Acute coronary syndromes Flashcards
What is an acute coronary syndrome?
Which conditions are included?
A range of conditions associated with a sudden, reduced blood flow to the heart.
The conditions included are:
- Unstable angina
- nSTEMI
- STEMI
Definition of unstable angina
o An unprovoked or prolonged episode of chest pain- raising suspicion of acute myocardial infarction
o Without definite ECG or lab evidence
Definition of nstemi
o Chest pain suggestive of AMI
o Non-specific ECG changes (ST depression/ T inversion/ normal)
o Lab tests showing release of troponins
o Not necessarily caused by stenosis/ occlusion (e.g., sepsis, hypotension)
Definition of STEMI
o Sustained chest pain suggestive of AMI
o Acute ST elevation or new LBBB
Pathophysiology- atherosclerosis
- Epithelial injury
- Migration of monocytes/ macrophages
- LDL lipids consumed transition to foam cells
- Release of growth factors smooth muscle changes from contractile phenotype to secretory phenotype, collagen deposition
- Atheromatous plaque forms within intima
- Plague ruptures and prothrombotic factors are released (plaque and stenosis grows or emboli forms)
Risk factors
Modifiable risk factors of acute coronary syndrome
Smoking
Obesity
Diet
Lack of exercise
High serum cholesterol
Hypertension
Diabetes
Postcode
Non- modifiable risk factors of acute coronary syndrome
Increasing age
Gender (male)
Ethnicity
Family history
Diabetes
Pre-eclampsia
Cardiac differentials for ACS
o MI
o Angina
o Pericarditis
o Aortic dissection
Respiratory differentials for ACS
o PE
o Pneumothorax
o Pneumonia
GI differentials for ACS
o Oesophageal spasm
o GORD
o Pancreatitis
MSK differentials for ACS
o Osteochondrosis
o Trauma
Clinical features (SOCRATES)
o Site- central/ left sided
o Onset- often sudden
o Character- crushing
o Radiation- left arm, neck and jaw
o Associated symptoms- nausea, sweating, clamminess, SOB, vomiting, syncope, confusion
o Timing- constant
o Exacerbating symptoms/ relieving factors- worsened by exertion, relieved by GTN spray
o Severity- often very severe
Distinguishing features between stable and unstable angina
- Stable angina- cardiac chest pain + abnormal/ normal ECG + normal troponin precipitated by stress or exertion+ <20 mins + relieved by GTN
- Unstable angina- cardiac chest pain + abnormal/ normal ECG + normal troponin + occurs at rest + >20 mins + poor GTN relief
Distinguishing between NSTEMI and STEMI
NSTEMI- cardiac chest pain + abnormal/ normal ECG (but not ST elevation) + raised troponin
SETMI- cardiac chest pain + persistent ST-elevation/ new LBBB (no need for raised troponin)
Diagnosis criteria for NSTEMI
2 of the following:
• Cardiac chest pain
• Newly abnormal ECG which is NOT ST-elevation
• Raised troponin
Diagnosis criteria for STEMI
ST elevation >2mm in ADJACENT chest leads
ST elevation >1mm in adjacent limb leads
New LBBB with chest pain or suspicious MI
Investigations for suspected MI
- ECG- looking for ST elevation, LBBB or T wave inversion (most important investigation)
- Bloods- FBC and CRP to rule out infective causes of chest pain
- Troponin- done at least 3 hours after pain starts
- Renal function
- Blood glucose
- Lipid profile
- D-dimer may be appropriate to rule out PE
- CXR- look for pulmonary causes of angina
Results of troponin and ECG for unstable angina
Normal troponin
ECG normal
possible ST depression
Results of troponin and ECG for NSTEMI
raised troponin
ST depression
can be normal ECG
possible T wave inversion
Results of troponin and ECG for STEMI
raised troponin
ST elevation
hyperacute T waves
new LBBB
T inversion (hrs)
Q waves (days)
Draw and label a normal ECG
draw the ECG of a STEMI
draw an ST depression
draw t wave inversion
