STEMI vs NSTEMI
typically have ST elevation in two contiguous leads on a 12-lead ECG
- ST elevation in leads II, III and aVF
- Progressive development of Q waves in II, III and aVF
- Reciprocal ST depression in aVL (± lead I)
- This indicates myocardial infarction/necrosis
STEMI is attributable to rupture of the
fibrous atherosclerotic plaque leading to platelet aggregation and thrombus formation at the site of rupture .
- The thrombus causes an abrupt 100% occlusion to the coronary artery, is a medical emergency, and requires immediate revascularization of the blocked coronary artery.
- using fibrinolytics dissolves thrombi in the coronary arteries and restores myocardial blood flow. Examples of these agents, which target the fibrin component of the coronary thrombosis, include:
• Tissue plasminogen activator (t-PA, alteplase [Activase]) (IV or intracoronary)
• Reteplase (Retavase) (IV or intracoronary)
• Tenecteplase (TNK) (IV push [IVP])
Thrombolytic agents are most effective when
- Thrombolytic agents are most effective when administered within the first 6 hours of a coronary event. They are used in men and women, young and old.
- It is indicated for chest pain of longer than 30 minutes' duration that is unrelieved by nitroglycerin, with indications of STEMI by the ECG.
- The goal is to start the infusion of fibrinolytics within 30 minutes of ED admission.
For some patients having an ACS, primary percutaneous coronary intervention (PCI) may be used to reopen the clotted coronary artery and restore perfusion.
Percutaneous intervention has been associated with excellent return of blood flow through the coronary artery when it can be performed by an interventional cardiologist within 2 to 3 hours of the onset of symptoms.
Monitor the patient for indications that the clot has been lysed (dissolved) and the artery reperfused. These indications include:
• Abrupt cessation of pain or discomfort
• Sudden onset of ventricular dysrhythmias
• Resolution of ST-segment depression/elevation or T-wave inversion
• A peak at 12 hours of markers of myocardial damage