To evaluate the electrical impulses generated by the heart during the cardiac cycle to assist with diagnosis of cardiac dysrhythmias, blocks, damage, infection, or enlargement.

Patient Preparation
There are no food, fluid, activity, or medication restrictions unless by medical direction.

Normal Findings

Normal Resting Heart Rate by Age
Newborns (0–1 mo)70–180
Infants (2–11 mo)80–160
1–2 yr80–130
3–4 yr75–140
5–7 yr70–130
8–9 yr70–120
10 yrs and older, adults, older adults60–100
  • Normal resting heart rate for trained athletes is in the range of 40 to 60 beats/min.
  • Normal, regular rhythm and wave deflections with normal measurement of ranges of cycle components and height, depth, and duration of complexes are as follows:
    • P wave: 0.12 sec, or three small blocks with amplitude of 2.5 mm
    • Q wave: Less than 0.04 mm
    • R wave: 5 to 27 mm amplitude, depending on lead
    • T wave: 1 to 13 mm amplitude, depending on lead
    • QRS complex: 0.1 sec or two and a half small blocks
    • ST segment: 1 mm

Critical Findings and Potential InterventionsAdult

  • Acute changes in ST elevation are usually associated with acute myocardial infarction (MI) or pericarditis
  • Asystole
  • Heart block, second- and third-degree with bradycardia less than 60 beats/min
  • Pulseless electrical activity
  • Pulseless ventricular tachycardia
  • Premature ventricular contractions greater than three in a row, pauses greater than 3 sec, or identified blocks
  • Unstable tachycardia
  • Ventricular fibrillation


  • Asystole
  • Bradycardia less than 60 beats/min
  • Pulseless electrical activity
  • Pulseless ventricular tachycardia
  • Supraventricular tachycardia
  • Ventricular fibrillation

Timely notification to the requesting health-care provider (HCP) of any critical findings and related symptoms is a role expectation of the professional nurse. A listing of these findings varies among facilities.

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