title: Impact of etiology on the outcomes in heart failure patients treated with cardiac resynchronization therapy: a meta-analysis.
abstract: BACKGROUND
  Cardiac resynchronization therapy (CRT) has been extensively demonstrated to benefit heart failure patients, but the role of underlying heart failure etiology in the outcomes was not consistently proven. This meta-analysis aimed to determine whether efficacy and effectiveness of CRT is affected by underlying heart failure etiology.
  
  
  RESULTS
  Searches of MEDLINE, EMBASE and Cochrane databases were conducted to identify RCTs and observational studies that reported clinical and functional outcomes of CRT in ischemic cardiomyopathy (ICM) and non-ischemic cardiomyopathy (NICM) patients. Efficacy of CRT was assessed in 7 randomized controlled trials (RCTs) with 7072 patients and effectiveness of CRT was evaluated in 14 observational studies with 3463 patients In the pooled analysis of RCTs, we found that CRT decreased mortality or heart failure hospitalization by 29% in ICM patients (95% confidence interval [CI], 21% to 35%), and by 28% (95% CI, 18% to 37%) in NICM patients. No significant difference was observed between the 2 etiology groups (P = 0.55). In the pooled analysis of observational studies, however, we found that ICM patients had a 54% greater risk for mortality or HF hospitalization than NICM patients (relative risk: 1.54; 95% CI: 1.30-1.83; P<0.001). Both RCTs and observational studies demonstrated that NICM patients had greater echocardiographic improvements in the left ventricular ejection fraction and end-systolic volume, as compared with ICM patients (both P<0.001).
  
  
  CONCLUSIONS
  CRT might reduce mortality or heart failure hospitalization in both ICM and NICM patients similarly. The improvement of the left ventricular function and remodeling is greater in NICM patients.
authors.affiliation: Department of Cardiology and National Key Lab for Organ Failure Research, Nanfang Hospital, Southern Medical University, Guangzhou, China.
authors.forename: Yanmei
authors.initials: Y
authors.lastname: Chen
authors.affiliation: Department of Biostatistics, Southern Medical University, Guangzhou, China.
authors.forename: Chongyang
authors.initials: C
authors.lastname: Duan
authors.affiliation: Department of Cardiology and National Key Lab for Organ Failure Research, Nanfang Hospital, Southern Medical University, Guangzhou, China.
authors.forename: Feng
authors.initials: F
authors.lastname: Liu
authors.affiliation: Department of Cardiology and National Key Lab for Organ Failure Research, Nanfang Hospital, Southern Medical University, Guangzhou, China.
authors.forename: Shuxin
authors.initials: S
authors.lastname: Shen
authors.affiliation: Department of Biostatistics, Southern Medical University, Guangzhou, China.
authors.forename: Pingyan
authors.initials: P
authors.lastname: Chen
authors.affiliation: Department of Cardiology and National Key Lab for Organ Failure Research, Nanfang Hospital, Southern Medical University, Guangzhou, China.
authors.forename: Jianping
authors.initials: J
authors.lastname: Bin
mesh_terms: D058406:Cardiac Resynchronization Therapy; D004452:Echocardiography; D006333:Heart Failure / Q000209:etiology* / Q000503:physiopathology / Q000628:therapy*; D006760:Hospitalization; D006801:Humans; D064887:Observational Studies as Topic; D016032:Randomized Controlled Trials as Topic; D012306:Risk; D016896:Treatment Outcome; D018487:Ventricular Dysfunction, Left / Q000503:physiopathology; D016277:Ventricular Function, Left / Q000502:physiology
references.citation: Eur Heart J. 2009 Oct;30(20):2470-7
references.pmid: 19717847
references.citation: Eur Heart J. 2008 Oct;29(20):2497-505
references.pmid: 18515806
references.citation: Pacing Clin Electrophysiol. 2003 Jan;26(1P2):175-80
references.pmid: 12687807
references.citation: Eur Heart J. 2011 Jan;32(1):93-103
references.pmid: 20971745
references.citation: Eur Heart J. 2007 Nov;28(22):2738-48
references.pmid: 17959621
references.citation: Eur Heart J. 2007 Jan;28(1):33-41
references.pmid: 17121757
references.citation: N Engl J Med. 2005 Apr 14;352(15):1539-49
references.pmid: 15753115
references.citation: N Engl J Med. 2002 Jun 13;346(24):1845-53
references.pmid: 12063368
references.citation: N Engl J Med. 2010 Dec 16;363(25):2385-95
references.pmid: 21073365
references.citation: JAMA. 2007 Dec 12;298(22):2654-64
references.pmid: 18073361
references.citation: Heart Rhythm. 2011 Mar;8(3):377-82
references.pmid: 21070886
references.citation: Eur Heart J. 2009 Sep;30(18):2275-83
references.pmid: 19515689
references.citation: J Am Coll Cardiol. 2010 Nov 23;56(22):1826-31
references.pmid: 21087711
references.citation: PLoS Med. 2009 Jul 21;6(7):e1000097
references.pmid: 19621072
references.citation: Eur Heart J. 2003 Mar;24(5):430-41
references.pmid: 12633545
references.citation: Eur Heart J. 2009 Apr;30(7):782-8
references.pmid: 19168870
references.citation: J Am Coll Cardiol. 1998 Nov;32(5):1167-72
references.pmid: 9809921
references.citation: J Am Soc Echocardiogr. 2006 Mar;19(3):307-13
references.pmid: 16500494
references.citation: Control Clin Trials. 1996 Feb;17(1):1-12
references.pmid: 8721797
references.citation: Ann Cardiol Angeiol (Paris). 2004 Jul;53(4):171-6
references.pmid: 15369312
references.citation: J Am Coll Cardiol. 2008 Dec 2;52(23):1834-1843
references.pmid: 19038680
references.citation: Lancet. 2000 Mar 25;355(9209):1064-9
references.pmid: 10744093
references.citation: JAMA. 2007 Jun 13;297(22):2502-14
references.pmid: 17565085
references.citation: Int J Cardiol. 2013 Oct 9;168(4):4378-80
references.pmid: 23711444
references.citation: Am J Cardiol. 2009 Mar 1;103(5):690-4
references.pmid: 19231335
references.citation: Am J Cardiol. 2004 Apr 1;93(7):860-3
references.pmid: 15050489
references.citation: Eur Heart J. 2011 Jul;32(13):1622-30
references.pmid: 21075774
references.citation: Eur Heart J. 2011 Jul;32(13):1580-2
references.pmid: 21324935
references.citation: N Engl J Med. 2001 Mar 22;344(12):873-80
references.pmid: 11259720
references.citation: N Engl J Med. 2004 May 20;350(21):2140-50
references.pmid: 15152059
references.citation: JAMA. 2000 Apr 19;283(15):2008-12
references.pmid: 10789670
references.citation: Heart. 2009 Feb;95(2):113-8
references.pmid: 18653570
references.citation: Circulation. 2006 Jan 17;113(2):266-72
references.pmid: 16401777
references.citation: J Card Fail. 2012 Feb;18(2):94-106
references.pmid: 22300776
references.citation: JAMA. 2011 Sep 21;306(11):1241-9
references.pmid: 21934057
references.citation: J Am Coll Cardiol. 1997 Oct;30(4):1002-8
references.pmid: 9316531
references.citation: J Cardiovasc Med (Hagerstown). 2011 Apr;12(4):227-33
references.pmid: 21252694
references.citation: N Engl J Med. 2009 Oct 1;361(14):1329-38
references.pmid: 19723701
references.citation: Am J Cardiol. 2007 Aug 1;100(3):464-9
references.pmid: 17659930
references.citation: Circulation. 2011 Jan 4;123(1):70-8
references.pmid: 21173353
references.citation: Rev Esp Cardiol. 2007 Dec;60(12):1264-71
references.pmid: 18082092