Skip to main page content
U.S. flag

An official website of the United States government

Dot gov

The .gov means it’s official.
Federal government websites often end in .gov or .mil. Before sharing sensitive information, make sure you’re on a federal government site.

Https

The site is secure.
The https:// ensures that you are connecting to the official website and that any information you provide is encrypted and transmitted securely.

Access keys NCBI Homepage MyNCBI Homepage Main Content Main Navigation
. 2017 Jul 1;2(7):767-774.
doi: 10.1001/jamacardio.2017.1413.

Association of Implantable Cardioverter Defibrillators With Survival in Patients With and Without Improved Ejection Fraction: Secondary Analysis of the Sudden Cardiac Death in Heart Failure Trial

Selcuk Adabag  1 , Kristen K Patton  2 , Alfred E Buxton  3 , Thomas S Rector  4 , Kristine E Ensrud  5 , Kairav Vakil  1 , Wayne C Levy  2 , Jeanne E Poole  2
Affiliations

Association of Implantable Cardioverter Defibrillators With Survival in Patients With and Without Improved Ejection Fraction: Secondary Analysis of the Sudden Cardiac Death in Heart Failure Trial

Selcuk Adabag et al. JAMA Cardiol. .

Abstract

Importance: Improvement in left ventricular ejection fraction (EF) to >35% occurs in many patients with reduced EF at baseline. To our knowledge, whether implantable cardioverter defibrillator (ICD) therapy improves survival for these patients is unknown.

Objective: To examine the efficacy of ICD therapy in reducing risk of all-cause mortality and sudden cardiac death among patients with an EF ≤35% at baseline, with or without an improvement in EF to >35% during follow-up.

Design, setting, and participants: This retrospective analysis examined data collected in the Sudden Cardiac Death in Heart Failure Trial (SCD-HeFT), which randomly assigned 2521 patients to placebo, amiodarone, or ICD between 1997 and 2001. A subset of 1902 participants (75.4%) of the SCD-HeFT had a repeated assessment of EF a mean (SD) of 13.5 (6) months after randomization. We stratified these patients by EF ≤35% and >35% based on the first repeated EF measurement after randomization and compared all-cause mortality in 649 patients randomized to placebo vs 624 patients randomized to ICD. Follow-up started with the repeated EF assessment. Analysis was performed between January 2016 and July 2016.

Exposures: Implantable cardioverter-defibrillator therapy.

Main outcomes and measures: All-cause mortality and sudden cardiac death.

Results: Of the included 1273 patients, the mean (SD) age was 59 (12) years, and 977 (76.7%) were male and 1009 (79.3%) were white. Repeated EF was >35% in 186 participants (29.8%) randomized to ICD and 185 participants (28.5%) randomized to placebo. During a median follow-up of 30 months, the all-cause mortality rate was lower in the ICD vs placebo group, both in patients whose EF remained ≤35% (7.7 vs 10.7 per 100 person-year follow-up) and in those whose EF improved to >35% (2.6 vs 4.5 per 100 person-year follow-up). Compared with placebo, the adjusted hazard ratio for the effect of ICD on mortality was 0.64 (95% CI, 0.48-0.85) in patients with a repeated EF of ≤35% and 0.62 (95% CI, 0.29-1.30) in those with a repeated EF >35%. There was no interaction between treatment assignment and repeated EF for predicting mortality.

Conclusions and relevance: Among participants in the SCD-HeFT who had a repeated EF assessment during the course of follow-up, those who had an improvement in EF to >35% accrued a similar relative reduction in mortality with ICD therapy as those whose EF remained ≤35%. Prospective randomized clinical trials are needed to test ICD efficacy in patients with an EF >35%.

Trial registration: clinicaltrials.gov Identifier: NCT01114269.

PubMed Disclaimer

Conflict of interest statement

Conflict of Interest Disclosures: All authors have completed and submitted the ICMJE Form for Disclosure of Potential Conflicts of Interest. Dr Adabag has received research support from Medtronic and Boston Scientific. Dr Buxton has received research support from Medtronic and Biosense-Webster. Dr Vakil has received research support from Medtronic. Dr Ensrud serves on the Data Monitoring Committee of Merck, Sharpe, & Dohme. Dr Levy is a member of the Clinical Endpoint Committee of Novartis and CardioMems (St Jude Medical) and of the Steering Committee with GE Healthcare; has received research support from Thoratec (St Jude Medical), HeartWare (Medtronic), Novartis, Amgen, and ResMed; and has consulted for Biotronik. Dr Poole has received honoraria from Biotronik, Boston Scientific, Medtronic, and St Jude Medical; has served as a member of the advisory board with Boston Scientific, Physio Control, and BDX Diagnostics; has received fellowship educational support from Biotronik, Boston Scientific, Medtronic, and St Jude Medical; has received research support from Boston Scientific and Physio Control; and has equity with Cameron Health. No other disclosures were reported.

Figures

Figure 1.
Figure 1.. Incidence Rate of All-Cause Mortality of Patients Assigned to Implantable Cardioverter Defibrillator (ICD) vs Placebo
Adjusted hazard ratios of all-cause mortality in the ICD vs the placebo groups were 0.64 (95% CI, 0.48-0.85) in patients with a repeated ejection fraction (EF) ≤35% and 0.62 (95% CI, 0.29-1.30) in those with an EF >35%.
Figure 2.
Figure 2.. Kaplan-Meier Survival Curves of Patients With or Without an Increase in Ejection Fraction (EF) to Greater Than 35% Assigned to Implantable Cardioverter Defibrillator (ICD) or Placebo
See this image and copyright information in PMC

Comment in

References

    1. Bardy GH, Lee KL, Mark DB, et al. ; Sudden Cardiac Death in Heart Failure Trial (SCD-HeFT) Investigators . Amiodarone or an implantable cardioverter-defibrillator for congestive heart failure. N Engl J Med. 2005;352(3):225-237. - PubMed
    1. Moss AJ, Zareba W, Hall WJ, et al. ; Multicenter Automatic Defibrillator Implantation Trial II Investigators . Prophylactic implantation of a defibrillator in patients with myocardial infarction and reduced ejection fraction. N Engl J Med. 2002;346(12):877-883. - PubMed
    1. Myerburg RJ, Reddy V, Castellanos A. Indications for implantable cardioverter-defibrillators based on evidence and judgment. J Am Coll Cardiol. 2009;54(9):747-763. - PubMed
    1. Epstein AE, DiMarco JP, Ellenbogen KA, et al. ; American College of Cardiology Foundation; American Heart Association Task Force on Practice Guidelines; Heart Rhythm Society . 2012 ACCF/AHA/HRS focused update incorporated into the ACCF/AHA/HRS 2008 guidelines for device-based therapy of cardiac rhythm abnormalities: a report of the American College of Cardiology Foundation/American Heart Association Task Force on Practice Guidelines and the Heart Rhythm Society. J Am Coll Cardiol. 2013;61(3):e6-e75. - PubMed
    1. Punnoose LR, Givertz MM, Lewis EF, Pratibhu P, Stevenson LW, Desai AS. Heart failure with recovered ejection fraction: a distinct clinical entity. J Card Fail. 2011;17(7):527-532. - PubMed

Associated data