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LBBAP as CRT — EECC MCQ

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ModerateCardiac DevicesLBBAP as CRTEECC

A 55-year-old man with HFrEF and complete heart block undergoes conduction system pacing (left bundle branch area pacing, LBBAP) instead of conventional CRT. At 6-month follow-up, his QRS has narrowed from 160 ms (intrinsic LBBB) to 118 ms (paced). His LVEF has improved from 28% to 42%. Is LBBAP providing CRT effect?

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Correct answer: E — Yes — LBBAP achieves cardiac resynchronisation by engaging the native left bundle branch, producing rapid physiological LV activation with narrow QRS; LVEF improvement from 28% to 42% demonstrates effective resynchronisation comparable to conventional BiV CRT

Yes. Left bundle branch area pacing is a form of conduction system pacing that can deliver cardiac resynchronisation by recruiting the native His–Purkinje/left bundle system distal to the site of left bundle branch block, producing rapid and more physiological left ventricular activation. In this patient, the paced QRS has narrowed substantially from 160 ms to 118 ms and LVEF has improved from 28% to 42% at 6 months, which is the expected electrical and echocardiographic response to effective resynchronisation. Therefore LBBAP is providing a CRT effect; CRT is not limited to conventional biventricular pacing when conduction system pacing successfully restores synchronous ventricular activation.

Reference: European Society of Cardiology (ESC) clinical consensus statement on indications for conduction system pacing, EP Europace, 2025. https://academic.oup.com/europace/article/27/4/euaf050/8100402