RT Journal
A1 Magee CD, Byars L, DeZee KJ
T1 LImitations of subgroup analyses in meta-analysis of cardiac resynchronization therapy by qrs duration
JF Archives of Internal Medicine
JO Archives of Internal Medicine
YR 2012
FD February 27
VO 172
IS 4
SP 375
OP 376
DO 10.1001/archinternmed.2011.1499
UL http://dx.doi.org/10.1001/archinternmed.2011.1499
AB 
Sipahi et al1 report a meta-analysis to evaluate the impact of QRS duration in patients with heart failure receiving cardiac resynchronization therapy (CRT) as measured by composite clinical events. This analysis including 5 randomized controlled trials attempts to address a discordance between Heart Failure Society of America (HFSA) and European Society of Cardiology (ESC) guidelines recommending CRT in patients with New York Heart Association (NYHA) III/IV heart failure and a QRS interval greater than 120 milliseconds, and published data suggesting greater benefit at higher QRS cutoffs. The conducted meta-analysis represents a post hoc subgroup analysis, according to QRS cutoff values used in each study. There are 2 major concerns that threaten the validity of the authors' conclusions in this study, namely multiplicity of analysis and loss of randomization.