skip to main content

Familial SCD Screening - Molecular Autopsy — EECC MCQ

Instant feedback + full explanation. One question, done properly.

HardGeneral CardiologyFamilial SCD Screening - Molecular AutopsyEECC

A 24-year-old competitive cyclist with asymptomatic ventricular pre-excitation undergoes invasive risk stratification. Atrial fibrillation is induced, the shortest pre-excited RR interval is 230 ms and the accessory-pathway effective refractory period is 240 ms. Which finding most strongly identifies a high-risk pathway and supports ablation?

Educational content. Not a substitute for clinical judgement or local policy.

Reveal the answer and explanation

Correct answer: E — A 230-ms shortest pre-excited RR interval during induced atrial fibrillation

A shortest pre-excited RR interval of 250 ms or less during atrial fibrillation indicates rapid antegrade accessory-pathway conduction and is a recognised high-risk feature supporting ablation. Abrupt loss of pre-excitation with exercise suggests a longer refractory period and lower risk. An accessory-pathway refractory period above 300 ms is not high risk. Self-terminating orthodromic AVRT shows re-entry but not the dangerous antegrade conduction rate, while left free-wall location without multiple pathways is not independently a high-risk marker.

Reference: 2019 ESC Guidelines for supraventricular tachycardia. https://academic.oup.com/eurheartj/article/41/5/655/5556821