what are auricles and what are their function?

Answer 16

One auricle is attached to each of the anterior surfaces of the outer-walls of the atria. Their purpose is to increase the capacity of the atrium, and so also increase the volume of blood that it is able to contain

Question 17

what is the phrenic nerve?

Answer 17

The phrenic nerve is a mixed nerve that originates from the the neck (C3, C4, C5) and descends through the thorax to innervate the diaphragm, to allow contraction.

Question 18

what is the function of the phrenic nerve?

Answer 18

It is important for breathing and is the only source of motor innervation to the diaphragm.
It passes motor information to the diaphragm and receives sensory information from it. There are two phrenic nerves, a left and a right one.

Question 19

What is a pericardial effusion?

Answer 19

Pericardial effusion (“fluid around the heart”) is an abnormal accumulation of fluid in the pericardial cavity.

Question 20

what is the effect of pericardial effusion?

Answer 20

Due to the limited amount of space in the pericardial cavity, fluid accumulation leads to an increase in pressure in the pericardial space which can negatively affect heart function.
A pericardial effusion with enough pressure to adversely affect heart function is called cardiac tamponade.

Question 21

what are the 4 main valves in the heart?

Answer 21

1. The mitral/ bicuspid valve (atrioventricular valve)
2. The tricuspid valve (atrioventricular valve)
3. The aortic valve (semilunar valve)
4. The pulmonary valve (semilunar valve)

Question 22

describe the location and function of the mitral valve?

Answer 22

The mitral valve is found in the left side of the heart, it connects the left atrium to the left ventricle.
It prevents a backflow of blood from the ventricles into the atria.

Question 23

describe the location and function of the tricuspid valve?

Answer 23

The tricuspid valve is found in the right side of the heart and it connects the right atrium to the right ventricle.
It prevents a backflow of blood from the ventricles into the atria.

Question 24

describe the location and function of the aortic valve?

Answer 24

The aortic valve is found at the base of the aorta and it’s used to prevent a back flow of blood form the arteries into the ventricles

Question 25

describe the location and function of the pulmonary valve?

Answer 25

The pulmonary valve is found at the base of the pulmonary trunk and it’s used to prevent a back flow of blood from the arteries into the ventricles.

Question 26

What is aortic stenosis?

Answer 26

Aortic valve stenosis occurs when the heart’s aortic valve narrows.
This narrowing prevents the valve from opening fully, which reduces or blocks blood flow from your heart into the main artery and onward to the rest of your body.

Question 27

what is the effect of aortic stenosis?

Answer 27

When the blood flow through the aortic valve is reduced or blocked, your heart needs to work harder to pump blood to your body. Eventually, this extra work limits the amount of blood it can pump, and this can cause symptoms as well as possibly weaken your heart muscle.

Question 28

What is aortic valve regurgitation?

Answer 28

Aortic valve regurgitation — or aortic regurgitation — is a condition that occurs when your heart’s aortic valve doesn’t close tightly.

Aortic valve regurgitation allows some of the blood that was pumped out of your heart’s main pumping chamber (left ventricle) to leak back into it.

Question 29

how many main coronary arteries are there?

Answer 29

3
the right coronary artery, the left anterior descending and the circumflex artery. The two main branches from the aorta are the right and left coronary arteries but the left coronary artery quickly branches into the LAD and circumflex artery.

Question 30

which areas of the heart does the LAD and circumflex artery supply?

Answer 30

The left anterior descending artery perfuses the interventricular septum and anterior wall of the left ventricle
The left circumflex artery runs towards the back of the heart and perfuses the lateral and posterior aspects of the left ventricle

Question 31

which areas of the heart does the right coronary artery supply?

Answer 31

The right marginal arteries perfuse the right ventricle and the posterior descending artery perfuses the left ventricular posterior and inferior walls.

Question 32

what is tranoesophageal echocardiography?

Answer 32

Transesophageal echocardiography (TEE) is a test that produces pictures of your heart. TEE uses high-frequency sound waves (ultrasound) to make detailed pictures of your heart and the arteries that lead to and from it.

Question 33

what does Coronary arterial dominance mean?

Answer 33

Coronary arterial dominance is defined by the vessel which gives rise to the posterior descending artery (PDA), which supplies the myocardium of the inferior 1/3rd of the interventricular septum.

Most hearts (80-85%) are right dominant where the PDA is supplied by the RCA. The remaining 15-20% of hearts are roughly equally divided between left dominant (~10%) and codominant (~20%). 
In left dominant hearts the PDA is supplied by the LCx (circumflex) wrapping around the left atrioventricular groove or less commonly the LAD coursing around the apex of the heart. In a codominant heart a single or duplicated PDA is supplied by branches of both the RCA and LAD or LCx.

Question 34

What is a CT angiography and what can it be used for?

Answer 34

A computed tomography angiogram (CT angiogram) is a test that uses X-rays to provide detailed pictures of the heart and blood vessels that go to the body.

A CT angiogram can show narrowed or blocked areas of a blood vessel.

Question 35

What is the Cardiac-thoracic ratio?

Answer 35

This a method used to measure the size of the heart.
Accurate assessment of the size of the heart is carried out using a Posterior-Anterior X-ray.
The ratio should be less than 50% as this mean that the heart size is within normal limits.
If the size of the heart is greater than 50% it can indicate pathology.

Question 36

Describe the coronary veins

Answer 36

The coronary veins include the great cardiac vein, the middle cardiac vein, the small cardiac vein, the smallest cardiac veins, and the anterior cardiac veins.

Question 37

describe the coronary sinus

Answer 37

The coronary sinus is a collection of veins joined together to form a large vessel that collects blood from the myocardium of the heart.
It delivers less-oxygenated blood to the right atrium.