title: The determinants of clinical outcome and clinical response to CRT are not the same.
abstract: The purpose of treatment is to alter outcomes favourably. From a clinical perspective, these outcomes may include symptoms, quality of life, disability, morbidity and mortality. However, a good outcome does not mean that the intervention was effective and a seemingly poor outcome could have been worse without intervention. Patients may have a good outcome either because their disease was due to run a benign course, or because they responded to the intended treatment or because they responded to some other ancillary treatment. Clearly, there is a link between response and outcome but it is loose and uncertain. The clinical substrate being treated is often a stronger determinant of outcome than the response to the intervention. The concepts of outcome and response can both be useful when deciding whether or not to implant a device but they are not the same and their determinants will differ. Patients with dilated cardiomyopathy and those with inter-ventricular mechanical dyssynchrony have a better prognosis than those who do not have these features, but this is true whether or not they receive cardiac resynchronisation therapy (CRT). Many characteristics predict outcome in patients considered for CRT but none consistently predict response. On the other hand, guidelines recommend CRT in populations that have not yet been adequately studied, such as those with atrial fibrillation. Clinicians should follow the criteria for patient selection in the landmark trials when selecting patients for CRT, should extrapolate with caution from these and should be extremely cautious in the interpretation of observational data.
authors.affiliation: Department of Cardiology, Hull York Medical School, Castle Hill Hospital, University of Hull, Kingston-upon-Hull, UK. j.g.cleland@hull.ac.uk
authors.forename: John G F
authors.initials: JG
authors.lastname: Cleland
authors.forename: Stefano
authors.initials: S
authors.lastname: Ghio
mesh_terms: D058406:Cardiac Resynchronization Therapy; D002986:Clinical Trials as Topic; D006333:Heart Failure / Q000503:physiopathology / Q000628:therapy*; D006801:Humans; D018579:Patient Selection; D011379:Prognosis; D016896:Treatment Outcome
references.citation: Eur Heart J. 2006 Aug;27(16):1928-32
references.pmid: 16782715
references.citation: Circulation. 2009 Apr 14;119(14):1977-2016
references.pmid: 19324967
references.citation: Eur J Heart Fail. 2009 May;11(5):480-8
references.pmid: 19287017
references.citation: JAMA. 2002 Dec 25;288(24):3115-23
references.pmid: 12495391
references.citation: Am J Cardiol. 2007 Jan 15;99(2):232-8
references.pmid: 17223424
references.citation: Circulation. 2009 Nov 10;120(19):1858-65
references.pmid: 19858419
references.citation: Heart Rhythm. 2010 Oct;7(10):1421-7
references.pmid: 20620231
references.citation: Circulation. 2008 May 20;117(20):2608-16
references.pmid: 18458170
references.citation: Eur J Heart Fail. 2005 Mar 2;7(2):205-14
references.pmid: 15701468
references.citation: Lancet. 2007 Sep 29;370(9593):1103-4
references.pmid: 17905146
references.citation: Ann Noninvasive Electrocardiol. 2005 Oct;10(4 Suppl):34-43
references.pmid: 16274414
references.citation: Circulation. 2011 Mar 15;123(10):1061-72
references.pmid: 21357819
references.citation: Eur J Heart Fail. 2005 Aug;7(5):931-6
references.pmid: 16087144
references.citation: Eur Heart J. 2009 Oct;30(20):2470-7
references.pmid: 19717847
references.citation: J Am Coll Cardiol. 2006 Apr 18;47(8):1603-11
references.pmid: 16630997
references.citation: JACC Cardiovasc Imaging. 2010 May;3(5):541-9
references.pmid: 20466352
references.citation: Circulation. 2010 May 11;121(18):1985-91
references.pmid: 20421518
references.citation: Eur Heart J. 2007 Aug;28(15):1827-34
references.pmid: 17540848
references.citation: Eur Heart J. 2009 Apr;30(7):782-8
references.pmid: 19168870
references.citation: BMJ. 2007 Apr 14;334(7597):756-7
references.pmid: 17431231
references.citation: JAMA. 2003 May 28;289(20):2685-94
references.pmid: 12771115
references.citation: Circulation. 2010 Sep 7;122(10):985-92
references.pmid: 20733097
references.citation: J Am Coll Cardiol. 1995 Apr;25(5):1154-61
references.pmid: 7897129
references.citation: J Am Coll Cardiol. 2008 Oct 28;52(18):1442-9
references.pmid: 19017510
references.citation: J Am Coll Cardiol. 2008 Dec 2;52(23):1834-1843
references.pmid: 19038680
references.citation: J Am Coll Cardiol. 2011 Feb 15;57(7):813-20
references.pmid: 21310317
references.citation: J Am Coll Cardiol. 2009 Nov 10;54(20):1837-46
references.pmid: 19800193
references.citation: Eur Heart J. 2010 Apr;31(7):832-41
references.pmid: 19906690
references.citation: N Engl J Med. 2007 Dec 13;357(24):2461-71
references.pmid: 17986493
references.citation: Eur Heart J. 1992 Oct;13(10):1316-24
references.pmid: 1396802
references.citation: Eur J Heart Fail. 2009 Jul;11(7):699-705
references.pmid: 19505883
references.citation: Am Heart J. 2009 Mar;157(3):457-66
references.pmid: 19249415
references.citation: Eur J Heart Fail. 2002 Jun;4(3):243-7
references.pmid: 12034147
references.citation: J Am Coll Cardiol. 2008 Aug 5;52(6):438-45
references.pmid: 18672164
references.citation: J Am Coll Cardiol. 2002 May 1;39(9):1414-21
references.pmid: 11985901
references.citation: Heart Rhythm. 2005 Jun;2(6):611-5
references.pmid: 15922268
references.citation: J R Coll Physicians Edinb. 2010 Sep;40(3):229-39
references.pmid: 21127768
references.citation: Eur J Heart Fail. 2008 Jun;10(6):614-20
references.pmid: 18502685
references.citation: Nat Rev Cardiol. 2010 Feb;7(2):69-70
references.pmid: 20104242
references.citation: Eur Heart J. 2011 Jul;32(13):1622-30
references.pmid: 21075774
references.citation: J Am Coll Cardiol. 2009 Feb 17;53(7):608-611
references.pmid: 19215836
references.citation: N Engl J Med. 2004 May 20;350(21):2140-50
references.pmid: 15152059
references.citation: Eur J Heart Fail. 2010 Nov;12(11):1143-53
references.pmid: 20965877
references.citation: J Am Coll Cardiol. 2005 Mar 1;45(5):685-9
references.pmid: 15734611
references.citation: N Engl J Med. 2005 Apr 14;352(15):1539-49
references.pmid: 15753115
references.citation: J Am Coll Cardiol. 2009 Feb 10;53(6):483-90
references.pmid: 19195605
references.citation: Eur J Heart Fail. 2008 Jul;10(7):696-702
references.pmid: 18501670
references.citation: Circulation. 1989 Dec;80(6):1675-80
references.pmid: 2598430
references.citation: N Engl J Med. 2002 Jun 13;346(24):1845-53
references.pmid: 12063368
references.citation: Heart Fail Clin. 2007 Jul;3(3):267-73
references.pmid: 17723935
references.citation: Eur J Heart Fail. 2008 Oct;10(10):933-89
references.pmid: 18826876
references.citation: Eur Heart J. 2008 Jul;29(13):1644-52
references.pmid: 18390869
references.citation: N Engl J Med. 2010 Dec 16;363(25):2385-95
references.pmid: 21073365
references.citation: Am J Cardiol. 2001 Mar 1;87(5):655-7, A10-1
references.pmid: 11230859
references.citation: Lancet. 2002 Nov 23;360(9346):1631-9
references.pmid: 12457785
references.citation: N Engl J Med. 2009 Oct 1;361(14):1329-38
references.pmid: 19723701
references.citation: Eur J Heart Fail. 2008 Apr;10(4):412-20
references.pmid: 18395672
references.citation: Nat Clin Pract Cardiovasc Med. 2007 Feb;4(2):90-101
references.pmid: 17245403
references.citation: Heart. 2008 Mar;94(3):278-83
references.pmid: 17984215