T Wave

Aka: T Wave, Peaked T Wave, Tall T Wave, Prominent T Wave, Hyperacute T Wave, T Wave Inversion, T Wave Alternans, Flattened T Wave, T Wave Flattening, Deep T Wave Inversion, Cerebral T Waves

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II. Definitions

  1. T Wave
    1. EKG electrical signal following the ST Segment
    2. Represents repolarization of the ventricular Muscles

III. Findings: Normal

  1. Upright: I, II, V3, V4, V5, V6
  2. Inverted: aVR
  3. Variable (upright, inverted or biphasic): all other leads
  4. Increased Amplitude: aVL and aVF (if QRS over 5 mm)
  5. Shape: Asymmetrical
    1. An upright T Wave normally rises gradually, and falls with a steeper slope

IV. Findings: T Wave Shape

  1. Smooth: Normal
  2. Notched: Pericarditis
  3. Pointed: Myocardial Infarction
  4. T Wave Alternans
    1. Upright T Wave alternates with inverted T Wave on every other beat
    2. Ominous finding that heralds Cardiac Arrest

V. Findings: T Wave Height

  1. Normal
    1. Limb leads: <6 mm
    2. Precordial leads: < 10 mm
  2. Tall, peaked, prominent or Hyperacute T Wave Causes
    1. Hyperkalemia
      1. See Hyperkalemia Related EKG Changes
      2. T Waves are narrow, tall and symmetric
      3. T Waves may be inverted (negatively peaked)
    2. Myocardial Infarction or Myocardial Ischemia
      1. T Waves are less tall and more wide and asymmetric than in Hyperkalemia
      2. Prominent T Waves often immediately precede ST Elevation in STEMI
      3. De Winter T Wave is a Hyperacute T Wave with J Point depression and consistent with acute LAD Occlusion
    3. Cerebrovascular Accident
    4. Acute Pericarditis
    5. Left Ventricular Hypertrophy
    6. Early Repolarization
    7. Bundle Branch Block
    8. Preexcitation Syndrome
    9. References
      1. Mattu (2008) Crit Dec Emerg Med 33(12): 11
  3. T-Wave Flattening (T Wave height -1 to 1 mm)
    1. Post-coronary ischemic event
    2. Hypokalemia
    3. Digitalis

VI. Causes: T Wave Inversion

  1. Very Deep T Wave Inversion (Cerebral T Waves)
    1. Associated with large Intracranial Hemorrhage (also seen in cerebral edema, Ischemic CVA, PRES)
    2. Typically in precordial leads, and Inversion may be >20 mm
    3. May be associated with Prolonged QTc
    4. Images: Deep Inverted T Waves Precordial in Hypertensive Encephalopathy (PRES)
      1. ekg20214c_1_deepInvertedTwavesPRES.jpg
      2. ekg20214c_2_deepInvertedTwavesPRES.jpg
      3. ekg20214c_3_deepInvertedTwavesPRES.jpg
    5. References
      1. Mattu and Brady (2008), EKGs for the Emergency Physician 2, BMJ, London, p. 11, 23
      2. Mattu (2022) Crit Dec Emerg Med 36(3): 7
  2. T Wave Inversion (in general)
    1. Heart Block
    2. Ischemic Heart Disease with Myocardial Ischemia or infarction
    3. Bradycardia
    4. Right Ventricular Hypertrophy
    5. Right Bundle Branch Block
    6. Metabolic disturbance
    7. Takotsubo Cardiomyopathy
    8. Pulmonary Edema
    9. Cocaine Use
    10. Acute CNS events
    11. References
      1. Said (2015) World J Cardiol 7(2): 86-100 +PMID:25717356 [PubMed]
      2. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4325305/
  3. T Wave Inversion specific to anterior leads (V1 to V4)
    1. Anterior Myocardial Ischemia
    2. Proximal Left Anterior Descending Occlusion
      1. See Wellen's Syndrome
      2. Deeply inverted T Waves or biphasic T Waves in V2-3
    3. Posterior Myocardial Infarction
    4. Pulmonary Embolism with right heart strain
    5. Neurogenic T Waves
      1. Precedes ischemic cerebrovascular event
    6. Yamaguchi Syndrome
      1. Hypertrophic Cardiomyopathy involving the cardiac apex
    7. Hypokalemia
      1. Biphasic T Wave in mid-precordial leads
      2. Mattu (2017) Crit Dec Emerg Med 31(3): 11
    8. References
      1. Herbert (2012) EM:RAP 12(1): 12

VII. References

  1. Berberian (2023) Crit Dec Emerg Med 37(5): 12-3

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