Chest pain has many potential causes, both cardiac and non-cardiac. A thorough history and physical exam are important to establish a pre-test probability of different diseases. Clinical decision rules can help quantify the likelihood of conditions like myocardial infarction, pneumonia, and pulmonary embolism. No single diagnostic test is perfect, so likelihood ratios provide a framework for interpreting test results in the context of the pre-test probability. An evidence-based approach uses all available information to guide appropriate testing and diagnosis.

1. DIAGNOSING THE CAUSE
OF CHEST PAIN
Dr. Rashidi Ahmad
Emergentist
MD(USM), MMED(USM), FADUSM
School of Medical Sciences
USM Health Campus

2. Knowledge is a process of pilling up
facts. Wisdom lies in their simplification
Martin Luther King, Jr

3. Introduction
Chest pain is the chief complaint in about 1-2% of
outpatient visits.
The cause is often non-cardiac BUT heart disease
remains the leading cause of death.
Chest pain in ED, > 50% due to CV condition.
In outpatient primary: musculoskeletal conditions,
GIT disease, stable CAD, pulmonary disease, etc.
Unstable CAD is rare.
15% never reach a definitive diagnosis.
Buntinx F, et al. Chest pain in general practice or in the hospital emergency
department: is it the same? Fam Pract 2001;18:586-9.

5. Epidemiology of Chest pain in
primary care setting & ED
Buntinx F, et al. Chest pain in general practice or in the hospital emergency
department: is it the same? Fam Pract 2001;18:586-9.

6. Chest Pain Origin - Difficult?
Various disease processes in a variety of organs.
The severity of pain is often unrelated to its life
threatening potential.
The location of pain perceived by the patient
frequently does not correspond with its source.
PE, lab Ix, X-rays are often unavailable or non
diagnostic.
More than one disease process may be present.

8. Misdiagnosis of ACS
Young patient
Atypical presentation & silent ischemia
Poor documentation & incomplete history &
physical examination
ECG misinterpretation
Reliance on laboratory assay
Inexperience doctor
Hesitance to admit patients with vague
symptoms

9. History
Chest discomfort ~ 80 - 85%
Atypical presentation ~ 20%
burning/indigestion ~ > 20%
chest ache ~ 13%
sharp, stabbing pain ~ 5%
pain reproduced by palpation ~ 5%
Silent ischemia ~ 23%

10. History
• Up to 33% of patients (elderly &
diabetes), who have AMI do not have
pain. Canto et al,. JAMA, vol. 283, p. 3223, 2000
• The presence or absence of risk factors
does not change the likelihood of
cardiac. Graber & et al. Emergency Medicine April 2001

11. Accuracy of chest pain diagnosis
using the Hx & PE
WILLIAM E. CAYLEY, American family Physician. Volume 72, Number 10 , November 15, 2005

12. Physical examination
Most often normal
Levine’s sign

13. "No astute clinician is reassured by chest wall
tenderness that reproduces a patient's pain,
because 15% of patients with acute MI will
have chest wall tenderness on palpation that
reproduces their pain"
Rosen and Barkin. Emergency Medicine Concepts
and Clinical Practice, St. Louis, Mosby, 1999

14. Electrocardiogram
NOT a perfect indicator of cardiac disease
ONLY 50% with a proven AMI have positive
initial ECG indicating the disorder
Up to 76% of ACS – normal an initial ECG, non
specific, or unchanged from previous ECG
Around 5% of chest pain patients with normal
ECG who were discharged from the ED were
ultimately found to have ACS
Mc Carthy B, Wong J. Detecting acute ischaemia in ED.
J Gen Int Med 1990; 5: 381-8

15. Relation between time &
ECG changes
Time Indication of infarct in
ECG
1st to 3 hours 40%
4th to 6th hour 50%
7th to 9th hour 90%
10th to 12th hour Up to 100%

16. Relation between
Cardiac markers & time
Cardiac marker Within time of
elevation
Myoglobin 1 – 3 hour
CK-MB/Trop I 4 – 8 hour
Troponin T 6 – 8 hour

17. •At hours: 4 to 8 and 8 to 12 the CPK level is
more sensitive (84% and 94%, respectively) in
indicating AMI, than is troponin level (74% and
88%, respectively).
•After 12 hours: troponin level is essentially
100% sensitive, whereas the CPK level becomes
less sensitive
Graber & et al. Emergency Medicine April 2001

19. Acute Pulmonary embolism
Diagnosing PE requires a high degree of
clinical suspicion
Sharp chest pain - 59%
Dyspnea - 78%
Cough - 43%
Tachycardia - 30%
Syncope 13%

20. Acute Pulmonary embolism
• Not all patients with pulmonary embolus will
be hypoxic or have tachycardia or tachypnea.
• Up to 50% of patients with DVT have a silent,
or asymptomatic PE.
• Among PE patients without underlying
pulmonary disease, ~ 12% have a PaO2>80
mmHG
Meingnan 7 et al. Archives of Internal Medicine, 2000, Vol 160; 159
Stein & et al. Chest .1996, Vol. 109, 78

21. Chest X Ray
Without infarction, the chest x-ray may be
normal, or diminished pulmonary vascular
markings in the embolized area may be
noted.
With infarction, the x-rays frequently
shows a peripheral infiltrative lesion, with
elevation of the diaphragm & pleural fluid
on the affected site.

22. DIAGNOSING THE CAUSE OF
CHEST PAIN

23. Outpatient
Diagnosis of
Chest pain
William E. Cayley, Jr., M.D., American Family Physician;
Vol. 72/no. 10 (November 15, 2005)

24. Diagnostic test makes sense

25. Likelihood ratios (LR)
& Bayes' nomogram
are a useful &
practical way of
expressing the power
of diagnostic tests in
increasing or
decreasing the
likelihood of disease
Graber & et al. Emergency Medicine April 2001

26. 2 methods of estimating the
pre-test probability:
Emergency gut feeling (educated
guess) after the history &
examination
Clinical decision rules.

27. Accuracy of chest pain diagnosis
using the Hx & PE
WILLIAM E. CAYLEY, American family Physician. Volume 72, Number 10 , November 15, 2005

28. •The Rouan decision rule reliably
predicts which patients with chest
pain & a normal or nonspecific
electrocardiogram are at higher risk
for MI
•However, 3% of patients initially
diagnosed with a non-cardiac cause
of chest pain suffer death or MI
within 30 days of presentation.
•Patients with cardiac risk factors
warrant close follow-up.

29. •The Diehr diagnostic rule,
uses 7 clinical findings to
predict the likelihood of
pneumonia .
•Other findings that suggest
pneumonia include egophony
& dullness to percussion, but
their absence does not rule
out the diagnosis.

30. •Well’s clinical decision
rules for the diagnosis of
PE consists of 7 signs &
symptoms.
•The strength of the Wells
model is that it does not
require a CXR or ABG
measurements. It relies on
a careful history &
physical examination.

32. Accuracy of chest pain diagnosis
using diagnostic & prognostic tests

33. DIAGNOSTIC TESTING –
PULMONARY EMBOLISM
D-dimer* testing has become an important part of the evaluation for
PE & deep venous thrombosis (DVT).
A low clinical suspicion for PE (Wells score <2) plus a normal
quantitative ELISA D-dimer assay safely rules out PE, with a negative
predictive value >99.5 %.
If further testing is needed, helical computed tomography (CT),
combined with clinical suspicion and other testing such as lower
extremity venous ultrasound, can be used to rule in or rule out PE.
* Quantitative enzyme-linked immunosorbent antibody assay (ELISA) D-dimer assays are more sensitive & have been
more thoroughly tested in clinical settings than whole-blood agglutination assays.

34. Summary
Although diagnostic tests are impressive, they
should not replace the history & physical
examination.
Clinician decision rule can be given a point score
to arrive at a pre-test probability of a disease &
help rule in or out specific diagnoses.
After history taking & physical examination, we
formulate prior probability of the disease –
decide as to whether no test, a screening test,
or a definitive test should be performed.

35. Summary
Likelihood ratios (LR) are a useful &
practical way of expressing the power of
diagnostic tests.
An evidence-based approach tailors the
diagnostic strategy to the patient - uses
clinical evaluation to guide the selection of
tests & their interpretation.

36. “ Having cross the bridge of understanding, we still
must cross the bridge to practice ”

37. Outpatient
Diagnosis of
Chest pain
William E. Cayley, Jr., M.D., American Family Physician;
Vol. 72/no. 10 (November 15, 2005)