Quick ECG Interpretation (Assessment Notes)

For quick ECG Interpretation Result look to the following Normal values.

Normal Rate 60–100 bpm

Normal P-R 0.12–0.20 sec

Normal QRS 0.08–0.12 sec

P wave atrial depolarization; QRS ventricular

depolarization; T wave ventricular repolarization


Basic ECG Assessment

Follow these steps for basic electrocardiogram interpretation.

  1. Determine ventricular rate.
  2. Determine QRS duration and shape.
  3. Identify P waves and determine if a P wave precedes every QRS complex.
  4. If more than 1 P wave precedes a QRS complex, determine ratio of P waves to QRS complex (ex., 4:1, 3:1, 2:1).
  5. Is P wave shape consistent?
  6. Determine atrial rate and rhythm.
  7. Determine P-R intervals and if they are consistent.


Analyzing the P-R Interval (PRI)

  • PRI is consistent and between 0.12 and 0.20 sec (3–5 small boxes): This is considered a normal PRI.
  • PRI is [1]0.12 sec (3 small boxes): consider junctional rhythm.
  • PRI is longer than 0.20 sec (5 small boxes), it remains consistent in length from PRI to PRI: Consider 1 AV block.
  • PRI undergoes progressive lengthening until a QRS is dropped: Consider 2 AV block, type I.
  • PRI is consistent; however, there are additional P waves that do not preceed a QRS complex: Consider 2 AV block, type II.
  • PRI is not consistent, nor is there any correlation between the P wave and the QRS: Consider 3 AV block (CHB).


Analyzing the QRS Complex

  • QRS between 0.08 and 0.12 (2–3 small boxes): Consider normal.
  • QRS 0.12 sec, “wide and bizarre”: Consider ventricular ectopy.
  • QRS 0.12 sec (3 small boxes), with notched or “rabbit ears” appearance: Consider BBB.
  • QRS preceded by 1–2 very narrow “spikes”: Think pacemaker.

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