Stable Angina Flashcards
(42 cards)
What is the definition of angina?
A discomfort in the chest or/and adjacent areas associated with myocardial ischaemia but without myocardial necrosis
Explain the pathophysiology of myocardial ischaemia
A reduction in coronary artery blood flow to the myocardium caused by obstructive atheroma, spasm of coronary artery or abnormal flow
What are some more uncommon causes for myocardial ischaemia?
Reduced O2 transport - anaemia
Increased myocardial O2 demand - left ventricular hypertension
Thyrotoxicosis - whole body increased O2 demand
What is the most common cause for angina?
Coronary atheroma
Increased myocardial O2 demand as blood flow is obstructed leads to myocardial ischaemia
Oxygen demand increases in situations of HR and BP rise like exercise or stress
What is stable angina?
Typical distribution of pain or discomfort
Precipitated by excess myocardial O2 demand - exercise, cold air, stress, following a heavy meal
When is stable angina seen - due to obstruction?
When obstructive plaque is more than 70% of artery as atherosclerosis is a progressive process
What is acute coronary syndromes seen?
When there is spontaneous rupture and local thrombosis with degree of occlusion
What characteristics of patients pain show stable angina signs?
Site of pain - retrosternal
Character of pain - often tight pressure or heaviness
Radiation site - neck, jaw, arms
Aggravation - on exertion, stress, or any relieving factors like improvement with rest
What are factors that make angina less likely?
Sharp stabbing pain, pericardial pain, localised, associated with inspiration, superficial, no pattern to pain, lasts for long time and begins after some time from exercise
What are some differential diagnoses for chest pain?
Cardiovascular causes - aortic dissection, pericarditis
Resp. - pneumonia, pleurisy, peripheral pulmonary emboli
Musculoskeletal - cervical disease, muscle spasm or strain
GI causes - oesophageal spasm, ulceration, pancreatitis
What are some signs of myocardial ischaemia where there is no chest pain?
Breathlessness on exertion
Excessive fatigue on exertion
Near syncope on exertion
This is seen in the elderly or diabetes as reduced pain sensation
How is severity of stable angina measured?
Canadian classification of angina severity (CCS0
I - least symptoms
IV - most symptoms like on any activity
What are some non-modifiable risk factors for stable angina?
Age, gender, creed, family history, and genetic factors
What are some modifiable factors for stable angina?
Smoking, lifestyle, diet, diabetes mellitus, hypertension and hyperlipidaemia
What are some examinational findings that can show other condition?
Tar staining
Obesity
Xanthalasma and corneal arcus - hypercholesterolaemia
Hypertension
Abdominal aortic aneurysm bruits, absent or reduced peripheral pulses
Diabetic retinopathy or hypertensive retinopathy
What blood examinations should be carried out for stable angina?
FBC, lipid profile, fasting glucose, electrolytes, liver and thyroid tests
What is CXR used for in stable angina?
Show other causes for chest pain
Can show pulmonary oedema
What will an electrocardiogram show in patient with stable angina?
Normal in over 50% of cases
May be evidence of prior myocardial infarction - pathological Q waves
May be evidence of left ventricular hypertrophy - lateral ST segment depression or strain pattern
What does exercise tolerance test show for a patient with stable angina?
Often confirms angina diagnosis - produces CV stress
Shows typical symptoms and ST-segment depression for a positive test
Evaluated with an ECG
Explain myocardial perfusion imaging
Superior to ETT in detection of CAD, localisation of ischaemia and assessing size of area affected
Involves radioactivity
If cant exercise then pharmacological stress is used
What is given to produce pharmacological stress?
Adenosine
Dipyridamole
Dobutamine
How does myocardial perfusion imaging work?
Radionuclide tracer is injected at peak stress on one occasion and image obtained and rest on another so compare
Normal myocardium take up tracer
What are the results of a myocardial perfusion imaging?
Tracer is seen at rest but not after stress = ischaemia
Tracer neither seen at rest or after stress = infarction
Describe an ECHO test?
US looking at cardiac structure - particular left articular myocardium
Can be done at rest using a stressor
See if area has reduced contractibility on stress - reduced blood flow so MI
