Funding Source: This work was supported by an unrestricted educational grant from Medtronic.
Rates of Upgrade of ICD Recipients to CRT in Clinical Practice and the Potential Impact of the More Liberal Use of CRT at Initial Implant
Article first published online: 6 NOV 2011
©2011, The Authors. Journal compilation ©2011 Wiley Periodicals, Inc.
Pacing and Clinical Electrophysiology
Volume 35, Issue 1, pages 73–80, January 2012
How to Cite
SCOTT, P. A., WHITTAKER, A., ZEB, M., WATTS, E., YUE, A. M., ROBERTS, P. R. and MORGAN, J. M. (2012), Rates of Upgrade of ICD Recipients to CRT in Clinical Practice and the Potential Impact of the More Liberal Use of CRT at Initial Implant. Pacing and Clinical Electrophysiology, 35: 73–80. doi: 10.1111/j.1540-8159.2011.03255.x
Conflicts of interest: PAS and MZ are supported by educational grants from Medtronic. PRR and JMM have received Honoraria and research grants from Medtronic, St Jude, Sorin, and Boston Scientific. AW, EW, and AMY report no conflicts of interest.
- Issue published online: 12 JAN 2012
- Article first published online: 6 NOV 2011
- Received June 9, 2011; revised August 12, 2011; accepted September 5, 2011.
- implantable cardioverter defibrillators;
- heart failure;
- cardiac resynchronization therapy;
Background: Many implantable cardioverter defibrillator (ICD) recipients may develop indications for cardiac resynchronization therapy (CRT) during follow-up. However, the actual upgrade rate during follow-up in clinical practice is not known.
Methods: We performed a single center retrospective observational study of all new ICD implants over 5 years (2003–2007). The rate of CRT upgrade of patients initially implanted with a single-/dual-chamber ICD during follow-up was assessed. The impact of using alternative criteria on the need for CRT in ICD recipients at initial implant was also evaluated.
Results: During the study period, there were 549 new ICD implants. The initial implant was a single/dual-chamber ICD in 73% (n = 399) and a CRT-D in 27% (n = 150). During follow-up (48±20 months) of the 399 ICD recipients, 70 (17.5%) died and 15 (3.8%) were upgraded to CRT, including eight cases where left ventricular lead implant had been initially unsuccessful. Upgrade rates at 1, 3, and 5 years were 0.03%, 2.4%, and 5.1%, respectively. Using alternative CRT criteria (left ventricular ejection fraction [LVEF]≤30%, QRS ≥130 ms, New York Heart Association I-IV) 42.6% (n = 234) of ICD recipients met criteria for CRT at initial implant.
Conclusion: In this retrospective single center study, rates of CRT upgrade in ICD recipients over the medium term were low, which may reflect underuse in otherwise appropriate candidates. The more liberal use of CRT at initial implant in patients with a reduced LVEF, a broad QRS, but only mild heart failure symptoms would require approximately 50% increase in CRT use in ICD recipients at initial implant, and may help address some of the suggested underutilization. (PACE 2012; 35:73–80)