Atrial Rhythms: Summary of Characteristics

What are the characteristics of PACs?

Rhythm: Irregular because of the early beat(s)
Rate: Usually within normal range but depends on underlying rhythm
P waves: Premature, positive, one before each QRS, differ from sinus P waves, may be lost in preceding T wave
PR Interval: May be WNL or prolonged
QRS: 0.11 sec or less unless abnormally conducted

What are the characteristics of Wandering atrial pacemaker?

Rhythm: Usually irregular as pacemaker site shifts from SA node to ectopic atrial locations or AV junctions
Rate: Usually 60 to 100; if rate greater than 100 beats/min, rhythm is multifocal atrial tachycardia
P waves: Size, shape, and direction may change from beat to beat
PR Interval: Varies
QRS: 0.11 sec or less

What are the characteristics of Atrial tachycardia?

Rhythm: Regular
Rate: 101 to 250
P waves: One precedes each QRS; atrial P waves differ from sinus P waves; isoelectric baseline usually present between P waves
PR Interval: May be shorter or longer than normal
QRS: 0.11 sec or less unless abnormally conducted

What are the characteristics of AVNRT?

Rhythm: Ventricular rhythm is usually very regular
Rate: 150 to 250
P waves often hidden in QRS complex
PR Interval: May be shorter or longer than normal
QRS: 0.11 sec or less unless abnormally conducted

What are the characteristics of Atrial flutter?

Rhythm: Atrial regular; ventricular regular or irregular
Rate: Atrial rate usually 240 to 300; ventricular rate varies
P waves: No identifiable P waves; saw-tooth “flutter” waves present
PR Interval: Not measurable
QRS: 0.11 sec or less unless abnormally conducted

What are the characteristics of Atrial fibrillation (AFib)?

Rhythm: Ventricular rhythm usually irregularly irregular
Rate: Atrial rate usually 300 to 600; ventricular rate variable
P waves: No identifiable P waves: fibrillatory waves present; erratic, wave baseline
PR Interval: Not measurable
QRS: 0.11 sec or less unless abnormally conducted

What type of rhythm is PACS?

Irregular due to early beats

What is the rate of PACS?

Usually within normal range but depends on underlying rhythm

What are the P waves for PACS like?

Premature, positive, one before each QRS, may differ from sinus P waves

What is the PR Interval of PACS like?

May be within normal limits or prolonged (PACS)

How long is the QRS with PACS?

0.11 sec or less unless abnormally conducted

What type of rhythm in Wandering atrial pacemaker?

Usually irregular as pacemaker site shifts from SA node to ectopic atrial locations or AV junction

What is the rate for Wandering atrial pacemaker?

Usually 60 to 100; more than 100 is multifocal atrial tachycardia

What are the P waves like in Wandering atrial pacemaker?

Size, shape, and direction may change from beat to beat

What is the PR Interval like in Wandering atrial pacemaker?

Varies (Wandering atrial pacemaker)

What is the QRS duration of Wandering atrial pacemaker?

0.11 sec or less unless abnormally conducted(Wandering atrial pacemaker)

What is the ventricular rhythm of Atrial tachycardia?

Regular

What is the rate of Atrial tachycardia?

101 to 250

What do the P waves look like in Atrial tachycardia?

One precedes each QRS; atrial P waves differ from sinus P waves; isoelectric baseline is usually present between P waves

What is the PR Interval like with Atrial Tachycardia?

May be shorter or longer than normal (Atrial Tachycardia)

What is QRS for Atrial Tachycardia?

0.11 sec or less unless abnormally conducted (atrial tachycardia)

What is the ventricular rhythm of AVNRT?

Usually very regular

What is the rate of AVNRT?

150 to 250

What are P waves like for AVNRT?

P waves are often hidden in QRS complex

What is the PR Interval for AVNRT?

Not measurable (AVNRT)

What is the QRS of AVNRT?

0.11 sec or less unless abnormally conducted (AVNRT)

What is the rhythm in atrial flutter?

Atrial rhythm is regular, ventricular rhythm can be regular or irregular

What is the atrial and ventricular rate of atrial flutter?

Atrial rate - 240 to 300
Ventricular rate - varies

What determines the ventricular rate in atrial flutter?

AV blockade

What are the P waves like in atrial flutter?

No identifiable P waves; saw-toothed “flutter” waves present

What is the PR Interval for Atrial flutter?

Not measurable (atrial flutter)

What is the QRS for Atrial flutter?

0.11 sec or less unless abnormally conducted (atrial flutter)

What is the ventricular rhythm of Atrial fibrillation (AFib)?

Usually irregularly irregular

What are the P waves like for Atrial fibrilation (AFib)?

No identifiable P waves; fibrillatory waves present; erratic, wave baseline

What is the PR interval of Atrial fibrilation?

Not measurable (atrial fibrillation)

What is the QRS of Atrial fibrillation?

0.11 sec or less unless abnormally conducted (atrial fibrillation)