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Editor's Correspondence
Nov 14, 2011

QRS Morphology Rather Than QRS Duration for Predicting CRT Response

Author Affiliations

Author Affiliations: Pacing Defibrillator and Leads Branch, Division of Cardiovascular Devices, Office of Device Evaluation, Center for Devices and Radiological Health, Food and Drug Administration, Silver Spring, Maryland.

Arch Intern Med. 2011;171(20):1861-1862. doi:10.1001/archinternmed.2011.516

Sipahi et al reported in their meta-analysis of 5 cardiac resynchronization therapy (CRT) trials that QRS duration was an important predictor of response to CRT.1 They concluded that patients with a QRS of 150 milliseconds (ms) or greater had a reduction in heart failure events, whereas those with a QRS less than 150 ms did not. Unfortunately, there was no analysis of QRS morphology, eg, type of bundle branch block. Although they proposed a future meta-analysis to further refine QRS duration cutoffs, they failed to mention that QRS morphology may be equally or more important than QRS duration.

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