Acute Coronary Syndromes Flashcards
acute coronary syndromes
umbrella term for any acute presentation of coronary artery disease covers unstable angina, NSTEMI and STEMI
aetiology
usually the result of a thrombus from an atherosclerotic plaque blocking a coronary artery
pathophysiology 1
The mechanism that is common to all ACSs is rupture or erosion of the fibrous cap of a coronary artery plaque
pathophysiology 2
This leads to platelet aggregation and adhesion, localized thrombosis, vasoconstriction and distal thrombus embolization
pathophysiology 3
Thrombus formation and the vasoconstriction produced by platelet release of serotonin and thromboxane A2 result in myocardial ischaemia due to reduction of coronary blood flow
what can acute coronary syndromes lead to
can lead to cardiac arrest
Ischaemia of the heart causes myocytes to be replaced with scar tissue, decreasing the hearts ability to pump blood, potentially leading to left-sided heart failure
unstable angina
subtotal occlusion, supply led ischaemia without infarction, high (50%) risk of MI in subsequent 30 days
NSTEMI
subtotal occlusion
STEMI
complete occlusion
MI
myocardial necrosis with a raised troponin and at least one other symptom suggestive of an mi
type 1 MI
Traditional MI due to an acute coronary event
type 2 MI
Ischaemia secondary to increased demand or reduced supply of oxygen
type 3 MI
Sudden cardiac death or cardiac arrest suggestive of an ischaemic event
type 4 MI
MI associated with PCI / coronary stunting / CABG
non ischaemic myocardial injury with necrosis
- Not technically a type II MI
- Can be caused by cardiac contusion, ablation, pacing, cardiotoxic chemotherapy
- Can raise Troponin even though it is not an atherosclerotic MI
symptoms
- Severe crushing central chest pain at rest
- Pain radiates to jaw and arms
- Similar to angina but more prolonged and not relieved by GTN
- Associated with sweating, nausea, and often vomiting
- Can occur at rest, as opposed to stable angina
- 30 mins or longer
atypical presentation - silent MI
- Particularly important in women, the elderly and patients with diabetes
- Milder symptoms (without chest pain) especially in younger women
- Shortness of breath, fatigue, body aches, overall feeling of illness
- Unusual feeling/mild discomfort in the back, chest, arm, neck or jaw (without chest pain)
- Heartburn, nausea/vomiting, abdominal pain
- Symptoms may occur up to a month before MI: fatigue, sleep disturbance, SOB, anxiety, indigestion, palpitations
signs
xanthelasma - sign of atherosclerosis
what do to when a suspected acute coronary syndrome 1
- 12 lead electrocardiogram
- ST elevation acute coronary syndrome
- troponin positive
- ST elevation MI
what do to when a suspected acute coronary syndrome 2
- 12 lead electrocardiogram
- Non ST elevation acute coronary syndrome
- troponin positive
- non ST elevation MI
what do to when a suspected acute coronary syndrome 3
- 12 lead electrocardiogram
- Non ST/ ST elevation acute coronary syndrome
- troponin negative
- unstable angina
STEMI ECG
- ST segment elevationin leads consistent with an area of ischaemia
- T wave inversion
- Q waves
evolution of abnormal ECG in a STEMI
- ST elevation - first few hours
- Q wave formation and T wave inversion - first day
- Old MI (previous heart attack) - Q waves with out without inverted T waves
NSTEMI ECG
- May be normal
- ST segment depressionin a region
- Deep T Wave Inversion
- Pathological Q Waves(suggesting a deep infarct - a late sign)
