History and exam
Key diagnostic factors
common
chest pain
Patients typically present with central chest pain:[1][2][82]
Classically retrosternal, crushing, heavy, severe, and diffuse in nature
Might be described by the patient as ‘pressing or squeezing’
May occur at rest or on activity
May be constant or intermittent, or wax and wane in intensity
Sometimes radiating to the left arm, neck, or jaw
May be associated with nausea, vomiting, dyspnoea, diaphoresis, lightheadedness, palpitations, or syncope.[82]
Always ask about the characteristics of the chest pain as part of your history; in particular:[82]
“Have you ever had this type of pain before?”
Nature, severity, duration of pain
Radiation
Associated symptoms
Time since symptom onset – this is crucial to inform the appropriate reperfusion strategy[2][74][75]
If symptoms are intermittent, it is important to ask when the last episode of pain occurred.[82]
Practical tip
The choice of coronary reperfusion strategy depends on time since symptom onset – but obtaining an exact time for this can be difficult.
Patients can often give only an approximate idea of when their symptoms began.
Patients sometimes ignore chest pain (or associated symptoms) until they can no longer tolerate it.
The reliability of the assessment of time since symptom onset is determined by a combination of the patient’s ability to give an accurate history and the experience and skill of the clinician taking the history.
If you question the patient carefully, they may describe warning signs, or less severe or less long-lasting symptom episodes preceding the more severe episode that has prompted them to seek medical help.
Practical tip
Do not rely on a positive patient response to glyceryl trinitrate as a reliable diagnostic indicator of ischaemic chest pain.[2][82][96]
Response to nitrates can be misleading. Patients who get symptom relief still need confirmatory ECG testing to inform the diagnosis.
Complete normalisation of ST-segment elevation along with resolution of chest pain after buccal or sublingual nitrates suggests coronary vasospasm (with or without associated MI).[2]
dyspnoea
Dyspnoea is a common feature secondary to pulmonary congestion from left ventricular systolic dysfunction.[2]
It can also occur due to other mechanical and electrical complications of acute MI, which occur less commonly in the context of contemporary rapid revascularisation, for example:
Left ventricular aneurysm
Ventricular septal rupture
Left ventricular free wall rupture
Acute mitral regurgitation
Papillary muscle rupture
Functional (ischaemic) mitral regurgitation
Pericardial effusion
Cardiac tamponade
Supraventricular tachyarrhythmias
Ventricular tachyarrhythmias
Bradycardia and atrioventricular block.
pallor
Pallor is a common feature due to high sympathetic output resulting in peripheral vasoconstriction.
cardiac risk factors
Check for any history of cardiovascular disease: in particular, ischaemic heart disease.[82]
Also check for any previous episodes of investigation or treatment for chest pain.
A history of coronary artery disease should increase your index of suspicion.[2]
A cardiovascular risk factor profile is an important part of your history-taking. Check:[82]
Smoking status
Hypertension
Diabetes mellitus
Hypercholesterolaemia
Family history of premature coronary artery disease (<60 years)
Established coronary artery disease
Advanced age
Obesity
Metabolic syndrome
Physical inactivity
Chronic kidney disease
Cocaine use.
uncommon
abnormal breath sounds
Auscultate the heart and lungs.
Crackles/crepitations or cardiac wheeze would suggest congestive cardiac failure ± pulmonary oedema.
additional heart sounds
Auscultate the heart and lungs.
Muffled heart sounds could suggest a pericardial effusion or even cardiac tamponade.
Is there a third (S3) or fourth (S4) heart sound?
These added heart sounds could suggest severe heart failure.
A murmur might suggest:
Acute ventricular septal defect
Acute mitral regurgitation
Underlying chronic valvular heart disease.
cardiogenic shock
Cardiogenic shock complicates 5% to 10% of STEMI admissions.[80][99][100]
There is a bimodal presentation: the majority occur within 24 hours; the remainder occur within the first week.[100][101]
Seek immediate senior support and specialist input if your clinical assessment suggests cardiogenic shock.
See Shock.
Patients present with signs of hypoperfusion and/or fulminant heart failure, such as:[80]
Altered mental status/reduced consciousness
Tachypnoea
Severe dyspnoea
Tachycardia
Orthopnoea
Cool peripheries
Grey, ashen, pale appearance.
Cardiogenic shock is primarily a clinical diagnosis supported by haemodynamic measures. It is defined as persistent hypotension (systolic blood pressure [SBP] <90 mmHg) together with signs of end-organ hypoperfusion.[78][79][80][140]
SBP <90 mmHg despite adequate volume replacement, or if inotropes and/or mechanical circulatory support are needed to maintain SBP ≥90 mmHg
Urine output <30 mL/hour
Cool extremities
Elevated lactate.
Haemodynamic criteria:[78][80]
Cardiac index ≤2.2 L/minute/m2
Wedge pressure ≥15 mmHg.
Cardiogenic shock results from extensive left ventricular infarction and/or mechanical complications such as:
Papillary muscle rupture
Ventricular septal rupture
Left ventricular free wall rupture leading to pericardial tamponade
Right ventricular infarction.
Other diagnostic factors
common
nausea and/or vomiting
dizziness or light-headedness
Patients commonly report feeling lightheaded or weak/lethargic.[2]
This is due to cerebral hypoperfusion as a result of hypotension and/or symptomatic bradycardia.
distress and anxiety
The patient may report an impending sense of doom or death.
palpitations
Some patients present with palpitations.[2][94]
Tachycardia
Supraventricular tachyarrhythmias such as atrial fibrillation
Ventricular tachyarrhythmias such as ventricular tachycardia
Bradycardia
Sinus bradycardia
Atrioventricular block secondary to inferior STEMI
Atrioventricular block secondary to anterior STEMI
Irregular heart beat
Supraventricular tachyarrhythmias such as atrial fibrillation
Ventricular extrasystoles
uncommon
reduced consciousness
hypotension
Hypotension may be present in:
Cardiogenic shock – systolic blood pressure (SBP) <90 mmHg despite adequate volume replacement, or if inotropes and/or mechanical circulatory support are needed to maintain SBP ≥90 mmHg[78][79][80]
Inferior STEMI
Right ventricular infarction
Complicating inferior STEMI or an extensive anterior STEMI
Always think of the triad of hypotension, elevated jugular venous pressure, and clear lung fields[83]
Cardiac tamponade
Haemodynamically significant atrioventricular block, supraventricular tachyarrhythmias, or ventricular arrhythmias.[100]
non-chest pain presentation (chest pain-equivalent symptoms)
Be aware of patient groups who present without chest pain as the predominant feature (i.e., with chest pain-equivalent symptoms).[2][82]
Women, older patients, and patients with diabetes are more likely to present with atypical features.[2][95]
Patients might describe their chest symptoms as burning, throbbing, tight, or a feeling like trapped wind.
The patient may describe indigestion rather than chest pain.
In the absence of chest pain, there may be epigastric pain, back (interscapular) pain, neck or jaw pain, or arm pain (typically left-sided).
Clinical suspicion is key to making the diagnosis. It is, therefore, vital to make a full assessment based on the history, examination, and serial ECGs.[1][92]
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