Competing risk analysis of cause-specific mortality in patients with an implantable cardioverter-defibrillator: The EVADEF cohort study. Impact of atrial fibrillation on early complications and one year-survival after cardioverter defibrillator implantation: results from the German DEVICE registry. Sinus rhythm restoration by catheter ablation in patients with long-lasting atrial fibrillation and congestive heart failure: impact of the left ventricular ejection fraction improvement on the implantable cardioverter defibrillator insertion indication. Comparison between atrial fibrillation-triggered implantable cardioverter-defibrillator (ICD) shocks and inappropriate shocks caused by lead failure: different impact on prognosis in clinical practice. Predictors of early mortality in implantable cardioverter-defibrillator recipients Association Between Use of Primary Prevention Implantable Cardioverter-Defibrillators and Mortality in Patients with Heart Failure: A Prospective Propensity-Score Matched Analysis from the Swedish Heart Failure Registry. Exercise training and implantable cardioverter-defibrillator shocks in patients with heart failure: results from HF-ACTION (Heart Failure and A Controlled Trial Investigating Outcomes of Exercise TraiNing). Catheter ablation versus standard conventional treatment in patients with left ventricular dysfunction and atrial fibrillation (CASTLE-AF) - study design. Prognostic importance of atrial fibrillation in implantable cardioverter-defibrillator patients. Implantable cardioverter defibrillators and quality of life: results from the defibrillators in nonischemic cardiomyopathy treatment evaluation study. Impact of sleep-disordered breathing on life-threatening ventricular arrhythmia in heart failure patients with implantable cardioverter-defibrillator. Impact of Age and Medical Comorbidity on the Effectiveness of Implantable Cardioverter-Defibrillators for Primary Prevention Predictors of Implantable Cardioverter Defibrillator Shocks During the First Year Changes in Follow-Up Left Ventricular Ejection Fraction Associated With Outcomes in Primary Prevention Implantable Cardioverter-Defibrillator and Cardiac Resynchronization Therapy Device Recipients. Clinical Outcomes of Single- versus Dual-Chamber Implantable Cardioverter Defibrillators: Lessons from the Israeli ICD Registry.
BACKGROUND Although implantable cardioverter-defibrillator ( ICD ) therapy has been evaluated in r and omized controlled trials , enrolling highly selected patients , mortality events in ICD patients have received little attention in routine medical care . We sought to assess the 24-month total and cause-specific mortality rates and their predictors in " real life " patients with an ICD . METHODS The Evaluation Médico-Economique du Défibrillateur Automatique Implantable study was a French multicenter , prospect i ve , observational cohort study of ICD patients with a 2-year follow-up . Cause-specific mortality rates and predictors at implantation of  sudden cardiac death ( SCD ) or progressive heart failure ( HF ) death were assessed using competing risk methodology . RESULTS From June 2001 to June 2003 , 2,296 unselected patients were implanted and followed until June 2005 . During a mean follow-up of 20.5 + /- 6.7 months , 274 deaths occurred : 29 ( 10.6 % ) were SCD and 146 ( 53.3 % ) were HF deaths , corresponding to 24-month cause-specific mortality rates of 1.4 % ( 95 % confidence interval 0.9%-1.9 % ) and 6.9 % ( 95 % confidence interval 5.8%-8.0 % ) , respectively . Among the characteristics at implantation , ejection fraction ( EF ) < 30 % and history of atrial fibrillation were independently associated with SCD ; age , high New York Heart Association class , systemic hypertension , prior atrial fibrillation , QRS duration , EF < 30 % , and lack of beta-blocker therapy were independently associated with HF death . CONCLUSIONS In this large cohort of " daily " patients , the 2-year incidence of SCD ( 1.4 % ) was comparable with the event rate observed in r and omized controlled trials ; HF remained the predominant mode of death . An EF < 30 % at implantation appears to be the most important predictor of ICD-unresponsive SCD AIMS AND OBJECTIVE Outcome data of patients with implantable cardioverter defibrillators ( ICD ) and atrial fibrillation ( AF ) are conflicting . The German DEVICE registry aims to add further information on this particular cohort . METHODS AND RESULTS The German DEVICE registry is a nationwide prospect i ve multicenter data base of ICD implantations . 3261 patients are included ( 81 % males , 2701 ( 82.8 % ) first ICD implantations , 560 ( 17.2 % ) ICD replacements ) .  Cardiac resynchronization therapy ( CRT-D ) was performed in 882 patients ( 27.0 % ) . Sinus rhythm ( SR ) was present in 2654 ( 81.4 % ) and atrial fibrillation ( AF ) in 607 ( 18.6 % ) . Left ventricular ejection fraction ( LVEF ) did not differ between groups ( SR 32.3 % , AF 30.4 % ; p = 0.09 ) . AF patients were older ( AF 70.9 versus SR 63.9 years ; p < 0.0001 ) , presented with more co-morbidities ( diabetes , hypertension , chronic kidney disease ; all p < 0.001 ) . In-hospital complications were not significantly different between groups ( p = 0.58 ) . Follow-up information after one year was available in 2967 patients ( 91 % ) . One-year overall mortality after first ICD implantation was 4.9 % for SR and 11.2 % for AF patients ( p < 0.0001 ) ; mortality one year after ICD replacement was 8.4 % for SR and 12.0 % for AF ( p = 0.34 ) . No statistically significant difference between SR and AF patients receiving a CRT device was observed ( SR 6.9 % , AF 10.7 % , p = 0.16 ) in terms of one-year mortality . CONCLUSION The German DEVICE registry demonstrates that patients with AF who receive ICD devices are older , have more co-morbidity and more severe heart failure . AF carries an independent 1.39 fold risk ( 95 % CI 1.02 - 1.89 ) of death after one year in patients only with first ICD implantation AIMS In the setting of congestive heart failure ( CHF ) , atrial fibrillation ( AF ) ablation can improve clinical status and the left ventricular ejection fraction ( LVEF ) value . However , the impact of AF ablation on the implantable cardioverter defibrillator ( ICD ) indication has never been specifically addressed . METHODS AND RESULTS Study subject were six CHF ( mean age 61.1 + /- 6.9 years , mean LVEF 25.8 + /- 7.3 % ) patients refractory to conventional medical treatment with long-lasting AF unresponsive to external cardioversion . Five patients had an idiopathic dilated cardiomyopathy ( DCM ) and one had an ischaemic cardiomyopathy ( ICM ) . Their New York Heart Association ( NYHA ) class was III-IV . Two patients had renal insufficiency . No patient had left ventricular delay . All patients underwent AF ablation .  LVEF and NYHA class were dramatically improved in the five DCM patients . New York Heart Association class , but not the LVEF , was improved in the ICM patient . A redo ablative procedure was undertaken in four of five DCM patients and in the ICM patient due to arrhythmia recurrence . Left ventricular ejection fraction and NYHA were improved again in the DCM patients ( 56 + /- 4.4 % , I-II , respectively ) and led to ICD indication preclusion . The LVEF remained low in the ICM patient ( 30 % ) and led to ICD insertion . Sinus rhythm has been stable during the 18.1 + /- 5.7 months follow-up period . CONCLUSION  Atrial fibrillation ablation in CHF patients can improve both the clinical status of patients and their LVEF , especially among those affected by DCM . The LVEF improvement has the potential to preclude the indication for a primary prevention ICD insertion INTRODUCTION Recent studies suggest a worse impact of inappropriate shock therapies on the outcome of patients with an implantable cardioverter-defibrillator ( ICD ) .  However , it is not known whether the worse impact is attributed to the ICD shock itself or due to the underlying heart disease . The aim of the study was to evaluate the impact of inappropriate ICD shocks on clinical outcome by comparing ICD shocks triggered by atrial fibrillation ( AF ) with shocks caused by lead failure . METHODS AND RESULTS A total of 1,411 consecutive patients of the prospect i ve single-center ICD-registry Ludwigshafen who underwent an ICD implantation between 1992 and 2008 for primary or secondary prevention of sudden cardiac death were analyzed . During the median follow-up of 3 years , 297 ( 21 % ) patients experienced inappropriate ICD shocks . Sixty percent of patients had inappropriate shocks due to AF and 24 % due to lead defect or T-wave oversensing . Multiple ICD shocks ( ≥2 ) triggered by AF were associated with a worse prognosis , whereas a single shock due to AF or 1 or multiple shocks result ing from lead failure were not . ICD shocks caused by AF occurred more often in t and em with a serious adverse event than in patients with a lead failure ( 15 % vs 6 % , P < 0.05 ) . CONCLUSION Multiple ICD shocks triggered by AF are associated with a worse prognosis in ICD patients , whereas a single shock due to AF or shocks result ing from lead failure are not . These data support that the ICD shock itself has no worse impact on the outcome of ICD patients Aims Multiple trials have shown that implantable cardioverter defibrillators ( ICDs ) prolong survival in secondary and primary prevention population s. However , in spite of the efficacy of these devices in terminating life-threatening arrhythmias , total mortality remains high . Methods and results We evaluated 1703 patients ( mean age : 67 ± 12 years , 82 % male ) with conventional ICD indications , who were enrolled and followed between 2001 and 2004 at 128 US centres . Patients were followed for up to a year , and vital status was obtained for 1655 patients ( 97 % , median follow-up : 377 days ) . There were 183 deaths within 1 year of ICD implantation ( 1-year mortality rate : 16 % ) . Predictors of mortality included a history of atrial fibrillation ( AF , P < 0.0001 ) , diabetes ( P = 0.0001 ) , failure to use cholesterol-lowering medications ( P < 0.001 ) , use of digitalis and derivatives ( P < 0.0001 ) , use of diuretics ( P < 0.0001 ) , low body mass index ( BMI , P < 0.0001 ) , increasing age ( P < 0.0001 ) , low left ventricular ejection fraction ( P < 0.0001 ) , low activity hours ( P < 0.0001 ) , elevated resting heart rate ( P = 0.014 ) , low mean arterial pressure ( MAP , P = 0.007 ) , and poor functional status ( New York Heart Association class , P < 0.0001 ) . In multivariate modelling , AF ( P ≤ 0.001 ) , diabetes ( P = 0.004 ) , BMI ( P = 0.001 ) , MAP ( P = 0.040 ) , and functional class ( P = 0.006 ) predicted mortality . Conclusion In this population undergoing ICD implantation , poor functional status , low MAP , diabetes , low BMI , and AF were strongly associated with death within a year BACKGROUND Most r and omized trials on implantable cardioverter-defibrillator ( ICD ) use for primary prevention of sudden cardiac death in heart failure with reduced ejection fraction ( HFrEF ) enrolled patients > 20 years ago . We investigated the association between ICD use and all-cause mortality in a contemporary HFrEF cohort and examined relevant subgroups . METHODS Patients from the Swedish HF Registry ( SwedeHF ) fulfilling the European Society of Cardiology criteria for primary prevention ICD were included . The association between ICD use and 1-year and 5-year all-cause and cardiovascular ( CV ) mortality was assessed by Cox Regression models in a 1:1 propensity score matched cohort and in prespecified subgroups . RESULTS Of 16,702 eligible patients , only 1,599 ( 10 % ) had an ICD . After matching , 1,305 ICD recipients were compared to 1,305 non-recipients . ICD use was associated with a reduction in all-cause mortality risk within 1 year [ hazard ratio ( HR ) : 0.73 , 95 % confidence interval ( CI ) : 0.60 - 0.90 ] and 5 years ( HR : 0.88 , 95%CI : 0.78 - 0.99 ) . Results were consistent in all subgroups including patients with vs. without ischemic heart disease , males vs. females , in those aged < 75 vs. ≥75 years , in those with earlier vs. later enrollment in SwedeHF and in patients with vs. without cardiac resynchronization therapy . CONCLUSIONS In a contemporary HFrEF population , ICD for primary prevention was underused although it was associated with reduced short- and long-term all-cause mortality . This association was consistent across all the investigated subgroups . These results call for better implementation of ICD therapy OBJECTIVES The purpose of this study was to determine whether exercise training is associated with an increased risk of implantable cardioverter-defibrillator ( ICD ) therapy  in patients with heart failure ( HF ) . BACKGROUND Few data are available regarding the safety of exercise training in patients with ICDs and HF . METHODS HF-ACTION ( Heart Failure and A Controlled Trial Investigating Outcomes of Exercise TraiNing ) r and omized 2,331 out patients with HF and an ejection fraction ( EF ) ≤35 % to exercise training or usual care .  Cox proportional hazards modeling was used to examine the relationship between exercise training and ICD shocks . RESULTS We identified 1,053 patients ( 45 % ) with an ICD at baseline who were r and omized to exercise training ( n = 546 ) or usual care ( n = 507 ) . Median age was 61 years old , and median EF was 24 % . Over a median of 2.2 years of follow-up , 20 % ( n = 108 ) of the exercise patients had a shock versus 22 % ( n = 113 ) of the control patients . A history of sustained ventricular tachycardia/fibrillation ( hazard ratio [ HR ] : 1.93 [ 95 % confidence interval ( CI ) : 1.47 to 2.54 ] ) , previous atrial fibrillation/flutter ( HR : 1.63 [ 95 % CI : 1.22 to 2.18 ] ) , exercise-induced dysrhythmia ( HR : 1.67 [ 95 % CI : 1.23 to 2.26 ] ) , lower diastolic blood pressure ( HR for 5-mm Hg decrease < 60 : 1.35 [ 95 % CI : 1.12 to 1.61 ] ) , and nonwhite race ( HR : 1.50 [ 95 % CI : 1.13 to 2.00 ] ) were associated with an increased risk of ICD shocks . Exercise training was not associated with the occurrence of ICD shocks ( HR : 0.90 [ 95 % CI : 0.69 to 1.18 ] , p = 0.45 ) . The presence of an ICD was not associated with the primary efficacy composite endpoint of death or hospitalization ( HR : 0.99 [ 95 % CI : 0.86 to 1.14 ] , p = 0.90 ) . CONCLUSIONS We found no evidence of increased ICD shocks in patients with HF and reduced left ventricular function  who underwent exercise training . Exercise therapy should not be prohibited in ICD recipients with HF . ( Exercise Training Program to Improve Clinical Outcomes in Individuals With Congestive Heart Failure ; NCT00047437 BACKGROUND Electrical isolation of the pulmonary veins by catheter ablation is an emerging treatment modality for the treatment of atrial fibrillation ( AF ) and is increasingly used in patients with heart failure . METHODS The catheter ablation versus st and ard conventional treatment in patients with left ventricular dysfunction and atrial fibrillation trial ( CASTLE-AF ) is a r and omized evaluation of ablative treatment of atrial fibrillation in patients with left ventricular dysfunction . The primary endpoint is the composite of all-cause mortality or worsening of heart failure requiring unplanned hospitalization using a time to first event analysis . Secondary endpoints are all-cause mortality , cardiovascular mortality , cerebrovascular accidents , worsening of heart failure requiring unplanned hospitalization , unplanned hospitalization due to cardiovascular reason , all-cause hospitalization , quality of life , number of therapies ( shock and antitachycardia pacing ) delivered by the implantable cardioverter-defibrillator ( ICD ) , time to first ICD therapy , number of device-detected ventricular tachycardia and ventricular fibrillation episodes , AF burden , AF free interval , left ventricular function , exercise tolerance , and percentage of right ventricular pacing . CASTLE-AF will r and omize 420 patients for a minimum of 3 years at 48 sites in the United States , Europe , Australia , and South America OBJECTIVES This study aim ed to assess the prevalence of different types of  atrial fibrillation ( AF ) and their prognostic importance in  implantable cardioverter-defibrillator ( ICD ) patients . BACKGROUND The prevalence of AF has taken epidemic proportions in the population with cardiovascular disease . The prognostic importance of different types of AF in ICD patients remains unclear . METHODS Data on 913 consecutive patients ( 79 % men , mean age 62 + or - 13 years ) receiving an ICD at the Leiden University Medical Center were prospect ively collected . Among other characteristics , the existence and type of AF ( paroxysmal , persistent , or permanent ) were assessed at implantation . During follow-up , the occurrence of appropriate or inappropriate device therapy as well as mortality was noted . RESULTS At implantation , 73 % of patients had no history of AF , 9 % had a history of paroxysmal AF , 7 % had a history of persistent AF , and 11 % had permanent AF . During 833 + or - 394 days of follow-up , 117 ( 13 % ) patients died , 228 ( 25 % ) patients experienced appropriate device discharge , and 139 ( 15 % ) patients received inappropriate shocks . Patients with permanent AF exhibited more than double the risk of mortality , ventricular arrhythmias triggering device discharge , and inappropriate device therapy .  Patients with paroxysmal or persistent AF did not show a significant increased risk of mortality or appropriate device therapy but demonstrated almost 3 times the risk of inappropriate device therapy . CONCLUSIONS In the population currently receiving ICD treatment outside the setting of clinical trials , a large portion has either a history of AF or permanent AF . Both types of AF have prognostic implication s for mortality and appropriate as well as inappropriate device discharge BACKGROUND The Defibrillators in Nonischemic Cardiomyopathy Treatment Evaluation study demonstrated that implantable cardioverter defibrillators ( ICDs ) significantly reduce the risk of sudden cardiac death in patients with nonischemic cardiomyopathy and an ejection fraction of 35 % or less , with no statistically significant decrease in overall mortality . The impact of ICD placement and shock on health-related quality of life ( HRQL ) in this population is unknown . METHODS The 12-Item Medical Outcomes Short-Form Health Survey and the Minnesota Living with Heart Failure Question naire were administered to 458 patients with nonischemic cardiomyopathy , an ejection fraction of 35 % or less , and either nonsustained ventricular tachycardia or 10 or more premature ventricular depolarizations per hour at baseline , 1 month after r and omization , and every 3 months thereafter throughout the trial . The subjects were r and omized to an ICD or st and ard medical therapy . Outcomes were compared using hierarchical linear regression . RESULTS Overall , there were no significant differences in HRQL throughout the trial between patients r and omized to an ICD or st and ard medical therapy . However , in patients with 1 or more ICD shocks , HRQL declined 0.5 + /- 0.2 ( mean + /- SD ) points per shock on the emotional scale of the Minnesota Living with Heart Failure Question naire ( P = .04 ) and 1.0 + /- 0.5 points per shock on the mental component score of the 12-Item Medical Outcomes Short-Form Health Survey ( P = .04 ) . CONCLUSIONS Overall , HRQL was not affected by ICD implantation in patients in the Defibrillators in Nonischemic Cardiomyopathy Treatment Evaluation study . Implantable cardioverter defibrillator shock was associated with a reduction in some measures of HRQL , but the effects were unlikely to result in a clinical ly observable alteration until 5 or more shocks were experienced It was recognized that sleep-disordered breathing ( SDB ) is associated with cardiac arrhythmia and sudden cardiac death . However , it was unclear whether the presence of SDB increased the risk of life-threatening ventricular arrhythmia in patients with heart failure ( HF ) with an implantable cardioverter-defibrillator ( ICD ) . Seventy-one patients with HF and an ICD who were followed up for 180 days after a sleep study were prospect ively studied . All patients had an ejection fraction < or=35 % . SDB was defined as an apnea-hypopnea index > or=10 events/hour on the sleep study . The frequency of appropriate ICD therapy and the day-night pattern of ICD therapies were compared between patients with and without SDB . SDB was diagnosed in 47 of 71 patients ( 66 % ) . There were no statistical differences between patients with and without SDB in baseline cardiac function . However , appropriate ICD therapies occurred more frequently in patients with ( 43 % ) than without SDB ( 17 % ; p = 0.029 ) . On multivariate analysis , the presence of SDB was an independent predictor for appropriate ICD therapy ( hazard ratio 4.05 , 95 % confidence interval 1.20 to 13.65 , p = 0.015 ) . Moreover , the rate of total ICD therapy from midnight to 6 A.M. was significantly higher in patients with ( 34 % ) than without SDB ( 13 % ; p = 0.046 ) . In conclusion , in patients with HF with an ICD , the presence of SDB was common and an independent predictor of life-threatening ventricular arrhythmias that were more likely to occur during sleep Background —Although implantable cardioverter-defibrillators ( ICDs ) reduce mortality in primary prevention patients with left ventricular systolic dysfunction , recent studies have question ed their overall role in clinical practice , especially in older patients and those with major comorbid conditions . Methods and Results —In a prospect i ve cohort of 965 patients with ischemic and nonischemic cardiomyopathies ( ejection fraction ≤35 % ) and no prior ventricular arrhythmias , we compared long-term mortality in patients who did ( n=494 [ 51 % ] ) and did not receive ICDs over a mean follow-up period of 34±16 months . Using a l and mark analysis , multivariable Cox proportional hazards models that included propensity scores for ICD implantation assessed the relationship between ICD therapy and mortality in the entire cohort and by age and the presence of major comorbid conditions . Data from these analyses were then used as inputs in a Markov model to generate incremental cost-effectiveness ratios for ICD therapy . Patients who received ICDs were similar in age and prevalence of most major comorbid conditions , including symptomatic heart failure . After multivariable adjustment , ICD therapy was associated with a 31 % lower risk for all-cause mortality ( adjusted hazard ratio , 0.69 ; 95 % CI , 0.50 to 0.96 ; P=0.03 ) . The relationship between ICD therapy and lower all-cause mortality was consistent after stratification by age ( < 65 , 65 to 74 , and ≥75 ) , ischemic etiology , ejection fraction ( > 25 % versus ≤25 % ) , and the presence of major comorbid conditions ( probability values for all interactions > 0.05 ) . Incremental cost-effectiveness ratios  for ICD therapy were similar between patients aged ≥75 years and younger patients but rose slightly in those with multiple comorbid conditions . Conclusions —Routine use of ICDs in primary prevention patients with left ventricular systolic dysfunction was associated with lower all-cause mortality , even among older patients and those with major comorbid conditions . Although their use needs to be individualized , our findings suggest that these groups should not be routinely excluded from ICD treatment The purpose of this study was to predict implantable cardioverter defibrillator ( ICD ) shocks using demographic and clinical characteristics in the first year after implantation for secondary prevention of cardiac arrest . A prospect i ve design was used to follow 168 first-time ICD recipients over 12 months . Demographic and clinical data were obtained from medical records at the time of ICD insertion . Implantable cardioverter defibrillator shock data were obtained from ICD interrogation reports at hospital discharge , 3 , 6 , and 12 months . Logistic regression was used to predict ever receiving an ICD shock using background characteristics . Patients received an ICD for secondary prevention of sudden cardiac arrest , they were 64.1 years old , 89 % were white , 77 % were male , with a mean ( SD ) ejection fraction of 33.7 % ( 14.1 % ) . The cumulative percentage of ever receiving an ICD shock was 33.3 % over 1 year . Three variables predicted shocks in the first year : history of chronic obstructive pulmonary disease ( COPD ) ( odds ratio [ OR ] , 4.42 ; 95 % confidence interval [ CI ] , 1.2 - 16.4 ; P = .03 ) , history of congestive heart failure ( OR , 3.55 ; 95 % CI , 1.4 - 9.3 ; P = .01 ) , and documented ventricular tachycardia ( VT ) at the time of ICD implant ( OR , 10.05 ; 95 % Cl , 1.8 - 55.4 ; P = .01 ) . High levels of anxiety approached significance ( OR = 2.82 ; P = .09 ) . The presence of COPD , congestive heart failure , or VT at ICD implant was a significant predictor of receiving an ICD shock in the first year after ICD implantation . Because ICD shocks are distressing , painful , and associated with greater mortality , healthcare providers should focus attention on prevention of shocks by controlling VT , careful management of HF symptoms , reduction of the use of short acting β agonist medications in COPD , and perhaps recognizing and treating high levels of anxiety BACKGROUND Heart failure patients with primary prevention implantable cardioverter-defibrillators ( ICD )  may experience an improvement in left ventricular ejection fraction ( LVEF ) over time . However , it is unclear how LVEF improvement affects subsequent risk for mortality and sudden cardiac death . OBJECTIVES This study sought to assess changes in LVEF after ICD implantation and the implication of these changes on subsequent mortality and ICD shocks . METHODS We conducted a prospect i ve cohort study of 538 patients with repeated LVEF assessment s after ICD implantation for primary prevention of sudden cardiac death . The primary endpoint was appropriate ICD shock defined as a shock for ventricular tachyarrhythmias . The secondary endpoint was all-cause mortality . RESULTS Over a mean follow-up of 4.9 years , LVEF decreased in 13.0 % , improved in 40.0 % , and was unchanged in 47.0 % of the patients . In the multivariate Cox models comparing patients with an improved LVEF with those with an unchanged LVEF , the hazard ratios were 0.33 ( 95 % confidence interval : 0.18 to 0.59 ) for mortality and 0.29 ( 95 % confidence interval : 0.11 to 0.78 ) for appropriate shock . During follow-up , 25 % of patients showed an improvement in LVEF to > 35 % and their risk of appropriate shock decreased but was not eliminated . CONCLUSIONS Among primary prevention ICD patients , 40.0 % had an improved LVEF during follow-up and 25 % had LVEF improved to > 35 % . Changes in LVEF were inversely associated with all-cause mortality and appropriate shocks for ventricular tachyarrhythmias . In patients whose follow-up LVEF improved to > 35 % , the risk of an appropriate shock remained but was markedly decreased OBJECTIVE To compare the clinical outcomes of a single- versus dual-chamber ICD for primary prevention of sudden cardiac death in a large , national ICD registry . METHODS Data were collected from the prospect i ve Israeli ICD Registry . Baseline characteristics and clinical outcomes including mortality , admissions for heart failure ( HF ) , and ICD therapy were compared between the two groups . RESULTS A total of 1,125 subjects , 37 % with a single-chamber and 63 % with a dual-chamber ICD , constructed the baseline cohort . Approximately 80 % had ischemic heart disease ( IHD ) . Mean follow-up was 22 months , mean ejection fraction was 30 % , and mean QRS width was 103 milliseconds in both groups . During follow-up , there were no significant differences in the rate of mortality , admissions for HF , appropriate or inappropriate therapy , or in time to any of the clinical outcomes . Using multivariate analysis , single-chamber ICD was not associated with increased risk of death or admission for HF . In a subgroup of patients with IHD , single-chamber ICD was associated with a higher rate of inappropriate therapy . CONCLUSIONS In this large retrospective population -based cohort , dual-chamber ICD showed no benefit in reducing the incidence of death or HF admissions , whereas in a subgroup of patients with IHD , single-chamber ICD was associated with increased inappropriate therapy . Further prospect i ve studies are necessary to assess the benefit of dual-chamber ICD in reducing the rate of inappropriate therapy
Atrial fibrillation history is statistically significantly associated with adverse major clinical outcomes in ICD-implanted HF patients .
Patients with AF have a higher risk of all-cause mortality , appropriate , and inappropriate ICD interventions compared with patients with no AF history .
AIMS To assess the association between atrial fibrillation ( AF ) and all-cause mortality and implantable cardioverter-defibrillators ( ICDs ) therapies  in heart failure ( HF ) patients with reduced ejection fraction and an ICD implanted .