“…4,6,7,[10][11][12] The rate of CRT upgrade varies widely among studies: in a retrospective single center study, the upgrade rates from ICD to CRT-D at 1, 3, and 5 years were 0.03%, 2.4%, and 5.1%, respectively, 10 and Palmisano et al report a 3.2% rate of upgrade from pacemaker to CRT-P or ICD to CRT-D in their survey of 2671 consecutive procedures from 2 centers in Italy. 6 Conversely, in the European Cardiac Resynchronization Therapy Survey of 2367 CRT implant procedures, 29.2% were identified as having an upgrade from pacemaker to CRT-P or ICD to CRT-D. 7 Previously cited reasons for not performing upgrades in potential candidates include increased cost if performed before ICD generator change, an increased risk of complications, and lack of established trial data demonstrating efficacy of CRT in this patient population. 10 The initial success rate of ICD upgrade to CRT-D in our study was 91% during RAFT and 90% in the substudy, after the presentation of the RAFT results.…”