Ischaemic Heart Disease Flashcards
What are the three layers of the heart muscle?
Endocardium, Myocardium, Epicardium
Endocardium resembles endothelial cells; myocardium is the thickest layer formed of cardiomyocytes; epicardium forms the visceral layer of the pericardium.
What is hs-CTN and its significance?
High-sensitivity cardiac troponin, either troponin I (hs-cTnI) or troponin T (hs-cTnT)
It has high sensitivity and specificity for measuring sub-clinical cardiac damage.
What is the normal range for troponin T?
14 ng/L
Levels above this indicate myocardial damage or infarction.
What characterizes atherosclerosis?
Thickening of the tunica intima due to hypercholesterolemia, LDL infiltration, and inflammation
This process leads to foam cell formation, necrotic core development, and possible plaque complications.
What is aortic dissection?
Aortic dissection is a life-threatening condition caused by tearing of the tunica intimia wall of the aorta, causing blood to acccumulate between the intima and media which creates a false lumen that compromises blood flow to vital organs. It tends to affect the very young with connective tissue disorders or elderly
Anterograde dissection affects the lower branches such as the iliac arteries
Retrograde move back towards the aortic valve at the root of the aorta, resulting in bleeding into pericardium and cardiac tamponade.
What are the two types of aortic dissection
It is more common in individuals with connective tissue disorders
It is classified based on the Stanford classification into:
Type A: involves the ascending aorta- THIS IS A MEDICAL EMERGENCY
Type B: occurs in the aortic arch or descending aorta
Type A involves the ascending aorta and is a medical emergency; Type B occurs in the aortic arch or descending aorta.
What is presentation of aortic dissection?
It presents with a tearing chest pain radiating to the back between the shoulder blades, most severe at onset.
Because thrombolysis may be fatal if incorrectly diagnosed, it is important to assess for history of signs of dissection like car accident, falls, pregnancy, vascular disorders, connective tissue disorders and hypertension.
What is the clinical signs of of aortic dissection?
Common clinical signs include
Unequal pulses and BP on separate arms
tachycardia
hypotension
signs of end organ hypoperfusion such as acute limb ischaemia, abdominal pain, renal failure, stroke and MI.
What are common risk factors for aortic dissection?
- Hypertension
- Atherosclerotic disease
- Male sex
- Connective tissue disorders
- Bicuspid aortic valve
What is the features of atherosclerosis?
Athoersclerosis is characterised by thickening of the tunica intima, when there is a hypercholesterolaemia state where LDL infiltrates the endothelial wall and become oxidised, creating an inflammatory state which causes recruitment of macrophages and T lymphocytes resulting in foam cells forming. This is intnially protective however LDL accumualation. Macrophage cell death is triggered, contributing to further inflammation and development of necrotic core of soft unstable atheroma. This core can become hypoxic which stimulates angiogenesis and can lead to intra-plaque haemorrhage.
Vascular smooth muscle proliferates can differentiate to forms a fibrous cap and release calcifying extracellular deposits which create microcalcifications. The death of the cells like monocytes as they become foam cells contributes to calcification. calcified plaques are least likely to rupture and form over time.
Low density non calcified plaques are made up of fat and connective tissue and most likely to rupture.
Plaque inflammation triggers loss of smooth muscle and produces matrix metallo-proteinases that weaken the fibrous cap
What are common clinical signs of aortic dissection?
- Tearing chest pain radiating to the back
- Tachycardia
- Hypotension
- Signs of end-organ hypoperfusion
What ae the complications of aortic dissection?
Aortic rupture, aortic, regurgitation, myocardial ischaemia, cardiac tamponade and stroke.
Sign is high BP, unequal pulses, new diastolic murmur and pericardial friction rub.
What is pericarditis?
Inflammation of the pericardial sac surrounding the heart typically presents with central chest pain that is pleuritic, relieved by sitting forward and associated with breathlessness and tachycardia.
On examination, there may be a pericardial friction rub and an ECG may show an initial ST elevation with T wave inversion but there is always ST depression in avR .
Pericarditis may result in fluid accumulation and pericardial effusion which can become severe.
It typically presents with pleuritic chest pain that is relieved by sitting forward and may be associated with symptoms like fever and cough.
What is the presentation of pericarditis?
Pain relieved by sitting up. Or leaning forward
Pain worsened with PALPATION, exertion and positions
Precipitated by viral infection
-> Symptoms such as fever, cough, dizziness and rash secondary to the pain that is linked to the underlying disease.
Pain may radiate to the trapezius if the phrenic nerve is damaged.
Suspicion of oesopagitis or acute pancreatitis should be had if it is assoicated with food intake.
What are the causes of pericarditis?
- Infection (bacterial, tuberculosis, HIV)
- Malignancy
- Autoimmune conditions (lupus, rheumatoid arthritis)
- Dressler syndrome
What is Dressler syndrome?
Dressler syndrome, an immune response where pericarditis, fever and pleuritic pain occurs after an MI, when there is damage to the heart muscle which can lead to the formation of anti-myocardial antibodies
What is the presentation of musculoskeletal pain?
sharp and localised pain, which has tenderness over chest wall
It is not affected by exertion
Worsened with palpation, movements like coughing and heavy breathing
What is oesophageal spasm?
Oesophageal spasm are painful contractions that can prevent food and liquids travelling through the oesophagus and there are two types:
Hyppercontractile oesophageal spasm in absence of regurgitation
Diffuse oesophageal spasm in the lower region causing regurgitatoin
How does oesophageal spasm present?
It is characterised by squeezing chest pain, with difficulty swallowing solids and liquids, feeling of object stuck in the throat and regurgitation. There is water brash, where excessive saliva mixes with stomach acids in the throat causes a foul mouth taste typically at night, increasing the risk of oesophageal cancer. It is ore likely in women and people in their 60s
What is cardiac tamponade?
Build-up of fluid in the pericardial sac causing cardiac compression
It presents with sharp pain, breathlessness, and signs similar to pericarditis.
How does cardiac tamponade present?
Sharp pain that worsens when deep breathing or coughing and lying flat or on the left side, breathlessness, dysphagia and hoarseness. It has the same signs as pericarditis with decreased palpable pulse, tachycardia,hypotension, shockmuffled heart sounds and JVP distention.
What are the signs of cardiac tamponade?
- Pulsus paradoxus: Decreased palpable pulse
-> Pain relieved by sitting forward - Tachycardia
- Hypotension
- Muffled heart sounds
- JVP distention
Management involves the drainage of pericardial fluid, and supportive therapy with IV colloids to expand the intravascular volume to prevent shock and adrenaline.
How does pleuritic chest pain present?
Pleuritic chest pain is inflammation of the pleura lining that causes chest pain which worsens when breathing a dn coughing, shortness of breath and the pain may radiate to the shoulders or back.
It can be caused by an infection or injury
How does oesophageal rupture?
Oesophageal rupture can result in sudden retrosternal chest pain, along with respiratory distress, severe vomiting/retching and subcutaneous emphysema. On examination, patient will have dullness to percussion, reduced air entry and oelural effusion.
There is a high risk of sepsis and low BP regulation, so acute management is fluid resuscitation with high flow oxygen, broad spectrum antibiotics and antifungals. Definitive management is removal of contamination in the mediastinum, Decompression of the oesophagus and nutritional support