Atrial Rhythms

Question 1

Premature Atrial Complex (PAC)

Answer 1

Rate: 60-100 bpm
Rhythm: Irregular due to ectopic beat
P waves: upright P waves
PR interval: typically 0.12-0.20
QRS interval: <0.12

Question 2

Supraventricular Tachycardia (SVT) 
or Atrial Tachycardia

Answer 2

Rate: 160-240
Rhythm: Regular
P waves: appears different than sinus P waves if present
PR interval: 0.12-0.20 when P wave is present
QRS interval: <0.12

Question 3

Atrial Flutter

Answer 3

Rate: 220-350 (atrial)
Rhythm: usually regular
P waves: replaced by flutter (or F) wave
PR interval: not discernible
QRS interval: <0.12

Question 4

Atrial Fibrillation

Answer 4

Rate: >400 (atrial)
Rhythm: irregularly irregular (NO pattern)
P waves: replaced with fibrillation line
PR interval: not measurable
QRS interval: <0.12