***TASK*** the task is to summarize an input biomedical literature in six sentences 
    ***INPUT*** the input is a biomedical literature 
    ***OUTPUT*** the output is the summary of an input biomedical literature in six sentences 
    ***DOCUMENTATION*** 
    ***EXAMPLES*** 
    Input: The implantable cardioverter defibrillator ( ICD ) is a costly new treatment for patients at high risk of sudden cardiac death . R and omized trials of the ICD showed it to be effective in some groups of patients but not in others . While new trials testing the ICD were ongoing to clarify the evidence , policymakers faced immediate decisions about providing insurance coverage for the device . The high cost of ICDs , the large population of patients potentially eligible to receive them , the potential to reduce preventable deaths , and the unsettled state of the medical evidence provided a challenge to evidence -based medicine and to policymakers BACKGROUND The implantable cardioverter-defibrillator ( ICD ) is highly effective in reducing mortality among patients at risk for fatal arrhythmias , but inappropriate ICD activations are frequent , with potential adverse effects . METHODS We r and omly assigned 1500 patients with a primary -prevention indication to receive an ICD with one of three programming configurations . The primary objective was to determine whether programmed high-rate therapy ( with a 2.5-second delay before the initiation of therapy at a heart rate of ≥200 beats per minute ) or delayed therapy ( with a 60-second delay at 170 to 199 beats per minute , a 12-second delay at 200 to 249 beats per minute , and a 2.5-second delay at ≥250 beats per minute ) was associated with a decrease in the number of patients with a first occurrence of inappropriate antitachycardia pacing or shocks , as compared with conventional programming ( with a 2.5-second delay at 170 to 199 beats per minute and a 1.0-second delay at ≥200 beats per minute ) . RESULTS During an average follow-up of 1.4 years , high-rate therapy and delayed ICD therapy , as compared with conventional device programming , were associated with reductions in a first occurrence of inappropriate therapy ( hazard ratio with high-rate therapy vs. conventional therapy , 0.21 ; 95 % confidence interval [ CI ] , 0.13 to 0.34 ; P<0.001 ; hazard ratio with delayed therapy vs. conventional therapy , 0.24 ; 95 % CI , 0.15 to 0.40 ; P<0.001 ) and reductions in all-cause mortality ( hazard ratio with high-rate therapy vs. conventional therapy , 0.45 ; 95 % CI , 0.24 to 0.85 ; P=0.01 ; hazard ratio with delayed therapy vs. conventional therapy , 0.56 ; 95 % CI , 0.30 to 1.02 ; P=0.06 ) . There were no significant differences in procedure-related adverse events among the three treatment groups . CONCLUSIONS Programming of ICD therapies for tachyarrhythmias of 200 beats per minute or higher or with a prolonged delay in therapy at 170 beats per minute or higher , as compared with conventional programming , was associated with reductions in inappropriate therapy and all-cause mortality during long-term follow-up . ( Funded by Boston Scientific ; MADIT-RIT Clinical Trials.gov number , NCT00947310 . ) BACKGROUND Living with an implanted cardioverter-defibrillator  increases survival , but the effects of the device on health status , quality of life , and psychological state over time are not clear . OBJECTIVES To investigate changes in health status , quality of life , and psychological state associated with implantation of a cardioverter-defibrillator from implantation to 4 years later . METHODS A prospect i ve , longitudinal design was used to measure changes in scores on the Short Form 36 of the Medical Outcomes Study , the Quality of Life Index-Cardiac III , and the Profile of Moods States short form at implantation , 6 months , and 1 , 2 , 3 , and 4 years later . RESULTS A total of 30 men and 11 women ( mean age , 60.4 years ) completed all 4 years of follow-up . The physical and mental health composite summary scores of the Short Form 36 changed significantly over time ; the mental health score improved ( F = 2.95 ; P = .03 ) , and the physical score worsened ( F = 3.69 ; P = .003 ) . Scores on the Quality of Life Index-Cardiac III did not change significantly . Negative moods were significantly fewer , and the total psychological distress score was significantly lower ( F = 10.21 ; P < .001 ) during the 4 years of follow-up . CONCLUSIONS Patients had improved mental health and reduced psychological distress by 6 months after implantation . Perception of physical health declined during the 4 years after implantation ; the role physical subscore of the Short Form 36 indicated significant improvement in functioning at 6 months and a trend toward reduced functioning at 3 and 4 years after implantation BACKGROUND  Implantable cardioverter defibrillator recipients sometimes report " phantom shocks " ( PSs ) , defined as a reported shock lacking objective evidence . The aim of this study was to describe the subjective experience of PSs and their psychosocial correlates using a mixed methods approach . METHODS PS participants were matched on sex and age with individuals who received objective shocks only ( OSO ) .  Participants were interviewed and completed measures of posttraumatic stress disorder ( PTSD Checklist-Civilian Version ) , depression and anxiety ( Hospital Anxiety and Depression Scale ) , disease-specific distress ( Cardiac Anxiety Question naire-CAQ ) , and social desirability ( Socially Desirable Response Set-SDRS ) . Interviews were analyzed using interpretative phenomenological analysis ( IPA ) . RESULTS Seventeen male patients participated ( PS : n = 9 ; OSO : n = 8) . Three themes emerged from IPA : ( 1 ) PS as a somatic experience , ( 2 ) the emotional impact of PSs , and ( 3 ) search ing for meaning . Quantitative analyses showed that both groups exhibited elevated trauma and anxiety levels . Effect size differences ( ESD ) suggested a medium ESD on depression ( P = 0.176 , ηp ( 2 ) = 0.118 ) and PTSD ( avoidance : P = 0.383 , ηp ( 2 ) = 0.055 , numbing : P = 0.311 , ηp ( 2 ) = 0.068 ) , and a large ESD on SDRS ( P = 0.081 , ηp ( 2 ) = 0.189 ) , where PS participants , comparatively , exhibited elevated levels . A medium ESD was detected on CAQ-fear ( P = 0.237 , ηp ( 2 ) = 0.092 ) where OSO participants exhibited greater heart-focused worry . CONCLUSION The qualitative and quantitative findings of this mixed method study show convergence in terms of the emotional factors associated with the experience of PSs . PSs are often reported to be indistinguishable from objective shocks , evoking alarm , frustration , and confusion , forcing the individual to face the uncertainties of what to them is a novel and confusing experience 
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Conclusion This review provides insight into the perspectives and experiences of ICD recipients .