Overview
Definition
Progressive lengthening of the PR interval until a P wave is completely blocked (not followed by a QRS).
Epidemiology
Usually benign and transient.
Etiology & Risk Factors
- High vagal tone
- Inferior MI (AV node ischemia)
- Medications
Clinical Symptoms
- Usually asymptomatic
- Occasionally lightheadedness
Clinical Approach
Diagnosis
- ECG: Progressively lengthening PR interval until a dropped QRS ('Long, longer, longest, drop... now you have a Wenckebach')
Management
- If asymptomatic: Observe
- If symptomatic: Atropine, adjust medications. Rarely requires pacing.
Complications
- Minimal risk of progression to complete heart block