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CRT Indication is ECG-based Not Echo — EECC MCQ

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ModerateHeart FailureCRT Indication is ECG-based Not EchoEECC

A 58-year-old man with HFrEF and LVEF 30% presents with new complete LBBB (QRS 165 ms). His echocardiographer performs speckle-tracking strain analysis showing severe septal-to-lateral wall delay (mechanical dyssynchrony). He is already on optimal GDMT. What is the next step?

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Correct answer: C — CRT implantation — he meets Class I criteria: sinus rhythm, LVEF ≤35%, LBBB with QRS ≥150 ms, symptomatic despite optimal GDMT; the echocardiographic dyssynchrony provides additional supporting evidence but is NOT required for the CRT indication (which is ECG-based)

CRT indication is ECG-based (QRS duration + morphology + LVEF), NOT echocardiography-based. The EchoCRT trial (2013) showed that CRT guided by echocardiographic dyssynchrony in narrow-QRS patients (<130 ms) was HARMFUL (increased mortality). Therefore: (1) echocardiographic dyssynchrony does NOT add to CRT indication when ECG criteria are met; (2) echocardiographic dyssynchrony alone does NOT justify CRT when ECG criteria are NOT met. This patient: sinus rhythm + LVEF 30% (≤35%) + LBBB + QRS 165 ms (≥150 ms) = Class I CRT indication per ESC 2021 Pacing/CRT Guidelines. The echo dyssynchrony is confirmatory but not required. CRT-D vs CRT-P: for ischaemic aetiology → CRT-D preferred (strong ICD evidence); for non-ischaemic → individualised (DANISH trial). Expected response with LBBB ≥150 ms: ~70% of patients improve ≥1 NYHA class with significant LVEF improvement.

Reference: ESC (2021): Pacing/CRT; EchoCRT Trial