Study selection
Two independent reviewers (Y.L and D.C) screened the citations through
the title and abstract, and we make mutual agreement procedural to reach
a consensus if divergences exist. Studies met the following explicit
selection criteria as follow were evaluated as complete reports: 1)
English language publication; 2) randomized controlled trials or
observational trials; 3) the subjects of interest was heart failure
patients undergoing CRT with or without defibrillator; 4) the outcome
was all-cause mortality; 5) a hazard ratio (HR) adjusted by Cox
multivariate analysis was available.
The standard of exclusion criteria includes: case reports, case series,
editorials, literature review, conference abstract, non-English articles
and duplicate reports (we selected the study reporting the largest
sample of patients in these cases).