Document Detail

Effect of QRS morphology on clinical event reduction with cardiac resynchronization therapy: meta-analysis of randomized controlled trials.
MedLine Citation:
PMID:  22305845     Owner:  NLM     Status:  MEDLINE    
BACKGROUND: Cardiac resynchronization therapy (CRT) is effective in reducing clinical events in systolic heart failure patients with a wide QRS. Previous retrospective studies suggest only patients with QRS prolongation due to a left bundle-branch block (LBBB) benefit from CRT. Our objective was to examine this by performing a meta-analysis of all randomized controlled trials of CRT.
METHODS: Systematic searches of MEDLINE and the Food and Drug Administration official website were conducted for randomized controlled CRT trials. Trials reporting adverse clinical events (eg, all-cause mortality, heart failure hospitalizations) according to QRS morphology were included in the meta-analysis.
RESULTS: Four randomized trials totaling 5,356 patients met the inclusion criteria. In patients with LBBB at baseline, there was a highly significant reduction in composite adverse clinical events with CRT (RR = 0.64 [95% CI (0.52-0.77)], P = .00001). However no such benefit was observed for patients with non-LBBB conduction abnormalities (RR = 0.97 [95% CI (0.82-1.15)], P = .75). When examined separately, there was no benefit in patients with right-bundle branch block (RR = 0.91 [95% CI (0.69-1.20)], P = .49) or non-specific intraventricular conduction delay (RR = 1.19 [95% CI (0.87-1.63)], P = .28). There was no heterogeneity among the clinical trials with regards to the lack of benefit in non-LBBB patients (I(2) = 0%). When directly compared, the difference in effect of CRT between LBBB versus non-LBBB patients was highly statistically significant (P = .0001 by heterogeneity analysis).
CONCLUSIONS: While CRT was very effective in reducing clinical events in patients with LBBB, it did not reduce such events in patients with wide QRS due to other conduction abnormalities.
Ilke Sipahi; Josephine C Chou; Marshall Hyden; Douglas Y Rowland; Daniel I Simon; James C Fang
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Publication Detail:
Type:  Journal Article; Meta-Analysis; Review    
Journal Detail:
Title:  American heart journal     Volume:  163     ISSN:  1097-6744     ISO Abbreviation:  Am. Heart J.     Publication Date:  2012 Feb 
Date Detail:
Created Date:  2012-02-06     Completed Date:  2012-03-27     Revised Date:  2014-08-13    
Medline Journal Info:
Nlm Unique ID:  0370465     Medline TA:  Am Heart J     Country:  United States    
Other Details:
Languages:  eng     Pagination:  260-7.e3     Citation Subset:  AIM; IM    
Copyright Information:
Copyright © 2012 Mosby, Inc. All rights reserved.
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MeSH Terms
Cardiac Resynchronization Therapy / methods*
Heart Failure / physiopathology,  therapy*
Randomized Controlled Trials as Topic*
Treatment Outcome
Grant Support

From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine

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