Cardiovascular Medicine Book




QRS Complex

Aka: QRS Complex, QRS Duration, Wide QRS, QRS Widening
  1. See Also
    1. R Wave
  2. Normal findings: Duration
    1. Limb leads (I, II, III): 0.05 to 0.10
    2. Precordial leads (V1 to V6): 0.06 to 0.12
  3. Causes: Wide QRS or Prolonged QRS Complex (over 0.12)
    1. Abnormal interventricular conduction (e.g. Left Bundle Branch Block)
      1. See Bundle Branch Block
      2. Hypothermia
      3. Hyperkalemia
      4. Wolff-Parkinson-White Syndrome (WPW)
      5. Ventrciular ectopy
      6. Ventricular Tachycardia
    2. Medications (e.g. Toxin Ingestion or Overdose)
      1. Results from Sodium channel blockade
      2. Emergency management
        1. See Toxin Ingestion
        2. See Tricyclic Overdose
        3. Sodium Bicarbonate 1-2 amps IV push with repeat bolus until QRS narrows (adults)
      3. Causes
        1. Tricyclic Antidepressants
          1. Dry and sedated
        2. Cocaine
          1. Diaphoretic and agitated
        3. Diphenhydramine (Benadryl)
        4. Local Anesthetics (esp. Bupivacaine)
        5. Antiarrhythmics (e.g. Quinidine, Flecainide)
        6. Propoxyphene (not available in U.S.)
        7. Digoxin Toxicity
          1. Associated with frequent PVCs and sagging ST depression
  4. Causes: Low QRS amplitude (<5 mm in limb leads)
    1. Diffuse Coronary Artery Disease
    2. Congestive Heart Failure
    3. Pericardial Effusion
    4. Myxedema
    5. Amyloidosis
    6. Obesity
    7. Emphysema (?OPD)
    8. Anasarca
  5. Causes: High QRS amplitude
    1. Evaluate for Left Ventricular Hypertrophy
  6. References
    1. Mattu (2016) Crit Dec Emerg Med 30(8):16

QRS complex duration (observable entity) (C0429025)

Concepts Organism Attribute (T032)
SnomedCT 251208001
LNC LP31031-5, MTHU019811
English QRS complex duration (observable entity), QRS duration, QRS complex duration
Spanish duración del complejo QRS (entidad observable), duración del complejo QRS
Derived from the NIH UMLS (Unified Medical Language System)

QRS complex feature (C0429097)

Definition (NCI) An electrocardiographic finding that represents depolarization of the ventricular myocardium. Normally the ventricles are activated simultaneously.
Concepts Finding (T033)
SnomedCT 142119004, 164949005
LNC LP31569-4, MTHU024513
Dutch QRS-complex
French Complexe QRS
German QRS-Komplex
Italian Complesso QRS
Portuguese Complexo QRS
Spanish Complejo QRS, característica del complejo QRS (entidad observable), característica del complejo QRS, complejo QRS (entidad observable), complejo QRS
Japanese QRS群, QRSグン
Czech QRS komplex
English qrs complex, QRS Complex, QRS complex (observable entity), QRS complex, QRS complex feature (observable entity), QRS complex feature
Hungarian QRS komplex
Derived from the NIH UMLS (Unified Medical Language System)

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