EKG Readings

normal sinus rhythm

• rate = 60-100 BPM or equivalent age-appropriate rate in children

• QRS complex preceded by P wave

• P waves upright in I and II, inverted in AVR

• PR interval constant

• QRS complexes <100 mm wide

sinus tachycardia

• increased electrical impulses from SA node

• heart rate >100 BPM

sinus bradycardia

• rate: <60 BPM

• regular rhythm

• P waves upright, consistent, and normal

• PR interval: 0.12-0.20 seconds

• QRS complex: <0.12 seconds, consistent

sinus arrest

• sudden absence of electrical activity in SA node → no depolarization/contraction

• 6 second pause = medical emergency, call 911 and carry out emergency procedures

atrial flutter

• narrow complex tachycardia

• regular atrial activity @ ~300 BPM

• loss of isoelectric baseline

• sawtooth pattern and inverted at II, III, AVF

atrial fibrillation

• irregular rhythm

• no P waves

• no isoelectric baseline

• variable ventricular rate

• QRS complexes usually <120 milliseconds

asystole

• colloquially referred to as a flatline

• complete cessation of electrical and mechanical activity in the heart

ventricular fibrillation

• rate: 150-500 BPM

• no identifiable waves

• chaotic irregular deflections of varying amplitude

premature ventricular contraction

• atrial rhythm is regular

• ventricular rhythm is irregular

• QRS complex is premature, wide, and/or distorted (>0.14 seconds)

• premature QRS complexes occur in singles, pairs, or groups of 3

ventricular tachycardia

• regular fast rhythm

• large, irregular QRS complexes

• P waves are either absent or random

somatic tremor

• caused by irregular muscle movement (Parkinson’s, shivering from cold, etc)

electrical/60-cycle interference

• caused by poor grounding and external electricity interfering with tracing

wandering baseline

• caused by movement associated with unusual breathing or poor electrode connection

interrupted baseline

• obvious break in the tracing

• usually related to a disconnected or broken lead wire