Dysrhythmia Basics Test Answers
Normal Sinus Rhythm
● Rhythm: Regular
● Rate: 60-100 bpm (e.g., 80 bpm as provided)
● P Waves: Upright, uniform, one P wave before each QRS complex
● PR Interval: 0.12-0.20 seconds (e.g., 0.16 sec as provided)
● QRS: 0.06-0.12 seconds (e.g., 0.08 sec as provided)
● Clinical Significance: No significant clinical concern unless the patient exhibits
symptoms or signs of instability.
Sinus Bradycardia
● Rhythm: Regular
● Rate: < 60 bpm
● P Wave: Present, upright, uniform, one P wave before each QRS complex
● PR Interval: 0.12-0.20 seconds
● QRS: 0.06-0.12 seconds
● Clinical Significance: May be normal in athletes; can cause symptoms like
dizziness, fatigue, or syncope if cardiac output is compromised.
Sinus Tachycardia
● Rhythm: Regular
● Rate: 101-150 bpm
● P Wave: Present, upright, uniform, one P wave before each QRS complex
● PR Interval: 0.12-0.20 seconds
● QRS: 0.06-0.12 seconds
● Clinical Significance: Often a physiological response to stress, fever, pain, or
hypovolemia. Can be problematic if prolonged or in patients with underlying heart
disease.
, Premature Atrial Contraction (PAC)
● Rhythm: Irregular (due to premature beat)
● Heart Rate: Varies (depends on underlying rhythm)
● P Wave: Premature, abnormal shape (may be flattened, notched, or hidden
within the preceding T wave), followed by a QRS.
● PR Interval: Usually normal or slightly shorter/longer, but < 0.20 seconds
● QRS: 0.06-0.12 seconds (typically normal)
● Clinical Significance: Usually benign; can be caused by stress, caffeine, fatigue.
Frequent PACs may indicate underlying heart disease or precede atrial
fibrillation.
Atrial Fibrillation (AFib)
Normal Sinus Rhythm
● Rhythm: Regular
● Rate: 60-100 bpm (e.g., 80 bpm as provided)
● P Waves: Upright, uniform, one P wave before each QRS complex
● PR Interval: 0.12-0.20 seconds (e.g., 0.16 sec as provided)
● QRS: 0.06-0.12 seconds (e.g., 0.08 sec as provided)
● Clinical Significance: No significant clinical concern unless the patient exhibits
symptoms or signs of instability.
Sinus Bradycardia
● Rhythm: Regular
● Rate: < 60 bpm
● P Wave: Present, upright, uniform, one P wave before each QRS complex
● PR Interval: 0.12-0.20 seconds
● QRS: 0.06-0.12 seconds
● Clinical Significance: May be normal in athletes; can cause symptoms like
dizziness, fatigue, or syncope if cardiac output is compromised.
Sinus Tachycardia
● Rhythm: Regular
● Rate: 101-150 bpm
● P Wave: Present, upright, uniform, one P wave before each QRS complex
● PR Interval: 0.12-0.20 seconds
● QRS: 0.06-0.12 seconds
● Clinical Significance: Often a physiological response to stress, fever, pain, or
hypovolemia. Can be problematic if prolonged or in patients with underlying heart
disease.
, Premature Atrial Contraction (PAC)
● Rhythm: Irregular (due to premature beat)
● Heart Rate: Varies (depends on underlying rhythm)
● P Wave: Premature, abnormal shape (may be flattened, notched, or hidden
within the preceding T wave), followed by a QRS.
● PR Interval: Usually normal or slightly shorter/longer, but < 0.20 seconds
● QRS: 0.06-0.12 seconds (typically normal)
● Clinical Significance: Usually benign; can be caused by stress, caffeine, fatigue.
Frequent PACs may indicate underlying heart disease or precede atrial
fibrillation.
Atrial Fibrillation (AFib)
