***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 
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    ***EXAMPLES*** 
    Input: Background —The benefit of novel implantable cardioverter defibrillator ( ICD ) programming in reducing inappropriate ICD therapy and mortality was demonstrated in Multicenter Automatic Defibrillator Implantation Trial-Reduce Inappropriate Therapy ( MADIT-RIT ) . However , the cause of mortality reduction remains incompletely evaluated . We aim ed to identify factors associated with mortality , with focus on ICD therapy and programming in the MADIT-RIT population . Methods and Results —In MADIT-RIT , 1500 patients with a primary prophylactic indication for ICD or cardiac resynchronization therapy with defibrillator were r and omized to 1 of 3 different ICD programming arms : conventional programming ( ventricular tachycardia zone ≥170 beats per minute ) , high-rate programming ( ventricular tachycardia zone ≥200 beats per minute ) , and delayed programming ( 60-second delay before therapy ≥170 beats per minute ) . Multivariate Cox models were used to assess the influence of time-dependent appropriate and inappropriate ICD therapy ( shock and antitachycardia pacing ) and r and omized programming arm on all-cause mortality . During an average follow-up of 1.4±0.6 years , 71 of 1500 ( 5 % ) patients died : cardiac in 40 patients ( 56.3 % ) , noncardiac in 23 patients ( 32.4 % ) , and unknown in 8 patients ( 11.3 % ) . Appropriate shocks ( hazard ratio , 6.32 ; 95 % confidence interval , 3.13–12.75 ; P<0.001 ) and inappropriate therapy ( hazard ratio , 2.61 ; 95 % confidence interval , 1.28–5.31 ; P=0.01 ) were significantly associated with an increased mortality risk . There was no evidence of increased mortality risk in patients who experienced appropriate antitachycardia pacing only ( hazard ratio , 1.02 ; 95 % confidence interval , 0.36–2.88 ; P=0.98 ) . R and omization to conventional programming was identified as an independent predictor of death when compared with patients r and omized to high-rate programming ( hazard ratio , 2.0 ; 95 % confidence interval , 1.06–3.71 ; P=0.03 ) . Conclusions —In MADIT-RIT , appropriate shocks , inappropriate ICD therapy , and r and omization to conventional ICD programming were independently associated with an increased mortality risk . Appropriate antitachycardia pacing was not related to an adverse outcome . Clinical Trial Registration —URL : clinical trials.gov Unique identifier : NCT00947310 Background —Left ventricular ejection fraction ( LVEF ) predicts device discharges in patients with implantable cardioverter-defibrillators ( ICDs ) .  The relationship between severity of congestive heart failure ( CHF ) and ICD discharges is less clear . Methods and Results —We prospect ively analyzed the association between CHF and risk of appropriate ICD discharges  in the Triggers Of Ventricular Arrhythmias ( TOVA ) study , a cohort study of ICD patients conducted at 31 centers in the United States . Reported shocks were confirmed for sustained ventricular tachycardia ( VT ) or fibrillation ( VF ) by analysis of stored electrograms . Proportional hazards models included CHF categorized by New York Heart Association class . Baseline CHF was present among 502 ( 44 % ) of 1140 patients ; 170 ( 34 % ) had class I , 230 ( 46 % ) had class II , 97 ( 19 % ) had class III , and only 5 ( 1 % ) had class IV symptoms . During median follow-up of 212 days , 92 patients experienced 1 or more appropriate ICD discharges . Class III CHF was associated in a statistically significantly manner with ICD discharge for VT/VF ( hazard ratio 2.40 , 95 % CI 1.16 to 4.98 ) , even with adjustment for LVEF . The combination of LVEF < 0.20 and class III symptoms result ed in a particularly high risk of shocks for VT/VF ( hazard ratio 3.90 , 95 % CI 1.28 to 11.92 ) . Conclusions —Class III CHF , an easily accessible clinical measure , is an independent risk factor , along with LVEF , for ventricular arrhythmias that require shock therapy among ICD patients . Whether patients with class III CHF benefit to a greater degree from ICDs and whether aggressive treatment of CHF in ICD patients may prevent ventricular arrhythmias remains to be determined Background —Implantable cardioverter defibrillator ( ICD ) use reduces mortality in patients with serious ventricular arrhythmias compared with antiarrhythmic drug ( AAD ) use . However , the relative impact of these therapies on self-perceived quality of life ( QoL ) is unknown . Methods and Results —Three self-administered instruments were used to measure generic and disease-specific QoL in  Antiarrhythmics  Versus  Implantable Defibrillators  trial participants . Generalized linear models were used to assess the relationships between self-perceived QoL and treatment ( AAD versus ICD ) and adverse symptoms and ICD shocks . To minimize the impact of missing data , only patients surviving 1 year were included in the primary analyses . Baseline characteristics among QoL participants ( n=905 ) and non participants ( n=111 ) were similar , but participants who survived 1 year ( n=800 ) were healthier at baseline than nonsurvivors ( n=105 ) . Of the 800 patients in the primary analysis , characteristics of those r and omized to AAD ( n=384 ) versus ICD ( n=416 ) were similar . Overall , ICD and AAD use were associated with similar alterations in QoL. The development of sporadic shocks and adverse symptoms were each associated with reduced physical functioning and mental well-being and increased concerns among ICD recipients , whereas development of adverse symptoms was associated with reduced physical functioning and increased concerns among AAD recipients . Conclusions —ICD and AAD therapy are associated with similar alterations in self-perceived QoL over 1-year follow-up . Adverse symptoms were associated with reduced self-perceived QoL in both groups , and sporadic shocks were associated with reduced QoL in ICD recipients INTRODUCTION Depression predicts mortality in patients with coronary artery disease and heart failure . However , its effect on patient outcome in the presence of an implantable cardioverter defibrillator ( ICD ) has not been investigated . METHODS A total of 236 ICD patients ( 76 females , 58.6 ± 14.0 years ) were screened for depressive symptoms  using the Hospital Anxiety and Depression Scale ( HADS ) . The outcome measure was all-cause mortality and the prognostic effect of depression was evaluated with Cox proportional hazards regression analysis . RESULTS Fifty ( 21 % ) patients reported depressive symptoms ( HADS score ≥ 8) . Renal failure ( odds ratio [OR]= 4.0 , 95 % confidence intervals [CI]= 1.47 - 10.87 , P = 0.007 ) , prior angina ( OR = 2.1 , 95 % CI = 1.07 - 4.12 , P = 0.03 ) , but not the experience of ICD shocks were associated with baseline depressive symptoms . In a mean follow-up period of 6.1 ± 2.5 years , 74 patients ( 31 % ) died . Mortality significantly increased from 45.1 deaths per 1,000 person-years among patients without depression to 80.3 deaths per 1,000 person-years in patients with depressive symptoms ( P = 0.039 ) . In the univariate model , depression ( HADS score ≥8 ) was a significant predictor of mortality ( OR = 1.81 , 95 % CI = 1.1 - 3.0 , P = 0.02 ) . However , in the multivariate model , depression lost its prognostic significance . CONCLUSIONS In our prospect i ve patient cohort , one-fifth of ICD recipients  reported depressive symptoms . Depression increased the absolute mortality risk but was not an independent predictor of mortality 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 Patients with reduced left ventricular function after myocardial infa rct ion are at risk for life-threatening ventricular arrhythmias . This r and omized trial was design ed to evaluate the effect of an implantable defibrillator on survival in such patients . METHODS Over the course of four years , we enrolled 1232 patients with a prior myocardial infa rct ion and a left ventricular ejection fraction of 0.30 or less . Patients were r and omly assigned in a 3:2 ratio to receive an implantable defibrillator ( 742 patients ) or conventional medical therapy ( 490 patients ) . Invasive electrophysiological testing for risk stratification was not required . Death from any cause was the end point . RESULTS The clinical characteristics at base line and the prevalence of medication use at the time of the last follow-up visit were similar in the two treatment groups . During an average follow-up of 20 months , the mortality rates were 19.8 percent in the conventional-therapy group and 14.2 percent in the defibrillator group . The hazard ratio for the risk of death from any cause in the defibrillator group as compared with the conventional-therapy group was 0.69 ( 95 percent confidence interval , 0.51 to 0.93 ; P=0.016 ) . The effect of defibrillator therapy on survival was similar in subgroup analyses stratified according to age , sex , ejection fraction , New York Heart Association class , and the QRS interval . CONCLUSIONS In patients with a prior myocardial infa rct ion and advanced left ventricular dysfunction , prophylactic implantation of a defibrillator improves survival and should be considered as a recommended therapy BACKGROUND Patients with heart failure who receive an implantable cardioverter-defibrillator ( ICD ) for primary prevention ( i.e. , prevention of a first life-threatening arrhythmic event ) may later receive therapeutic shocks from the ICD . Information about long-term prognosis after ICD therapy in such patients is limited . METHODS Of 829 patients with heart failure who were r and omly assigned to ICD therapy , we implanted the ICD in  811 . ICD shocks that followed the onset of ventricular tachycardia or ventricular fibrillation were considered to be appropriate . All other ICD shocks were considered to be inappropriate . RESULTS Over a median follow-up period of 45.5 months , 269 patients ( 33.2 % ) received at least one ICD shock , with 12 
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Subgroup analysis in heart failure patients also did not find any difference in mortality between inappropriate-shock and no-therapy patients .
No increased risk of mortality was found in the patients who experienced appropriate or inappropriate ATP only .
Appropriate shocks were associated with an increased  mortality in ICD patients .