RT Journal
A1 Sipahi I
T1 QRs morphology rather than qrs duration for predicting crt response—reply
JF Archives of Internal Medicine
JO Archives of Internal Medicine
YR 2011
FD November 14
VO 171
IS 20
SP 1861
OP 1862
DO 10.1001/archinternmed.2011.517
UL http://dx.doi.org/10.1001/archinternmed.2011.517
AB 
Selzman and Shein from the FDA point out that QRS morphology is also important for predicting response to CRT. In our article my colleagues and I stated, “Patients with LBBB have left ventricular activation times that are on average 36 ms longer than patients with RBBB. Consequently, the QRS duration above which CRT will be beneficial is probably significantly different with different types of conduction abnormalities”1(p1461) and called for an individual patient-level meta-analysis of all relevant clinical trials to further refine the indications for CRT.