EKG Waveform Lesson

Definition of Dysrhythmia

A cardiac dysrhythmia is an abnormal heart beat: the rhythm may be irregular in its pacing or the heart rate may be low or high. Some dysrhythmias are potentially life threatening while other dysrhythmias (such as sinus arrhythmia) and normal.

Dysrhythmia Categories

  • Tachycardia, which is a fast heart rhythm.
    • Atrial dysrhythmias, such as include:
      • Atrial fibrillation
      • Atrial flutter
      • Paroxysmal Supraventricular tachycardia
      • Wolff-Parkinson-White syndrome
      Ventricular dysrhythmias, including:
      • Premature ventricular contractions
      • Ventricular fibrillation
  • Bradycardia, a slow heart rhythm.
    • Bradyarrhythmias include:
      • Heart Conduction Block
      • Sick Sinus Syndrome
      • Sinus bradycardia
  • A premature beat.

Dysrhythmia Diagnosis

This website contains a number of free training tools:
  • Introduction Course
  • Interative Presentations
  • EKG Interpretation Quizzes

Getting Started

A good starting point for learning cardiac arrhythmias is our EKG Basics training course.

EKG Waveforms »

Directory of Dysrhythmia Types

Accelerated Idioventricular Rhythm

Accelerated Idioventricular Rhythm EKG tracing
RhythmRegular
Rate50-120 bpm
P WaveAbsent
PR IntervalNot measurable
QRSWide (>0.10 sec), bizarre looking
Notes 


Accelerated Junctional Rhythm

Accelerated Junctional Rhythm EKG tracing
RhythmRegular
RateNormal (60-100 bpm)
P WavePresent before, during (hidden) or after QRS, if visible it is inverted
PR IntervalNot measurable
QRSNormal (0.06-0.10 sec)
Notes 


Asystole

Asystole EKG tracing
RhythmNot present
RateAbsent
P WaveAbsent
PR IntervalAbsent
QRSAbsent
NotesConfirm with multiple leads



Atrial Fibrillation

Atrial Fibrillation EKG tracing
RhythmIrregular
RateVery fast (> 350 bpm) for Atrial, but ventricular rate may be slow, normal or fast
P WaveAbsent - erratic waves are present
PR IntervalAbsent
QRSNormal but may be widened if there are conduction delays
Notes 



Atrial Flutter

Atrial Flutter EKG tracing
RhythmRegular or irregular
RateFast (250-350 bpm) for Atrial, but ventricular rate is often slower
P WaveNot observable, but saw-toothed flutter waves are present
PR IntervalNot measurable
QRSNormal (0.06-0.10 sec)
Notes 



First Degree Heart Block

First Degree Heart Block EKG tracing
RhythmRegular
RateThe underlying rate
P WaveNormal
PR IntervalProlonged (>0.20 sec)
QRSNormal (0.06-0.10 sec)
NotesA first degree AV block occurs when electrical impulses moving through the Atrioventricular (AV) node are delayed (but not blocked). First degree indicates slowed conduction without missed beats.



Idioventricular Rhythm

Idioventricular Rhythm EKG tracing
RhythmRegular
RateSlow (20-40 bpm)
P WaveAbsent
PR IntervalNot measurable
QRSWide (>0.10 sec), bizarre appearance
Notes 



Junctional Escape Rhythm

Junctional Escape Rhythm EKG tracing
RhythmRegular
RateSlow (40-60 bpm)
P WavePresent before, during (hidden) or after QRS, if visible it is inverted
PR IntervalNot measurable
QRSNormal (0.06-0.10 sec)
Notes 



Junctional Tachycardia

Junctional Tachycardia EKG tracing
RhythmRegular
RateFast (100-180 bpm)
P WavePresent before, during (hidden) or after QRS, if visible it is inverted
PR IntervalAbsent or short
QRSNormal (0.06-0.10 sec)
Notes 



Multifocal Atrial Tachycardia

Multifocal Atrial Tachycardia EKG tracing
RhythmIrregular
RateFast (> 100 bpm)
P WaveOften changing shape and size from beat to beat (at least three differing forms)
PR IntervalVariable
QRSNormal (0.06-0.10 sec)
NotesT wave is often distorted Also review wandering atrial pacemaker lesson



Normal Sinus Rhythm

Normal Sinus Rhythm EKG tracing
RhythmRegular
RateNormal (60-100 bpm)
P WaveNormal (positive & precedes each QRS)
PR IntervalNormal (0.12-0.20 sec)
QRSNormal (0.06-0.10 sec)
Notes 



Pacemaker Failure to Capture

Pacemaker Failure to Capture EKG tracing
RhythmIrregular
RateSlow or normal
P Wave 
PR Interval 
QRS 
NotesPacemaker spikes are not followed by P waves or QRS complexes



Pacemaker Failure to Pace

Pacemaker Failure to Pace EKG tracing
RhythmIrregular
Rate 
P Wave 
PR Interval 
QRS 
NotesPacemaker spikes do not appear



Pacemaker Single Chamber Atrial

Pacemaker Single Chamber Atrial EKG tracing
RhythmRegular
Rate60 bpm
P WaveNormal
PR IntervalNormal
QRSNormal
Notes 



Premature Atrial Complex

Premature Atrial Complex EKG tracing
RhythmIrregular
RateUsually normal but depends on underlying rhythm
P WavePremature, positive and shape is abnormal
PR IntervalNormal or longer
QRS0.10 sec or less
Notes 



Premature Junctional Complex

Premature Junctional Complex EKG tracing
RhythmRegular with premature beats
RateThe underlying rate
P WavePresent before, during (hidden) or after QRS, if visible it is inverted
PR IntervalAbsent or short
QRSNormal (0.06-0.10 sec)
Notes 



Premature Ventricular Complex

Premature Ventricular Complex EKG tracing
RhythmIrregular
RateThe underlying rate
P WaveAbsent
PR IntervalNot measurable
QRSWide (> 0.10 sec), bizarre appearance
NotesTwo PVCs together are termed a couplet while three PVCs in a row with a fast rhythm is ventricular tachycardia



Premature Ventricular Complex Bigeminy

Premature Ventricular Complex Bigeminy EKG tracing
RhythmIrregular
RateThe underlying rate
P WaveAbsent
PR IntervalNot measurable
QRSWide (> 0.10 sec), bizarre appearance
NotesPVC appears every second beat

Premature Ventricular Complex Quadrigeminy

Premature Ventricular Complex Quadrigeminy EKG tracing
RhythmIrregular
RateThe underlying rate
P WaveAbsent
PR IntervalNot measurable
QRSWide (> 0.10 sec), bizarre appearance
NotesPVC appears every fourth beat



Premature Ventricular Complex Trigeminy

Premature Ventricular Complex Trigeminy EKG tracing
RhythmIrregular
RateThe underlying rate
P WaveAbsent
PR IntervalNot measurable
QRSWide (> 0.10 sec), bizarre appearance
NotesPVC appears every third beat



Second Degree Heart Block Type I

Second Degree Heart Block Type I EKG tracing
RhythmIrregular but with progressively longer PR interval lengthening
RateThe underlying rate
P WaveNormal
PR IntervalProgressively longer until a QRS complex is missed, then cycle repeats
QRSNormal (0.06-0.10 sec)
Notes 



Second Degree Heart Block Type II

Second Degree Heart Block Type II EKG tracing
RhythmRegular (atrial) and irregular (ventricular)
RateCharacterized by Atrial rate usually faster than ventricular rate (usually slow)
P WaveNormal form, but more P waves than QRS complexes
PR IntervalNormal or prolonged
QRSNormal or wide
Notes 



Sinoatrial Block

Sinoatrial Block EKG tracing
RhythmIrregular when SA block occurs
RateNormal or slow
P WaveNormal
PR IntervalNormal (0.12-0.20 sec)
QRSNormal (0.06-0.10 sec)
NotesPause time is an integer multiple of the P-P interval Try to identify specific type of atrial tachycardia - see other pages



Sinus Arrest

Sinus Arrest EKG tracing
RhythmIrregular due to pause
RateNormal to slow
P WaveNormal
PR IntervalNormal (0.12-0.20 sec)
QRSNormal (0.06-0.10 sec)
NotesPause time is not an integer multiple of the P-P interval



Sinus Arrhythmia

Sinus Arrhythmia EKG tracing
RhythmIrregular, varying with respiration
RateNormal (60-100 bpm) and rate may increase during inspiration
P WaveNormal
PR IntervalNormal (0.12-0.20 sec)
QRSNormal (0.06-0.10 sec)
NotesHeart rate frequently increases with inspiration, decreasing with expiration



Sinus Bradycardia

Sinus Bradycardia EKG tracing
RhythmRegular
RateSlow (< 60 bpm)
P WaveNormal
PR IntervalNormal (0.12-0.20 sec)
QRSNormal (0.06-0.10 sec)
Notes 



Sinus Tachycardia

Sinus Tachycardia EKG tracing
RhythmRegular
RateFast (> 100 bpm)
P WaveNormal, may merge with T wave at very fast rates
PR IntervalNormal (0.12-0.20 sec)
QRSNormal (0.06-0.10 sec)
NotesQT interval shortens with increasing heart rate



Supraventricular Tachycardia

Supraventricular Tachycardia EKG tracing
RhythmRegular
RateFast (150-250 bpm)
P WaveMerged with T wave
PR IntervalNormal (0.12 sec)
QRSNormal (.10 sec)
NotesPR interval can be difficult to measure



Third Degree Heart Block

Third Degree Heart Block EKG tracing
RhythmRegular, but atrial and ventricular rhythms are independent
RateCharacterized by Atrial rate usually normal and faster than ventricular rate
P WaveNormal shape and size, may appear within QRS complexes
PR IntervalAbsent: the atria and ventricles beat independently.
QRSNormal, but wide if junctional escape focus
Notes 



Ventricular Fibrillation

Ventricular Fibrillation EKG tracing
RhythmHighly irregular
RateUnmeasurable
P WaveAbsent
PR IntervalNot measurable
QRSNone
NotesEKG tracings is a wavy line



Ventricular Tachycardia

Ventricular Tachycardia EKG tracing
RhythmRegular
RateFast (100-250 bpm)
P WaveAbsent
PR IntervalNot measurable
QRSWide (>0.10 sec), bizarre appearance
Notes 



Ventricular Tachycardia Monomorphic

Ventricular Tachycardia Monomorphic EKG tracing
RhythmRegular
RateFast (100-250 bpm)
P WaveAbsent
PR IntervalNot measurable
QRSWide (>0.10 sec), bizarre looking
Notes 



Ventricular Tachycardia Polymorphic

Ventricular Tachycardia Polymorphic EKG tracing
RhythmRegular or irregular
RateFast (100-300 bpm)
P WaveAbsent
PR IntervalNot measurable
QRSNormal or wide (>0.10 sec), bizarre looking
Notes 



Ventricular Tachycardia Torsade de Pointes

Ventricular Tachycardia Torsade de Pointes EKG tracing
RhythmIrregular
RateFast (200-250 bpm)
P WaveAbsent
PR IntervalNot measurable
QRSWide (>0.10 sec), bizarre looking
Notes 



Wandering Atrial Pacemaker

Wandering Atrial Pacemaker EKG tracing
RhythmMay be irregular
RateNormal (60-100 bpm)
P WaveChanging shape and size from beat to beat (at least three different forms)
PR IntervalVariable
QRSNormal (0.06-0.10 sec)
NotesT wave normal. If heart rate exceeds 100 bpm, then rhythm may be multifocal atrial tachycardia (MAP)



Wolff-Parkinson-White Syndrome

Wolff-Parkinson-White Syndrome EKG tracing
RhythmRegular unless atrial fibrillation present
RateNormal (60-100 bpm)
P WaveNormal
PR IntervalCan be short (<0.12 sec)
QRSUsually wide (> 0.12 sec)
NotesLook for short PR interval and/or delta wave A delta wave (positive or negative) distorts the early part of the QRS complex