Differential outcome of cardiac resynchronization therapy in ischemic cardiomyopathy and idiopathic dilated cardiomyopathy.
BACKGROUND
Cardiac resynchronization therapy (CRT) is a therapy of proven benefit in patients with advanced heart failure. Identifying potential responders remains challenging, and whether the etiology of the heart failure is related to the potential hemodynamic benefit and long-term outcome of CRT is unclear.


OBJECTIVE
The purpose of this study was to evaluate whether heart failure etiology (ischemic cardiomyopathy [ICM] vs nonischemic dilated cardiomyopathy [DCM]) was associated with CRT outcome and implantable cardioverter-defibrillator (ICD) shocks.


METHODS
The study included 503 CRT recipients (CRT-D 90%) in a longitudinal CRT database: ICM (n = 312) and DCM (n = 191). Clinical variables and echocardiographic measures preimplant and postimplant were collected. Actuarial survival and ICD therapy data were assessed with Kaplan-Meier curve and log rank tests.


RESULTS
Pre-CRT, ICM patients were older and had higher creatinine levels (P <.001). At median follow-up of 7.1 months, the DCM group experienced greater improvement in left ventricular ejection fraction (8.3% ± 10% vs 6.2% ± 10%, P = .05) and left ventricular end-diastolic volumes than did those with ICM (-28%.4 ± 53 mL vs -15.3 ± 46 mL, P = .024). Survival estimates at 4 years were 55% for ICM and 77% for DCM groups (P <.001), respectively, whereas no significant difference in the incidence of appropriate/inappropriate ICD shocks was observed. The ICM group remained at higher risk for death compared to the DCM group after controlling for preimplant variables (hazard ratio 1.6, 95% confidence interval 1.1-2.3, P = .008).


CONCLUSIONS
In response to CRT and in contrast to ICM, DCM patients experienced greater improvement in left ventricular systolic function and reverse remodeling while also sustaining a greater survival benefit.
Division of Cardiovascular Diseases, Mayo Clinic, Rochester, Minnesota 55905, USA.
Christopher J
CJ
McLeod
Win-Kuang
WK
Shen
Robert F
RF
Rea
Paul A
PA
Friedman
David L
DL
Hayes
Anita
A
Wokhlu
Tracy L
TL
Webster
Heather J
HJ
Wiste
David O
DO
Hodge
David J
DJ
Bradley
Stephen C
SC
Hammill
Douglas L
DL
Packer
Yong-Mei
YM
Cha
D000368:Aged; D058406:Cardiac Resynchronization Therapy; D002311:Cardiomyopathy, Dilated / Q000097:blood / Q000150:complications* / Q000401:mortality / Q000473:pathology; D003324:Coronary Artery Disease / Q000453:epidemiology; D003404:Creatinine / Q000097:blood; D016757:Death, Sudden, Cardiac / Q000453:epidemiology / Q000517:prevention & control; D017147:Defibrillators, Implantable; D005260:Female; D006333:Heart Failure / Q000209:etiology* / Q000401:mortality / Q000628:therapy*; D006801:Humans; D053208:Kaplan-Meier Estimate; D008297:Male; D008875:Middle Aged; D017202:Myocardial Ischemia / Q000097:blood / Q000150:complications* / Q000401:mortality / Q000473:pathology; D011379:Prognosis; D016896:Treatment Outcome; D018497:Ventricular Dysfunction, Right / Q000209:etiology / Q000628:therapy; D020257:Ventricular Remodeling
D003404:Creatinine