Document Detail

The relationship of QRS morphology and mechanical dyssynchrony to long-term outcome following cardiac resynchronization therapy.
MedLine Citation:
PMID:  22351700     Owner:  NLM     Status:  MEDLINE    
AIMS: Because benefits of cardiac resynchronization therapy (CRT) appear to be less favourable in non-left bundle branch block (LBBB) patients, this prospective longitudinal study tested the hypothesis that QRS morphology and echocardiographic mechanical dyssynchrony were associated with long-term outcome after CRT.
METHODS AND RESULTS: Two-hundred and seventy-eight consecutive New York Heart Association class III and IV CRT patients with QRS ≥120 ms and ejection fraction ≤35% were studied. The pre-specified primary endpoint was death, heart transplant, or left ventricular assist device over 4 years. Dyssynchrony assessed before CRT included interventricular mechanical delay (IVMD) and speckle-tracking radial strain using pre-specified cut-offs for each. Of 254 with baseline quantitative echocardiographic data available, 128 had LBBB, 81 had intraventricular conduction delay (IVCD), and 45 had right bundle branch block (RBBB). Radial dyssynchrony was observed in 85% of the patients with LBBB, 59% with IVCD*, and 40% with RBBB* (*P < 0.01 vs. LBBB). Of 248 (98%) with follow-up, LBBB patients had a significantly more favourable long-term survival than non-LBBB patients. However, non-LBBB patients with dyssynchrony had a more favourable event-free survival than those without dyssynchrony: radial dyssynchrony hazard ratio 2.6, 95% confidence interval (CI) 1.47-4.53 (P = 0.0008) and IVMD hazard ratio 4.9, 95% CI 2.60-9.16 (P = 0.0007). Right bundle branch block patients who lacked dyssynchrony had the least favourable outcome.
CONCLUSION: Non-LBBB patients with dyssynchrony had a more favourable long-term survival than non-LBBB patients who lacked dyssynchrony. Mechanical dyssynchrony and QRS morphology are associated with outcome following CRT.
Hideyuki Hara; Olusegun A Oyenuga; Hidekazu Tanaka; Evan C Adelstein; Toshinari Onishi; Dennis M McNamara; David Schwartzman; Samir Saba; John Gorcsan
Publication Detail:
Type:  Journal Article; Research Support, N.I.H., Extramural; Research Support, Non-U.S. Gov't     Date:  2012-02-19
Journal Detail:
Title:  European heart journal     Volume:  33     ISSN:  1522-9645     ISO Abbreviation:  Eur. Heart J.     Publication Date:  2012 Nov 
Date Detail:
Created Date:  2012-11-02     Completed Date:  2013-04-18     Revised Date:  2013-11-07    
Medline Journal Info:
Nlm Unique ID:  8006263     Medline TA:  Eur Heart J     Country:  England    
Other Details:
Languages:  eng     Pagination:  2680-91     Citation Subset:  IM    
The Cardiovascular Institute, University of Pittsburgh, Scaife 564, 200 Lothrop Street, Pittsburgh, PA 15213-2582, USA.
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MeSH Terms
Analysis of Variance
Bundle-Branch Block / physiopathology,  therapy*
Cardiac Resynchronization Therapy*
Echocardiography, Doppler / methods
Heart Failure / therapy
Heart Transplantation / statistics & numerical data
Kaplan-Meier Estimate
Prospective Studies
Stroke Volume / physiology
Treatment Outcome
Ventricular Dysfunction, Left / physiopathology,  therapy*
Grant Support

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