EKG Rounds

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EKG Rounds

• Elizabeth Haney
• 19 October 2006

2
Case

• 32 y.o. Caucasian male presents w/ 4 hours sharp
  RSCP
• Radiation to Lt shoulder and arm
• Worse with deep inspiration, no exertional change
• PMHx healthy, URTI Sx x 5/7
• Meds occasional tylenol
• NKDA

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Case (contd)

• Vitals HR 120 reg, RR 24, BP 124/82 bilat,
  
• T 37.1, O2 sat 99
• O/E sitting up in bed, moderate distress,
  otherwise exam normal

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EKG
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Pericarditis

• Overview of the pericardium and pericarditis
• 4 EKG stages
• Differentiating between pericarditis and early
  repolarization

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Pericardium

• Back to basics
• Pericardium fibroelastic sac, composed of
  parietal and visceral layers with narrow
  potential space between
• Normally contains 15-60ml plasma ultrafiltrate.
• Drainage via thoracic duct and right lymphatic
  duct into Rt pleural space

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Pericarditis

• Inflammation of pericardium
• Etiology Most cases idiopathic, with specific
  etiology in only 22

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Pericarditis

• Classical features RSCP (varies w/ respiration,
  sharp, worse w/ lying down, relieved w/ sitting
  up, may radiate to trapezius), EKG abnormalities,
  /- pericardial friction rub (25 of cases)

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EKG Findings

• Changes reflect superficial inflammation of the
  epicardium
• 90 will show STE, most commonly in leads
  I,II,V5-6 (70 of patients)
• PR depression in all leads except aVR (elevation)
  may be 1st sign, reflecting repolarization
  abnormality of atria
• Changes follow typical 4 stage evolution over
  weeks to months

Demangone,D., ECG Manifestations Noncoronary
Heart Disease., Emerg Med Clin N Am 24 (2006)
113-115
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4 Stages of EKG changes

• Stage I  Typically occurs during the first hours
  days. Diffuse
  concave-upward ST segment elevation with
  concordance of T waves ST-segment depression in
  aVR or V1 PR segment depression
• Stage II Normalization of ST and PR segments T
  wave flattening. Days weeks.
• Stage III Symmetric T wave inversion. 3 weeks
  -2 months
• Stage IV Gradual resolution of T-wave inversion
  (may remain inverted). May last 3 months

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What causes STE in the Emerg?

• LVH with Strain (25)
• Undefined STE (17)
• Acute MI (15)
• LBBB (15)
• Benign Early repolarization (12)
• RBBB (5)
• Non-specific BBB (5)
• LV aneurysm (3)
• Pericarditis (1)
• Retrospective review of 202 patients with chest
  pain and STE gt1mm in limb leads, gt2mm precordial
  leads, 2 or more contiguous leads

Brady WJ et al. Cause of ST Segment Abnormality
in ED Chest Pain Patients. Am J Emerg Med 2001
19 25-28.
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Benign Early Repolarization

• Normal EKG variant
• May be related to enhanced vagal tone
• Prevalent in patients with high (T5 or higher)
  spinal cord injuries where sympathetic flow
  interrupted
• Males gt Females
• Predominantly age lt50
• Incidence 1-2

Rosens, Mehta, et al. Early Repolarization.
Clin.Cardiol. 1999 22, 59-65
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Early Repolarization

• Characterized by
• Diffuse ST segment elevation on EKG
• Upward concavity of the initial portion of the ST
  segment
• Notching of the terminal portion of the QRS
  complex at the J point (jcn of QRS with ST)
• Symmetrical, concordant T waves of large
  amplitude
• Relative temporal stability over time
• Maximal STE typically in precordial leads V2-V5

Rosens
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How can we distinguish between Early
Repolarization and Pericarditis?
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ST/T Ratio Tool
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ER vs. Pericarditis
Pericarditis Early
ST Concave up Concave up
STT in V6 gt0.25 lt0.25
ST elevation location limb and precordial leads precordial leads
PR depression present absent
Temporal change in EKG present absent
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Summary

• 4 stages of Pericaritis EKG changes
• Ddx of STE
• Early Repolarization
• Use of the ST/T wave ratio to help differentiate
  pericarditis from early repolarization

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References

• www.uptodate.com
• Marx Rosens Emergency Medicine Concepts and
  Clinical Practice, 6th ed., 2006 Ch. 81 1280-88
• Demangone,D., ECG Manifestations Noncoronary
  Heart Disease., Emerg Med Clin N Am 24 (2006)
  113-115
• Brady WJ et al. Cause of ST Segment Abnormality
  in ED Chest Pain Patients. Am J Emerg Med 2001
  19 25-28.
• Mehta, et al. Early Repolarization. Clin.Cardiol.
  1999 22, 59-65

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Pericarditis vs. AMI
Pericarditis MI
ST Concave Up Convex
Reciprocal Changes Absent Present
ST elevation Limb and precordial Specific coronary territory
Q waves Absent/no evolution Evolution
T wave inversion After ST segments return to baseline Before/as ST segments elevate
PR depression Present Absent unless atrial infarct