Session 10 - Chest pain and IHD Flashcards
Where does cardiovascular chest pain occur in the thorax?
-Central
What type of pain is experienced in myocardial ischaemia?
-Tightening
What type of pain is associated with pericarditis?
-Sharp pain
What type of pain is associated with aortic dissection?
-Tearing pain
What are the common respiratory causes of chest pain?
- Infection (pneumonia)
- Pulmonary embolism
- Pneumothorax
Where does respiratory chest pain occur in the thorax?
-Lateral chest pain
What type of pain is associated with respiratory chest pain?
-Pleuritic pain (worsens on inspiration or coughing)
What are the common causes of GI chest pain?
- Reflux oesophagitis
- Gastric/gallbladder or pancreatic disease
What type of pain is associated with GI chest pain?
-Burning pain
What are common causes of musculoskeletal chest pain?
- Trauma
- Muscle pain
- Bone metastases
What type of pain is associated with musculoskeletal chest pain?
-Often localised pain which may increase on movement
Simply, when does myocardial ischaemia occur?
-When supply cannot meet demand
What determines the O2 demand of the heart?
-HR, Wall tension (pre-load and after load), contractility
What determines O2 supply to the heart?
- Coronary bloodflow (perfusion and resistance)
- O2 carrying capacity of the blood
What is the most common cause of ischaemic heart disease?
-A fixed narrowing of the arteries due to atheromatous coronary artery disease
Why is the sub-endocardial muscle most vulnerable to ischaemia?
-Blood flow occurs from epicardium to endocardium
How is flow increased to meet demand?
-Vasodilation of coronary arteries
When do the coronary arteries mainly fill?
-During diastole
Why are collaterals relevant in IHD?
-There is little collateral circulation in the heart, meaning narrowing and occlusion severely deplete the supple to the heart
What are the rare causes of IHD?
- Severe anaemia
- Severe hypotension
- Non-atheromatous causes of coronary artery narrowing
- Thyrotoxicosis (increased BMR)
- Tachycardia
- Aortic stenosis
Why can aortic stenosis cause IHD?
-Pressure in root of aorta decreased and thus less blood driven through coronary arteries
What are the non-modifiable risk factors for CAD?
- Age
- Gender (males )
- Family history
What are the modifiable risk factors for CAD?
- Hyperlipidaemia (LDL/HDL ratio)
- Smoking
- Hypertension
- Diabetes mellitus
- Lack of exercise
- Obesity
What are the two main features of an atheromatous plaque?
- Necrotic core
- Fibrous cap
Describe a stable plaque
-Small necrotic core with a thick fibrous cap, unlikely to fissue/rupture
Describe a vulnerable plaque
-Large necrotic core with thin fibrous cap, likely to fissure/rupture
Why can thrombus formation occur with vulnerable plaques?
- Fibrous cap undergoes erosion or fissuring
- Exposes blood to thrombogenic material in necrotic core
- Platelet aggregation followed by fibrin clot formation -> thrombus
What is a thrombus?
-Mass of coagulated blood causing partial or complete occlusion of an artery
What symptoms are produced from a stable plaque?
-No symptoms or stable angina
By how much can the lumen be reduced by in stable angina?
-70%
What are the possible consequences of an unstable plaque?
- Plaque fissure with thrombus formation causes sudden reduction in artery lumen-> severe reduction in bloodflow -> ischaemia -> infarction
- Acute coronary syndrome