ST Elevation Myocardial Infarction - STEMI
Early recognition and differentiation of ischaemic chest pain is important. The Cardiac Society of Australia and New Zealand (CSANZ) & The National Heart Foundation of Australia ACS Treatment Algorithm [#national-heart-foundation-of-australia.-2011] identifies this pathway in a stepwise process.
When someone presents with symptoms consistent with ACS they should immediately have an ECG, followed by a clinical medical assessment. All patients need to be given oral aspirin150-300mg if ACS is suspected and there are no contra-indications.
If they meet the criteria for reperfusion, then dependant on their location and access to a cardiac catheter lab, and time from onset of symptoms, they should receive fibrinolysis or percutaneous coronary intervention (PCI).
ECG Criteria for STEMI:
Persistent ST elevation in two contiguous chest lead of >2mm, OR
Two contiguous limb leads of >1mm, OR
New left bundle branch block (LBBB) pattern
Non-ST Elevation Acute Coronary Syndrome – NSTEACS
When someone presents with minor or no ECG changes a careful clinical history should be taken which includes, assessment of cardiovascular risk factors and history of current symptoms. Further assessments include, physical assessment, ECG, CXR and high sensitivity troponin, among other blood tests.
Patients will be stratified as being low, intermediate or high risk according to their troponin levels, clinical presentation and risk factor profile.
To facilitate this risk stratification assessment of troponin levels may be required at 3 hours and up to 6 hours from presentation, if initially negative.
A positive troponin test supported by clinical history in the absence of other causes for elevated troponin, is strongly suggestive of acute myocardial infarction (MI) – high risk ACS.
A negative troponin test throughout this time frame in the absence of ongoing symptoms suggests a low risk category, and these patients will be referred for coronary artery disease ‘rule-out’, through exercise stress testing.
For further information on low, intermediate and high risk NSTEACS refer to the ACS treatment algorithm pathway.
All patients eligible for cardiac rehabilitation should be given the opportunity to enrol in a cardiac rehabilitation program during or shortly after their stay in hospital. Cardiac rehabilitation aims to slow or reverse disease progression and to optimise functioning by providing physical, mental and social support and improving health behaviours.
Cardiovascular risk factor education is provided in a way that motivates patients and enables them to self-manage their lifestyle risks and identified needs for change. [#woodruffe-s-neubeck-l-clark-ra-et-al.-2015]
Effective strategies to manage patients with ACS include: