Most recent data, with troponin Is the initial diagnostic impression of noncardiac chest pain adequa

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Most recent data, with troponinIs the initial
diagnostic impression of noncardiac chest pain
adequate to exclude cardiac disease? Miller CD,
Ann EM December 2004 44(6)565-574

• 17,000 patients with CP
• 1992 thought to be noncardiac (75 d/ced to
  home)
• Physicians blinded to trop results, did not use
  them
• Of 1992, 71 (2.4) had first trop 0.6 - 1.0
• Troponin assay is critical.
• Our trop today is a new generation high
  sensitivity troponin
• (Dade Stratus CS cTNI)
• Very sensitive, but how much more?

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Inverse relation between with a "rule out MI
evaluation" and the miss MI rate.
Graff Am J Cardiol, Volume 80(5)563-568,
9/1/1997
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39 yo with atypical CP
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Risk of MI with Chest PainLee TH, et al. Acute
chest pain in the emergency room. Identification
and examination of low-risk patients. Arch Int
Med 1985 14565-69

• increased with history of known angina
• increased when identical to previous MI
• Deceptive
• "burning," "indigestion," (23 with MI) and
  "numbness" or inability to characterize the pain
  (23 with MI) are as likely to be MI as
  "pressure," "tightness", "crushing (24 with MI)
  
• 5 prob. if pain was "sharp" or "stabbing"

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Chest Pain characteristics and MILee TH, et al.
Acute chest pain in the emergency room.
Identification and examination of low-risk
patients. Arch Int Med 1985 14565-69

• with ACS if pain is pleuritic, positional, or
  reproducible
• 13 (n 96) if pain partly pleuritic or
  positional
• 0 (n 36) fully pleuritic or positional
• 24 (n158) if pain is partly reproduced on exam
• 7 (n 124) if fully reproduced
• greater with radiation to left arm, shoulder or
  neck
• less with radiation to back, abdomen, or legs
• Probability of MI
• greater with duration 60 minutes

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Positive Likelihood Ratios for MIPanju AA,
Hemmelgarn BR, Guyatt GH, Simel DL. Is this
patient having a myocardial infarction? JAMA
1998 Oct 14280(14)1256-63.

• new ST-segment elevation 11.2 (LR range,
  5.7-53.9)
• New ST depression, T wave inversion
• new Q wave 7.0 (LR range, 5.3-24.8)
• new conduction defect 6.3 (LR range 2.5-15.7)
• chest pain radiating to both the left and right
  arm simultaneously 7.1 (3.6-14.2)
• radiation to left (2.3) or right arm (2.9)
• presence of a third heart sound 3.2 (LR, 3.2)
• hypotension 3.1 (LR, 1.8-5.2).
• crackles 2.1 (1.4-3.1)
• diaphoresis 2.0 (1.9-2.2)

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Negative Likelihood Ratios for MIPanju AA,
Hemmelgarn BR, Guyatt GH, Simel DL. Is this
patient having a myocardial infarction? JAMA
1998 Oct 14280(14)1256-63.

• a normal ECG result (LR, 0.2)
• pleuritic chest pain (LR, 0.2)
• sharp or stabbing chest pain (LR, 0.3)
• positional chest pain (LR, 0.3)
• chest pain reproduced by palpation (LR, 0.3)
• Not associated with exertion (LR, 0.8)
• Infra-mammary location (LR, 0.8)
• These calculations did not distinguish between
  partial or full reproducibility

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Low risk Features, summary (ECG must be normal
or nonspecific)

• Right side only
• Pain primarily in middle or lower abdomen
• Pain lasts seconds only
• While the patient has this pain, it improves with
  exertion
• (e.g. goes away if I play basketball)
• clear non-ischemic cause for pain is found
• Chest wall trauma or chest x-ray abnormality
• GI etiology is NEVER a clear alternative Dx
• Palpation reproduces pain exactly on multiple
  exams
• Pain is pleuritic
• Pain is brought on by changes in position or
  movement
• Pain is localized to a fingertip
• Sharp (stabbing) pain

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Pitfalls in diagnosis of ischemia

• Pts. often interpret "sharp" to mean severe
• Therapeutic trials may be very misleading
• Nitroglycerin no different from placebo
• Henrickson, CA.  Chest Pain relief by
  Nitroglycerin Does Not Predict Active Coronary
  Artery Disease.  Ann Int Med 139(12)979-986,
  Dec. 16, 2003
• Antacids may improve up to 25 of MI pain
• Up to 33 of pts. with ACS have some chest wall
  tenderness, (24 partly, 7 fully reproducible)
• Lee TH, Arch Int Med 14565-69, 1985.
• Fully v. partly pleuritic or positional pain

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Pitfalls (contd)

• Unchanged ECG, even normal ECG
• with an atypical history, a normal ECG is rarely
  an MI, but not so rarely unstable angina
• Clinical presentation particularly variable in
  the elderly
• 40-50 fail to c/o chest pain
• Bayer AJ et al. J Am Soc Geriatr 34263-266
• Common atypical symptoms--shortness of breath,
  abdominal pain, dizziness, arm/shoulder/jaw pain
  
• Pain that persists in ED or recurs in ED
• associated with 3.8 x the risk of complications
  (Fesmire FM. Wears RL. Am J Em Med 1989 July
  7(4)372-377)