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CRT Eligibility Narrow QRS Non-LBBB — EECC MCQ

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ModerateHeart FailureCRT Eligibility Narrow QRS Non-LBBBEECC

A 60-year-old man with HFrEF (LVEF 28%) on sacubitril/valsartan, bisoprolol, eplerenone, and dapagliflozin remains in NYHA class III. His ECG shows sinus rhythm with QRS 125 ms and non-LBBB morphology. Is CRT indicated?

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Correct answer: A — CRT may be considered (Class IIb) for QRS 130-149 ms with non-LBBB morphology and LVEF ≤35%, but the evidence is substantially weaker than for LBBB ≥150 ms — this patient with QRS 125 ms does not meet the minimum 130 ms threshold

The ESC 2021 Pacing/CRT Guidelines require a minimum QRS duration of 130 ms for CRT consideration. At QRS 125 ms, this patient does NOT meet the threshold — CRT is contraindicated in narrow QRS based on the EchoCRT trial (which showed increased mortality). CRT recommendations by QRS: ≥150 ms + LBBB = Class I (strongest); 130-149 ms + LBBB = Class I; ≥150 ms + non-LBBB = Class IIa; 130-149 ms + non-LBBB = Class IIb. For this patient, management should focus on: (1) primary prevention ICD (if LVEF remains ≤35% after ≥3 months GDMT); (2) further GDMT optimisation; (3) consideration of ivabradine if HR >70 bpm; (4) evaluation for advanced HF therapies if symptoms persist.

Reference: ESC (2021): Pacing/CRT Guidelines; ESC (2023): HF Guidelines