CASE 04 • FREE SAMPLE
The slow pulse before surgery
A 64-year-old asymptomatic man has a pulse of 58/min before surgery; every P wave is followed by QRS but the PR interval is prolonged.
Clinical questions
1. Interpret the ECG systematically.
2. What is the most likely ECG diagnosis?
3. What is the immediate clinical significance?
4. What should be done next?
1. Interpret the ECG systematically.
2. What is the most likely ECG diagnosis?
3. What is the immediate clinical significance?
4. What should be done next?
First-degree AV block
Systematic interpretation & clinical correlation
Sinus rhythm with 1:1 AV conduction and a constant PR interval >200 ms. QRS width and associated fascicular/bundle-branch disease should be assessed because a prolonged PR with a broad QRS may reflect more extensive conduction-system disease.
Sinus rhythm with 1:1 AV conduction and a constant PR interval >200 ms. QRS width and associated fascicular/bundle-branch disease should be assessed because a prolonged PR with a broad QRS may reflect more extensive conduction-system disease.
Immediate approach / management
Isolated asymptomatic first-degree AV block usually needs no acute treatment. Review AV-nodal drugs, potassium, magnesium, thyroid status and structural/ischaemic context. Marked PR prolongation with exertional symptoms or associated conduction disease merits cardiology evaluation; pacing is not indicated solely for a mildly prolonged PR.
Isolated asymptomatic first-degree AV block usually needs no acute treatment. Review AV-nodal drugs, potassium, magnesium, thyroid status and structural/ischaemic context. Marked PR prolongation with exertional symptoms or associated conduction disease merits cardiology evaluation; pacing is not indicated solely for a mildly prolonged PR.
High-yield ECG pearl
A long PR is a conduction delay, not a dropped-beat AV block; the QRS width and symptoms help determine significance.
A long PR is a conduction delay, not a dropped-beat AV block; the QRS width and symptoms help determine significance.
ECG source/licence: Wikimedia Commons file page.