Implantable cardioverter defibrillators for primary prevention of death in left ventricular dysfunction with and without ischaemic heart disease: a meta-analysis of 8567 patients in the 11 trials.
OBJECTIVE
Primary prevention implantable cardioverter defibrillators (ICDs) are established therapy for reducing mortality in patients with left ventricular systolic dysfunction and ischaemic heart disease (IHD). However, their efficacy in patients without IHD has been controversial. We undertook a meta-analysis of the totality of the evidence.


RESULTS
We systematically identified all RCTs comparing ICD vs. no ICD in primary prevention. Eligible RCTs were those that recruited patients with left ventricular dysfunction, reported all-cause mortality, and presented their results stratified by the presence of IHD (or recruited only those with or without). Our primary endpoint was all-cause mortality. We identified 11 studies enrolling 8567 participants with left ventricular dysfunction, including 3128 patients without IHD and 5439 patients with IHD. In patients without IHD, ICD therapy reduced mortality by 24% (HR 0.76, 95% CI 0.64 to 0.90, P = 0.001). In patients with IHD, ICD implantation (at a dedicated procedure), also reduced mortality by 24% (HR 0.76, 95% CI 0.60 to 0.96, P = 0.02).


CONCLUSIONS
Until now, it has never been explicitly stated that the patients without IHD in COMPANION showed significant survival benefit from adding ICD therapy (to a background of CRT). Even before DANISH, meta-analysis of patients without ischaemic heart disease already showed reduced mortality. DANISH is consistent with these data. With a significant 24% mortality reduction in both aetiologies, it may no longer be necessary to distinguish between them when deciding on primary prevention ICD implantation.
Imperial College London, National Heart and Lung Institute, Hammersmith Hospital Campus, B Block, 2nd floor, NHLI - Cardiovascular Science, Du Cane Road, W12 0NN London, UK.
Matthew J
MJ
Shun-Shin
Imperial College London, National Heart and Lung Institute, Hammersmith Hospital Campus, B Block, 2nd floor, NHLI - Cardiovascular Science, Du Cane Road, W12 0NN London, UK.
Sean L
SL
Zheng
Imperial College London, National Heart and Lung Institute, Hammersmith Hospital Campus, B Block, 2nd floor, NHLI - Cardiovascular Science, Du Cane Road, W12 0NN London, UK.
Graham D
GD
Cole
Imperial College London, National Heart and Lung Institute, Hammersmith Hospital Campus, B Block, 2nd floor, NHLI - Cardiovascular Science, Du Cane Road, W12 0NN London, UK.
James P
JP
Howard
Imperial College London, National Heart and Lung Institute, Hammersmith Hospital Campus, B Block, 2nd floor, NHLI - Cardiovascular Science, Du Cane Road, W12 0NN London, UK.
Zachary I
ZI
Whinnett
Imperial College London, National Heart and Lung Institute, Hammersmith Hospital Campus, B Block, 2nd floor, NHLI - Cardiovascular Science, Du Cane Road, W12 0NN London, UK.
Darrel P
DP
Francis
D016757:Death, Sudden, Cardiac / Q000517:prevention & control*; D017147:Defibrillators, Implantable; D006801:Humans; D008875:Middle Aged; D017202:Myocardial Ischemia / Q000150:complications* / Q000401:mortality; D016032:Randomized Controlled Trials as Topic; D018487:Ventricular Dysfunction, Left / Q000150:complications* / Q000401:mortality
Cardiomyopathy; Heart failure; Implantable cardiac defibrillators; Ischaemic heart disease; Meta-analysis; Non-ischaemic