Cardiovascular Medicine Book





Aka: Electrocardiogram, EKG, ECG
  1. See Also
    1. Electrocardiogram in Myocardial Infarction
    2. Electrocardiogram in Pulmonary Embolism
    3. Electrocardiogram in Pericarditis
    4. Electrocardiogram in Atrial Fibrillation
  2. Background
    1. Interpretation requires patient age, EKG indication
    2. Images
      1. heartElectrical.jpg
  3. Precautions
    1. Standard EKG speed and amplitude is nearly always the best setting
      1. Although EKG gain can be increased and EKG speed can be slowed, the result is often more difficult to interpret
    2. Do not rely on computerized EKG Interpretation (aside from interval measurement)
      1. There is no standardization for software quality across EKG manufacturers and accuracy varies widely
      2. Computer interpretations miss STEMIs in up to 23-41% of cases
      3. Atrial Fibrillation is a frequent False Positive on computer interpretations
      4. Pacemaker rhythms are frequently misinterpreted by computers (STEMI False Positives and False Negatives)
      5. References
        1. Orman and Mattu in Herbert (2018) EM:Rap 18(3): 1-2
        2. Schlapfer (2017) J Am Coll Cardiol 70(9): 1183-92 [PubMed]
        3. Willems (1991) N Engl J Med 325(25):1767-73 +PMID:1834940 [PubMed]
  4. Components: EKG Paper
    1. Record speed: 25 mm/sec
    2. Small square (1 mm): 0.04 seconds
    3. Large square (5 mm): 0.20 seconds
  5. Components: Leads
    1. Limb leads (bipolar)
      1. Lead I: Left arm - Right arm (0 degrees)
      2. Lead II: Left leg - Right arm (60 degrees)
      3. Lead III: Left leg - Left arm (120 degrees)
    2. Augmented Limb Leads (unipolar)
      1. Lead aVR: (-150 degrees)
      2. Lead aVL: (-30 degrees)
      3. Lead aVF: (90 degrees)
    3. Precordial Leads (unipolar chest)
      1. Lead V1: Right sternal border (Right Ventricle)
      2. Lead V2: Left sternal border
      3. Lead V3: Medial Breast (Septum)
      4. Lead V4: Nipple
      5. Lead V5: Lateral Breast
      6. Lead V6: Lateral chest wall (Left Ventricle)
  6. Evaluation: Approach
    1. Assess EKG Validity
    2. Rate and Rhythm: "Watch your P's and Q's and the 3R's"
      1. Lead II P Waves upright? Otherwise not sinus rhythm
      2. QRS wide or narrow?
      3. Rate?
      4. Regularity of Rhythm?
      5. Relationship between P Waves and QRS Complex
    3. EKG Axis
      1. EKG-Axes.png
    4. Intervals (prolonged?)
      1. PR interval
      2. QRS Complex
      3. QT Interval
    5. Hypertrophy?
      1. Left Ventricular Hypertrophy
      2. Right Ventricular Hypertrophy
      3. Right Atrial Enlargement
      4. Left Atrial Enlargement
    6. Infarction?
      1. Q Waves
      2. R Wave Progression
      3. ST Segments
      4. T Waves
    7. Reference
      1. Grauer (2001) 12 Lead EKGs, KG/EKG Press, Gainesville
  7. Interpretation: Specific Circumstances
    1. See Electrocardiogram in Myocardial Infarction
    2. See EKG Changes in Syncope due to Arrhythmia
    3. See Electrocardiogram in Atrial Fibrillation
    4. See EKG Changes During Pregnancy
    5. See Hyperkalemia Related EKG Changes
    6. See Hypokalemia Related EKG Changes
    7. Ventricular Tachycardia
      1. Northwest axis (opposite Nl axis)
      2. V1-V6 positive QRS Complex
      3. See AV dissociation
    8. Pericarditis
      1. See Electrocardiogram in Pericarditis
      2. Stage I: Diffuse ST inc all leads except aVR, V1
      3. Stage II: ST segments temporarily normalize
      4. Stage III: Diffuse ST depress +/- T inversion
      5. Stage IV: Gradual normalization of ST and T Waves
    9. Pulmonary Embolism
      1. See Electrocardiogram in Pulmonary Embolism
      2. Right Strain Pattern (Classic PE, but rarely seen)
        1. S1 (deep S wave in lead I)
        2. Q3 (Q Wave in lead III)
        3. T3 (inverted T Wave in lead III)
    10. Atrial Fibrillation or Atrial Flutter with Rapid Ventricular Rate
      1. See Electrocardiogram in Atrial Fibrillation
      2. At a rapid rate (e.g. 140-150 bpm), may be difficult to differentiate AFib/Flutter from ST, PSVT
        1. Increase EKG "paper speed" to 50 mm/sec (rapid) to spread out complexes (P Waves may be seen)
        2. Mattu (2020) Crit Dec Emerg Med 34(4): 18

Electrocardiogram (C0013798)

Concepts Finding (T033)
MSH D004562
SnomedCT 142008000
LNC LP149975-7, MTHU044181
English Electrocardiogram, Electrocardiograms, ecgs, electrocardiograms, electrocardiograph, electrocardiography, EKG, ekgs, electrocardiogram (EKG, ECG), ECG, electrocardiogram
Italian Elettrocardiogramma
French Électrocardiogramme, ECG (ÉlectroCardioGramme)
Czech elektrokardiogram, elektrokardiografický záznam
Norwegian Elektrokardiogram
Derived from the NIH UMLS (Unified Medical Language System)

Electrocardiography (C1623258)

Definition (NCI_NCI-GLOSS) A line graph that shows changes in the electrical activity of the heart over time. It is made by an instrument called an electrocardiograph. The graph can show that there are abnormal conditions, such as blocked arteries, changes in electrolytes (particles with electrical charges), and changes in the way electrical currents pass through the heart tissue.
Definition (NCI) A procedure that displays the electrical activity of the heart.
Definition (CSP) measurement and interpretation of electrical manifestations of heart activity.
Definition (MSH) Recording of the moment-to-moment electromotive forces of the HEART as projected onto various sites on the body's surface, delineated as a scalar function of time. The recording is monitored by a tracing on slow moving chart paper or by observing it on a cardioscope, which is a CATHODE RAY TUBE DISPLAY.
Concepts Diagnostic Procedure (T060)
MSH D004562
ICD9 89.52
SnomedCT 164960001, 164844004, 146485007, 142135006, 142007005, 271334005, 46825001, 29303009
LNC LP6244-0, LP100599-2, LP57609-7
English ECG, EKG, electrocardiography, Electrocardiography NOS, Electrocardiography NOS (regime/therapy), ELECTROCARDIOGR, electrocardiogram (procedure), electrocardiogram, Electrocardiograph, Electrocardiography (procedure), Electrocardiography NOS (procedure), Electrocardiographs, Electrocardiogram, Electrocardiographic procedure (procedure), Electrocardiographic procedure, Electrocardiographic procedure, NOS, Electrocardiogram, NOS, EKG (Electrophysiology), ECG NOS, Electrocardiography
Italian Elettrocardiogramma, ECG, EKG, Elettrocardiografia
French ECG, EKG, ECG (ÉlectroCardioGraphie), Electrocardiogramme, Électrocardiographie
Swedish Elektrokardiografi
Spanish electrocardiografía, SAI (régimen/tratamiento), electrocardiografía, SAI (procedimiento), Electrocardiography NOS, electrocardiografía, SAI, ECG, electrocardiograma, procedimiento electrocardiográfico (procedimiento), procedimiento electrocardiográfico, Electrocardiograma, EKG, Electrocardiografía
Japanese シンデンズ, 心電図記録法, 心電図検査, 心電図検査法, 心電図記録, 心電計, 心電図
Czech elektrokardiografie, Elektrokardiogram, EKG
Finnish Elektrokardiografia
Polish Wykres EKG, Badanie elektrokardiograficzne, EKG, Elektrokardiografia, Zapis EKG
Hungarian EKG, Elektrokardiogram
Norwegian ECG, Elektrokardiografi, Elektrocardiografi, EKG
Portuguese Electrocardiograma, ECG, EKG, Eletrocardiografia
Dutch elektrocardiogram, ECG, Elektrocardiografie
German Elektrokardiogramm, ECG, EKG, Elektrokardiographie
Derived from the NIH UMLS (Unified Medical Language System)

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