• Default treatment for STEMI in the UK is primary PCI (pPCI)
• Role of thrombolysis is limited to cases where there is a delay in the system, that means that pPCI is unlikely to be achieved within 120 min, then a thrombolytic strategy should be deployed 
• Aim should be to deliver thrombolysis within 10 min of taking decision that the patient will not achieve pPCI within the 120 min window
• Once thrombolysis delivered, arrange transfer to a pPCI centre
• Typical STEMI criteria apply
  
  • presentation within 12 hr of onset of symptoms
  • typical cardiac chest pain persisting for >30 min
  • >1 mm ST segment elevation in 2 or more precordial leads or 2 or more bipolar leads or >1 mm ST segment depression in leads V1–V3 (suggesting acute posterior infarction) or LBBB with any of the following in leads V1–V3:
    
    • >1 mm ST segment depression
    • >1 mm ST segment elevation where QRS complex positive
    • >5 mm ST segment elevation where QRS complex negative

• Absolute:
• active bleeding
• Relative:
• major trauma/major surgery within previous 4 weeks
• stroke/TIA within previous 3 months
• confirmed subarachnoid haemorrhage at any time
• traumatic cardiac massage or intracardiac injection
• known bleeding disorder
• active dyspepsia or history of GI haemorrhage
• sustained systolic BP ≥180 mmHg
• proliferative retinopathy
• recent head injury
• pericarditis
• INR >2.0

• Administer tenecteplase based on body weight, with a maximum dose of 10,000 units (tenecteplase 50 mg) according to table below. However, any bolus, fibrin specific thrombolytic is acceptable (such as alteplase – check BNF for treatment regimen). For patients aged >75 yr use half dose of bolus thrombolytic

Choose a body weight:

• Administer by giving unfractionated heparin 5000 units by IV bolus, followed by tenecteplase administered as a single IV bolus over approximately 10 seconds, then give unfractionated heparin 1000 units/hr via infusion pump for 48 hr, adjusting dose to maintain APTT ratio 1.5-2.0

• Hypotension - if occurs de novo, review for cardiogenic shock, mitral regurgitation or tamponade. If thrombolysis being administered, stop IV infusion and recommence at a slower rate after BP has recovered
• Bradycardia - usually responds to atropine 300 microgram IV
• Ventricular tachycardia or idioventricular rhythm - usually self-limiting and requires no therapy. If sustained - see Cardiac arrhythmias guideline
• Avoid arterial puncture, central venous cannulation and IM injections in patients undergoing thrombolytic therapy, unless essential to patient care