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First-Degree Heart Block — FRCA Final MCQ

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EasyPreoperative AssessmentFirst-Degree Heart BlockFRCA Final

A 45-year-old man is listed for elective laparoscopic cholecystectomy. He is asymptomatic, has normal exercise tolerance and takes no regular medication. Cardiovascular examination and serum electrolytes are normal. His preoperative ECG shows sinus rhythm with a PR interval of 0.24 seconds, 1:1 atrioventricular conduction and a narrow QRS complex, with no other abnormality. What is the most appropriate management?

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Correct answer: D — Proceed with surgery without additional cardiac investigation for this finding

The correct answer is D. A PR interval above 0.20 seconds with every P wave conducted defines first-degree AV block. In this asymptomatic patient, the modest PR prolongation, narrow QRS complex, normal examination and absence of medication or electrolyte causes indicate isolated AV nodal conduction delay. It does not require postponement, echocardiography, ambulatory monitoring or prophylactic pacing; surgery may proceed with standard intraoperative monitoring. Cardiology assessment would become relevant if there were syncope, significant bradycardia, structural heart disease, a wide QRS or additional conduction abnormalities. Marked PR prolongation, usually above 0.30 seconds, can occasionally cause symptoms from impaired atrioventricular timing, but that is not present here.

Reference: NHS, Heart block, sections 'Types of heart block' and 'Treatments for heart block', reviewed 10 March 2025. https://www.nhs.uk/conditions/heart-block/