Presentation
Chest pain. Central, crushing, radiation to arm, neck or jaw. Lasting >20 mins
Dyspnoea and palpitations also common
Beware abnormal presentations, especially in the elderly or diabetics with 'silent' infarct - epigastric pain, pulmonary oedema, acute confusion
History
Features of pain - SOCRATES - sight, onset, character, radiation, associated features (autonomic features), time course, exacerbating/relieving factors (breathing, position, exertion, eating) and severity (0-10)
Recent trauma?
Does the patient have a GTN spray and has it helped their symptoms?
Does the patient have any risk factors for developing vascular disease - Hypertension, hypercholesterolaemia, obesity, diabetes, previous acute coronary event/stroke, smoker, lifestyle/occupation, family history of ischaemic heart disease?
PMHx - consider other causes for the presenting symptoms, such as gastric, respiratory problems, MSK
Medications - cardiac or respiratory medications, antacids, anticoagulants
Determine if any absolute contraindications to thrombolysis - Ongoing internal bleeding, recent trauma, previous allergic reaction, recent hemorrhagic stroke
Vital signs / observations
Tachycardia/Bradycardia
Tachypnoeic
Hypotensive/ hypertensive
Examination
'clammy' - cool and sweaty, pallor
Signs of heart failure? - raised JVP, basal crepitations, 3rd heart sound
Added heart sounds - pan systolic murmer may suggest rupture/dysfunction of papillary muscle/VSD
Bedside tests
ECG - ST Elevation (>1mm in 2 or more contiguous limb leads or >2mm in chest leads)| Area of Myocardial damage | Lead Changes |
| Anterioseptal | V1-V4 |
| Anteriorlateral | V4-V6, I, aVL |
| Inferior | II, III, aVF |
| Posterior | tall R and ST depression in V1-V2 |
Subsequent Q waves in the hours following event
T wave inversion days following the event
New LBBB
Laboratory investigations
FBC, U&E, LFT, D-dimer, lipids, glucose, lactate
Cardiac Markers - various cardiac markers so check locally which you should send at what time-points after the onset of chest pain. Troponin I or T will show an increase 6 hour post-pain and remain raised for up to 14 days. Treatment should Not be withheld waiting on results as ECG findings and history alone are sufficient to make the diagnosis
Consider ABG if patient acutely unwell
Radiological investigations
CXR - cardiomegaly, signs of LV failure (pulmonary oedema)
Urgent echo/CT if suspect other pathologies such as PE, Aortic dissection etc
Management
Immediate management
Continually monitor pulse oximeter, BP and ECG
Morphine - eg IV Diamorphine 2.5-5mg + Antiemetic (Metoclopramide 10mg IV)
Oxygen - only if SpO2 shows evidence of hypoxaemia
Nitratrates - GTN 400micrograms SL, 2 puffs SL every 5 minutes until pain free
Aspirin 300mg PO STAT
+
Clopidogrel 300mg PO
If presence of ST-elevation or new LBBB
PPCI is indicated. The patient must have presented <12 hours from symptom onset and PCI must be delivered within 120 minutes from ECG diagnosis.
These patients will require a CCU bed and consideration for glycoprotein IIb/IIIa inhibitors (Tirofiban/Abciximab)
If PCI is not available, thrombolytic therapy should be offered providing no absolute contraindications (e.g. Active bleeding, CNS trauma, neurological neoplasm and previous stroke <6 months). Check local policy for choice of thrombolytic agent:
Streptokinase is a non-fibrin specific agent - standard dose 1.5 million units in 50ml 0.9% slain by IV infusion over 1 hour
Alteplase specific fibrin activator - Given as bolus infusion and heparin commenced following infusion
Prior to discharge
Following acute myocardial infarction best rest for 48 hours plus with continuous ECG monitoring due to high risk of complications. Thromboprophylaxis also required.
Patients having received PCI will have shorter stay in hospital, thrombolysis patients will require risk stratification and consideration for in-patient angiography
Aim to reduce modifiable risk factors such as smoking, obesity, control of diabetes, blood pressure and cholesterol.
Non-pharmacological
Smoking cessation and referral to cardiac rehabilitation to provide support for lifestyle modifications such as diet and re-introduction of physical activity following MI
Pharmacological
ACE inhibitor - eg ramipril. Start on low dose for example Ramipril 2.5mg daily, then increase to either 5mg then maximally 10mg
Statin, eg atorvastatin 10-80mg PO ON
Beta blocker, eg bisoprolol 5mg PO OD (this can be uptitrated as BP allows)
Aspirin - 75mg OD for life
Clopidogrel - 75mg OD for 12 months in people who have received a bare metal or drug-eluting stent.
Consider giving 75mg clopidogrel for 1 month and consider extending unto 12 months in patients who have had a STEMI and medical management with or without reperfusion treatment with a fibrinolytic agent
Symptomatic treatment with nitrates (GTN) and possible addition of calcium channel blockers etc
Follow up
Review in out-patient clinic at 5 weeks and 3 months for symptoms and to check both lipid and BP
Complications
Early
Recurrent Ischaemia or failure to reperfuse
Dysrhythmias
Cardiac Arrest
Pericarditis
Systemic Embolism
Valvular Pathology
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Late
Late malignant ventricular arrhythmias
Dreslers Syndrome (Recurrent pericarditis, pleural effusion, fever)
Left Ventricular Aneurysm
Prognosis
50% of deaths occur within the first 2 hours of onset of symptoms
Up to 7% die before discharge
Worse prognosis if elderly and LV failure
