STEMI Guidelines for Healthcare Professionals
This section provides STEMI management guidelines for doctors and physicians that are compliant with AHA & ACC STEMI heart attack guidelines.
Identifying a STEMI withan EKG
Definition
The STEMI definition varies by sex and age.
For men ≥ 40 years old – 2mm in V2-V3 and 1mm in all other leads.
For men ≤ 40 years old – 2.5mm in V2-V3 and 1mm in all other leads.
For women – 1.5mm in V2-V3 and 1mm in all other leads.
Localization
A STEMI can be localized by identification of ST elevation in the following.
STEMI type EKG changes Likely Artery
Anterior STEMI – V3 V4 LAD
Inferior STEMI – II III AVF RCA >> Lcx
Posterior STEMI – STdepression V1 V2 V4 V4 RCA >> Lcx
Lateral STEMI – I AVL V5 V6 Lcx
Anterolateral STEMI – I AVL V3 V4 V5 V6 LAD / Lcx
Septal STEMI – V1 V2 LAD
Anteroseptal STEMI – V1 V2 V3 V4 LAD
LBBB and STEMI EKG
The baseline EKG in LBBB makes diagnosis of STEMI more challenging. Although not perfect, the Sgarbossa criteria are often applied. The points as seen below are added together and a total score of ≥ 3 has 90% specificity for diagnosing LBBB and STEMI.
- Concordant (Upward) ST elevation > 1mm in leads with a positive QRS complex (a score of 5)
- Concordant ST depression > 1 mm in V1-V3 (a score of 3)
- Excessively discordant ST elevation > 5 mm in leads with a negative QRS complex (a score of 2).
RiskFactors for ST-Elevation Myocardial Infarctions
Some scores have been developed to work out a STEMI patient’s risk of poor outcomes. These scores incorporate many factors that include the following:
- Older age
- Worsening heart failure
- Time taken to treat the STEMI
- Cardiac Arrest
- Earlobe Crease
- Fast heart rate
- Low blood pressure
- Diabetes
- Smoking
- Kidney disease
We can use these scores to determine risk and how aggressive we should be in treating patients presenting with STEMI.
TIMI Score http://www.mdcalc.com/timi-risk-score-for-stemi
Grace Score http://www.outcomes-umassmed.org/grace/acs_risk/acs_risk_content.html
STEMI Protocol for Treatment
STEMI patients who present within 12 hours of symptom onset should receive treatment to try and open up the blockage known as reperfusion. This can either be by clot busting drugs given through the veins or by a procedure known as balloon angioplasty and stent placement (PCI). PCI is by far the preferred option as long as it can be done in time.
- If there is a possibility of PCI starting within 120 minutes (within 90 preferred, the faster the better) then this is preferred
- If there isn’t the possibility of being taken to a PCI center and the procedure started by 120 minutes then clot busting drugs should be given
- If its decided that clot busting drugs be used, then these should be given within 30 minutes
STEMI and Cardiac Arrest
STEMI and Cardiac Arrest- Patients with cardiac arrest caused by lethal heart rhythms should have initiation of a cooling hypothermia protocol
- Patients with cardiac arrest surviving to hospital and STEMI initially should have PCI
STEMI and Angiography after Lytics
- Those who got lytics but are in in shock, HF, or high-risk findings on testing should have angiography
- In those even with successful reperfusion therapy its reasonable to perform angiography prior to discharge, although not within 2-3 hours of lytic therapy
Medications After ST-Elevation Myocardial Infarction
Aspirin
Aspirin should be given for STEMI and continued life long
P2Y12receptor Inhibitor
This includes Ticagrelor, Plavix and Prasugrel; this should be given early or at time of stent placement in STEMI. Should be given for a year if stent is placed.
Heparin After Lytics
Heparin should be given for at least 48 hours after lytic therapy and continued for the hospitalization or until PCI performed.
Beta Blockers
Beta-blockers should be given after STEMI in those patients without contraindications
ACE-inhibitors
It’s reasonable to use ACE inhibitors in all patients after STEMI without contraindications
Please share your experience in the comments for others to learn from.
