STEMI/AMI is a medical emergency caused by the complete or partial occlusion of a coronary artery and requires prompt hospitalization and intensive care intervention management.

Signs and symptoms

Severe chest pain with the following characteristics, site: retrosternal or epigastric, quality: crushing, constricting or burning pain or discomfort, radiation: to the neck and/or down the inner part of the left arm, duration: at least 20 minutes and often not responding to sublingual nitrates, occurrence: at rest. May be associated with: pulmonary oedema sweating, hypotension or hypertension, arrhythmias

Diagnostic criteria

Initial diagnosis:

Management including both diagnosis and treatment of STEMI/AMI starts at the point of first medical contact (FMC), defined as the point at which the patient is either initially assessed by a paramedic or physician or other medical personnel in the pre-hospital setting, or the patient arrives at the hospital emergency department.

Simple recognition triage: Two out of three points most likely point to STEMI/AMI diagnosis

• Symptoms - typical/atypical chest pain

• ECG – ST elevation in in two contiguous leads≥0.1mV

• Raised cardiac biomarkers– Total Creatine Kinase (Total-CK), Creatine Kinase MB (CK-MB) and Standard/High Sensitive Troponin I or T

Control cardiac pain

• Glyceryl trinitrate sub-lingual/ spray 0.5mg (make sure patient hasn’t taken phosphodiesterase-5 inhibitor). For persistent pain and if oral therapy is insufficient

• Glyceryl Trinitrate IV, 1–2 µg/kg/min titrated with chest pain over 8–24 hours.

OR

Morphine, IV, 1–2 mg/minute dilute 10 mg up to 10 mL with sodium chloride solution 0.9%. Total maximum dose: 10 mg, repeat after 4 hours if necessary.

Anti-platelets therapy

Aspirin 300mg PO stat then followed by 75mg/100mg daily

Plus

• D: Clopidogrel 300–600 mg PO stat, then 75 mg every 24 hours,

• OR S: prasugrel 60 mg PO stat (given after the coronary anatomy is defined, before PCI), then 10 mg daily,

• OR S: ticagrelor 180 mg PO stat, then 90 mg every 12 hours.

Statin high dose

B: Atorvastatin 80 mg PO stat, then 40 mg every 24 hours

OR

S: Rosuvastatin 10–40 mg PO every 24 hours

Anticoagulant

Heparin UFH 70–100U/Kg body weight IV every 24 hours. ⚠ Dose check note: UFH 70–100 U/kg IV is normally given as a bolus, followed by a continuous infusion adjusted by aPTT; follow the local protocol or senior advice.

OR

Enoxaparin 1mg/kg body weight sc bid, Reduce dose in renal failure patient to 0.5mg/kg

Beta blocker (ß –blockers)

In case of LV dysfunction

Carvedilol initial dose 6.25mg twice daily preferred, titrate dose upward to maximum dose 25mg twice daily In the settings of normal systolic function

Atenolol 12.5mg or 25mg or 50mg once a day,

OR

• C: Metoprolol succinate (SR) 25–200 mg PO every 24 hours,

• OR S: metoprolol tartrate 5 mg IV over 2 minutes (maximum 3 doses), then 50–100 mg PO every 12 hours,

• OR S: bisoprolol 2.5–10 mg PO every 24 hours,

• OR S: verapamil SR 240–480 mg PO daily in 1–2 doses – start from 7 days after the infarction, single dose not above 240 mg (secondary prevention).

Angiotensin-Converting Enzyme Inhibitors (ACEIs)

Captopril 6.25mg or 12.5mg (PO) 8 hourly

OR

Enalapril 10mg twice a day

OR

C: Lisinopril 5–10 mg PO every 24 hours

If ACE inhibitors are not tolerated, use an ARB: B: losartan 25–50 mg, OR S: candesartan 8–16 mg, OR S: telmisartan 40–80 mg, OR S: irbesartan 150–300 mg, each PO every 24 hours.

Definitive management of STEMI – Reperfusion therapy (Myocardial reperfusion)

Myocardial reperfusion with rapid recanalization of infarct related artery is the key to success in the management of ST Elevation Myocardial Infarction (STEMI).

Timely reperfusion is crucial for minimization of infarct size and thereby for preservation of left ventricular function and reduction in mortality in STEMI patients

The two main reperfusion strategies for STEMI patients are;

• Thrombolytic (fibrinolytic) therapy – preferably when chest pain has lasted less than 12 hours.

• Primary percutaneous coronary intervention (PPCI) – preferably within 90 minutes.

Thrombolytic agents

Streptokinase IV, 1.5 million units diluted in 100 mL sodium chloride 0.9%, infused over 30–60 min

OR

Alteplase (TPA) 15mg as bolus, 0.75mg/kg over 30min, then 0.5mg/kg over 60min

OR

S: Tenecteplase 0.25–0.5 mg/kg IV bolus

⚠ Dose check note: STG 2026 prints tenecteplase as "0.25–0.5 mg/kg IV bolus" with no maximum dose. WHO and standard product guidance give one weight-banded IV bolus of about 0.5 mg/kg with a maximum of 50 mg: under 60 kg 30 mg, 60–69 kg 35 mg, 70–79 kg 40 mg, 80–89 kg 45 mg, 90 kg or more 50 mg (half dose from 75 years of age); without the 50 mg cap a heavy patient would be overdosed and bleed. Cross-check this dose against the WHO recommendation before prescribing.

Absolute contraindication for thrombolytic

• Previous allergy to streptokinase or used within the last year for streptokinase only

• Stroke CVA within the last 3 months

• History of recent major trauma

• Bleeding within the last month

• Aneurysms

• Brain or spinal surgery or head injury within the preceding month

• Active bleeding or known bleeding disorder

Relative contraindication for Thrombolytic

• Refractory hypertension

• TIA in the preceding 6 months,

• Subclavian central venous catheter

• Warfarin therapy

• Pregnancy

• Traumatic resuscitation

• Recent retinal laser treatment

Refer urgently all suspected or diagnosed cases to a facility with a cardiac catheterisation laboratory for coronary angiography followed by PCI. In triple-vessel, multivessel or left main disease consider coronary artery bypass grafting (CABG), especially in diabetes or a high SYNTAX score.

Non pharmacological

Supportive therapy

• Cardiopulmonary resuscitation before transfer if cardiac arrest occurs.

• Oxygen 40% by face mask if saturation is below 92% or the patient is in distress.

• Admit to HDU/ICU/CCU for haemodynamic monitoring, bed rest in Fowler's position and reassurance; peripheral IV line; monitor BP, heart rate and ECG rhythm.