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
. 2013 May 10;8(5):e63911.
doi: 10.1371/journal.pone.0063911. Print 2013.

Impact of shocks on mortality in patients with ischemic or dilated cardiomyopathy and defibrillators implanted for primary prevention

Florian Streitner  1 , Thomas Herrmann, Juergen Kuschyk, Siegfried Lang, Christina Doesch, Theano Papavassiliu, Ines Streitner, Christian Veltmann, Dariusch Haghi, Martin Borggrefe
Affiliations

Impact of shocks on mortality in patients with ischemic or dilated cardiomyopathy and defibrillators implanted for primary prevention

Florian Streitner et al. PLoS One. .

Abstract

Background: Emerging interest is seen in the paradox of defibrillator shocks for ventricular tachyarrhythmia and increased mortality risk. Particularly in patients with dilated cardiomyopathy (DCM), the prognostic importance of shocks is unclear. The purpose of this study was to compare the outcome after shocks in patients with ischemic cardiomyopathy (ICM) or DCM and defibrillators (ICD) implanted for primary prevention.

Methods and results: Data of 561 patients were analyzed (mean age 68.6±10.6 years, mean left ventricular ejection fraction 28.6±7.3%). During a median follow-up of 49.3 months, occurrence of device therapies and all-cause mortality were recorded. 74 out of 561 patients (13.2%) experienced ≥1 appropriate and 51 out of 561 patients (9.1%) ≥1 inappropriate shock. All-cause mortality was 24.2% (136 out of 561 subjects). Appropriate shock was associated with a trend to higher mortality in the overall patient population (HR 1.48, 95% CI 0.96-2.28, log rank p = 0.072). The effect was significant in ICM patients (HR 1.61, 95% CI 1.00-2.59, log rank p = 0.049) but not in DCM patients (HR 1.03, 95% CI 0.36-2.96, log rank p = 0.96). Appropriate shocks occurring before the median follow-up revealed a much stronger impact on mortality (HR for the overall patient population 2.12, 95% CI 1.24-3.63, p = 0.005). The effect was driven by ICM patients (HR 2.48, 95% CI 1.41-4.37, p = 0.001), as appropriate shocks again did not influence survival of DCM patients (HR 0.63, 95% CI 0.083-4.75, p = 0.65). Appropriate shocks occurring after the median follow-up and inappropriate shocks occurring at any time revealed no impact on survival in any of the groups (p = ns).

Conclusion: Appropriate shocks are associated with reduced survival in patients with ICM but not in patients with DCM and ICDs implanted for primary prevention. Furthermore, the negative effect of appropriate shocks on survival in ICM patients is only evident within the first 4 years after device implantation.

PubMed Disclaimer

Conflict of interest statement

Competing Interests: The authors have declared that no competing interests exist.

Figures

Figure 1
Figure 1. Comparison of VTA episodes and appropriate shocks in patients with DCM and ICM.
app. shock  =  appropriate shock; DCM  =  dilated cardiomyopathy; ES  =  electrical storm; ICM  =  ischemic cardiomyopathy; VF  =  ventricular fibrillation; VT  =  ventricular tachycardia; VTA  =  ventricular tachyarrhythmia.
Figure 2
Figure 2. A-C. Kaplan Meier survival estimation after appropriate shocks (complete follow-up).
A significant association between appropriate shocks and survival is only determined in patients with ICM.
Figure 3
Figure 3. A-B. Kaplan Meier survival estimation after occurrence of appropriate shocks before median follow-up.
Kaplan Meier Curves displaying that the significant effect of appropriate shocks on survival in the overall patient population is primarily driven by the ICM subgroup.
See this image and copyright information in PMC

References

    1. Connolly SJ, Hallstrom AP, Cappato R, Schron EB, Kuck KH, et al. (2000) Meta-analysis of the implantable cardioverter defibrillator secondary prevention trials. AVID, CASH and CIDS studies. Antiarrhythmics vs Implantable Defibrillator study. Cardiac Arrest Study Hamburg. Canadian Implantable Defibrillator Study. Eur Heart J 21: 2071–2078. - PubMed
    1. Moss AJ, Zareba W, Hall WJ, Klein H, Wilber DJ, et al. (2002) Prophylactic implantation of a defibrillator in patients with myocardial infarction and reduced ejection fraction. N Engl J Med 346: 877–883. - PubMed
    1. Bardy GH, Lee KL, Mark DB, Poole JE, Packer DL, et al. (2005) Amiodarone or an implantable cardioverter-defibrillator for congestive heart failure. N Engl J Med 352: 225–237. - PubMed
    1. Sweeney MO (2010) The contradiction of appropriate shocks in primary prevention ICDs: increasing and decreasing the risk of death. Circulation 122: 2638–2641. - PubMed
    1. Moss AJ, Greenberg H, Case RB, Zareba W, Hall WJ, et al. (2004) Long-term clinical course of patients after termination of ventricular tachyarrhythmia by an implanted defibrillator. Circulation 110: 3760–3765. - PubMed

MeSH terms

LinkOut - more resources