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Database of Abstracts of Reviews of Effects (DARE): Quality-assessed Reviews [Internet]. York (UK): Centre for Reviews and Dissemination (UK); 1995-.

Database of Abstracts of Reviews of Effects (DARE): Quality-assessed Reviews [Internet].

Effect of QRS morphology on clinical event reduction with cardiac resynchronization therapy: meta-analysis of randomized controlled trials

Review published: 2012.

Bibliographic details: Sipahi I, Chou JC, Hyden M, Rowland DY, Simon DI, Fang JC.  Effect of QRS morphology on clinical event reduction with cardiac resynchronization therapy: meta-analysis of randomized controlled trials. American Heart Journal 2012; 163(2): 260-267.e3. [PMC free article: PMC4113034] [PubMed: 22305845]

Abstract

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.

Copyright © 2012 Mosby, Inc. All rights reserved.

CRD has determined that this article meets the DARE scientific quality criteria for a systematic review.

Copyright © 2014 University of York.

PMID: 22305845

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