Chest Pain Syndromes

Acute chest pain is a common presenting complaint: it accounts for approximately 700 000 presentations to the emergency department (ED) per year in England and Wales and for 25% of emergency medical admissions [1].

Chest pain is caused by a spectrum of pathology ranging from the innocent to the extremely serious (see Table 1); amongst the latter are a number of conditions which are potentially catastrophic and can cause death within minutes or hours. The large volume of patients presenting with a potentially serious condition places chest pain at the very core of emergency medicine work.

Emergency physicians are responsible for robustly identifying and treating a significant minority of patients with serious pathologies whilst also avoiding unnecessary investigation and admission for the majority of patients who can be safely discharged. This is a difficult challenge: it has been reported that 6% of patients discharged from a UK ED have subsequently been proven to have prognostically significant myocardial damage [2].

Table 1: The spectrum of pathology presenting with chest pain.

System	Life-threatening	Urgent	Non-urgent
Cardiovascular	Acute myocardial infarction Aortic dissection Pulmonary embolism	Unstable angina Coronary vasospasm Pericarditis Myocarditis	Stable angina Valvular heart disease Hypertrophic cardiomyopathy
Pulmonary	Tension pneumothorax	Simple pneumothorax	Viral pleurisy Pneumonia
Musculoskeletal			Costochondritis Chest wall injury
Gastrointestinal	Oesophageal rupture	Pancreatitis	Cholecystitis Oesophageal reflux Biliary colic Peptic ulcer
Other		Mediastinitis	Postherpetic neuralgia Herpes zoster Malignancy Psychological/anxiety

The diagnostic approach to chest pain in the emergency department

Patients attending the ED with chest pain present a classic diagnostic challenge.

A minority will have an imminently or potentially life-threatening condition and need to be quickly and robustly identified and treated.

A significant minority will have benign pathology or no significant cause identifiable for their pain and these also need to be identified, reassured and discharged.

The rest will have a specific identifiable cause for their pain that will require a diagnosis and treatment plan during their ED attendance.

A logical and systematic approach to patients will achieve a diagnosis in the vast majority of cases whilst they are in the ED (see algorithm in the chart click the image to see a larger version).

A focused history and physical examination supported by an ECG and chest x-ray in most, with some specific ancillary investigations in a few, will allow a firm diagnosis to be made or confident reassurance to be given.

All of the assessments and investigations discussed in this session are within the remit of the emergency physician and should be available within the ED.

This module is about achieving a diagnosis in a patient presenting with chest pain, not about the treatment of a condition once a diagnosis has been made.

When a diagnosis has been reached with the required degree of certainty, management of that condition is covered in the relevant learning session and the patient drops out of the algorithm.

Figure 1: The diagnostic approach to patients with chest pain

Note According to Chest Pain NICE guideline 95, anginal pain is (1) a constricting discomfort in the front of the chest, or in the neck, shoulders, jaw, or arms that is (2) precipitated by physical exertion, and (3) relieved by rest or GTN within 5 minutes.

NICE defines chest pain as being atypical if only two of these three features are present, or non-anginal if one or none of these exist. (3)

The European Society of Cardiology describes atypical presentations of MI include epigastric pain, indigestion-like symptoms and isolated dyspnoea. (4)

One of the main purposes of early and rapid assessment of a patient with chest pain is to identify life-threatening conditions and, in particular, to rule-in or rule-out an acute coronary syndrome (ACS). There are various features in the history that are traditionally associated with cardiac ischaemic chest pain and various features that make it less likely.

A thorough description of the pain is the first step in the diagnostic process and will help to make the initial differentiation between cardiac and non-cardiac pain and ischaemic and non-ischaemic pain (See Figure 2 and Table 2). Symptom evaluation will include a description of the character of the pain, the location, severity and radiation of the pain, onset and duration of the pain, relieving and aggravating factors, and associated symptoms. Other important features of the history will include risk factor determination, previous episodes and relevant past medical history.

Likelihood Ratios

Likelihood ratios have been calculated in various studies linking features of the history with acute myocardial infarction (AMI)^(11-14) (see Table 3). It numerically indicates the probability of a patient having an AMI based on their description of the pain. Conventionally, a likelihood ratio greater than 10 provides very strong evidence to rule in a diagnosis whilst a ratio less than 0.1 provides very strong evidence to rule it out; ratios greater than 5 and less than 0.2 provide good evidence, and ratios greater than 2 and less than 0.5 provide moderate evidence to rule a diagnosis in or out respectively⁽¹⁵⁾.

Table 3: Value of specific components of the chest pain history for the diagnosis of acute myocardial infarction^(11-14)

Historical factor	Likelihood factor
Increased likelihood of AMI:Radiation to right arm/shoulder Radiation to both arms/shoulders Associated with exertion Radiation to left arm Associated with diaphoresis Associated with nausea/vomiting Worse than previous angina/similar to previous MI Described as a pressure	[Ref 11] 4.7 4.1 2.4 2.3 2.0 1.9 1.8 1.3	[Ref 12] 2.9 7.1 2.3 2.0 1.9	[Ref 13] 2.6 1.4 1.5 2.1 1.9 1.3 1.4	[Ref 14] 1.3 2.6 1.5-1.8 1.3 1.3-1.4 0.9-1.1 2.2
Decreased likelihood of AMI:Described as pleuritic Described as positional Described as sharp Reproducible with palpation Inframammary location Not associated with exertion Associated Palpitations Associated Syncope	0.2 0.3 0.3 0.3 0.8 0.8	0.2 0.3 0.3 0.2-0.4*	0.2 0.3 0.3 0.2	0.4-0.6 0.2 0.3 0.3 0.2 0.6-0.8 0.7 0.4-0.8
*In heterogenous studies, likelihood ratios expressed as a range.

Burning pain (LR 1-1.4), improvement with GTN (LR 0.93-1.3) and abrupt onset of pain (LR 1-1.2) have no meaningful effect on the likelihood ratio of AMI.⁽¹⁴⁾

Therefore, based on these analyses, chest pain history is a helpful, but not diagnostic, first step in the assessment of these patients. Specifically, no single factor in the history carries with it a consistently powerful enough likelihood ratio to allow the emergency physician to safely discharge a patient without further diagnostic testing. Studies have reiterated that clinician gestalt although suggestive, cannot be used to rule in or rule out ACS.⁽¹⁶⁾

Learning Bite

No single factor in the history alone can confidently rule in or rule out AMI.

Chest Pain History – A Starting Point

The history does, however, form a start point in the diagnostic process, broadly establishing whether pain is likely to be cardiac ischaemic (or not) in origin; it provides information to add to baseline risk factors (see Table 4) which makes the diagnosis of ACS significantly more or less likely. Specifically, radiation of the pain to the arms or shoulders, and its association with exertion or diaphoresis will make the diagnosis more likely.

Table 4: Risk factors associated with major life-threatening causes of chest pain

Condition	Risk Factors
Acute coronary syndromes	Previous known coronary artery disease (previous myocardial infarction, angioplasty, etc)Positive family history Advanced age, male gender Diabetes, hypertension, hypercholesterolaemia Active smoker, obesity, sedentary lifestyle Aspirin usage
Aortic dissection(6,7)	Chronic hypertensionInherited connective tissue disorder e.g. Marfans Syndrome, Ehlers-Danlos Syndrome Bicuspid aortic valve Atheroscleroisis Iatrogenic related to cardiac catheterisation Coarctation of the aorta Pregnancy Cocaine use Inflammatory aortic disease e.g. Giant Cell Arteritis
Pulmonary embolism(8,9)	Previous history of venous thromboembolic diseasePregnancy particularly 6 weeks post partum Positive family history of venous thromboembolic disease (two or more family members) Recent prolonged immobilisation (> 3 days) Major surgery within previous 12 weeks Fracture of lower limb within previous 12 weeks Active cancer (within previous 6 months, recent treatment, palliation) Lower extremity paralysis

Likelihood of ACS

Chest pain that is pleuritic, sharp, positional and reproducible on palpation makes an alternative diagnosis much more likely. This information, in addition to other rapidly available clinical features (e.g. examination findings and the ECG), will determine the continued direction of investigation and initial management.

To refresh your memory on the diagnostic approach to patients with chest pain, click this thumbnail image:

Learning Bite

Characteristics of the pain with the highest likelihood for AMI are radiation of the pain to the right arm/shoulder or to both arms/shoulders.

Chest Pain Score

Various studies have used a chest pain score (based upon ascribing positive or negative points to typical or atypical aspects of chest pain location, character, radiation, onset, and associated symptoms⁽¹⁷⁾) and then combined this with historical risk factors to generate positive predictive values for ruling in or ruling out an acute coronary syndrome^(18,19). However, this approach has not led to sufficiently robust positive likelihood ratios to definitively rule in ACS (i.e. commit to specific therapies) or rule out ACS (i.e. allow safe discharge).

Other life-threatening conditions present with chest pain other than ACS. The above discussion of likelihood applies specifically to AMI. The clinician will have to consider the presenting features in the history that are typical of other conditions (e.g. a tearing feeling and radiation to the back in aortic dissection (see Table 5), or haemoptysis and shortness of breath in pulmonary embolism) alongside risk factors specific to these conditions (see Table 4) in order to narrow the differential diagnosis and guide subsequent investigation and management.

Table 5: Presenting features of aortic dissection as per the international Registry of Acute Aortic Dissection⁽⁵⁾

Symptom	Type A (n=617)	Type B (n=384)	Overall (n=1001 except * n=381)
Chest or Back Pain	507 (85%)	328 (86%)	835 (85%)
Severe or worst-ever pain	211 (90%)*	135 (90%)*	346 (90%)*
Abrupt onset of pain	453 (91%)	332 (89%)	785 (90%)
Migrating pain	85 (15%)	80 (25%)	175 (19%)
Pain presenting within 6hrs of symptoms	334 (79%)	..	..

The history will have established whether a patients chest pain is ischaemic in nature and likely to be related to an ACS, or whether it is pleuritic or atypical in nature, and unlikely to be related to an ACS. Examination findings will further refine the differential diagnosis generated from the history.

Physical findings associated with ACS are generally non-specific and include pallor, anxiety, sweating, tachycardia and tachypnoea.
Generally, specific physical findings are associated with other (non-ischaemic) causes for chest pain or are associated with the complications of AMI: for example, a third heart sound occurring in heart failure, a pan-systolic murmur from mitral valve regurgitation, hypotension related to cardiogenic shock, or pulmonary crepitations secondary to left ventricular failure. These physical findings make AMI more likely [17-20].

Table 6: Value of specific components of the physical examination for the diagnosis of acute myocardial infarction^(19-21)

Examination finding	Likelihood ratio
	Ref12		Ref13	Ref14**
Increased likelihood of AMI:
Third heart sound	3.2		3.2
Hypotension (systolic BP <80 mmHg)	3.1		2.1	0.98-15
Pulmonary crepitations	52.1		2.1	1.0-4.0
Decreased likelihood of AMI:
Chest pain reproducible by palpation	0.3		0.2-0.4*	0.14-0.54*

Learning Bite

The finding of a third heart sound, hypotension or pulmonary crepitations makes AMI more likely.

Table 7 shows the key physical findings associated with conditions presenting with chest pain in the emergency department. Pivotal physical signs, or combinations of signs, which are highly suggestive of the relevant diagnoses, are shown in bold. Aortic dissection is renowned for being very difficult to diagnose, with the classic clinical signs occurring infrequently, see percentage of occurrence within the brackets.(6) Diagnosing PE is also a challenge because the symptoms and signs are common and not specific, Table 8(9)

Learning Bite

Various combinations of physical findings can be pathognomonic for non-ischaemic chest pain conditions

Table 7: Key physical findings associated with conditions causing chest pain

Diagnosis	Physical findings
Acute coronary syndrome	Diaphoresis, tachycardia, tachypnoea, pallor
Complications of acute MI	Hypotension, third heart sound, pulmonary crepitations, elevated JVP, bradycardia, new murmur
Aortic dissection	Diaphoresis, hypotension, hypertension, tachycardia, differential blood pressures and/or pulses (27%), new murmur (aortic regurgitation 32%), focal neurological findings (12%)
Pulmonary embolism	Acute respiratory distress, diaphoresis, hypotension, tachycardia, hypoxaemia, elevated JVP, pleural rub
Pneumonia	Fever, signs of pulmonary collapse / consolidation, tachycardia, tachypnoea
Oesophageal rupture	Diaphoresis, hypotension, tachycardia, fever, Hammans sign*, subcutaneous emphysema, epigastric tenderness
Simple pneumothorax	Tachypnoea, tachycardia, unilateral diminished air entry and breath sounds, subcutaneous emphysema
Tension pneumothorax	Tachypnoea, hypotension, tachycardia, hypoxaemia, elevated JVP, unilateral diminished air entry and breath sounds, subcutaneous emphysema, tracheal deviation
Pericarditis	Tachycardia, fever, pericardial rub
Myocarditis	Hypotension, tachycardia, fever, third heart sound, pulmonary crepitations, displaced apex beat
Mediastinitis	Tachycardia, fever, Hammans sign*, subcutaneous emphysema, hypotension
Cholecystitis	Diaphoresis, fever, tachycardia, right upper quadrant tenderness
*Hammans sign: audible systolic noise on cardiac auscultation

Certain physical signs, or combinations of signs, are highly suggestive of certain diagnoses and are highlighted in bold.

* Hammans sign: audible systolic noise on cardiac auscultation

Table 8: Prevalence of Symptoms and Signs in Patients with suspected PE according to final diagnosis.⁽⁹⁾

Symptoms of PE	PE confirmed (n=219)	PE Excluded (n=546)
Dyspnoea	80%	59%
Pleuritic Chest Pain	52%	43%
Substernal Chest Pain	12%	8%
Cough	20%	25%
Haemoptysis	11%	7%
Syncope	19%	11%
Signs of PE
Tachypnoea (> 20/min)	70%	68%
Tachycardia >100	26%	23%
Signs of DVT	15%	10%
Fever (>38.5oc)	7%	17%
Cyanosis	11%	9%

The Electrocardiogram (ECG)

After taking a history and performing a physical examination, the most commonly and rapidly performed investigation for a patient with chest pain in the ED is an ECG (see Figure 1). An ECG should be performed as soon as possible in all patients presenting with chest pain, particularly if cardiac ischaemia is suspected from the history.

Table 10 presents the likelihood ratios for the association of various ECG changes and AMI^(12-14). The presence of ST segment elevation, new Q wave formation, or a new conduction deficit (eg. left bundle branch block) in the context of acute ischaemic chest pain is associated with such significantly positive likelihood ratios for AMI that the diagnosis can be made with confidence and appropriate therapy commenced.

The presence of ST segment depression and/or T wave changes in the context of acute ischaemic chest pain normally indicates myocardial ischaemia (i.e. unstable angina) but is also associated with a positive likelihood ratio for AMI (i.e. non-ST elevation AMI see Table 9). Approximately 50% of patients with ST depression and 33% of patients with T wave inversion will subsequently be shown to have myocardial infarction as defined by an elevated cardiac marker^(20,21). This group of patients are presenting with an ACS (i.e. unstable angina or non-ST elevation myocardial infarction).

Learning Bite

ST segment elevation is associated with the highest likelihood of AMI followed, in order, by new Q waves, new conduction deficit, ST depression and T wave changes

A normal ECG significantly reduces the probability of AMI^(12-14). It does not, however, reduce this probability enough to allow confident safe discharge based upon the history and ECG alone^(2,3,4,5,16). Therefore, patients who present with chest pain in whom cardiac ischaemia is suspected and who have a normal ECG should undergo further diagnostic testing (ie. delayed cardiac markers, before they can be confidently ascribed to a low risk group.

Learning Bite

A normal ECG in a patient with chest pain does not allow safe discharge without further investigation

ECG Likelihood Ratios

Table 9: Value of specific components of the ECG for the diagnosis of acute myocardial infarction^(12-14)

ECG finding	Likelihood ratio
	Ref12		Ref13	Ref14
Increased likelihood of AMI:
New ST segment elevation	5.7-53.9*		13.1	2.1-8.6
New Q wave formation	5.3-24.8*		5.0
New conduction deficit	6.3
ischaemic ECG				1.6-5.7
New ST segment depression	3.0-5.2*		3.13
T-wave peaking and/or inversion	3.1		1.9
Decreased likelihood of AMI:
Normal ECG	0.1-0.3		0.1

^* In heterogenous studies likelihood ratios expressed as a range

** Ischemic ECG defined as any T wave inversion, ST depression, Q waves

ECG Results

The ECG must be considered in the context of the history and physical examination. The discussion above refers to the pivotal role of an ECG in the patient with a history of ischaemic cardiac chest pain. However, the ECG will also be useful in patients who have non-ischaemic pain (see Figure 1 and Table 10).

Normal ECG

A normal ECG significantly reduces the probability of AMI [4,5]. It does not, however, reduce this probability enough to allow confident safe discharge based upon the history and ECG alone [2].

Therefore, patients who present with chest pain in whom cardiac ischaemia is suspected and who have a normal ECG should undergo further diagnostic testing (i.e. delayed cardiac markers, exercise testing, etc.) before they can be confidently ascribed to a low risk group.

Table 10: ECG findings associated with non-ischaemic chest pain conditions^(4,6)

ECG finding	Context	Diagnosis
Diffuse concave-upward ST segment elevation	Positional pain Pericardial rub	Pericarditis
Right ventricular strain Pattern	Pleuritic pain Hypoxia Pleural rub	Pulmonary embolus
Diffuse ST/T wave changes	Atypical pain Heart failure	Myocarditis
Inferior ST elevation Normal (30%) LVH (26%)	Tearing chest pain Radiation to back Differential pulses Differential blood pressures New diastolic murmur	Aortic dissection

Learning Bite

A normal ECG in a patient with chest pain does not allow safe discharge without further investigation.

Chest X-ray (CXR)

The CXR is the next investigation commonly performed in the ED for patients presenting with chest pain following initial clinical assessment and ECG (see Figure 1). Table 11 shows the radiographic findings in conditions presenting with chest pain.

The CXR is particularly useful in patients presenting with non-cardiac chest pain and can definitively confirm a diagnosis suspected on clinical grounds (e.g. pneumothorax or pneumonia) or contribute significantly to the diagnostic process (e.g. widened mediastinum in aortic dissection or pneumomediastinum from oesophageal rupture). A normal CXR will also be helpful in making a diagnosis by excluding other potential causes for a certain clinical presentation: for example, a normal CXR in a patient with respiratory distress, pleuritic pain and hypoxia will exclude pneumothorax, make pneumonia unlikely, and increase the probability of pulmonary embolism.

There are no specific diagnostic findings on chest radiography associated with ACS; the usefulness of the CXR in this setting is to exclude other (non-cardiac) causes of chest pain or to evaluate complications of AMI (e.g. pulmonary oedema).

Table 11: Radiographic findings in conditions presenting with chest pain

Condition	Radiocraphic Finding	Comment
Acute coronary syndrome	No specific radiographic finding
Aortic dissection	Mediastinal widening Abnormal aortic contour Globular heart shadow (haemopericardium) Pleural effusion (haemothorax)	Suggestive in context Unusual finding Rare finding Rare finding
Pneumothorax	Absence of pulmonary vascular markings	Diagnostic
Tension pneumothorax	Absence of pulmonary vascular markings Mediastinal displacement	Diagnostic Diagnostic
Pneumonia	Localised or diffuse pulmonary infiltration Localised pulmonary atelectasis/consolidation	Diagnostic in context
Pulmonary embolism	Normal chest radiograph Localised pulmonary atelectasis Small pleural effusion	Suggestive in context Rare finding Rare finding
Oesophageal rupture	Pneumomediastinum	Diagnostic in context
Mediastinitis	Pneumomediastinum	Diagnostic in context
Pericarditis	Globular heart shadow	Pericardial effusion
Myocarditis	Enlarged cardiac shadow	Dilated cardiomyopathy

The history, physical examination, ECG and CXR will normally allow the emergency physician to be fairly confident to achieve a diagnosis in a patient with chest pain presenting to the ED. There will still be a significant number of patients in whom the diagnosis is not clear or who require further investigations to allow safe discharge or definitive treatment.

Various studies have used a chest pain score (based upon ascribing positive or negative points to typical or atypical aspects of chest pain location, character, radiation, onset, and associated symptoms⁽¹⁷⁾) and then combined this with historical risk factors to generate predictive values for ruling in or ruling out an acute coronary syndrome^(18,19). This approach alone has not led to sufficiently robust likelihood ratios to definitively rule in ACS (i.e. commit to specific therapies) or rule out ACS (i.e. allow safe discharge).

However, more robust scoring systems have been generated to assess risk by looking at components of the initial presentation AND by including additional factors, in particular biochemical cardiac markers. The most robustly validated risk scores are the TIMI, HEART and GRACE risk scores, the latter providing a score of future mortality^(3,4,5). These scores help clinicians to identify those who are at high risk and requiring admission and treatment, and those who are at low risk and safe to discharge (with or without appropriate follow up).

Patients who present with a history of ischaemic chest pain who have a normal examination, ECG and CXR will require further risk stratification in order to allow safe discharge from the emergency department. Such a rule-out strategy will involve the use of cardiac markers (e.g. troponin) and possible exercise testing. Clinical pathways which combine clinician gestalt with the admission ECG and subsequent troponin assay(s) have shown a 100% sensitivity.⁽¹⁶⁾

Pulmonary Embolism

Pulmonary embolism is a relatively common condition that needs to be excluded with confidence due to its significant associated mortality if undiagnosed. Unfortunately, the history is variable, and there are no common diagnostic findings on examination, ECG or CXR. However, these findings, considered in association with historical risk factors for venous thromboembolic disorders, will allow the emergency physician to confidently ascribe the patient to a likely or unlikely risk category (two level PE Wells score is endorsed by NICE- see Table 12)⁽⁹⁾.

Table 12: Two-level PE Wells score⁽⁹⁾

Clinical feature	Points
Clinical signs and symptoms of DVT (minimum of leg swelling and pain with palpation of the deep veins)	3
An alternative diagnosis is less likely than PE	3
Heart rate > 100 beats per minute	1.5
Immobilisation for more than 3 days or surgery in the previous 4 weeks	1.5
Previous DVT/PE	1.5
Haemoptysis	1
Malignancy (on treatment, treated in the last 6 months, or palliative)	1
Clinical probability simplified scores
PE likely	More than 4 points
PE unlikely	4 points or less

Without further investigation, however, patients at low risk cannot be confidently reassured and discharged, and those at high risk should not be committed to prolonged anticoagulation. For patients at low risk, the diagnosis can be confidently excluded with a negative D-dimer assay^(9,10,21). For patients at intermediate or high risk the diagnosis can be confidently confirmed or excluded with a ventilation perfusion (V/Q) scan or CT pulmonary angiogram (CTPA)^(9,10,21).

Learning Bite

Pulmonary embolism will rarely be definitively diagnosed without ancillary investigations (D-Dimer, V/Q scan, or CTPA)

Aortic Dissection

Aortic dissection is a diagnosis that should be strongly suspected if the appropriate features are present upon clinical assessment: the history (tearing pain), examination (new murmur of aortic regurgitation, differential blood pressures), ECG (inferior ischaemic changes) and CXR (widened mediastinum) will, when present in combination, be pathognomonic of aortic dissection. However, due to the potentially catastrophic nature of aortic dissection if undiagnosed, this condition will need to be definitively excluded even if the index of suspicion is low (e.g. if only one of the characteristic clinical features is present). In patients in whom the diagnosis is virtually certain from the clinical presentation, the anatomical extent of the dissection will need to be defined. In either case, a CT angiogram of the aorta will need to be performed and this will be diagnostic and define the anatomical extent.

Learning Bite

CT angiogram of the aorta will be required to definitively exclude aortic dissection and/or to define its anatomical extent

1. No single factor in the history is associated with a high enough likelihood ratio to confidently diagnose or exclude AMI (Grade of evidence 1b)
2. The features of the chest pain history most likely to be associated with AMI are radiation to the right arm/shoulder or radiation to both arms/shoulders (Grade of evidence 1b)
3. The features of the chest pain history least likely to be associated with AMI are sharp nature, positional, pleuritic and reproducible with palpation (Grade of evidence 1b)
4. Examination findings which increase the likelihood of AMI in the context of chest pain are the presence of a third heart sound, hypotension and pulmonary crackles (Grade of evidence 1b)
5. ECG findings diagnostic of AMI in the context of ischaemic chest pain are new ST segment elevation and new Q waves (Grade of evidence 1b)
6. A normal ECG in the context of ischaemic chest pain does not rule out prognostically significant myocardial damage and further diagnostic testing will be required (Grade of evidence 1b)
7. A normal examination ECG and CXR cannot rule out an Aortic dissection
8. Shortness of breath and pleuritic chest pain are sensitive but not specific for Pulmonary emboli. Use of clinical predictive rules are essential to assess the likelihood of the diagnosis and aid ongoing investigations.
9. A logical diagnostic approach to patients presenting with chest pain will achieve a diagnosis in the majority based on taking a history, performing an examination, ECG and CXR in the ED
10. Ancillary investigations will be required for the remainder and, specifically:

• • A rule-out strategy for patients with ischaemic pain and a normal ECG (Grade of evidence 1b)
  • D-dimer, V/Q scanning or CTPA for patients in whom pulmonary embolism is a possibility (Grade of evidence 1b)
  • CT angiogram of the aorta for patients suspected of having an acute aortic dissection

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