Basic ECG Rhythms
Normal
Sinus Rhythm
Rate: The atrial and ventricular rates are equal; the heart rate is usually 60 - 100 beats per minute
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| Normal Sinus Rhythm |
Rate: The atrial and ventricular rates are equal; the heart rate is usually 60 - 100 beats per minute
Rhythm:
The R - R intervals are constant; the rhythm is regular
P Wave:
The P waves are uniform. There is one P wave for every QRS complex.
PRI:
0.12 - 0.20 seconds and constant.
QRS:
less than 0.12 seconds
S-T Segment:: neither
elevated or depressed
T Waves:
usually slightly rounded and asymmetrical; T wave is less than half the height
of the QRS
Sinus
Bradycardia
 |
| Sinus Bradycardia |
Rate:
The atrial and ventricular rates are equal; the heart rate is less than 60
beats per minute
Rhythm:
The R - R intervals are constant; the rhythm is regular
P Wave:
The P waves are uniform. There is one P wave for every QRS complex.
PRI:
0.12 - 0.20 seconds and constant.
QRS:
less than 0.12 seconds
S-T Segment: neither
elevated or depressed
T Waves:
usually slightly rounded and asymmetrical; T wave is less than half the height
of the QRS
Sinus
Tachycardia
 |
| Sinus Tachycardia |
Rate:
The atrial and ventricular rates are equal; the heart rate is usually between
100 to 160 beats per minute
Rhythm:
The R - R intervals are constant; the rhythm is regular
P Wave:
The P waves are uniform. There is one P wave for every QRS complex.
PRI:
0.12 - 0.20 seconds and constant.
QRS:
less than 0.12 second
S-T Segment:
neither elevated or depressed
T Waves:
usually slightly rounded and asymmetrical; T wave is less than half the height
of the QRS
Sinus
Arrhythmia
 |
| Sinus Arrhythmia |
Rate:
The atrial and ventricular rates are equal; the heart rate is usually 60 to 100
beats per minute; can be slower.
Rhythm:
The R - R intervals vary; the rhythm is slightly irregular
P Wave:
The P waves are uniform. There is one P wave for every QRS complex.
PRI:
0.12 - 0.20 seconds and constant.
QRS:
less than 0.12 seconds
S-T Segment: neither
elevated or depressed
T Waves:
usually slightly rounded and asymmetrical; T wave is less than half the height
of the QRS
Wandering
Atrial Pacemaker
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| Wandering Atrial Pacemaker |
Rate:
The atrial and ventricular rates are equal; the heart rate is usually 60
to
100 beats per minute; can be slower.
Rhythm:
The R - R intervals vary as the pacemaker site changes; the rhythm can be
slightly irregular
P
Wave:
The shape of the P waves changes as the pacemaker site changes. There is
one P wave in front of every QRS complex. Some P waves may be difficult to see,
depending on the pacemaker site.
PRI:
The PRI measurement will vary slightly as the pacemaker site changes. PRI
measurements should be 0.12 - 0.20 seconds. Some PRI measurements may be less
than 0.12.
QRS:
less than 0.12 seconds
S-T
Segment:
neither elevated or depressed
T
Waves:
usually slightly rounded and asymmetrical; T wave is less than half the height
of the QRS
Multifocal
Atrial Tachycardia
 |
| Multifocal Atrial Tachycardia |
Rate:
The atrial and ventricular rates are equal; the heart rate is usually 150-250
beats per minute
Rhythm:
The R - R intervals are constant; the rhythm is regular
P
Wave:
There is one P wave for every QRS complex. The morphology of the P wave
will have a different morphology than the P waves of a sinus rhythm. Because of
the rapid rate, the P waves can be hidden in the preceding T wave.
PRI:
0.12 - 0.20 seconds and constant. The PRI may be difficult to measure if the P
wave is obscured by the preceding T waves.
QRS:
less than 0.12 seconds
S-T
Segment: neither
elevated or depressed
T
Waves:
usually slightly rounded and asymmetrical; T wave is less than half the height
of the QRS
Atrial
Flutter
 |
| Atrial Flutter |
Rate:
The atrial rate is between 250-350 beats per minute. Ventricular rate will
depend on the ratio of impulses conducted to the ventricles
Rhythm:
The atrial rhythm is regular. The ventricular rhythm will be regular if the AV
node conducts impulses through in a consistent pattern. If the pattern varies,
the ventricular rate will be irregular.
P Wave:
When the atria flutter, they produce a series of well-defined P waves. When
seen together, they resemble a "sawtooth"
pattern.
PRI:
Because of the flutter waves' proximity to the QRS complex, it is difficult, if
not impossible to determine the PRI
QRS:
less than 0.12 seconds - can be difficult to measure if any flutter waves are
concealed in the QRS complex
S-T Segment: neither
elevated or depressed
T Waves:
Difficult to see with flutter waves
Atrial
Fibrillation
 |
| Atrial Fibrillation |
Rate:
The atrial rate can't be measured because it is so chaotic. It probably exceeds
350 beat per minute. The ventricular rate is much slower because AV node blocks
most of the impulses. If the ventricular rate is below 100, the rhythm is said
to be "controlled." If the rate is over 100, it is called atrial
fibrillation with a rapid ventricular response
Rhythm:
The atrial rhythm is not measurable. All atrial activity is chaotic. The
ventricular rhythm is irregular.
P
Wave:
The atria aren't depolarizing in an effective method, they are fibrillating. So
no P wave is produced.
PRI:
Since there are no P waves visible, the PRI can't be measured
QRS:
less than 0.12 seconds - can be difficult to measure if any flutter waves are
concealed in the QRS complex
S-T
Segment:
neither elevated or depressed
T
Waves:
usually slightly rounded and asymmetrical; T wave is less than half the height
of the QRS
Junctional Rhythm
Rate: The atrial and ventricular rates are equal; the inherent heart rate of the AV Junction is 40 - 60 beats per minute
Rhythm: The R - R intervals are constant; the rhythm is regular
P Wave: The P wave can come before or after the QRS complex, or it can be lost in the QRS complex. If visible, the P wave will be inverted.
PRI: If the P wave precedes the QRS complex, the PRI will be less than 0.12 seconds. If the P wave falls within the QRS complex or following it, the will be no PRI
QRS: less than 0.12 seconds
S-T Segment: neither elevated or depressed
T Waves: usually slightly rounded and asymmetrical; T wave is less than half the height of the QRS
Accelerated Junctional Rhythm
Rate: The atrial and ventricular rates are equal. The rate will be faster than the AV junctions intrinsic rate but not yet a true tachycardia. Typically, the rate is between 60 - 100.
Rhythm: The R - R intervals are constant; the rhythm is regular
P Wave: The P wave can come before or after the QRS complex, or it can be lost in the QRS complex. If visible, the P wave will be inverted.
PRI: If the P wave precedes the QRS complex, the PRI will be less than 0.12 seconds. If the P wave falls within the QRS complex or following it, the will be no PRI
QRS: less than 0.12 seconds
S-T Segment: neither elevated or depressed
T Waves: usually slightly rounded and asymmetrical; T wave is less than half the height of the QRS
Junctional Tachycardia
Rate: The atrial and ventricular rates are equal. Typically, the rate is between 100 - 180.
Rhythm: The R - R intervals are constant; the rhythm is regular
P Wave: The P wave can come before or after the QRS complex, or it can be lost in the QRS complex. If visible, the P wave will be inverted.
PRI: If the P wave precedes the QRS complex, the PRI will be less than 0.12 seconds. If the P wave falls within the QRS complex or following it, the will be no PRI
QRS: less than 0.12 seconds
S-T Segment: neither elevated or depressed
T Waves: usually slightly rounded and asymmetrical; T wave is less than half the height of the QRS
First Degree Heart Block
Rate: Depends on underlying rhythm
Rhythm: Depends on underlying rhythm
P Wave: Upright and uniform. Each P wave followed by a QRS complex
PRI: > 0.20 seconds across entire strip
QRS: less than 0.12 seconds
S-T Segment: neither elevated or depressed
T Waves: usually slightly rounded and asymmetrical; T wave is less than half
the height of the QRS
A first degree block is not a rhythm in itself. It is a prolonged PRI that can be
encountered in an otherwise normal rhythm or in practically any other cardiac
rhythm.
2nd Degree Type I
Rate: Because some beats aren't conducted, the ventricular rate is usually slightly slower than normal. The atrial rate is normal
Rhythm: The R - R interval is irregular
P Wave: Upright and uniform. There are more P waves than QRS complexes
PRI: Interval get progressively longer, until one P wave isn't followed by a QRS complex. There is a pattern to this cycle as it is repeated.
QRS: less than 0.12 seconds
S-T Segment: neither elevated or depressed
T Waves: usually slightly rounded and asymmetrical; T wave is less than half the height of the QRS
2nd Degree Type II
Rate: Atrial rate is typically normal. Because many of the atrial impulses are blocked, the ventricular rate will be in the bradycardia range, usually with a 2 - 1, 3 - 1, or a 4 - 1 conduction rate.
Rhythm: If the conduction rate is consistent, the R - R interval will be constant, and the rhythm will be regular. If the conduction ratio varies, the R - R will be irregular.
P Wave: Upright and uniform. There are more P waves than QRS complexes
PRI: Will be constant on conducted beats. Could be prolonged in comparison to a normal PRI.
QRS: less than 0.12 seconds
S-T Segment: neither elevated or depressed
T Waves: usually slightly rounded and asymmetrical; T wave is less than half the height of the QRS
3rd degree Heart Block
Rate: The atrial rate is typically normal. The ventricular rate will be slower. If a junctional focus is controlling the ventricles, the rate will be 40 - 60. If the focus is ventricular, the rate will be 20 - 40.
Rhythm: Since the atrial and ventricular foci are firing regularly, the P - P and the R - R intervals will be regular.
P Wave: Upright and uniform. There are more P waves than QRS complexes
PRI: There is no PRI, because the block at the AV node is complete. There is no association between the P waves and the QRS complexes.
QRS: If the focus is junctional, less than 0.12 seconds. If the focus is ventricular, the QRS will be > 0.12.
S-T Segment: neither elevated or depressed
T Waves: usually slightly rounded and asymmetrical; T wave is less than half the height of the QRS
Ventricular Tachycardia
Rate:
The atrial rate can't be determined. The ventricular rate is 150 - 250. If the
rate is below 150, it is called a slow V tach.
Rhythm: The rhythm is usually regular.
P Wave: Not usually visible.
PRI: There is no PRI, as the focus is ventricular.
QRS: The QRS is wide and bizarre, usually 0.12 or greater. It is sometimes difficult to differentiate between QRS complexes and T waves.
S-T Segment: Noneifficult, if not impossible to see.
T Waves: Difficult to differentiate T waves from QRS complexes
Ventricular Fibrillation
Rate:
None
Rhythm: None. The baseline is totally chaotic
P Wave: None are visible.
PRI: There is no PRI.
QRS: None
S-T Segment: None: None
T Waves: None
Idioventricular Rhythm
Rate:
20 - 40 per minute, can drop below 20 as the heart dies
Rhythm: Regular
P Wave: There are none.
PRI: There is no PRI.
QRS: Wide and bizarre, > 0.12
S-T Segment: Generally deviates from the baseline
T Waves: Frequently deflecting opposite the QRS complex
Accelerated Idioventricular Rhythm
Rate: 40 - 100 per minute
Rhythm: Regular
P Wave: There are none.
PRI: There is no PRI.
QRS: Wide and bizarre, > 0.12
S-T Segment: Generally deviates from the baseline
T Waves: Frequently deflecting opposite the QRS complex
Asystole
Rate:
None
Rhythm: None.
P Wave: None
PRI: There is no PRI.
QRS: None
S-T Segment: None
T Waves: None
Source:
http://www.biotel.ws/quizzes/ekgs/TheRules.htm
Junctional Rhythm
 |
| Junctional Rhythm |
Rate: The atrial and ventricular rates are equal; the inherent heart rate of the AV Junction is 40 - 60 beats per minute
Rhythm: The R - R intervals are constant; the rhythm is regular
P Wave: The P wave can come before or after the QRS complex, or it can be lost in the QRS complex. If visible, the P wave will be inverted.
PRI: If the P wave precedes the QRS complex, the PRI will be less than 0.12 seconds. If the P wave falls within the QRS complex or following it, the will be no PRI
QRS: less than 0.12 seconds
S-T Segment: neither elevated or depressed
T Waves: usually slightly rounded and asymmetrical; T wave is less than half the height of the QRS
Accelerated Junctional Rhythm
 |
| Accelerated Junctional Rhythm |
Rate: The atrial and ventricular rates are equal. The rate will be faster than the AV junctions intrinsic rate but not yet a true tachycardia. Typically, the rate is between 60 - 100.
Rhythm: The R - R intervals are constant; the rhythm is regular
P Wave: The P wave can come before or after the QRS complex, or it can be lost in the QRS complex. If visible, the P wave will be inverted.
PRI: If the P wave precedes the QRS complex, the PRI will be less than 0.12 seconds. If the P wave falls within the QRS complex or following it, the will be no PRI
QRS: less than 0.12 seconds
S-T Segment: neither elevated or depressed
T Waves: usually slightly rounded and asymmetrical; T wave is less than half the height of the QRS
Junctional Tachycardia
 |
| Junctional Tachycardia |
Rate: The atrial and ventricular rates are equal. Typically, the rate is between 100 - 180.
Rhythm: The R - R intervals are constant; the rhythm is regular
P Wave: The P wave can come before or after the QRS complex, or it can be lost in the QRS complex. If visible, the P wave will be inverted.
PRI: If the P wave precedes the QRS complex, the PRI will be less than 0.12 seconds. If the P wave falls within the QRS complex or following it, the will be no PRI
QRS: less than 0.12 seconds
S-T Segment: neither elevated or depressed
T Waves: usually slightly rounded and asymmetrical; T wave is less than half the height of the QRS
First Degree Heart Block
 |
| First Degree Heart Block |
Rate: Depends on underlying rhythm
Rhythm: Depends on underlying rhythm
P Wave: Upright and uniform. Each P wave followed by a QRS complex
PRI: > 0.20 seconds across entire strip
QRS: less than 0.12 seconds
S-T Segment: neither elevated or depressed
T Waves: usually slightly rounded and asymmetrical; T wave is less than half
the height of the QRS
A first degree block is not a rhythm in itself. It is a prolonged PRI that can be
encountered in an otherwise normal rhythm or in practically any other cardiac
rhythm.
2nd Degree Type I
 |
| Second Degree Heart Block Type I |
Rate: Because some beats aren't conducted, the ventricular rate is usually slightly slower than normal. The atrial rate is normal
Rhythm: The R - R interval is irregular
P Wave: Upright and uniform. There are more P waves than QRS complexes
PRI: Interval get progressively longer, until one P wave isn't followed by a QRS complex. There is a pattern to this cycle as it is repeated.
QRS: less than 0.12 seconds
S-T Segment: neither elevated or depressed
T Waves: usually slightly rounded and asymmetrical; T wave is less than half the height of the QRS
2nd Degree Type II
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| Second Degree Heart Block Type II |
Rate: Atrial rate is typically normal. Because many of the atrial impulses are blocked, the ventricular rate will be in the bradycardia range, usually with a 2 - 1, 3 - 1, or a 4 - 1 conduction rate.
Rhythm: If the conduction rate is consistent, the R - R interval will be constant, and the rhythm will be regular. If the conduction ratio varies, the R - R will be irregular.
P Wave: Upright and uniform. There are more P waves than QRS complexes
PRI: Will be constant on conducted beats. Could be prolonged in comparison to a normal PRI.
QRS: less than 0.12 seconds
S-T Segment: neither elevated or depressed
T Waves: usually slightly rounded and asymmetrical; T wave is less than half the height of the QRS
3rd degree Heart Block
.JPG) |
| Third Degree Heart Block |
Rate: The atrial rate is typically normal. The ventricular rate will be slower. If a junctional focus is controlling the ventricles, the rate will be 40 - 60. If the focus is ventricular, the rate will be 20 - 40.
Rhythm: Since the atrial and ventricular foci are firing regularly, the P - P and the R - R intervals will be regular.
P Wave: Upright and uniform. There are more P waves than QRS complexes
PRI: There is no PRI, because the block at the AV node is complete. There is no association between the P waves and the QRS complexes.
QRS: If the focus is junctional, less than 0.12 seconds. If the focus is ventricular, the QRS will be > 0.12.
S-T Segment: neither elevated or depressed
T Waves: usually slightly rounded and asymmetrical; T wave is less than half the height of the QRS
Ventricular Tachycardia
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| Ventricular Tachycardia |
Rhythm: The rhythm is usually regular.
P Wave: Not usually visible.
PRI: There is no PRI, as the focus is ventricular.
QRS: The QRS is wide and bizarre, usually 0.12 or greater. It is sometimes difficult to differentiate between QRS complexes and T waves.
S-T Segment: Noneifficult, if not impossible to see.
T Waves: Difficult to differentiate T waves from QRS complexes
Ventricular Fibrillation
 |
| Ventricular Fibrillation |
Rhythm: None. The baseline is totally chaotic
P Wave: None are visible.
PRI: There is no PRI.
QRS: None
S-T Segment: None: None
T Waves: None
Idioventricular Rhythm
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| Idioventricular Rhythm |
Rhythm: Regular
P Wave: There are none.
PRI: There is no PRI.
QRS: Wide and bizarre, > 0.12
S-T Segment: Generally deviates from the baseline
T Waves: Frequently deflecting opposite the QRS complex
Accelerated Idioventricular Rhythm
 |
| Accelerated Idioventricular Rhythm |
Rate: 40 - 100 per minute
Rhythm: Regular
P Wave: There are none.
PRI: There is no PRI.
QRS: Wide and bizarre, > 0.12
S-T Segment: Generally deviates from the baseline
T Waves: Frequently deflecting opposite the QRS complex
Asystole
 |
| Asystole |
Rhythm: None.
P Wave: None
PRI: There is no PRI.
QRS: None
S-T Segment: None
T Waves: None
Source:
http://www.biotel.ws/quizzes/ekgs/TheRules.htm
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