Acute Coronary Syndromes Flashcards
(31 cards)
What is the site of ischaemic chest pain? Where can it radiate to?
Central (usually) radiating down inner left arm, neck + abdomen
What does ischaemic chest pain feel like?
Crushing
Band-like
Heavy
How long does ischaemic chest pain last?
Remits in several minutes with rest, if its effort related
What are the exacerbating and relieving factors of ischaemic chest pain?
Exacerbating: exercise, effort, stress + tachycardia
Relieving: rest + sublingual nitrate (GTN)
What conditions can be confused with ischaemic chest pain? How can you tell the difference?
MSK pain + chrondritis: localised, reproducible on palpation/movement
Reflux oesophagitis: not effort related, nausea, odynophagia + dysphagia
Gastritis: epigastric modified by antacids
Pericarditis: sharp, better on sitting, pericardial rub + ECG
Mediastinitis: septic + ill, febrile, constant pain + inflammatory markers raised
What may you notice on examination of ischaemic chest pain?
Pallor Hypotension Tachycardia Diaphoresis Cold/clammy Distressed/impending doom (due to chest discomfort, dyspnoea, weakness or dizziness) Central/peripheral cyanosis Low SpO2 Bilateral crackles Raised JVP Hepatomegaly Pedal, lower limb + sacral oedema Mitral regurg, 3/4 sound gallop rhythm, AF or extrasystoles
When could a examination be completely normal regarding ischaemic chest pain?
If the pain has settled
What is unstable angina?
Clinical entity which is the first episode of pain at rest or with minimal exertion with sudden worsening of intensity of frequency of episodes
What is NSTEMI?
Clinico-pathological entity where there is evidence of myocardial damage w/o ST segment changes but many have non-specific ECG changes
What will the history of a NSTEMI look like?
Similar to unstable angina or STEMI
How would you investigate acute coronary syndromes?
- Patient comes in with chest pain
- Working diagnosis is ACS
- ECG
- Biochemistry (e.g. troponin)
- Diagnosis
What are some complications of acute coronary syndrome?
Hypotension Cardiogenic shock AKI Right ventricular infarction Tachy/brady arrhythmias Conduction defects Papillary muscle rupture Pericarditis Ventricular aneurysm Cardiac rupture Recurrent ischaemia Mural thrombosis Post MI (Dressler's) syndrome
What are the 3 main signs of unstable angina?
- Non-occlusive thrombus
- Normal or non-specific ECG
- Normal cardiac enzymes e.g. troponin T
What are the 3 main signs of NSTEMI?
- Non-occlusive thrombus sufficient to cause tissue damage + mild myocardial necrosis
- ST depression/T wave inversion on ECG
- Elevated troponin T by 6 hrs after symptoms commence
What are the 4 main signs of STEMI?
- Complete thrombus occlusion
- ST elevation >1mm in 2 contiguous leads or new LBBB
- Elevated troponin T by 6 hrs after symptoms commence
- Most severe symptoms
Why else can troponin be raised other than for cardiac reasons?
Renal failure
How does vascular injury result in a platelet-fibrin thrombus?
Exposure of collagen + vWF -> platelet adhesion + release -> platelet recruitment + activation -> platelet aggregation
TF exposure -> activation of coagulation -> thrombin generation -> fibrin formation
What types of clots do unstable angina and NSTEMI’s tend to be associated with?
White, platelet-rich + partially occlusive -> microemboli can detach + embolise downstream casing myocardial ischaemia/infarction
What types of clots do STEMI’s tend to be associated with?
Red, fibrin rich + more stable thrombus
What is the pathophysiology of ischaemic heart disease?
- Atherosclerotic plaque causes a fixed coronary obstruction
- Severe fixed coronary obstruction may ensue causing chronic IHD
- Plaque disruption may occur
- Occlusive thrombus may cause acute transmural MI/sudden death
- Mural thrombus with variable obstruction/emboli may cause unstable agina or acute subendocardial MI/sudden death
Explain the phases of a myocardial infarction.
- Ischaemic: survives on anaerobic metabolism initially for several minutes
- Infarction: anaerobic metabolism cannot keep up with metabolic needs causing irreversible damage + cell death
-> affected area contributes less to depolarization
What is an indicative ECG change of ischaemia?
Inverted T waves
ST segment depression
What is an indicative ECG change of injury?
ST segment elevation
What is an indicative ECG change of infarct/scar?
Pathological Q wave formation (old injury)
