Dysrhythmia Definition, Categories

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 training tools such as:

Introduction Course
Interative Presentations
EKG Interpretation Quizzes

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

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Directory of Dysrhythmia Types

Accelerated Idioventricular Rhythm

Rhythm	Regular
Rate	50-120 bpm
P Wave	Absent
PR Interval	Not measurable
QRS	Wide (>0.10 sec), bizarre looking
Notes

Accelerated Junctional Rhythm

Rhythm	Regular
Rate	Normal (60-100 bpm)
P Wave	Present before, during (hidden) or after QRS, if visible it is inverted
PR Interval	Not measurable
QRS	Normal (0.06-0.10 sec)
Notes

Asystole

Rhythm	Not present
Rate	Absent
P Wave	Absent
PR Interval	Absent
QRS	Absent
Notes	Confirm with multiple leads

Atrial Fibrillation

Rhythm	Irregular
Rate	Very fast (> 350 bpm) for Atrial, but ventricular rate may be slow, normal or fast
P Wave	Absent - erratic waves are present
PR Interval	Absent
QRS	Normal but may be widened if there are conduction delays
Notes

Atrial Flutter

Rhythm	Regular or irregular
Rate	Fast (250-350 bpm) for Atrial, but ventricular rate is often slower
P Wave	Not observable, but saw-toothed flutter waves are present
PR Interval	Not measurable
QRS	Normal (0.06-0.10 sec)
Notes

First Degree Heart Block

Rhythm	Regular
Rate	The underlying rate
P Wave	Normal
PR Interval	Prolonged (>0.20 sec)
QRS	Normal (0.06-0.10 sec)
Notes	A 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

Rhythm	Regular
Rate	Slow (20-40 bpm)
P Wave	Absent
PR Interval	Not measurable
QRS	Wide (>0.10 sec), bizarre appearance
Notes

Junctional Escape Rhythm

Rhythm	Regular
Rate	Slow (40-60 bpm)
P Wave	Present before, during (hidden) or after QRS, if visible it is inverted
PR Interval	Not measurable
QRS	Normal (0.06-0.10 sec)
Notes

Junctional Tachycardia

Rhythm	Regular
Rate	Fast (100-180 bpm)
P Wave	Present before, during (hidden) or after QRS, if visible it is inverted
PR Interval	Absent or short
QRS	Normal (0.06-0.10 sec)
Notes

Multifocal Atrial Tachycardia

Rhythm	Irregular
Rate	Fast (> 100 bpm)
P Wave	Often changing shape and size from beat to beat (at least three differing forms)
PR Interval	Variable
QRS	Normal (0.06-0.10 sec)
Notes	T wave is often distorted Also review wandering atrial pacemaker lesson

Normal Sinus Rhythm

Rhythm	Regular
Rate	Normal (60-100 bpm)
P Wave	Normal (positive & precedes each QRS)
PR Interval	Normal (0.12-0.20 sec)
QRS	Normal (0.06-0.10 sec)
Notes

Pacemaker Failure to Capture

Rhythm	Irregular
Rate	Slow or normal
P Wave
PR Interval
QRS
Notes	Pacemaker spikes are not followed by P waves or QRS complexes

Pacemaker Failure to Pace

Rhythm	Irregular
Rate
P Wave
PR Interval
QRS
Notes	Pacemaker spikes do not appear

Pacemaker Single Chamber Atrial

Rhythm	Regular
Rate	60 bpm
P Wave	Normal
PR Interval	Normal
QRS	Normal
Notes

Premature Atrial Complex

Rhythm	Irregular
Rate	Usually normal but depends on underlying rhythm
P Wave	Premature, positive and shape is abnormal
PR Interval	Normal or longer
QRS	0.10 sec or less
Notes

Premature Junctional Complex

Rhythm	Regular with premature beats
Rate	The underlying rate
P Wave	Present before, during (hidden) or after QRS, if visible it is inverted
PR Interval	Absent or short
QRS	Normal (0.06-0.10 sec)
Notes

Premature Ventricular Complex

Rhythm	Irregular
Rate	The underlying rate
P Wave	Absent
PR Interval	Not measurable
QRS	Wide (> 0.10 sec), bizarre appearance
Notes	Two PVCs together are termed a couplet while three PVCs in a row with a fast rhythm is ventricular tachycardia

Premature Ventricular Complex Bigeminy

Rhythm	Irregular
Rate	The underlying rate
P Wave	Absent
PR Interval	Not measurable
QRS	Wide (> 0.10 sec), bizarre appearance
Notes	PVC appears every second beat

Premature Ventricular Complex Quadrigeminy

Rhythm	Irregular
Rate	The underlying rate
P Wave	Absent
PR Interval	Not measurable
QRS	Wide (> 0.10 sec), bizarre appearance
Notes	PVC appears every fourth beat

Premature Ventricular Complex Trigeminy

Rhythm	Irregular
Rate	The underlying rate
P Wave	Absent
PR Interval	Not measurable
QRS	Wide (> 0.10 sec), bizarre appearance
Notes	PVC appears every third beat

Second Degree Heart Block Type I

Rhythm	Irregular but with progressively longer PR interval lengthening
Rate	The underlying rate
P Wave	Normal
PR Interval	Progressively longer until a QRS complex is missed, then cycle repeats
QRS	Normal (0.06-0.10 sec)
Notes

Second Degree Heart Block Type II

Rhythm	Regular (atrial) and irregular (ventricular)
Rate	Characterized by Atrial rate usually faster than ventricular rate (usually slow)
P Wave	Normal form, but more P waves than QRS complexes
PR Interval	Normal or prolonged
QRS	Normal or wide
Notes

Sinoatrial Block

Rhythm	Irregular when SA block occurs
Rate	Normal or slow
P Wave	Normal
PR Interval	Normal (0.12-0.20 sec)
QRS	Normal (0.06-0.10 sec)
Notes	Pause time is an integer multiple of the P-P interval Try to identify specific type of atrial tachycardia - see other pages

Sinus Arrest

Rhythm	Irregular due to pause
Rate	Normal to slow
P Wave	Normal
PR Interval	Normal (0.12-0.20 sec)
QRS	Normal (0.06-0.10 sec)
Notes	Pause time is not an integer multiple of the P-P interval

Sinus Arrhythmia

Rhythm	Irregular, varying with respiration
Rate	Normal (60-100 bpm) and rate may increase during inspiration
P Wave	Normal
PR Interval	Normal (0.12-0.20 sec)
QRS	Normal (0.06-0.10 sec)
Notes	Heart rate frequently increases with inspiration, decreasing with expiration

Sinus Bradycardia

Rhythm	Regular
Rate	Slow (< 60 bpm)
P Wave	Normal
PR Interval	Normal (0.12-0.20 sec)
QRS	Normal (0.06-0.10 sec)
Notes

Sinus Tachycardia

Rhythm	Regular
Rate	Fast (> 100 bpm)
P Wave	Normal, may merge with T wave at very fast rates
PR Interval	Normal (0.12-0.20 sec)
QRS	Normal (0.06-0.10 sec)
Notes	QT interval shortens with increasing heart rate

Supraventricular Tachycardia

Rhythm	Regular
Rate	Fast (150-250 bpm)
P Wave	Merged with T wave
PR Interval	Normal (0.12 sec)
QRS	Normal (.10 sec)
Notes	PR interval can be difficult to measure

Third Degree Heart Block

Rhythm	Regular, but atrial and ventricular rhythms are independent
Rate	Characterized by Atrial rate usually normal and faster than ventricular rate
P Wave	Normal shape and size, may appear within QRS complexes
PR Interval	Absent: the atria and ventricles beat independently.
QRS	Normal, but wide if junctional escape focus
Notes

Ventricular Fibrillation

Rhythm	Highly irregular
Rate	Unmeasurable
P Wave	Absent
PR Interval	Not measurable
QRS	None
Notes	EKG tracings is a wavy line

Ventricular Tachycardia

Rhythm	Regular
Rate	Fast (100-250 bpm)
P Wave	Absent
PR Interval	Not measurable
QRS	Wide (>0.10 sec), bizarre appearance
Notes

Ventricular Tachycardia Monomorphic

Rhythm	Regular
Rate	Fast (100-250 bpm)
P Wave	Absent
PR Interval	Not measurable
QRS	Wide (>0.10 sec), bizarre looking
Notes

Ventricular Tachycardia Polymorphic

Rhythm	Regular or irregular
Rate	Fast (100-300 bpm)
P Wave	Absent
PR Interval	Not measurable
QRS	Normal or wide (>0.10 sec), bizarre looking
Notes

Ventricular Tachycardia Torsade de Pointes

Rhythm	Irregular
Rate	Fast (200-250 bpm)
P Wave	Absent
PR Interval	Not measurable
QRS	Wide (>0.10 sec), bizarre looking
Notes

Wandering Atrial Pacemaker

Rhythm	May be irregular
Rate	Normal (60-100 bpm)
P Wave	Changing shape and size from beat to beat (at least three different forms)
PR Interval	Variable
QRS	Normal (0.06-0.10 sec)
Notes	T wave normal. If heart rate exceeds 100 bpm, then rhythm may be multifocal atrial tachycardia (MAP)

Wolff-Parkinson-White Syndrome

Rhythm	Regular unless atrial fibrillation present
Rate	Normal (60-100 bpm)
P Wave	Normal
PR Interval	Can be short (<0.12 sec)
QRS	Usually wide (> 0.12 sec)
Notes	Look for short PR interval and/or delta wave A delta wave (positive or negative) distorts the early part of the QRS complex