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T Wave

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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

  • See Also
  1. Electrocardiogram (EKG)
  2. Cardiac Electrophysiology Anatomy
  • Definitions
  1. T Wave
    1. EKG electrical signal following the ST Segment
    2. Represents repolarization of the ventricular Muscles
  • 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
  • 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. May be associated with Prolonged QTc (as well as predisposing Hypokalemia or Hypocalcemia)
    3. Marker of myocardial electrical instability
      1. Ominous finding that heralds ventricular Dysrhythmia, Torsades de Pointes or Cardiac Arrest
  • Findings
  • T Wave Height
  1. See Tall P Waves below
  2. Normal
    1. Limb leads: <6 mm
    2. Precordial leads: < 10 mm
  3. T-Wave Flattening (T Wave height -1 to 1 mm)
    1. Post-coronary ischemic event
    2. Hypokalemia
    3. Digitalis
  • Causes
  • 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. De Winter T Wave is a Hyperacute T Wave with J Point depression and consistent with acute LAD Occlusion
    3. Prominent T Waves often immediately precede ST Elevation in STEMI
      1. Obtain Serial EKGs
      2. AHA/ACC consider Hyperacute T Waves in ACS presentation as a STEMI Equivalent (consult cardiology)
      3. However, grading T Wave size is subjective, and there is no T height calculation that reliably predicts high risk ACS
        1. T Waves that are as tall or taller than the QRS Complex are significant
        2. Observe for associated ST deviation >=1mm or dynamic T Wave changes
        3. AVL T Wave Inversion precedes inferior Myocardial Infarction
  3. Other Causes of Tall T Waves
    1. Cerebrovascular Accident
    2. Acute Pericarditis
    3. Left Ventricular Hypertrophy
    4. Early Repolarization
    5. High voltage EKG
    6. Left Bundle Branch Block
    7. Preexcitation Syndrome
  4. References
    1. Mattu (2008) Crit Dec Emerg Med 33(12): 11
    2. Mattu and Swaminathan (2023) EM:Rap, accessed 10/1/2023
    3. Koechlin (2023) Ann Emerg Med 82(2):194-202 +PMID: 36774205 [PubMed]
    4. Smith (2023) Ann Emerg Med 82(2):203-6 +PMID: 36872197 [PubMed]
  • 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. Juvenile T Wave Pattern
      1. T Wave Inversion is normal in V1-V3 in age <16 years (athletes and non-athletes)
    2. Anterior Myocardial Ischemia
    3. Proximal Left Anterior Descending Occlusion
      1. See Wellen's Syndrome
      2. Deeply inverted T Waves or biphasic T Waves in V2-3
    4. Posterior Myocardial Infarction
    5. Pulmonary Embolism with right heart strain
    6. Neurogenic T Waves
      1. Precedes ischemic cerebrovascular event
    7. Yamaguchi Syndrome
      1. Hypertrophic Cardiomyopathy involving the cardiac apex
    8. Hypokalemia
      1. Biphasic T Wave in mid-precordial leads
      2. Mattu (2017) Crit Dec Emerg Med 31(3): 11
    9. References
      1. Herbert (2012) EM:RAP 12(1): 12
  • References
  1. Berberian (2023) Crit Dec Emerg Med 37(5): 12-3