***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: AIMS This multicentre prospect i ve r and omised trial was undertaken to evaluate the usefulness of an electrophysiological study (EPS)-guided/implantable cardioverter defibrillator ( ICD ) strategy in patients at high risk of sudden death ( SD ) early after myocardial infa rct ion ( MI ) . Previous studies have shown the benefits of such a strategy only in high-risk patients late after MI . METHODS AND RESULTS We enrolled 143 survivors of acute MI ( < 1 month ) with left ventricular ejection fraction < or = 35 % and either frequent ( > or = 10/h ) premature ventricular complexes ( PVCs ) , or depressed heart rate variability ( SDNN < 70 ms ) or abnormal signal-averaged ECG , who were able to tolerate optimised beta-blocker therapy ( 68 + /- 40 mg/day of metoprolol ) . Of these , 138 were r and omised , in a 2:3 ratio , to two therapeutic strategies : conventional ( CONV ) strategy ( n = 59 ) or EPS-guided/ICD strategy ( n = 79 ) . The latter result ed in ICD implantation in 24 inducible patients and in CONV therapy in the remaining 55 . During a mean follow-up of 540 + /- 378 days , 26 patients ( 19 % ) died : nine ( 6.5 % ) SD , nine ( 6.5 % ) non-SD , and four ( 3 % ) non-cardiac death ; in four patients ( 3 % ) the cause of death was unknown . The actuarial overall mortality for the CONV and EPS-guided/ICD arms was 18 % vs 14 % after 1 year and 29.5 % vs 20 % after 2 years , respectively ( P = 0.3 and 0.2 ) . CONCLUSIONS Despite optimal therapy , mortality remains significant in high-risk patients following MI . Although there is a trend in favour of EPS-guided/ICD , our data are insufficient to demonstrate a survival benefit of this strategy early after MI STUDY OBJECTIVES Pocket hematoma is a common complication after pacemaker or implantable cardioverter defibrillator ( ICD ) implantation . Thus , we investigated the influence of patient comorbidity , implantation strategy , operator experience , antiplatelet therapy , and anticoagulation therapy on hematoma rate . DESIGN Between 1990 and 2002 , a total of 3,164 devices ( pectoral pacemakers , 2,792 ; ICDs , 372 ) were implanted at our institution . Predictors of hematoma occurrence were determined prospect ively and were analyzed by multivariate regression analysis . Operator experience was grade d by individual implantation number , as follows : low , < 50 ; medium , 50 to 100 ; and high , > 100 . RESULTS The incidence of pocket hematoma was 4.9 % , leading to prolonged hospitalization in 2.0 % of all patients . Reoperation for pocket hematoma was required in 1.0 % of patients . High-dose heparinization ( hazard ratio [ HR ] , 4.2 ) , combined acetylsalicylic acid (ASA)/thienopyridine treatment after coronary stenting ( HR , 5.2 ) , and low operator experience ( HR , 1.6 ) were independently predictive of hematoma development . Therapy with ASA alone did not increase the hematoma rate compared to patients who did receive antiplatelet or anticoagulation therapy ( 3.1 % vs 2.5 % , respectively ; difference not significant ) . In patients with nonvalvular atrial fibrillation , postoperative high-dose heparinization substantially increased the hematoma rate ( 10.7 % vs 2.9 % , respectively ; p < 0.001 ) without reducing the rate of arterial embolism within the first month after implantation ( 0.18 % vs 0.21 % , respectively ; difference not significant ) . The infection rate ( 0.28 % within 3 months after implantation ) was not influenced by the presence of the pocket hematoma . CONCLUSIONS The use of high-dose heparinization and combined ASA/thienopyridine treatment are highly predictive for the occurrence of intraoperative bleeding and pocket hematoma in patients who have undergone pacemaker and ICD surgery . We propose recommendations for the management of antiplatelet and anticoagulation therapy in patients undergoing these interventions AIMS Electrical storm ( ES ) is a life-threatening arrhythmia complication affecting patients treated with an implantable cardioverter defibrillator ( ICD ) .  Despite its increasing importance , existing data on prognosis and management of ICD patients affected by ES are limited and conflicting . METHODS We prospect ively studied 169 consecutive patients receiving an ICD . Thirty-two patients presented with at least one episode of ES during the period of observation ( 33+/-26 months ) . ES patients were older ( 64+/-9 vs. 59+/-13 years , P=0.013 ) with more advanced congestive heart failure ( CHF ) but a similar incidence of an underlying organic heart disease . RESULTS Long-term total and cardiac mortality were both increased among ES patients . Seventeen of the 32 ES patients died as opposed to 19 of the 137 ICD patients without ES ( 53 vs. 14 % , P<0.001 ) . In multivariate Cox regression analysis adjusted for the main confounders , history of ES was significantly and independently associated with total and cardiac mortality ( risk ratio (RR)=2.13 , P=0.031 and RR=2.59 , P=0.019 , respectively ) . CONCLUSION ES is a relatively frequent complication affecting ICD patients treated for secondary prevention of sudden cardiac death ( SCD ) . Although the acute management of this serious arrhythmia complication is usually successful , occurrence of ES is a strong independent predictor of poor outcome in ICD patients BACKGROUND Implantable cardioverter-defibrillators ( ICDs ) have been shown in primary prevention efficacy trials to reduce mortality in patients with ischemic heart disease and left ventricular dysfunction . To investigate the generalizabilty of this mortality reduction , we examined the effectiveness of ICDs in clinical practice . METHODS We developed a prospect i ve multicenter cohort of 770 patients with ischemic left ventricular dysfunction ( ejection fraction < or = 35 % ) and without a history of ventricular arrhythmia , of whom 395 ( 52 % ) received ICDs .  Mean + /- SD follow-up was 27 + /- 12 months . We assessed the degree to which ICDs decreased mortality risk using Cox proportional hazards analyses that controlled for clinical predictors of death , receipt of ICD ( a propensity score analysis ) , and predictors of arrhythmic death ( including electrophysiologic variables ) . RESULTS Multivariate Cox analyses showed that those with ICDs had significantly lower all-cause mortality ( hazard ratio [ HR ] , 0.53 ; 95 % confidence interval [ CI ] , 0.33 - 0.86 ) . This mortality reduction was mediated through dramatically lower arrhythmia-related mortality ( HR , 0.35 ; 95 % CI , 0.17 - 0.73 ) , with no significant effect on cardiovascular nonarrhythmic ( HR , 0.81 ; 95 % CI , 0.34 - 1.96 ) and noncardiovascular ( HR , 0.76 ; 95 % CI , 0.29 - 2.05 ) mortality . No differences were found between the ICD and non-ICD groups for a composite outcome of all-cause mortality , appropriate ICD shocks , or documented symptomatic ventricular arrhythmia , which suggests that the 2 groups had similar baseline risk for life-threatening arrhythmic events ( HR , 0.96 ; 95 % CI , 0.63 - 1.45 ) . CONCLUSION In clinical practice , ICDs appear to reduce all-cause and arrhythmic rates of mortality at levels similar to those found in primary prevention trials Monitoring of atrial rhythm in patients implanted with ICDs  may improve accuracy in identifying supraventricular arrhythmias and , therefore , prevent inappropriate therapies . Since difficulties were found in dual chamber ICDs with separate leads , a new design ed single lead dual chamber ICD system was tested . Twenty-five patients implanted with a Deikos A+ ( single coil defibrillation lead with two atrial sensing rings combined with a dual chamber ICD with a high amplifying atrial channel ) were tested . Atrial and ventricular signals were analyzed during sinus rhythm ( SR ) and sinus tachycardias ( STs ) , atrial flutter and AF , and VT or VF . Follow-ups were performed after 1 , 3 , 6 , 9 , and 12 months after implantation . Analysis of EGM amplitudes of stored episodes revealed that atrial signals during atrial flutter ( 2.1 + /- 0.51 mV ) were comparable to those of ST ( 2.2 + /- 0.5 mV ) . Atrial amplitudes during AF were significantly lower ( 0.81 + /- 0.5 mV , P<0.01 ) . During VF atrial " sinus " signals ( 2 + /- 0.8 mV ) were stable . Ventricular parameters did not differ from a st and ard ICD lead ; defibrillation threshold was 11.4 + /- 4.5 J ( 16 patients ) . During intraoperative and prehospital discharge measurements , 97.1 % of SR-P waves and 99.2 % of atrial flutter waves were detected correctly . In AF 91.11 % of atrial signals were detected . Analysis of 505 stored episodes showed that 96.8 % of ST and 100 % of atrial flutter and 100 % of AF episodes have been classified correctly and no underdetection of VT/VF was found . The first experiences with the new VDD-ICD system show an increase of the specificity to detect ventricular tachycardias to a level comparable to dual chamber ICDs with two leads . The reliability of this system has to be proven in a prospect i ve r and omized study OBJECTIVES The purpose of this multicenter r and omized trial was to compare total mortality during therapy with amiodarone or an implantable cardioverter-defibrillator ( ICD ) in patients with nonischemic dilated cardiomyopathy ( NIDCM ) and nonsustained ventricular tachycardia ( NSVT ) . BACKGROUND Whether an ICD reduces mortality more than amiodarone in patients with NIDCM and NSVT is unknown . METHODS One hundred three patients with NIDCM , left ventricular ejection fraction < or = 0.35 , and asymptomatic NSVT were r and omized to receive either amiodarone or an ICD . The primary end point was total mortality . Secondary end points included arrhythmia-free survival , quality of life , and costs . RESULTS The study was stopped when the prospect i ve stopping rule for futility was reached . The percent of patients surviving at one year ( 90 % vs. 96 % ) and three years ( 88 % vs. 87 % ) in the amiodarone and ICD groups , respectively , were not statistically different ( p = 0.8 ) . Quality of life was also similar with each therapy ( p = NS ) . There was a trend with amiodarone , as compared to the ICD , towards improved arrhythmia-free survival ( p = 0.1 ) and lower costs during the first year of therapy ( $ 8,879 US dollars vs. $ 22,039 US dollars , p = 0.1 ) . CONCLUSIONS Mortality and quality of life in patients with NIDCM and NSVT treated with amiodarone or an ICD are not statistically different . There is a trend towards a more beneficial cost profile and improved arrhythmia-free survival with amiodarone therapy Background — Delivery of inappropriate shocks caused by misdetection of supraventricular tachycardia ( SVT ) remains a substantial complication of implanted cardioverter/defibrillator ( ICD ) therapy . Whether use of optimally programmed dual-chamber ICDs lowers this risk compared with that in single-chamber ICDs is not clear . Methods and Results — Subjects with a clinical indication for ICD ( n=400 ) at 27 participating centers received dual-chamber ICDs and were r and omly assigned to strictly defined optimal single- or dual-chamber detection in a single-blind manner . Programming minimized ventricular pacing . The primary end point was the proportion of SVT episodes inappropriately detected from the time of programming until crossover or end of study . On a per-episode basis , 42 % of the episodes in the single-chamber arm and 69 % of the episodes in the dual-chamber arm were due to SVT . Mortality ( 3.5 % in both groups ) and early study withdrawal ( 14 % single-chamber , 11 % dual-chamber ) were similar in both groups . The rate of inappropriate detection of SVT was 39.5 % in the single-chamber detection arm compared with 30.9 % in the dual-chamber arm . The odds of inappropriate detection were decreased by almost half with the use of the dual-chamber detection enhancements ( odds ratio , 0.53 ; 95 % confidence interval , 0.30 to 0.94 ; P=0.03 ) . Conclusions — Dual-chamber ICDs , programmed to optimize detection enhancements and to minim 
    Output:
    
In a series of univariate meta-regression sensitivity analyses , none of the covariates we examined ( duration of follow-up , primary vs. secondary prevention , ischemic cause , presence of cardiac resynchronization therapy , NYHA class , mean age , mean LVEF , or mean QRS duration ) contributed to the moderate statistical heterogeneity observed in our meta- analysis of all-cause mortality .