1. The Cardiovascular system
HCSW Study Day
GJNH Team Cardiothoracic

2. Aims
Be able to describe the structure and function of the cardiovascular system
Understand the components of blood and their functions
Understand blood pressure and normal values
Display knowledge of the coronary arteries and the effects of coronary artery disease
Explain the purpose of cardiac rehab

3. The Cardiovascular System
This consists of the heart and the blood transport mechanism of arteries, veins and smaller vessels
It carries blood continuously round venous and arterial circuits transporting O2 and vital nutrients

4. The Arterial system
This system carries oxygenated blood from the heart to the tissues of the body
Arterial walls are thicker and more elasticated than vein walls as the blood is pumped at higher pressure

5. The Venous system
This system returns the deoxygenated blood to the heart and onwards to the lungs for re-oxygenation
Veins are thinner as the pressure is lower on the return trip

6. Blood
Blood is made up of red blood cells (highest percentage), white blood cells and platelets which are carried in a liquid called plasma
Plasma is mainly water but also contains proteins and nutrients
The average human has about 8 pints of blood (5 litres)

7. Red blood cells These carry oxygen from the lungs to the tissues
The main component of red blood cells is haemoglobin
They are concave discs which have a large surface area for maximum efficiency of oxygen absorbs ion and transportation
If a patient has too little haemoglobin they are said to be anaemic and will often feel lethargic and short of breath on exertion

8. White Blood Cells These protect the body against infection
There are fewer in the blood compared to red blood cells
Higher levels than normal is usually a sign of infection
Lower than normal levels puts the patient at risk of getting an infection and can result in the patient being reversed barrier nursing in protective isolation- most commonly seen in oncology patients or transplant patients

9. Platelets Platelets main role in the blood is to stop bleeding
They are approximately 20% of the size of red blood cells
They are produced in the bone marrow and released into the blood
When bleeding occurs they bind to the surrounding structures causing a clot which seals the hole
If you have too many platelets in your blood you are at risk of developing clots
If you have too few platelets you are at risk of excessive bleeding after an injury

10. The Lymphatic System
This is a major part of the immune system and is based around white blood cells called lymphocytes
Lymph is a fluid which leaks out of blood vessels into the spaces between the spaces between the cells of body tissues
Lymph is circulated by the movements of muscles through one way valves to lymph nodes
If nodes have been removed or are blocked then severe swelling can occur because fluid has no longer got an escape route

11. The Heart
This is a four chambered pump which powers the cardiovascular system
It is divided into right and left by a septal wall which stops oxygenated blood and deoxygenated blood mixing

12. Right Atrium – Deoxygenated blood re-enters the heart from the body via the superior and inferior vena cava.
Right Ventricle – Blood drops through the tricuspid valve into the right ventricle and is then sent back through the pulmonary valve into the pulmonary artery and onwards to the lungs

13. Left Atrium – Oxygenated blood returns to the atrium from the lungs via the pulmonary veins
Left Ventricle – Blood drops through the mitral valve into the left ventricle and is the pushed through the aortic valve by the ventricular contraction into the aorta and off round the body

14. Right heart valves
Tricuspid valve – 3 leaflet valve between the right atrium and ventricle
Pulmonary valve – 3 leaflet valve between the right ventricle and the pulmonary artery

15. Left heart valves
Mitral valve – 2 leaflet valve (Bicuspid) between the left atrium and ventricle
Aortic valve – 3 leaflet valve between the left ventricle and the aorta

16. Main Blood Vessels in the heart
Aorta- Main artery of the heart , carries blood to all of the body except the lungs
Pulmonary veins- delivers oxygenated blood from the lungs to the heart
Pulmonary artery- Takes deoxygenated blood to the lungs
Inferior Vena Cava- Brings blood from the lower body to the heart
Superior Vena Cava- Brings blood from the upper body to the heart
Portal Vein- Transports blood from the digestive system to the liver for filtering

17. How does the heart contract?
The heart rate is controlled by an electrical signal from the Sinoatrial node to the Atrioventricular node.
This in turn causes myocardial contraction

18. Heartbeat The contraction of the heart can be seen in each ECG complex
P wave – atrial contraction (small)
QRS complex – ventricular contraction (much larger)
T wave – repolarisation (rest phase)

19. Blood Pressure
This is the force of blood against the walls of the arteries
It is recorded as Systolic pressure (as the heart beats) over Diastolic pressure (as the heart relaxes)
BP is written as systolic over diastolic i.e. 120/80
Normal blood pressure is less than (<) 120mmHg systolic and less than (<) 80mmHg diastolic

20. Low Blood Pressure (Hypotension)
This occurs when the pressure in the arteries is abnormally low
If it drops too low it can restrict the blood flowing to the head and other vital organs
If it drops too low patients can experience dizziness, fainting and light headedness
It can be caused by dehydration, sepsis, trauma, heart failure or sudden loss of blood
It is commonly treated in the acute setting with IV fluids +/- inotropes

21. High Blood Pressure (Hypertension)
During activity blood pressure naturally rises in order to supply blood to meet increased demand from muscles
This is triggered by the body producing Adrenaline (the fight or flight hormone)
Hypertension is defined as a blood pressure above 140/90 mmHg
It puts increased strain on the heart and smaller blood vessels.
A risk of hypertension is stoke due to the pressure on tiny vessels in the head
Lifestyle modification and medication are key to reducing hypertension with improved intake of fruit and veg, reduction of salt and saturated fats combined with increased exercise levels the main aims

22. Blood supply to the heart
The myocardium (heart muscle) is supplied by coronary arteries wrapped around the outside of the heart
These can be easily damaged or blocked as they are narrow

23. Coronary artery disease
Arteries can become narrowed or completely blocked by either fatty deposits or clots.
Narrowing leads to reduced blood supply which, when the demand for O2 is not met ,leads to pain called angina.
A complete blockage can lead to myocardial infarction (heart attack) and death of the muscle below the blockage if it is not addressed quickly.

24. Coronary Artery Bypass Graft (CABG)
This is the name of the surgery performed to improve the blood supply to the heart
Segments of harvested vein are used to create a supplementary route for blood which bypasses the blockage

25. Peripheral Vascular Disease
The same atherosclerotic plaque that causes coronary disease can occlude peripheral circulation also.
Most common areas affected are the arteries in the legs, arms, kidneys and neck.
It is common to have both types of disease

26. Cardiac Rehabilitation
All patients are invited to attend cardiac rehab after surgery.
This involves exercise in a supervised environment as well as education and social support from other patients in the group.
These are designed to reintroduce patients to a more active lifestyle as well as encouraging them to make positive changes to their daily lives.

27. The End