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Unique Features

Implantable Cardiac Devices

Importance of Shock Reduction

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Clinical Need

Clinical Need

Data from published studies reveal that up to 21% of ICD patients receive inappropriate shocks.1-4

Incidence of inappropriate shocks
 - Incidence of inappropriate shocks in ICD patients

Reducing shocks has been shown to improve ICD patients’ quality of life and increased ICD acceptance.

  • For patients, simply the fear of shocks can be disruptive to a normal, active life5,6
  • The Canadian ICD Study (CIDS) found that patients randomized to ICD therapy (versus those given amiodarone) had better quality of life until they received five shocks7
  • Some studies have demonstrated that experiencing just one shock causes temporary reductions in patients’ quality of life7

Avoiding shocks is important for:

  • Reducing pain and anxiety, and increasing patients’ acceptance of ICDs8,9
  • Reducing healthcare burden and improving patient quality of life8
  • Improving survival/heart failure10



Kadish A, Dyer A, Daubert JP, et al., for the Defibrillators in Non-Ischemic Cardiomyopathy Treatment Evaluation (DEFINITE) Investigators. Prophylactic defibrillator implantation in patients with nonischemic dilated cardiomyopathy. N Engl J Med. 2004;350:2151-2158.


Daubert JP, Zareba W, Cannom DS, et al., for the MADIT II Investigators. Inappropriate implantable cardioverter-defibrillator shocks in MADIT-II: frequency, mechanisms, predictors, and survival impact. J Am Coll Cardiol. 2008;5:1357-1365.


Poole JE, Johnson GW, Hellkamp AS, et al. Prognostic importance of defibrillator shocks in patients with heart failure. N Engl J Med. September 4, 2008;359:1009-1017.


Mitka M. New study supports lifesaving benefits of implantable defibrillation devices. JAMA. 2009;302:134-135.


Sears SF JR, Todaro JF, Lewis TS, et al. Examining the psychosocial impact of implantable cardioverter defibrillators: a literature review. Clin Cardiol. 1999;22:481-489.


Sears SF Jr, Conti JB. Understanding implantable cardioverter defibrillator shocks and storms: medical and psychosocial considerations for research and clinical care. Clin Cardiol. 2003;26:107-111.


Irvine J, Dorian P, Baker B, et al. Quality of life in the Canadian Implantable Defibrillator Study (CIDS). Am Heart J. 2002;144:282-289.


Wathen MS, DeGroot PJ, Sweeney MO, et al, for the PainFREE RX II Investigators. Prospective randomized multicenter trial of empirical antitachycardia pacing versus shocks for spontaneous rapid ventricular tachycardia in patients with implantable cardioverter-defibrillators. Circulation. 2004;110:2591-2596.


Ahmad M, Bloomstein L, Roelke M, et al. Patients’ attitudes toward implantable defibrillator shocks. PACE. 2000;23:934-938.


Sweeney MO, Sherfesee L, DeGroot PJ, et al. Differences in effects of electrical therapy type for ventricular arrhythmias on mortality in implantable cardioverter-defibrillator patients. Heart Rhythm. 2010;7:353-360.

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