Rhythm Interpretation and Strip Labeling
Domain 4 tests systematic rhythm analysis, recognition of common patterns, and correct strip labeling.
Analysis sequence
Rate: 300 divided by the number of large boxes between R waves, or 1500 divided by small boxes; for irregular rhythms count QRS complexes in 6 seconds and multiply by 10. Assess regularity, P waves (present, upright in II, one per QRS), PR interval 0.12–0.20 s, QRS width less than 0.12 s, QT, and ST segment.
Common patterns
Sinus bradycardia below 60; sinus tachycardia above 100; atrial fibrillation irregularly irregular with no distinct P waves; atrial flutter with sawtooth waves; PVC as a wide early beat; ventricular tachycardia as wide, regular, fast; ventricular fibrillation as chaotic; asystole as a flat line-confirm leads and patient.
Labeling
At the time of recording, label patient name and ID, date and time, lead or leads, paper speed and gain, and any symptoms or events. Do not write interpretations or normal. Use ink that will not smudge; do not label later from memory.
Worked example
A 6-second strip shows an irregularly irregular rhythm, no distinct P waves, and about 9 QRS complexes. The rate is about 90. The technician labels the strip, notes irregular rhythm with no P waves and that the patient denies symptoms, and reports it. The technician does not write atrial fibrillation as a diagnosis.
Traps
Calling artifact a rhythm; measuring rate from an irregular rhythm with the 300 method; labeling after the fact; omitting lead and speed; writing diagnoses.