title: Relationship of electro-mechanical remodeling to survival rates after cardiac resynchronization therapy.
abstract: Cardiac resynchronization therapy, when added to optimal medical therapy, increases longevity in symptomatic congestive heart failure patients with left ventricular ejection fractions (LVEF)≤0.35 and QRS durations>120 ms. Cardiac resynchronization therapy is also associated with electrical and mechanical reverse remodeling. We examined whether reverse remodeling predicts increased survival rates in non-trial settings. Recipients of cardiac resynchronization therapy and defibrillators (n=112; 78 men; mean age, 69±11 yr) underwent repeat echocardiography and electrocardiography at least 90 days after device implantation. Forty patients had mechanical responses of at least 0.05 improvement in absolute LVEF; 56 had electrical responses (any narrowing of biventricular-paced QRS duration compared with the electrocardiogram immediately after therapy). During a mean follow-up period of 3.1±1.7 years, 55 patients died. The average death rate per 100 person-years was lower among mechanical responders than nonresponders (9.2% vs 23.9%; P=0.009); the unadjusted hazard ratio was 0.39 (95% confidence interval [CI], 0.19-0.79). In a multivariate model adjusted for age, sex, baseline LVEF, and QRS duration, mechanical responders had 60% better survival than nonresponders (hazard ratio=0.40; 95% CI, 0.21-0.79; P=0.008). No difference in survival was observed in electrical response. In our association of absolute change in LVEF over the observed range with death (using restricted cubic splines), we observed a linear relationship with survival. In patients given cardiac resynchronization therapy, mechanical but not electrical remodeling was associated with better survival rates, suggesting that mechanical remodeling underlies this therapy's mechanism of conferring a survival benefit.
authors.affiliation: Cardiac Electrophysiology Section, University of Pittsburgh Medical Center, Pittsburgh, Pennsylvania 15213, USA. jawad.kiani@gmail.com
authors.forename: Jawad
authors.initials: J
authors.lastname: Kiani
authors.forename: Sunil Kumar
authors.initials: SK
authors.lastname: Agarwal
authors.forename: Swapna
authors.initials: S
authors.lastname: Kamireddy
authors.forename: Evan
authors.initials: E
authors.lastname: Adelstein
authors.forename: Samir
authors.initials: S
authors.lastname: Saba
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D058406:Cardiac Resynchronization Therapy / Q000009:adverse effects / Q000401:mortality*; D058409:Cardiac Resynchronization Therapy Devices; D017147:Defibrillators, Implantable; D004562:Electrocardiography; D005260:Female; D006329:Heart Conduction System / Q000503:physiopathology*; D006333:Heart Failure / Q000175:diagnosis / Q000401:mortality / Q000503:physiopathology / Q000628:therapy*; D006801:Humans; D053208:Kaplan-Meier Estimate; D016014:Linear Models; D008297:Male; D008875:Middle Aged; D015999:Multivariate Analysis; D010414:Pennsylvania; D016016:Proportional Hazards Models; D012189:Retrospective Studies; D012307:Risk Factors; D013318:Stroke Volume; D015996:Survival Rate; D062606:Tertiary Care Centers; D013997:Time Factors; D016896:Treatment Outcome; D016277:Ventricular Function, Left; D020257:Ventricular Remodeling
keywords: Cardiac resynchronization therapy/methods; combined modality therapy; heart conduction system/physiopathology; heart failure/mortality/physiopathology/therapy; predictive value of tests; survival analysis; ventricular dysfunction, left/mortality/prevention & control/therapy; ventricular remodeling
references.citation: J Am Soc Echocardiogr. 1989 Sep-Oct;2(5):358-67
references.pmid: 2698218
references.citation: Eur J Heart Fail. 2011 Jan;13(1):43-51
references.pmid: 21051462
references.citation: Eur J Heart Fail. 2001 Aug;3(4):481-9
references.pmid: 11511435
references.citation: Pacing Clin Electrophysiol. 2011 Mar;34(3):357-64
references.pmid: 21091740
references.citation: Stat Med. 2010 Apr 30;29(9):1037-57
references.pmid: 20087875
references.citation: N Engl J Med. 2002 Jun 13;346(24):1845-53
references.pmid: 12063368
references.citation: J Am Coll Cardiol. 2004 Jan 21;43(2):248-56
references.pmid: 14736445
references.citation: Nature. 2007 Dec 6;450(7171):819-24
references.pmid: 18064002
references.citation: J Am Coll Cardiol. 2003 Dec 17;42(12):2109-16
references.pmid: 14680736
references.citation: Am J Cardiol. 1999 Mar 11;83(5B):130D-135D
references.pmid: 10089855
references.citation: J Am Coll Cardiol. 2008 Oct 28;52(18):1442-9
references.pmid: 19017510
references.citation: Biochem Biophys Res Commun. 2000 Jan 19;267(2):551-7
references.pmid: 10631100
references.citation: J Am Coll Cardiol. 2005 Dec 20;46(12):2183-92
references.pmid: 16360044
references.citation: Eur Heart J. 2008 Oct;29(20):2497-505
references.pmid: 18515806
references.citation: Eur Heart J. 2000 Aug;21(15):1246-50
references.pmid: 10924314
references.citation: J Card Fail. 2000 Sep;6(3):276-85
references.pmid: 10997756
references.citation: Basic Res Cardiol. 2005 Jul;100(4):337-45
references.pmid: 15822004
references.citation: J Am Coll Cardiol. 2003 Oct 15;42(8):1454-9
references.pmid: 14563591
references.citation: J Cardiovasc Electrophysiol. 2009 Mar;20(3):293-8
references.pmid: 19175852
references.citation: Comput Methods Programs Biomed. 2004 Jul;75(1):45-9
references.pmid: 15158046
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: Am Heart J. 2002 Jun;143(6):1085-91
references.pmid: 12075267
references.citation: N Engl J Med. 2005 Apr 14;352(15):1539-49
references.pmid: 15753115
references.citation: J Am Coll Cardiol. 2005 Dec 20;46(12):2237-43
references.pmid: 16360052
references.citation: J Am Coll Cardiol. 2009 Feb 10;53(6):483-90
references.pmid: 19195605
references.citation: J Am Coll Cardiol. 2002 Jul 3;40(1):111-8
references.pmid: 12103264
references.citation: Circ Res. 2004 Mar 19;94(5):585-91
references.pmid: 15031271
references.citation: Circulation. 2005 Sep 13;112(11):1580-6
references.pmid: 16144994