rhythms Flashcards
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 in front of every QRS complex.
PRI: 0.12 – 0.20 seconds and constant
QRS: less than 0.12 seconds.
S-T Segment: neither elevated nor depressed
T waves: usually slightly rounded and asymmetrical; T wave is less than half the height of the QRS
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 in front of every QRS complex.
PRI: 0.12 – 0.20 seconds and constant
QRS: less than 0.12 seconds.
S-T Segment: neither elevated nor depressed
T waves: usually slightly rounded and asymmetrical; T wave is less than half the height of the QRS
Sinus Tach
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 in front of every QRS complex.
PRI: 0,12 – 0.20 seconds and constant
QRS: Less than 0.12 seconds
S-T Segment: neither elevated nor depressed
T Wave: usually slightly rounded and asymmetrical; T wave is less than half the height of the QRS
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 in front of every QRS complex
PRI: 0.12 – 0.20 seconds and constant
QRS: Less than 0.12 seconds
S-T Segment: neither elevated nor depressed
T Waves: usually slightly rounded and asymmetrical; T wave is less than half the height of the QRS
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 morphology 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 changed. 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 nor depressed
T Waves: usually slightly rounded and asymmetrical; T wave is less than half the height of the QRS
Premature Atrial Contraction
Rate: The overall rate will depend on the underlying rhythm
Rhythm: As this is a single premature ectopic beat, it will affect the regularity of the underlying rhythm.
P Wave: The P wave of the premature beat will differ from the morphology of the P waves of the underlying rhythm. The ectopic beat will have a P wave, but it can be unusual – can be notched or flattened. It can be buried in the preceding T wave.
PRI: The PRI should be 0.12 – 0.20 seconds, but can be prolonged. The PRI of the ectopic beat will more than likely be different from the PRI of the underlying rhythm.
QRS: Less than 0.12 seconds
S-T Segment: neither elevated nor depressed.
T Waves: usually slightly rounded and asymmetrical; T wave is less than half the height of the QRS.
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 in front of 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 nor depressed
T Waves: usually slightly rounded and asymmetrical; T wave is less than half the height of the QRS
Atrial Flutter
Rate: The atrial is between 250-350 beats per minute. Ventricular rate will depend on the ration 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 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 nor depressed
T Waves: Difficult to see with flutter wav
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 nor depressed
T Waves: usually slightly rounded and asymmetrical; T wave is less than half the height of the QRS
Premature Junctional Contraction
Rate: The rate will depend on the underlying rhythm
Rhythm: Slightly irregular – the premature ectopic beat will interrupt the regularity of the underlying rhythm, so the R-R interval will be irregular
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 nor depressed
T Waves: usually slightly rounded and asymmetrical; T wave less than half the height of the QRS
Junctional Escape 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, there 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, there 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, there will be no PRI
QRS: less than 0.12 seconds
S-T Segment: neither elevated or depressed
T Waves: usuall slightly rounded and asymmetrica; T wave is less than half the height of the QRS
