Carolinas Core Concepts Core Concepts in EM; a repository for Carolinas lecture summaries.


Littmann’s EKG Course: Miscellaneous

  • S1Q3T3 is a pattern of acute right heart strain and is not specific to pulmonary embolism.  It may be seen with severe pneumonia, ARDS, tension pneumothorax, or pulmonary hemorrhage.
    • Watch for RSR' in V1, this is a very ominous finding!
      S1Q3T3 Pulmonary Embolism

      An excellent example of S1Q3T3 in a patient with massive PE. Note the ominous RSR' finding in V1.

      S1Q3T3 no PE

      A similar EKG in a patient with pneumonia, hypoxia, and ARDS... with no PE on CTA.

  • Always check the EKG in a syncopal episode.  Brugada pattern - coved ST segments in V1&V2 - is an indication for ICD placement.

    Brugada Pattern

    This young, healthy patient presented with syncope. He died after being sent home with this EKG. It should have been the indication for an implanted ICD.


Littmann’s EKG Course: T Waves

  • 1-3mm upsloping ST depressions in V1-V6 with tall, symmetric T-waves is highly concerning for hyperacute proximal LAD STEMI.

    New Wellens LAD

    This EKG was taken prior to cath of a patient with a 100% proximal LAD lesion. Note the upsloping ST segments.

    • N Engl J Med 2008;359:2071-3       Heart 2009;95:1701-6
  • The T-waves in hyperkalemia are often simply narrow-based rather than tall.  Because of this, the computer software often "double counts" the heart rate.


    This patient has a K+ of 7.2. Note that the computer "double-counts" the heart rate.


Littmann’s EKG Course: The ST Segment

  • When faced with a QRS with a terminal "notch" and hammock shaped ST's:
    • Consider pericarditis if tachycardic.
    • Consider benign early repolarization if normal rate.
    • Consider hypothermia if bradycardic.

      Tachycardia, PR depression in lead II, and PR elevation in aVR is concerning for pericarditis.

      Benign Early Repolarization

      In the setting of normal rate and a young healthy patient, this EKG is most consistent with benign early repolarization.


      Osborn waves with hypothermia look similar to the above two examples but are seen in bradycardia.

  • The "aVR sign." Chest pain, ST elevation in aVR and diffuse ST depressions is 80% sensitive for LAD main and high mortality.

    aVR sign

    Pay close attention to aVR in this EKG; this patient has a 100% occlusion to the LAD.

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Littmann’s EKG Course: The QRS Complex

  • LBBB makes most EKG's unreadable, except in those where the ST is concordant.  Watch for STEMI!


    Inferior STEMI seen in II, III, aVF in a patient with LBBB. ST segments should not be concordant!

  • Electrical alternans can be easy to miss but may indicate an underlying effusion.

    Electrical Alternans

    Electrical Alternans in an HIV patient with an effusion.

  • The finding of marked axis deviation, RBBB, and prolonged PR interval is concerning for trifascicular block.  In a patient with unexplained syncope this is a potentially lethal finding; admit for emergent pacemaker.
    Trifascicular block

    RBBB, left posterior fascicular block, and prolonged PR: trifascicular block in a patient with syncope. Emergent indication for pacemaker!




Littmann’s EKG Course: P waves

  • P-wave inversions in lead I are never normal.  Consider 3 common etiologies:
    1. Ectopic atrial rhythm - V1-V6 also reveal inverted P's from an abnormal depolarization site.
    2. Dextrocardia - V1-V6 show r-wave regression.
    3. Limb lead reversal - lead II shows a "flat line", repeat the EKG with a better tech.
  • Parkinsonian tremor and oscillators both can cause a 5hz artifact (300bpm) and are mistaken for aflutter.  Look for sinus rhythm in other leads.

    Parkinsonian tremor masquerading as artifact

    NSR seen in lead III with "flutter waves" in other leads. This patient has Parkinsons.

  • Always look for atrial flutter if the computerized interpretation on an EKG is any of these red flags; the computer routinely misinterprets flutter.
    1. "Sinus tachycardia with 1° AV block"
    2. "Sinus tachycardia with short PR"
    3. * cannot find p-wave axis
      Missed atrial flutter
      Look for the red flags!