11/13/24, 7\:36 PM Guide | Acute coronary syndrome (ACS)

Acute coronary syndrome (ACS)

Table of contents

Introduction

This guide provides an overview of the recognition and immediate management of acute coronary syndrome (ACS) using an
ABCDE approach.
The ABCDE approach is used to systematically assess an acutely unwell patient. It involves working through the following
steps\:
Airway
Breathing
Circulation
Disability
Exposure
Each stage of the ABCDE approach involves clinical assessment, investigations and interventions. Problems are addressed as
they are identi
This guide has been created to assist healthcare students in preparing for emergency simulation sessions as part of their
training. It is not intended to be relied upon for patient care.

Acute coronary syndrome

Acute coronary syndrome (ACS) refers to a range of acute myocardial ischaemic states including\:
ST-elevation myocardial infarction (STEMI)
Non-ST elevation myocardial infarction (NSTEMI)
Unstable angina
Myocardial infarction (MI) or “heart attack” is classi
Type 1 MI results from an acute coronary event, such as plaque rupture and coronary artery thrombus. Type 2 MI is secondary
to ischaemia from causes other than coronary artery disease, such as coronary artery spasm, anaemia, hypotension, or
arrhythmia.
Regardless of the underlying diagnosis, the clinical features of ACS are similar.

Symptoms

Typical symptoms associated with ACS include\:
Chest pain
Referred pain­ \: chest pain can radiate to the epigastrium, arm, neck and jaw
Shortness of breath
Palpitations
Nausea and vomiting
Sweating
Fatigue
Pre-syncope and syncope
Remember that women, the elderly, and people with type 2 diabetes can present with more subtle symptoms.
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Clinical signs

Typical clinical signs associated with ACS include\:
Tachycardia
Tachypnoea
Pallor
Evidence of impaired myocardial function\: hypotension, raised jugular venous pressure (JVP), coarse crackles on chest
auscultation, and additional heart sounds (e.g. pan-systolic murmur)

Diagnosis

ACS and its subtypes are diagnosed based on symptoms, ECG
sounding chest pain is generally used as part of the diagnostic criteria, along with the following\:
STEMI\: persistent ST elevation or new LBBB on ECG; troponin rise
NSTEMI\: persistent ECG changes without ST elevation (typically ST depression or T wave inversion); troponin rise
Unstable angina\: transient ECG changes or no ECG changes; no troponin rise

Management

Management depends on the underlying diagnosis, but should always involve a cardiologist. Typical immediate treatment
includes\:
Aspirin\: 300 mg orally without delay
Analgesia\: options include morphine and nitrates for ischaemic pain
Oxygen\: if hypoxaemic
Primary percutaneous coronary intervention (PPCI) or thrombolysis\: for STEMI
Ongoing treatment may include a second antiplatelet, an anticoagulant such as fondaparinux, glycoprotein IIb/IIIa
inhibitors, beta-blockers, and statins.
ACS is life-threatening and must be recognised and treated in a timely manner. Remember\: time is myocardium!
For further information, read our guide to acute coronary syndrome.

Tips before you begin

General tips for applying an ABCDE approach in an emergency setting include\:
Treat problems as you discover them and re-assess after every intervention
Remember to assess the front and back of the patient when carrying out your assessment (e.g. looking underneath the
patient’s legs or at their back for non-blanching rashes or bleeding)
If the patient loses consciousness and there are no signs of life, put out a crash call and commence CPR
Make use of the team around you by delegating tasks where appropriate
All critically unwell patients should have continuous monitoring equipment attached
If you require senior input, call for help early using an appropriate SBAR handover
Review results as they become available (e.g. laboratory investigations)
Use local guidelines and algorithms to manage speciacute asthma)
Any medications or must be prescribed at the time (you may be able to delegate this to another sta
Your assessment and management should be documented clearly in the notes; however, this should not delay
management
Methodical approach
For each section of the ABCDE assessment (e.g. airway, breathing, circulation, etc.), ask yourself\:
Have I checked the relevant observations for this section? (e.g. checking respiratory rate and SpO2 as part of your
‘breathing’ assessment)
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Have I examined the relevant parts of the system in this section? (e.g. peripheral perfusion, pulses, JVP, heart sounds,
and peripheral oedema as part of your ‘circulation’ assessment)
Have I requested relevant investigations based on my
glucose as part of your ‘disability’ assessment)
Have I intervened to correct the issues I have identi
depletion/hypotension as part of your ‘circulation’ assessment)

Initial steps

Acute scenarios typically begin with a brief handover, including the patient's name, age, background and the reason the
review has been requested.

Introduction

Introduce yourself to whoever has requested a review of the patient and listen carefully to their handover.
In an ACS scenario, you may be asked to review a patient with chest pain and/or shortness of breath.

Preparation

Ensure the patient's notes, observation chart, and prescription chart are easily accessible.
Ask for another clinical member of sta

Interaction

Introduce yourself to the patient, including your name and role.
Ask how the patient is feeling, as this may provide useful information about their condition. In an ACS scenario, the patient may
volunteer that they have chest pain or feel breathless.
If the patient is unconscious or unresponsive, and there are no signs of life, start the basic life support (BLS) algorithm as per
resuscitation guidelines.

Airway

Clinical assessment

Can the patient talk?
Yes\: if the patient can talk, their airway is patent, and you can move on to the assessment of breathing.
No\:
Look for signs of airway compromise\: angioedema, cyanosis, see-saw breathing, use of accessory muscles
Listen for abnormal airway noises\: stridor, snoring, gurgling
Open the mouth and inspect\: look for anything obstructing the airway, such as secretions or a foreign object

Interventions

Regardless of the underlying cause of airway obstruction, seek immediate expert support from an anaesthetist and the
emergency medical team (often called the 'crash team'). You can perform basic airway manoeuvres to help maintain the
airway whilst awaiting senior input.
For details on airway manoeuvres, see our master ABCDE guide.

Re-assessment

Make sure to re-assess the patient after any intervention.

Breathing

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Clinical assessment

Observations
Review the patient’s respiratory rate\:
A normal respiratory rate is between 12-20 breaths per minute
Patients with ACS may be tachypnoeic in an attempt to increase myocardial tissue oxygenation
Review the patient’s oxygen saturation (SpO2)\:
A normal SpO2 range is 94-98% in healthy individuals and 88-92% in patients with COPD who are at high risk of CO2
retention
Hypoxaemia may occur due to cardiac failure and secondary pulmonary oedema
In ACS, SpO2 of 90% and above is tolerated (supplemental oxygen for these patients is not associated with clinical bene
1
General inspection
Inspect the patient whilst at rest, looking for clinical signs suggestive of underlying pathology\:
Cyanosis\: bluish discolouration of the skin, particularly in the extremities, could be a sign of severe cardiac and/or
respiratory compromise in MI
Shortness of breath\: shortness of breath may be observed in ACS. The inability to speak in full sentences indicates
signi
Tracheal position
Gently assess the position of the trachea, which should be central in those presenting with uncomplicated ACS. Palpation of
the trachea can be uncomfortable, so warn the patient and be gentle.
Chest expansion
Assess the patient's chest expansion, looking for evidence of reduced chest wall movement. Chest wall expansion is typically
normal in uncomplicated ACS.
Percussion
Percuss the patient's chest, listening to the resulting percussion note, which, in the absence of underlying respiratory
pathology, would be expected to be resonant.
Pleural e
context of heart failure - ACS may precipitate acute heart failure, and those with pre-existing heart failure may have an
increased risk of MI.
Auscultation
Auscultate both lungs\:
Coarse crackles or crepitations on auscultation, particularly when heard at both lung bases, may represent pulmonary
oedema secondary to impaired cardiac function. ACS can precipitate acute heart failure, resulting in pulmonary oedema.

Investigations and procedures

Arterial blood gas
Take an ABG if indicated (e.g. low SpO2) to quantify the degree of hypoxia and help determine the potential underlying cause.
See our guides for taking and interpreting an ABG for more details.
Chest X-ray
A portable chest X-ray may be indicated if abnormalities are noted during assessment. Many patients presenting with ACS
would have an unremarkable CXR; however, complications or related signs may be detected\:
Cardiomegaly\: suggests underlying cardiac disease (e.g. congestive cardiac failure, hypertrophic cardiomyopathy)
Pulmonary oedema\: including bilateral peri-hilar shadowing, Kerley B lines,
costophrenic angles
Pleural e
level)
Previous relevant procedures\: such as coronary artery bypass grafting (CABG), may be seen in the form of sternotomy wires
and arterial clips
See our CXR interpretation guide for more details.
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Interventions

Patient positioning
If the patient is breathless, sit them upright, which can help with oxygenation.
Oxygen
If the patient has oxygen saturations of 90% or above, oxygen should not be administered in the context of ACS.
If the patient is hypoxaemic, then titrate oxygen as required. This typically involves using a simple face mask, but a 15 L non-
rebreathe mask can be used initially in severe hypoxia. If the patient has COPD and a history of CO2 retention, use a venturi
mask to achieve a target SpO2 of 88–92%.
See our guide to oxygen administration and non-invasive ventilation for more details.
Diuretics
A patient with suspected ACS and new pulmonary oedema should be discussed with a senior doctor at the earliest
opportunity.
If a diagnosis of pulmonary oedema is suspected, diuretics such as furosemide should be considered. Before administration,
circulatory status should be assessed, as the administration of diuretics in the context of hypovolaemia can precipitate
hypovolaemic shock.
Continuous positive airway pressure
Continuous positive airway pressure (CPAP) is an intervention that can e
have not responded adequately to diuretics and supplemental oxygen. These patients should always have the involvement of a
more senior doctor.
For more information about the emergency management of pulmonary oedema, see our ABCDE guide.

Re-assessment

Make sure to re-assess the patient after any intervention.

Circulation

Clinical assessment

Observations
Assess the patient’s heart rate\:
Tachycardia (HR >99 bpm) is a common feature of ACS
Bradycardia (HR \<60 bpm) is a late sign and often precedes cardiac arrest
Assess the patient’s blood pressure\:
Patients may be hypertensive (BP >140/90 mmHg) due to increased sympathetic activity and pain. Chronic hypertension is a
risk factor for ACS.
Hypotension (BP \<90/60 mmHg) may occur as a late sign in ACS, representing cardiac failure
Fluid balance assessment
Calculate the patient’s
output can cause oliguria (\<0.5 mL/kg/hour output).
General inspection
Inspect the patient from the end of the bed whilst at rest, looking for clinical signs suggestive of underlying pathology\:
Pallor\: can suggest underlying anaemia (may precipitate type 2 MI) or poor perfusion (e.g. congestive cardiac failure)
Oedema\: typically presents with swelling of the limbs (e.g. pedal oedema) or abdomen (ascites) and may indicate acute or
chronic heart failure. ACS can precipitate acute heart failure.
Diaphoresis\: sweating and clamminess can be a sign of ACS
Palpation
Place the dorsal aspect of your hand onto the patient’s to assess temperature\:
Cool hands indicate poor peripheral perfusion, which may be seen in heart failure and ACS
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Cool and sweaty/clammy hands indicate poor peripheral perfusion and autonomic dysfunction, which can be signs of ACS
Measure capillary re
Check this centrally on the sternum and compare it with a peripheral CRT on the
A prolonged CRT, i.e. greater than two seconds, suggests poor peripheral perfusion, which may be seen in states that can
precipitate type 2 MI (e.g. hypovolaemia). It may also result directly from MI due to impaired circulatory function.
Pulses and blood pressure
Assess the patient's radial and brachial pulse to assess rate, rhythm, volume and character\:
An irregular pulse is associated with arrhythmias such as atrial (AF). Fast AF can precipitate type 2 MI due to
increased cardiac tissue oxygen demand and can also occur as a result of MI.
Jugular venous pressure (JVP)
A newly raised JVP in the context of ACS can be indicative of right ventricular infarction and subsequent right-sided heart
failure.
Cardiac auscultation
Brie
A pericardial rub or mupericarditis or cardiac tamponade, both of which can
present with chest pain and can be precipitated by MI.
A third heart sound in the context of ACS suggests LV dysfunction
New mitral regurgitation in the context of recent ACS may suggest papillary muscle rupture, a rare but serious complication
Ankles and sacrum
Assess the patient's ankles and sacrum for evidence of oedema, which may represent heart failure precipitated by MI.

Investigations and procedures

Intravenous cannulation
Insert at least one wide-bore intravenous cannula (14G or 16G) and take blood tests as discussed below.
See our intravenous cannulation guide for more details.
Blood tests
Collect blood tests after cannulating the patient, including\:
High sensitivity troponin\: to help con
FBC\: to screen for anaemia and signs of infection
U&Es\: to assess renal function and electrolyte levels
CRP\: to screen for evidence of infection
Serum glucose\: to identify hyperglycaemia, which should then be treated to improve outcomes
LFTs\: to assess liver function (e.g. ischaemic hepatitis secondary to cardiac failure)
Coagulation screen\: to assess for coagulopathy
ECG
For any patient presenting with chest pain or suspected ACS, an ECG is a vital investigation to perform. An ECG provides
valuable diagnostic information. ECG
should be repeated periodically. Typical
STEMI\: initial hyperacute T waves, followed by persistent ST elevation in at least two contiguous leads and/or new left
bundle branch block (LBBB)
NSTEMI\: persistent T wave inversion and/or ST depression in at least two contiguous leads
Unstable angina\: no changes, or non-speci
For more information about ECG changes, read our guide to ACS.

Interventions

Continuous ECG monitoring
Continuous ECG monitoring should be applied in suspected ACS. ECGs should be repeated periodically (e.g. every 20 minutes),
to assess for persistent changes.
Pharmacology
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ACS is diagnosed based on persistent ECG changes, clinical history, and troponin levels. However, for patients presenting with
cardiac-sounding chest pain, where ACS is strongly suspected, treatment should be initiated while waiting for further results,
i.e. serial ECGs and troponin serology. Time is myocardium!
Aspirin\: in suspected ACS, a 300 mg loading dose of aspirin should be given unless contraindicated. Chewable or
dispersible aspirin is preferred as it o
Morphine\: the evidence for routine administration of morphine in ACS is mixed, and therefore, morphine should be given for
analgesic purposes only. 1
IV morphine should be considered for severe chest pain.
Nitrates\: nitrates can be considered to help relieve ischaemic pain. Avoid in the context of hypotension, severe aortic
stenosis, and signi
Local guidelines should always be followed with regard to the pharmacological management of suspected ACS.
Fluid output/catheterisation
Ask the nursing sta
Consider catheterisation to allow accurate monitoring of urine output if there are concerns about
oedema or heart failure.
See our guide to catheterisation for more details.
Diuretics
If clinical signs of
bibasal crackles), consider administration of an intravenous diuretic (e.g. furosemide)\:
Furosemide increases diuresis and aids the clearance of pulmonary oedema
If a patient is hypotensive, diuretics should not be administered in a ward setting, and urgent critical care input should be
sought
For more information, see our ABCDE guide for pulmonary oedema.

Escalation

Suspected ACS is an emergency presentation. Patients presenting with chest pain and suspected ACS with ECG changes
should be discussed with cardiology at the soonest opportunity, particularly where there is ST elevation.
In practical terms, it is generally preferable to complete your A to E assessment before referring to a specialty, except for very
urgent interventions, e.g. airway. Time is of the essence, however, and so brevity is key.

Re-assessment

Make sure to re-assess the patient after any intervention.

Disability

Clinical assessment

Consciousness
Assess the patient's level of consciousness using the ACVPU scale.
A patient presenting with suspected ACS who develops a decreased level of consciousness (including confusion) would be a
great cause for concern and should be escalated immediately to a senior doctor. The patient may require crash team input.
Brief neurological assessment
Perform a brief neurological assessment by asking the patient to move their limbs and inspecting their pupils. In the context of
ACS, abnormalities would not be expected.
Drug chart review
A brief review of the drug chart may demonstrate relevant medication\:
Antihypertensives\: hypertension is a risk factor for MI, and beta-blockers, calcium channel blockers, and ACE inhibitors may
be used as treatment for coronary artery disease and/or heart failure
GTN\: suggestive of underlying angina
Statin\: hypercholesterolaemia increases the risk of MI
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Antiplatelet\: may suggest previous cardiovascular disease
Diuretics\: may indicate underlying heart failure

Investigations and procedures

Blood glucose and ketones
Measure the patient's capillary blood glucose level. A blood glucose level may already be available from earlier investigations
(e.g. ABG, venepuncture).
The normal reference range for fasting plasma glucose is 4.0 - 5.8 mmol/L.

Interventions

Correct hyperglycaemia
In the context of ACS, blood glucose levels >11 mmol/L may be associated with poorer outcomes. This should be discussed
with a senior doctor. In some cases, insulin infusions may be used to correct hyperglycaemia.

Re-assessment

Make sure to re-assess the patient after any intervention.

Exposure

Expose the patient during your assessment\: remember to prioritise patient dignity and conservation of body heat.

Clinical assessment

Begin by asking the patient if they have pain. In the case of ACS, the patient may have presented with chest pain; it would be
clinically relevant to establish whether there is pain elsewhere.
Inspection
Brie
Signs indicating increased cardiovascular risk (e.g. cigarettes, xanthelasma, corneal arcus)
Signs of causative underlying diagnoses (e.g. splinter haemorrhages suggestive of infective endocarditis; rectal
haemorrhage leading to type 2 MI)
Look for alternative causes of chest pain (e.g. unilateral calf swelling and erythema suggestive of venous
thromboembolism or a unilateral vesicular rash on the chest indicative of shingles)
Palpation
If the patient has presented with chest pain, palpate the chest wall. Depending on context, reproducible chest wall tenderness
may reduce the likelihood of an underlying ACS.
Brie
Palpate the calves for tenderness, which may suggest a deep vein thrombosis.
Temperature
Measure the patient’s temperature. If fever is present, make sure to consider co-existing infection.
Fever as a direct result of myocardial infarction is relatively uncommon, but infections, particularly sepsis, increase cardiac
oxygen demand and thus may precipitate ACS.

Investigations and interventions

Address any concerning
in the case of suspected bleeding, etc.
See our range of ABCDE guides for how to assess other emergency presentations.

Re-assessment

Make sure to re-assess the patient after any intervention.
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Results

As you progress through the ABCDE scenario, you are likely to receive the results of your investigations, which will aid in your
decision-making.

Important results

ECG
ECG results
As above, ECG
STEMI\: persistent ST elevation in at least two contiguous leads and/or new left bundle branch block (LBBB)
NSTEMI\: persistent T wave inversion and/or ST depression in at least two contiguous leads
Unstable angina\: no changes, or non-speci
ECG
emergency. ECG
cardiology.
Troponin results
The timings and thresholds for high-sensitivity troponin I or T testing for an ACS rule-in and rule-out protocol have signi
variation, and therefore, local guidelines should always be followed. As a rule, troponin should be measured at the onset of
chest pain and serially thereafter.
Raised and dynamic troponin levels are part of the diagnostic criteria for STEMI and NSTEMI and are not seen in unstable
angina.
An initial raised troponin level in the context of chest pain and ECG changes should be discussed urgently with cardiology.

Referral and escalation

If you have completed your A to E assessment and suspect ACS, the patient should be referred to cardiology as soon as
possible. This is particularly urgent in the case of ST elevation or in the case of acute complications, e.g. pulmonary oedema.
Depending on where you are working, you may wish to brie
appropriate specialty, e.g. in the emergency department, your senior doctor should be made aware that there is a patient with
suspected ACS what the plan is moving forwards.
Use an eSBAR handover to communicate the key information to other medical sta

Further management for ACS

A patient presenting with suspected ACS should have been given aspirin 300 mg unless contra-indicated. They should be
prescribed adequate analgesia. Ensure that they are on continuous cardiac monitoring and that they have had serial ECGs, and
that they are regularly having their vital signs checked.
A cardiologist may discuss or arrange the following interventions\:
Emergency primary percutaneous cardiac intervention (PPCI)\: particularly in the case of STEMI. This should ideally be
performed within 60 minutes of symptom onset in the hospital setting.
Thrombolysis\: generally only used where PPCI is unavailable or inappropriate
Pharmacological management\: e.g. a second antiplatelet (ticagrelor/prasugrel); IV beta-blockers; anticoagulants
(fondaparinux/enoxaparin); glycoprotein IIb/IIIa inhibitors; statin
Urgent angiography\: particularly in the case of NSTEMI or unstable angina
When discussing with a specialty, be sure to clarify what your role, tasks and next steps are for the ongoing care of the
patient and what the specialist's role will be. There may be no speci
continuing to monitor.

The unwell patient

If a patient is critically unwell (e.g. peri-arrest, cardiac arrest), the cardiac arrest team should be alerted (the team typically
consists of an anaesthetist, medical registrar and other clinicians).
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The ACS patient may also require escalation to critical care (CCU, HDU or ITU) if they are unstable (e.g. hypotension with
pulmonary and peripheral oedema).

Re-assessment

Re-assess the patient using the ABCDE approach to identify any changes in their clinical condition and assess the
e
Any clinical deterioration should be recognised quickly and acted upon immediately.
Seek senior help if the patient shows no signs of improvement or if you have any concerns.

Next steps

Well done; you’ve now assessed the patient, made them more comfortable, and they have a plan for the next steps. There are
just a few more things to do…
Take a thorough history
Take a thorough cardiovascular history. For patients with suspected ACS, calculate a GRACE score (ACS risk and mortality
calculator) and/or a HEART score (pathway for early discharge in acute chest pain).
Perform a cardiovascular examination
Perform an in-depth cardiovascular examination, and examination of other systems you feel are contributing to the patient
being acutely unwell.
Review
Review the patient’s notes, charts, and results of recent investigations.
Review the patient’s current medications and check that regular medications are prescribed appropriately.
Document
Clearly document your ABCDE assessment, including history, examination, observations, investigations, interventions, and the
patient’s response. Ensure that any discussions with specialists are documented.
See our documentation guides for more details.
Discuss
Who needs to know about this patient? This will likely be your department’s senior doctor and cardiology. The patient’s nursing
team should also be made aware of any evolving clinical situation.
If handing over, your colleagues will also need to know about this patient, including the next steps.
Use the SBAR to communicate with colleagues e

References

1. Byrne RA, Rossello X, Coughlan JJ, et al. 2 0 2 3 E u r o p e a n S o c i e t y o f C a r d i o l o g y G u i d e l i n e s f o r t h e m a n a g e m e n t o f a c u t e
c o r o n a r y s y n d r o m e s . European Heart Journal. 2023. Available from\: [LINK].
2. NICE. Acute coronary syndromes [NG185]. 2020. Available from\: [LINK].
Source\: geekymedics.com
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