Learning Objectives: AH1 Cardiology Flashcards
(136 cards)
Differential diagnosis for chest pain:
think: Cardiac, pulmonary, GI, vascular, mediastinal, MSK, MH other
Loss of consciousness: Differential diagnosis? (list 8)
Think- due to true syncope- (impaired cerebral blood flow) Vs Loss of consciousness due to impaired cerebral perfusion!
Differential for local edema, Generalised oedema?
List 4 for both
Generalized oedema ddx:
- increased hydrostatic pressure/fluid overload ■ HF, pregnancy, drugs (e.g. CCBs), iatrogenic (e.g. IV fluids)
- decreased oncotic pressure/hypoalbuminemia ■ liver cirrhosis, nephrotic syndrome, malnutrition
- increased interstitial oncotic pressure— myxedema
- increased capillary permeability ■ severe sepsis
- hormonal ■ hypothyroidism, exogenous steroids, pregnancy, estrogens
Differential diagnosis for Palpitations? - think causes of sinus tachy, then pathological tachycardias,
Differential diagnosis for dyspnoea? (Excercise, CVS, resp, parenchymal lung disease, pulmonary vascular, neurovascular, anxiety, haem/metabolic
ACS: ST elevation myocardial infarction:
How are the patients likely to present?
What should be done immediatley in pt with suspected ACS?
How do you make a clinical diagnosis of ACS? (e.g what bloods and ECG requirements)
What is the best management strategy for ACS if a patient is close to a teritary hospital?
What should all patients who survive and Acute MI
- ST-elevation myocardial infarction (STEMI) presents with central chest pain that is classically heavy in nature, like a sensation of pressure or squeezing. Examination is variable, and findings range from normal to a critically unwell patient in cardiogenic shock.
- Give a loading dose of aspirin as soon as possible to any patient with suspected acute coronary syndrome.
- Make a clinical diagnosis of STEMI and start immediate treatment when a patient presents with symptoms suggestive of myocardial ischaemia and has persistent ST-segment elevation in at least 2 anatomically contiguous ECG leads.
- A rise in cardiac-specific troponins confirms the diagnosis but do not wait for laboratory results before starting treatment.
- Immediate and prompt reperfusion can prevent or minimise myocardial damage and improve the chances of survival and recovery. Primary percutaneous coronary intervention (PCI) is the best management option for most patients, with fibrinolysis reserved for those without access to timely primary PCI.
- Survivors of acute MI should receive cardiac rehabilitation and be closely followed up to ensure adequate modification of risk factors and optimisation of (and adherence to) pharmacotherapy for secondary prevention, and to monitor for the development of post MI complications and/or residual angina symptoms
What is the definition of ACS? (e.g what is the STEMI requirements)
- Acute myocardial infarction is myocardial cell death that occurs because of a prolonged mismatch between perfusion and demand. In the case of ST-elevation myocardial infarction (STEMI) this is caused predominantly by complete atherothrombotic occlusion of a coronary artery.
- In the appropriate clinical context, a STEMI is diagnosed clinically when there is new (or increased) and persistent ST-segment elevation in at least two contiguous leads of ≥1 mm in all leads other than leads V2-V3 where the following cut-off points apply:
- ≥2.5 mm in men <40 years old
- ≥2 mm in men >40 years old
- ≥1.5 mm in women regardless of age
- 1 mm = 1 small square (at a standard ECG calibration of 10 mm/mV).
Contiguous ECG leads lie next to each other anatomically and indicate a specific myocardial territory
What are the major risk factors for ACS?
What is the Aetiology of MI?
What is the pathophysiology?
Aetiology
- MI is usually a consequence of coronary artery disease. Atherosclerosis with plaque fissuring or rupture and thrombus formation is the underlying aetiology for STEMI in most patients. A small proportion of patients present with STEMI caused by coronary spasm reducing myocardial perfusion, coronary embolism, or following chest trauma or spontaneous coronary or aortic dissection.
Pathophysiology
- Atherosclerotic plaques form gradually over years
- They begin with the accumulation of low-density lipoprotein cholesterol and saturated fat in the intima (the inner layer) of blood vessels.
- This is followed by the adhesion of macrophages to endothelium, then diapedesis and entry into the intima, where they accumulate lipids and become foam cells.
- Foam cells are a rich source of proinflammatory mediators.
- The lesion up to this point is referred to as a fatty streak, and may be reversible to a certain extent.
- Subsequent evolution involves migration of smooth muscle cells from the media, and their proliferation and deposition of extracellular matrix, including proteoglycans, interstitial collagen, and elastin fibres.
- Some of the smooth muscle cells in advanced plaques exhibit apoptosis.
- Plaques often develop areas of calcification as they evolve.
- The plaque initially evolves with the artery remodelling outwards, followed by encroachment on the arterial lumen. Eventually the stenosis can limit flow under conditions of increased demand, causing angina.
STEMI typically occurs after abrupt and catastrophic disruption of a cholesterol-laden plaque. This results in exposure of substances that promote platelet activation and aggregation, thrombin generation, and thrombus formation, causing interruption of blood flow. If the occlusion is severe and persistent, myocardial cell necrosis follows.
- On interruption of blood flow in the coronary artery, the zone of myocardium supplied by that vessel immediately loses its ability to shorten and perform contractile work.
- Early hyperkinesis of the non-infarcted zones occurs, probably as a result of acute compensatory mechanisms including increased sympathetic activity and Frank-Starling mechanism. As necrotic myocytes slip past each other, the infarction zone thins and elongates, especially in anterior infarction, leading to infarction expansion.
- If a sufficient quantity of myocardium undergoes ischaemic injury, left ventricular (LV) systolic function becomes depressed; cardiac output, stroke volume, blood pressure, and compliance are reduced; and end systolic volume increases.
- Clinical heart failure occurs if 25% of myocardium has abnormal contraction, and cardiogenic shock occurs on loss of >40% of LV myocardium.
- Decreased compliance and increased LV end diastolic pressure give rise to diastolic dysfunction.
How are MIs Classified?
What is the “Fourth Universal Definition of myocardial infarction”? (acute MI Types 1,2,3) What implications do each of these classifications have on management (they are different..)
Acute coronary syndrome (ACS)
- Historically ACS has been divided into three clinical categories according to the presence or absence of ST-segment elevation on a presenting ECG and on elevations of cardiac troponin T or I.
- ST-elevation myocardial infarction (STEMI): ECG shows persistent ST-segment elevation in at least two anatomically contiguous leads.
- Non-STEMI (NSTEMI): ECG does not show ST-segment elevation, but cardiac biomarkers are elevated. The ECG may show ischaemic changes such as ST-segment depression, T-wave inversion, or biphasic T waves.
- Unstable angina pectoris: non-specific ischaemic ECG changes, but cardiac biomarkers are within the normal range.
Case examples of ACS:
Outline some key recommendations for Urgent assessment and diagnosis of STEMI:
What is the classification of Cardiogenic shock?
What are important differentials to consider with pt presenting with chest pain?
Always consider alternative diagnoses that might explain the presenting symptoms and/or ST elevation on ECG, including:
- Aortic dissection (ST elevation can be present on the ECG)
- Pulmonary embolism (ST elevation or ST depression can be present on the ECG)
- Pericarditis (ST elevation can be present on the ECG)
- Myocarditis (ST elevation can be present on the ECG)
- Pneumothorax
- Pneumonia
- Intracranial pathology (e.g., subarachnoid haemorrhage)
- Gastro-oesophageal reflux disease
- Oesophageal spasm
- Costochondritis
- Anxiety or panic.
Outline ECG leads associated with each vessels:
Lateral circumflex-
Inferior RCA
Septal (LAD) -
Anterior (LAD)
Lateral circumflex or diagonal
How can a previous”silent MI’ be diagnosed?
Anterior STEMI ECG
-Example key fetaures?
Aneterolateral STEMI example:
Key features?
Inferoposterior STEMI
Key features ECG?
What are key features on hx and examination for ACS?
What are key investigations to undertake in patient with suspected ACS?
DDx for ACS?
Criteria for ACS - ST elevation ECG?
Criteria for acute, evlovling or recent MI?
Criteria for established MI?
ACS Qld Health clinical pathway page 1:
ACS Qld Health clinical pathway page: Day 1 Pathway (Acute STEMI/NSTEMI)
Investigations?
Medications?
Observations/Treatments? (how often and what and why)
Nutrition and mobility?
Education and discharge planning?