Clinical outcomes after upgrading from pacemakers to cardiac resynchronization therapy

Francisco Leyva, Abbasin Zegard, Kiran Patel, Jonathan Panting, Howard Marshall, Tian Qiu

Research output: Contribution to journalArticlepeer-review


Background and Aims: Right ventricular pacing may lead to heart failure (HF). Upgrades from pacemakers to cardiac resynchronization therapy (CRT) were excluded from most randomized, controlled trials. We sought to determine the long-term outcomes of upgrading from pacemakers to CRT with (CRT-D) or without (CRT-P) defibrillation in patients with no history of sustained ventricular arrhythmias.

Methods and Results: In this observational study, clinical events were quantified in relation to the type of implant (de novo or upgrade) and device type at upgrade (CRT-P or CRT-D). Patients underwent CRT implantation (n = 1,545; 1,314 [85%] de novo implants and 231 [15%] upgrades) over a median of 4.6 years [interquartile range: 2.4 - 7.0]). In analyses of crude event rates, upgrades had a higher total mortality (adjusted hazard ratio [aHR]: 1.33; 95% confidence interval [CI] 0.10-1.61), a higher total mortality or HF hospitalization (aHR: 1.26; 95% CI 1.05-1.51), but similar mortality or hospitalization for major adverse cardiac events (MACEs, aHR: 1.15; 95% CI 0.96-1.38). No group differences emerged in any of these endpoints after propensity score matching. After inverse probability weighting in upgrades, total mortality (HR: 0.55; 95% CI 0.36-0.73), total mortality or HF hospitalization (HR: 0.56; 95% CI 0.34-0.79) and total mortality or hospitalization for MACEs (HR: 0.61; 95% CI 0.40-0.82) were lower after CRT-D than after CRT-P.

Conclusion: Upgrading from pacemakers to CRT was associated with a similar long-term risk of mortality and morbidity to de novo CRT. After upgrade, CRT-D was CRT-D was associated with lower mortality than CRT-P
Original languageEnglish
Pages (from-to)290-298
JournalPacing and Clinical Electrophysiology
Issue number3
Early online date25 Jan 2018
Publication statusPublished - 8 Mar 2018

Bibliographical note

Copyright: 2018 The Authors. Pacing and Clinical Electrophysiology published by Wiley Periodicals, Inc. This is an open access article under the terms of the Creative Commons Attribution-NonCommercial License, which permits use, distribution and reproduction in any medium, provided the original work is properly cited and is not used for commercial purposes.

Funding: Boston Scientific


  • cardiac resynchronization therapy
  • pacemakers
  • implantable cardioverter defibrillators
  • device upgrade


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