Applied Anatomy of the Heart

Question 1

what are the borders of the heart

Answer 1

• Upper right 3rd costal cartilage
• Upper left 2nd costal cartilage
• Lower right 6th costal cartilage
• Lower left 5th intercostal space, midclavicular line

Question 2

what is the cardiac plexus made out of

Answer 2

• vagus nerve - decreases the heart rate
• sympathetic nerves - increases the heart rate
• general visceral afferent nerves

Question 3

describe the pathway of the vagus nerve

Answer 3

CNX comes from the medulla runs down into the neck into the thorax and then into the cardiac plexus, gives off small branches which feed into the SAN

Question 4

describe the pathway of the sympathetic nerves

Answer 4

from T1-T5 spinal cord levels, go to the sympathetic chain in then into the sympatheic chain ganglia then into the cardiac plexus, acts on the SAN to increase the rate of firing

Question 5

where does sympathetic fibres enter the spinal cord between

Answer 5

T1-T5

Question 6

where do the general visceral afferents enter the spinal cord and why is this important

Answer 6

T1 and T5 levels

• At these levels somatic afferents also enter the spinal cord
• Here they synapse with an interneuron and travel in the spinal cord to reach the brain
• The brain is unable to distinguish between visceral and somatic sensation and so pain is experienced within the somatic region

Question 7

what is the right coronary artery divided in to

Answer 7

• Right coronary arteries – divides into the PDA and marginal branch

Question 8

what is the left coronary artery divided in to

Answer 8

• Left coronary arteries – divides into the circumflex, left marginal branch of circumflex and LAD

Question 9

what is the difference in appearance of the right and left coronary artery in an angiograph

Answer 9

RCA always looks C shape as it loops around the heart whereas LCA does not

LCA has three branches which you can see on the angiograph, it looks M shaped, easier to look at the LCA as all the arteries are going towards the apex of the heart

Question 10

describe the blood supply to the conduction system

Answer 10

• RCA supplies the SA node
• The RCA supplies the AV node
• The interventricular descending arteries supply the bundle branches

Question 11

what is the difference between right and left side dominance

Answer 11

• Right dominant heart – gives of PDA

- Left dominant – circumflex gives of PDA (only 30% of population)

Question 12

what happens when there is bundle branch block

Answer 12

• Impulse travels through mycotyes – slows the impulse speed
• Prolongs QRS
• Loss of ventricular synchrony

Question 13

where are the most common places that cause a myocardial infraction

Answer 13

• LAD
• RCA
• Circumflex

Question 14

how do you do a coronary artery bypass

Answer 14

• take the great saphenous vein from the leg

- can sometimes use the internal thoracic mammary artery instead

Question 15

what does an ECG do

Answer 15

• records the electrical activity to the heart

Question 16

what types of leads are there and what plane do they look in in the heart

Answer 16

• 6 perocordial leads (chest) – horizontal plane

- 6 limb electrodes – vertical plane

Question 17

name what part of the heart each lead looks at

Answer 17

AVL – left side of the heart 
AVR – right side of the heart
AVF – inferior aspect of the heart 
Lead I – left side of the heart
Lead II- inferior asepct
Lead III – inferior aspect 
V1-V4- view of anterior 
V5-V6 – lateral/left side

Question 18

name the position of the heart valves

Answer 18

• Aortic – Right 2nd intercostal space sternal edge
• Pulmonary – left 2nd intercostal space sternal edge
• Tricuspid – Left 6th intercostal space sternal edge
• Mitral – 5th intercostal space midclavicular line

Question 19

what valves close in S1

Answer 19

mitral and tricuspid valves close- systole

Question 20

what valves close in S2

Answer 20

aortic and pulmonary valves close– diastole

Question 21

what is it called if a valve does not open properly

Answer 21

stenosis

Question 22

what is it called if a valve does not close properly

Answer 22

regurgitation

Question 23

what are some of the causes of valvular dysfunction

Answer 23

• ageing
• rheumatic fever
• bacterial endocarditis

Question 24

what are the systolic murmurs

Answer 24

• mitral regurgitation

- aortic stenosis

Question 25

what are the diastolic murmurs

Answer 25

- mitral stenosis | - aortic regurgitation

Question 26

describe mitral regurgitation

Answer 26

- Mitral valve is not closing properly so the blood passes back through the valve - Systole hear the heart murmur - Pansystolic often louder in late systole - Heard at apex - Most common form of valvular heart disease

Question 27

describe aortic stenosis

Answer 27

- Turbulence as blood has to be pushed through stenotic aortic valve - Systolic (typically mid-systolic) - Less severe – early systole, more severe – late systole because time taken to generate pressure to pass through stenotic valve - Heard at right second intercostal space

Question 28

describe mitral stenosis

Answer 28

- Rarely produces a soft rumbling diastolic murmur | - Mainly rheumatic in origin

Question 29

describe aortic regurgitation

Answer 29

- Aortic valve is not closing properly so all the blood coming back through aorta into the left ventricle - Rheumatic - Sometimes associated with aortic stenosis - Sound can be complex and often absent - Decreased cardiac output due to regurgitation - Elevates pre-load and afterload - LVH – typically very dilated

Question 30

what are the two types of cardiac remodelling

Answer 30

- Physiological – athletes or pregnancy | - Pathological – valvular disease and atrial fibrillation

Question 31

define preload

Answer 31

- Volume of blood in ventricles at the end of diastole

Question 32

define after load

Answer 32

- Resistance ventricle must overcome to circulate blood

Question 33

what is preload increased by

Answer 33

- Increase the preload by increasing the blood volume as a whole – hypervolemia, valve regurgitation, heart failure(not all blood pumped out of the heart) - Increased preload too much volume so the ventricle increases the volume of the ventricle and thins the walls

Question 34

what is after load increased by

Answer 34

- Increased in – hypertension, vasoconstriction, valve stenosis, outflow stenosis - Increased afterload makes it work harder so the heart gets thicker muscular walls and increases muscular mass

Question 35

what are the two types of ventricular hypertrophy

Answer 35

concentric hypertrophy | eccentric hypertrophy

Question 36

describe what concentric hyperstophy is caused by

Answer 36

- Due to Increased afterload – may be due to aortic stenosis or chronic hypertension - Increasing the stiffness of the wall and reduce the lumen of the ventricle as well thus compromise ventricular filling this causes it to lead to eccentric hypertrophy as you get volume overload - Can lead to eccentric hypertrophy - Reduced compliance leads to volume overload

Question 37

describe what eccentric hypertrophy can be caused by

Answer 37

- Volume overload/preload Chamber dilatation o Aortic and mitral regurgitation o Systolic dysfunction (loss of cardiac inotrophy) o Volume overload (hypervolaemia due to ventricular or renal failure) o Others eg alcohol cocaine - Elevates oxygen demand - Lowers mechanical efficacy (Laplace’s law)

Question 38

the larger the atrium the..

Answer 38

the higher the risk of Atrial Fibrillation (AF)

Question 39

describe the signs of atrial fibrillation

Answer 39

* Diagnosed ECG - absence P waves * Reduced cardiac output * Thrombi and syncope