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Background: Despite strong guideline recommendations for cardiac resynchronization therapy-defibrillator (CRT-D) in select patients, this therapy is underutilized with substantial variation among hospitals, and the association of this variation with outcomes is unknown., Objective: The purpose of this study was to assess whether facility variation in CRT-D utilization is associated with differences in hospital-level outcomes., Methods: We linked Medicare claims data with the National Cardiovascular Data Registry's ICD Registry from 2010 to 2015. We calculated the intraclass correlation coefficient to quantify the degree of variation in patient-level CRT use that can be explained by interfacility variation on a hospital level. To quantify the degree of hospital variation in patient-level outcomes (all-cause mortality, readmissions, and cardiac readmissions) that can be attributed to variations in CRT-D use, we utilized multilevel modeling., Results: The study included 30,134 patients across 1377 hospitals. The median rate of CRT-D implantation in those meeting guideline indications was 89%, but there was a wide variation across hospitals. After adjustment, most of the variation (74%) in hospital rates of CRT-D utilization was attributable to the hospital in which the patient was treated. Differences in hospital CRT-D utilization was associated with 8.76%, 5.26%, and 4.71% of differences in hospital mortality, readmissions, and cardiac readmission rates, respectively (P < .001 for all outcomes)., Conclusion: There is a wide variation in the use of CRT-D across hospitals that was not explained by case mix. Hospital-level variation in CRT-D utilization was associated with clinically significant differences in outcomes. A measure of CRT-D utilization in eligible patients may serve as a useful metric for quality improvement efforts., (Copyright © 2023 Heart Rhythm Society. Published by Elsevier Inc. All rights reserved.)

Importance: Use of dual-chamber implantable cardioverter-defibrillator (ICD) systems among patients without a pacing indication is an example of low-value care given higher procedural risks, higher costs, and little evidence for benefit from an atrial lead. However, variation in the use of dual-chamber systems was present among patients without a pacing indication., Objective: To examine the temporal trends and hospital variation in use of single- and dual-chamber ICD implantation among patients without a pacing indication undergoing first-time ICD implantation., Design, Setting, and Participants: A multicenter cross-sectional study was conducted using the US National Cardiovascular Data Registry ICD Registry. A total of 266 182 patients undergoing initial implantation of a single- or dual-chamber transvenous ICD without a bradycardia pacing indication, class I or II cardiac resynchronization therapy indication, or history of atrial fibrillation or atrial flutter were included. The study was conducted from April 1, 2010, to December 31, 2018; data analysis was performed from October 19, 2020, to January 5, 2022., Exposures: Implantation of a single- or dual-chamber ICD., Main Outcomes and Measures: Temporal trends among patients undergoing single- vs dual-chamber ICDs were determined using the Cochran-Armitage trend test, and hospital-level variation using adjusted hospital median odds ratios was examined., Results: A total of 266 182 patients (single-chamber ICD, 134 925; dual-chamber ICD, 131 257) were included in this analysis; mean (SD) age was 58.0 (14.0) years and 91 990 patients (68.2%) were men. The use of dual-chamber ICDs decreased from 64.7% (n = 15 694) in 2010 to 42.2% (n = 9762) in 2018 (P < .001). Adjusted for patient characteristics, the median hospital-level proportion of single-chamber ICDs increased from 42.9% (95% CI, 42.6%-45.0%) in 2010 to 50.0% (95% CI, 47.8%-51.0%) in 2018. The median odds ratio for the use of dual-chamber ICDs, adjusted for patient characteristics, was 1.6 (95% CI, 1.6-1.8) in 2010 and 1.5 (95% CI, 1.5-1.8) in 2018, indicating decreasing but persistent variation in use., Conclusions and Relevance: In this national study of US patients undergoing first-time ICD implantation without a clinical indication for an atrial lead, the use of dual-chamber devices decreased. However, institutional variability in the use of atrial leads persists, suggesting differences in individual or institutional cultures of real-world practice and opportunity to reduce this low-value practice.

Importance: Frequent right ventricular (RV) pacing can cause and exacerbate heart failure. Cardiac resynchronization therapy (CRT) has been shown to be associated with improved outcomes among patients with reduced left ventricular ejection fraction who need frequent RV pacing, but the patterns of use of CRT vs dual chamber (DC) devices and the associated outcomes among these patients in clinical practice is not known., Objective: To assess outcomes, variability in use of device type, and trends in use of device type over time among patients undergoing implantable cardioverter defibrillator (ICD) implantation who were likely to require frequent RV pacing but who did not have a class I indication for CRT., Design, Setting, and Participants: This retrospective cohort study used the National Cardiovascular Data Registry (NCDR) ICD Registry. A total of 3100 Medicare beneficiaries undergoing first-time implantation of CRT defibrillator (CRT-D) or DC-ICD from 2010 to 2016 who had a class I or II guideline ventricular bradycardia pacing indication but not a class I indication for CRT were included. Data were analyzed from August 2018 to October 2019., Exposures: Implantation of a CRT-D or DC-ICD., Main Outcomes and Measures: All-cause mortality, heart failure hospitalization, and complications were ascertained from Medicare claims data. Multivariable Cox proportional hazards models and Fine-Gray models were used to evaluate 1-year mortality and heart failure hospitalization, respectively. Multivariable logistic regression was used to evaluate 30-day and 90-day complications. All models accounted for clustering. The median odds ratio (MOR) was used to assess variability and represents the odds that a randomly selected patient receiving CRT-D at a hospital with high implant rates would receive CRT-D if they had been treated at a hospital with low CRT-D implant rates., Results: A total of 3100 individuals were included. The mean (SD) age was 76.3 (6.4) years, and 2500 (80.6%) were men. The 1698 patients (54.7%) receiving CRT-D were more likely than those receiving DC-ICD to have third-degree atrioventricular block (828 [48.8%] vs 432 [30.8%]; P < .001), nonischemic cardiomyopathy (508 [29.9%] vs 255 [18.2%]; P < .001), and prior heart failure hospitalizations (703 [41.4%] vs 421 [30.0%]; P < .001). Following adjustment, CRT-D was associated with lower 1-year mortality (hazard ratio [HR], 0.70; 95% CI, 0.57-0.87; P = .001) and heart failure hospitalization (subdistribution HR, 0.77; 95% CI, 0.61-0.97; P = .02) and no difference in complications compared with DC-ICD. Hospital variation in use of CRT was present (MOR, 2.00), and the use of CRT in this cohort was higher over time (654 of 1351 [48.4%] in 2010 vs 362 of 594 [60.9%] in 2016; P < .001)., Conclusions and Relevance: In this cohort study of older patients in contemporary practice undergoing ICD implantation with a bradycardia pacing indication but without a class I indication for CRT, CRT-D was associated with better outcomes compared with DC devices. Variability in use of device type was observed, and the rate of CRT implantation increased over time.

Background: Randomized trials evaluating cardiac resynchronization therapy (CRT) have excluded patients with a pre-existing implantable cardioverter-defibrillator (ICD). The association of CRT upgrade with clinical outcomes in patients with a pre-existing ICD is unclear., Objective: The purpose of this study was to examine a CRT-eligible population to evaluate clinical outcomes associated with CRT upgrade compared to patients who did not undergo CRT., Methods: Using the National Cardiovascular Data Registry (NCDR) ICD Registry between April 2010 and December 2014, we created a hierarchical logistic regression model to identify predictors of CRT upgrade in a CRT-eligible ICD population. In the subpopulation of patients with Medicare-linked claims data, differential outcomes were determined with censoring at 3 years. The primary endpoint of this study was all-cause mortality, with secondary endpoints of rates of hospitalization and procedural complications., Results: CRT upgrade was performed in 75.5% of CRT-eligible patients with pre-existing ICD (n = 15,803). Presence of left bundle branch block conduction was the strongest predictor of CRT upgrade (odds ratio [OR] 4.56; 95% confidence interval [CI] 4.08-5.11; P <.0001). In both unadjusted and adjusted analyses, CRT upgrade was associated with a reduction in mortality at 3 years (unadjusted hazard ratio [HR] 0.80; 95% CI 0.70-0.92; P = .001; adjusted HR 0.84; 95% CI 0.72-0.98; P = .02, respectively). Compared to patients with ICD generator replacement only, patients who underwent CRT upgrade experienced no different 3-year rates of hospitalization (adjusted HR 1.01; 95% CI 0.91-1.12; P = .81) or 1-year periprocedural complication rates (adjusted HR 1.07; 95% CI 0.79-1.45; P = .66)., Conclusion: In a national registry of CRT-eligible patients with pre-existing ICD, upgrade to CRT was associated with lower rates of mortality than continued medical management., (Copyright © 2020 Heart Rhythm Society. Published by Elsevier Inc. All rights reserved.)

Background: Patients with heart failure having a low expected probability of arrhythmic death may not benefit from implantable cardioverter defibrillators (ICDs)., Objective: The objective was to validate models to identify cardiac resynchronization therapy (CRT) candidates who may not require CRT devices with ICD functionality., Methods: Heart failure (HF) patients with CRT-Ds and non-CRT ICDs from the National Cardiovascular Data Registry and others with no device from 3 separate registries and 3 heart failure trials were analyzed using multivariable Cox proportional hazards regression for survival with the Seattle Heart Failure Model (SHFM; estimates overall mortality) and the Seattle Proportional Risk Model (SPRM; estimates proportional risk of arrhythmic death)., Results: Among 60,185 patients (age 68.6 ± 11.3 years, 31.9% female) meeting CRT-D criteria, 38,348 had CRT-Ds, 11,389 had non-CRT ICDs, and 10,448 had no device. CRT-D patients had a prominent adjusted survival benefit (HR 0.52, 95% CI 0.50-0.55, P < .0001 versus no device). CRT-D patients with SHFM-predicted 4-year survival ≥81% (median) and a low SPRM-predicted probability of an arrhythmic mode of death ≤42% (median) had an absolute adjusted risk reduction attributable to ICD functionality of just 0.95%/year with the majority of survival benefit (70%) attributable to CRT pacing. In contrast, CRT-D patients with SHFM-predicted survival median had substantially more ICD-attributable benefit (absolute risk reduction of 2.6%/year combined; P < .0001)., Conclusions: The SPRM and SHFM identified a quarter of real-world, primary prevention CRT-D patients with minimal benefit from ICD functionality. Further studies to evaluate CRT pacemakers in these low-risk CRT candidates are indicated., (Copyright © 2019 Elsevier Inc. All rights reserved.)

Background: Cardiac resynchronization therapy with defibrillator (CRT-D) implantation involves left ventricular (LV) lead placement for biventricular pacing and is more complex than implantable cardioverter-defibrillator (ICD)-only implantation. Differences in the prescription of CRT-D versus ICD may result from clinician biases based on patient body habitus, and body habitus may be associated with LV lead implantation failure., Objective: We sought to evaluate whether patient body mass index (BMI) was associated with planned use and implantation failure of CRT-D therapy., Methods: We studied all patients enrolled in the National Cardiovascular Data Registry ICD Registry who met standard CRT-D criteria and received either an ICD or CRT-D between 2010 and 2012. BMI was categorized based on World Health Organization classification. Using hierarchical logistic regression, two multivariate models adjusted for patient demographic and clinical characteristics were fit based on the following outcome variables: (1) planned implantation with CRT-D versus ICD and (2) failed versus successful LV lead placement., Results: Of 337,547 patients, 41,872 met inclusion criteria for the first analysis and 35,186 met criteria for the second analysis. After multivariable adjustment, patients with extreme (BMI > 40 kg/m 2 ) obesity were less likely to receive guideline-concordant CRT-D compared with patients with normal weight (adjusted odds ratio (AOR), 0.86; 95% confidence interval (CI), 0.75-0.99; p = 0.04). Extreme (BMI > 40 kg/m 2 ) obesity was associated with higher odds of failed LV lead placement (AOR, 1.35; 95% CI, 1.07-1.72, p = 0.01)., Conclusions: Compared with normal weight patients, extremely obese (BMI > 40 kg/m 2 ) CRT-D eligible patients were less likely to be prescribed CRT-D and were at higher odds for failed LV lead placement.

Background: The introduction of quadripolar (QP) cardiac resynchronization therapy (CRT) leads aimed to improve procedural and clinical outcomes., Objective: The National Cardiovascular Data Registry was analyzed to characterize the use as well as the procedural and clinical outcomes of QP leads in comparison with unipolar and bipolar (BP) leads., Methods: We evaluated data on 175,684 procedures reported between September 1, 2010, and December 31, 2015. Clinical outcomes were analyzed using Centers for Medicare & Medicaid Services claims data., Results: Among all CRT device implants, there was a drop in reported lead placement failure from 6.04% to 5.21% (P < .0001 for trend) and a drop in the reported diaphragmatic stimulation rates from 0.07% to 0.01% (P < .007 for trend) between the last quarters of 2010 and 2015. No significant difference in procedural complication rates between QP and BP leads occurred (1.34% and 1.39%, respectively; P = .50). Among patients linked to Centers for Medicare & Medicaid Services claims data, no statistically significant difference in the combined primary outcome of death, congestive heart failure admission, device malfunction, and reoperation between BP and QP leads was observed (34.15 and 34.19 events per 100 patient-years, respectively; P = .89)., Conclusion: Since the introduction of QP leads, there was a reduction in CRT lead placement failure rates and a reduction in diaphragmatic stimulation rates. However, no statistically significant difference in long-term clinical outcomes between BP and QP leads was observed in elderly patients undergoing CRT implantation., (Copyright © 2019 Heart Rhythm Society. Published by Elsevier Inc. All rights reserved.)

Aims: To assess the association of body mass index (BMI) with heart failure (HF) outcomes after cardiac resynchronization therapy with defibrillator (CRT-D) implantation., Methods and Results: Medicare beneficiaries with HF aged ≥ 65 years (n = 18 922) undergoing first-time CRT-D from the National Cardiovascular Data Registry (NCDR) Implantable Cardioverter-Defibrillator Registry between 2010 and 2013, were followed for 3 years post-implantation. Survival curves and covariate adjusted hazard ratio (aHR) or odds ratio were used to assess the risks for death, readmission, and device-related complications by BMI status. Of 18 922 HF patients receiving CRT-D, 5265 (27.8%) were normal weight, 6896 (37%) were overweight, 6318 (33.4%) were obese, and 353 (1.8%) were underweight. Compared to those of normal weight (BMI 18.5-24.9 kg/m 2 ), underweight patients had a higher 3-year post-device implantation risk of death [aHR: 1.34 (95% confidence interval 1.09-1.65); P < 0.001] and of readmission [sub-aHR: 1.25 (1.09-1.42); P < 0.001]. The corresponding 3-year aHRs for death were 0.83 (0.77-0.89) for overweight, 0.74 (0.67-0.82) for obesity class I (BMI 30-34.9 kg/m 2 ), 0.78 (0.68-0.90) for obesity class II (BMI 35-39.9 kg/m 2 ), and 0.75 (0.60-0.93) for obesity class III (BMI ≥ 40 kg/m 2 , P for all categories < 0.001). Individuals with class III obesity had a higher risk of readmission [sub-aHR: 1.17 (1.06-1.30)]. There were no differences in rates of device-related complications within 90 days across BMI categories., Conclusion: Most elderly patients with HF receiving CRT-D were overweight or obese. While being underweight was associated with greater risks of death and hospitalization, overweight and obese patients were at lower risk of death after CRT-D., (© 2019 The Authors. European Journal of Heart Failure © 2019 European Society of Cardiology.)

Background: The benefits of cardiac resynchronization therapy (CRT) in patients with non-left bundle branch block (LBBB) conduction abnormality have not been fully explored., Objectives: This study sought to evaluate clinical outcomes among Medicare-aged patients with nonspecific intraventricular conduction delay (NICD) versus right bundle branch block (RBBB) in patients eligible for implantation with a CRT with defibrillator (CRT-D)., Methods: Using the National Cardiovascular Data Registry implantable cardioverter-defibrillator (ICD) registry data between 2010 and 2013, the authors compared outcomes in CRT-eligible patients implanted with CRT-D versus ICD-only therapy among patients with NICD and RBBB. Also, among all CRT-D-implanted patients, the authors compared outcomes in those with NICD versus RBBB. Survival curves and multivariable adjusted hazard ratios (HRs) were used to assess outcomes including hospitalization and death., Results: In 11,505 non-LBBB CRT-eligible patients, after multivariable adjustment, among patients with RBBB, CRT-D was not associated with better outcomes, compared with ICD alone, regardless of QRS duration. Among patients with NICD and a QRS ≥150 ms, CRT-D was associated with decreased mortality at 3 years compared with ICD alone (HR: 0.602; 95% confidence interval [CI]: 0.416 to 0.871; p = 0.0071). Among 5,954 CRT-D-implanted patients, after multivariable adjustment NICD compared with RBBB was associated with lower mortality at 3 years in those with a QRS duration of ≥150 ms (HR: 0.757; 95% CI: 0.625 to 0.917; p = 0.0044)., Conclusions: Among non-LBBB CRT-D-eligible patients, CRT-D implantation was associated with better outcomes compared with ICD alone specifically in NICD patients with a QRS duration of ≥150 ms. Careful patient selection should be considered for CRT-D implantation in patients with non-LBBB conduction., (Copyright © 2019 American College of Cardiology Foundation. Published by Elsevier Inc. All rights reserved.)

Coronary venous dissection is a known complication of left ventricular lead placement during implantation of a cardiac resynchronization with defibrillator (CRT-D) system. A large-scale evaluation of the prevalence of coronary venous dissection and associated in-hospital clinical outcomes has not been performed. We sought to identify predictors of coronary venous dissection and evaluate subsequent in-hospital adverse events in those with the complication. We studied 140,991 first-time CRT-D recipients in the implantable cardioverter-defibrillator (ICD) Registry implanted between 2006 and 2011. Using hierarchical multivariable logistic regression adjusting for patient, implanting physician, and hospital characteristics, we examined predictors of coronary venous dissection and its association with other major complications, length of hospital stay, and in-hospital mortality. Coronary venous dissection occurred in 392 patients (0.28%). After multivariable adjustment, female gender and left bundle branch block were associated with greater odds of coronary venous dissection. Conversely, atrial fibrillation, previous coronary artery bypass graft, and higher implanter procedure volume were associated with lower odds of coronary venous dissection (all p values <0.05). After multivariable adjustment, CRT-D recipients with coronary venous dissection had greater odds of major complications (odds ratio [OR] 10.47, 95% confidence interval [CI] 6.75 to 16.24, p <0.0001), postprocedural hospital stays >3 days (OR 1.71, 95% CI 1.29 to 2.29, p <0.0001), but not in-hospital death (OR 0.78, 95% CI 0.12 to 5.25, p = 0.8012). In conclusion, in a large population of first-time CRT-D recipients, specific patient and implanter characteristics predicted coronary venous dissection risk. Coronary venous dissection was associated with major in-hospital complications and prolonged hospitalization, but not death., (Copyright © 2017 Elsevier Inc. All rights reserved.)

Importance: Cardiac resynchronization therapy (CRT) reduces the risk for mortality and heart failure-related events in select patients. Little is known about the use of CRT in combination with an implantable cardioverter defibrillator (ICD) in patients who are eligible for this therapy in clinical practice., Objective: To (1) identify patient, clinician, and hospital characteristics associated with CRT defibrillator (CRT-D) use and (2) determine the extent of hospital-level variation in the use of CRT-D among guideline-eligible patients undergoing ICD placement., Design, Setting, and Participants: Multicenter retrospective cohort from 1428 hospitals participating in the National Cardiovascular Data Registry ICD Registry between April 1, 2010, and June 30, 2014. Adult patients meeting class I or IIa guideline recommendations for CRT at the time of device implantation were included in this study., Main Outcomes and Measures: Implantation of an ICD with or without CRT., Results: A total of 63 506 eligible patients (88.6%) received CRT-D at the time of device implantation. The mean (SD) ages of those in the ICD and CRT-D groups were 67.9 (12.2) years and 68.4 (11.5) years, respectively. In hierarchical multivariable models, black race was independently associated with lower use of CRT-D (odds ratio [OR], 0.77; 95% CI, 0.71-0.83) as was nonprivate insurance (OR, 0.90; 95% CI, 0.85-0.95 for Medicare and OR, 0.73; 95% CI, 0.65-0.82 for Medicaid). Clinician factors associated with greater CRT-D use included clinician implantation volume (OR, 1.01 per 10 additional devices implanted; 95% CI, 1.01-1.01) and electrophysiology training (OR, 3.13 as compared with surgery-boarded clinicians; 95% CI, 2.50-3.85). At the hospital level, the overall median risk-standardized rate of CRT-D use was 79.9% (range, 26.7%-100%; median OR, 2.08; 95% CI, 1.99-2.18)., Conclusions and Relevance: In a national cohort of patients eligible for CRT-D at the time of device implantation, nearly 90% received a CRT-D device. However, use of CRT-D differed by race and implanting operator characteristics. After accounting for these factors, the use of CRT-D continued to vary widely by hospital. Addressing disparities and variation in CRT-D use among guideline-eligible patients may improve patient outcomes.

Background: A prolonged PR interval is common among cardiac resynchronization therapy (CRT) candidates; however, the association between PR interval and outcomes is unclear, and the data are conflicting., Methods: We conducted inverse probability weighted analyses of 26 451 CRT-eligible (ejection fraction ≤35, QRS ≥120 ms) patients from the National Cardiovascular Data Registry ICD Registry to assess the association between a prolonged PR interval (≥230 ms), receipt of CRT with defibrillator (CRT-D) versus implantable cardioverter defibrillator (ICD), and outcomes. We first tested the association between a prolonged PR interval and outcomes among patients stratified by device type. Next, we performed a comparative effectiveness analysis of CRT-D versus ICD among patients when stratified by PR interval. Using Medicare claims data, we followed up with patients up to 5 years for incident heart failure hospitalization or death., Results: Patients with a PR≥230 ms (15%; n=4035) were older and had more comorbidities, including coronary artery disease, atrial arrhythmias, diabetes mellitus, and chronic kidney disease. After risk adjustment, a PR≥230 ms (versus PR<230 ms) was associated with increased risk of heart failure hospitalization or death among CRT-D (hazard ratio, 1.23; 95% confidence interval, 1.14-1.31; P<0.001) but not ICD recipients (hazard ratio, 1.08; 95% confidence interval, 0.97-1.20; P=0.17) (P interaction =0.043). CRT-D (versus ICD) was associated with lower rates of heart failure hospitalization or death among patients with PR<230 ms (hazard ratio, 0.79; 95% confidence interval, 0.73-0.85; P<0.001) but not PR≥230 ms (hazard ratio, 1.01; 95% confidence interval, 0.87-1.17; P=0.90) (P interaction =0.0025)., Conclusions: A PR≥230 ms is associated with increased rates of heart failure hospitalization or death among CRT-D patients. The real-world comparative effectiveness of CRT-D (versus ICD) is significantly less among patients with a PR≥230 ms in comparison with patients with a PR<230 ms., (© 2016 American Heart Association, Inc.)

Background: Patients with moderate-to-severe chronic kidney disease (CKD) are poorly represented in clinical trials of cardiac resynchronization therapy (CRT)., Objectives: This study sought to assess the real-world comparative effectiveness of CRT with defibrillator (CRT-D) versus implantable cardioverter-defibrillator (ICD) alone in CRT-eligible patients with moderate-to-severe CKD., Methods: We conducted an inverse probability-weighted analysis of 10,946 CRT-eligible patients (ejection fraction <35%, QRS >120 ms, New York Heart Association functional class III/IV) with stage 3 to 5 CKD in the National Cardiovascular Data Registry (NCDR) ICD Registry, comparing outcomes between patients who received CRT-D (n = 9,525) versus ICD only (n = 1,421). Outcomes were obtained via Medicare claims and censored at 3 years. The primary endpoint of heart failure (HF) hospitalization or death and the secondary endpoint of death were assessed with Cox proportional hazards models. HF hospitalization, device explant, and progression to end-stage renal disease were assessed using Fine-Gray models., Results: After risk adjustment, CRT-D use was associated with a reduction in HF hospitalization or death (hazard ratio [HR]: 0.84; 95% confidence interval [CI]: 0.78 to 0.91; p < 0.0001), death (HR: 0.85; 95% CI: 0.77 to 0.93; p < 0.0004), and HF hospitalization alone (subdistribution HR: 0.84; 95% CI: 0.76 to 0.93; p < 0.009). Subgroup analyses suggested that CRT was associated with a reduced risk of HF hospitalization and death across CKD classes. The incidence of in-hospital, short-term, and mid-term device-related complications did not vary across CKD stages., Conclusions: In a nationally representative population of HF and CRT-eligible patients, use of CRT-D was associated with a significantly lower risk of the composite endpoint of HF hospitalization or death among patients with moderate-to-severe CKD in the setting of acceptable complication rates., (Copyright © 2015 American College of Cardiology Foundation. Published by Elsevier Inc. All rights reserved.)

Background: Women have been under-represented in trials of cardiac resynchronization therapy-defibrillators (CRT-D). Previous studies suggest that women benefit from CRT-D at shorter QRS duration than men and that there may be no benefit of CRT-D in patients without left bundle branch block (LBBB) regardless of patient sex., Methods and Results: We compared sex-specific death risk in 75 079 patients with New York Heart Association class III or IV heart failure, reduced left ventricular ejection fraction, and prolonged QRS duration (≥120 ms) receiving either CRT-D or implantable cardioverter defibrillator in subgroups according to QRS morphology and 10-ms increments in QRS duration. We applied propensity score weighting to control for differences between treatments. Among patients with LBBB, women receiving CRT-D had a lower relative death risk than those receiving an implantable cardioverter-defibrillator (absolute difference, 11%; hazard ratio=0.74 [95% confidence interval, 0.68-0.81]). In men, the lower mortality with CRT-D versus implantable cardioverter defibrillator was less pronounced (absolute difference, 9%; hazard ratio=0.84 [0.79-0.89]; sex×device interaction P=0.025). In those without LBBB, the mortality difference was modest and did not differ between women and men (absolute difference, 3%; hazard ratio=0.88 [0.79-0.97] in women and absolute difference, 2%; hazard ratio=0.95 [0.91-0.998] in men; interaction P=0.17). In subgroups according to QRS duration, CRT-D was associated with better survival in both sexes with LBBB and QRS ≥130 ms, whereas there was no clear relation between QRS duration and survival in patients without LBBB regardless of patient sex., Conclusions: In a large real-world population CRT-D was associated with a lower mortality risk in both sexes with LBBB, although more pronounced among women. Only among those with LBBB, both sexes had better survival with longer QRS duration. The mortality differences in patients without LBBB were attenuated in both sexes., (© 2015 American Heart Association, Inc.)

Background: Prior studies have suggested that women have better outcomes than men after cardiac resynchronization therapy-defibrillator (CRT-D) implantation., Objectives: The purpose of this study was to compare mortality after CRT-D implantation by sex, QRS morphology, and duration., Methods: Survival curves and covariate adjusted hazard ratios (HR) were used to assess mortality by sex in 31,892 CRT-D patients in the National Cardiovascular Data Registry (NCDR), implantable cardioverter defibrillator (ICD) registry between 2006 and 2009, with up to 5 years' follow-up (median 2.9 years, interquartile range: 2.0 to 3.9 years). Patients were grouped by QRS morphology and 10-ms increments in QRS duration., Results: Among patients with left bundle branch block (LBBB), women had a 21% lower mortality risk than men (HR: 0.79; 95% CI: 0.74 to 0.84; p < 0.001); however, there was no sex difference in non-LBBB (HR: 0.95; 95% CI: 0.85 to 1.06; p = 0.37). Longer QRS duration was associated with better survival in both sexes with LBBB, but not in patients without LBBB. Compared with women with LBBB and QRS of 120 to 129 ms, women with LBBB and QRS of 140 to 149 ms had a 27% lower mortality (HR: 0.73; 95% CI: 0.60 to 0.88; p = 0.001); this difference was 18% in men (HR: 0.82; 95% CI: 0.71 to 0.93; p = 0.003). Mortality in LBBB and QRS of 150 ms or longer compared with those with LBBB and QRS of 120 to 129 ms was similar between sexes (HR: 0.61 to 0.68; p < 0.001 for women and HR: 0.58 to 0.66; p < 0.001 for men). Sex interactions within 10-ms groups were not significant., Conclusions: Among patients with LBBB who received CRT-D, mortality is lower in women than men. Additionally, longer QRS duration in LBBB is associated with better survival in both sexes. In contrast, there is no sex difference in patients without LBBB, regardless of QRS duration. Further studies should include a non-CRT comparator group to confirm these findings., (Copyright © 2014 American College of Cardiology Foundation. Published by Elsevier Inc. All rights reserved.)

Cardiac resynchronization therapy (CRT) reduces morbidity and mortality among selected patients with left ventricular systolic dysfunction and severe heart failure symptoms despite guideline-directed medical therapy (GDMT). Contemporaneous guidelines provided clear recommendations regarding selection of patients for CRT, including that all patients should first receive GDMT with β blockers and renin-angiotensin axis antagonists. Prevalence of GDMT among real-world patients receiving CRT defibrillators (CRT-D) has not been well studied. We identified 45,392 patients in the National Cardiovascular Data Registry Implantable Cardioverter-Defibrillator Registry who underwent first CRT-D implantation for primary prevention of sudden death from January 2006 to June 2008. We calculated the proportion of patients with contemporaneous class I guideline indications for CRT-D, the proportion receiving GDMT for heart failure, and the proportion receiving GDMT who had class I guideline indications for CRT-D. Among patients without contraindications, 87% were prescribed β blockers, 78% an angiotensin-converting enzyme inhibitor or an angiotensin II receptor inhibitor, and 70% both a β blocker and an angiotensin-converting enzyme or angiotensin II receptor inhibitor at discharge. Finally, 50% of patients met class I guideline indications and were prescribed GDMT at discharge; 9% neither met class I indications nor were prescribed GDMT at discharge. The major limitation of this study is the lack of dosage information in the Implantable Cardioverter-Defibrillator Registry and lack of prescribing information at times other than discharge. In conclusion, many patients receiving CRT-D are not receiving GDMT at discharge. Ensuring that all patients receiving CRT-D are also receiving GDMT appears to be a quality improvement target., (Copyright © 2014 Elsevier Inc. All rights reserved.)

Background: Trials comparing implantable cardioverter-defibrillator (ICD) therapy with cardiac resynchronization therapy with a defibrillator (CRT-D) are limited to selected patients treated at centers with extensive experience., Objective: To compare outcomes after CRT-D versus ICD therapy in contemporary practice., Design: Retrospective cohort study using the National Cardiovascular Data Registry's ICD Registry linked with Medicare claims., Setting: 780 U.S. hospitals implanting both CRT-D and ICD devices., Patients: 7090 propensity-matched patients older than 65 years with reduced left ventricular ejection fraction (&lt;0.35) and prolonged QRS duration on electrocardiography (≥120 ms) having CRT-D or ICD implantation between 1 April 2006 and 31 December 2009., Measurements: Risks for death, readmission, and device-related complications over 3 years., Results: Compared with ICD therapy, CRT-D was associated with lower risks for mortality (cumulative incidence, 25.7% vs. 29.8%; adjusted hazard ratio [HR], 0.82 [99% CI, 0.73 to 0.93]), all-cause readmission (cumulative incidence, 68.6% vs. 72.8%; adjusted HR, 0.86 [CI, 0.81 to 0.93]), cardiovascular readmission (cumulative incidence, 45.0% vs. 52.4%; adjusted HR, 0.80 [CI, 0.73 to 0.88]), and heart failure readmission (cumulative incidence, 24.3% vs. 29.4%; adjusted HR, 0.78 [CI, 0.69 to 0.88]). It was also associated with greater risks for device-related infection (cumulative incidence, 1.9% vs. 1.0%; adjusted HR, 1.90 [CI, 1.07 to 3.37]). The lower risks for heart failure readmission associated with CRT-D compared with ICD therapy were most pronounced among patients with left bundle branch block or a QRS duration at least 150 ms and in women., Limitations: Patients were not randomly assigned to treatment groups, and few patients could be propensity-matched. The findings may not extend to younger patients or those outside of fee-for-service Medicare., Conclusion: In older patients with reduced left ventricular ejection fraction and prolonged QRS duration, CRT-D was associated with lower risks for death and readmission than ICD therapy alone., Primary Funding Source: Agency for Healthcare Research and Quality.

Background: The ICD Registry was established in 2006 in part to measure quality of care in patients undergoing implantation of implantable cardioverter-defibrillators (ICDs); however, whether outcomes have improved since initiation of the registry is unknown. Our objective was to examine changes over time in 3 quality metrics available from the registry., Methods and Results: We performed an observational study of 367 153 patients who received new ICD implants from April 2006 to March 2010. Three quality metrics were selected: Adverse events (in-hospital complications or mortality), optimal medical therapy (OMT), and cardiac resynchronization therapy (CRT). OMT was defined as prescription of β-blocker and either angiotensin-converting enzyme inhibitor or angiotensin receptor blocker in eligible patients. CRT eligibility was determined by QRS ≥120 ms, left ventricular ejection fraction ≤35%, and New York Heart Association class III/IV. Observation periods were divided into four 12-month intervals. We analyzed changes over time and used hierarchical logistic regression to adjust for potential confounders. Adverse events decreased over time (3.7% to 2.8%, P<0.001). Among eligible patients, rates of OMT and CRT increased over time (OMT: 69.0% to 74.3%, P<0.001; CRT: 80.5% to 84.2%, P<0.001). After adjustment for potential confounders, patients were significantly less likely to experience adverse events in year 4 than in year 1 (odds ratio, 0.75; 95% confidence interval, 0.71-0.79) and significantly more likely to receive OMT (odds ratio, 1.29; 95% confidence interval, 1.26-1.32) and CRT (odds ratio, 1.42; 95% confidence interval, 1.35-1.49)., Conclusions: Since initiation of the ICD Registry, adverse events have been decreasing, and rates of OMT and CRT among eligible patients have been increasing, although there is still significant room for improvement.

Importance: The benefits of cardiac resynchronization therapy (CRT) in clinical trials were greater among patients with left bundle-branch block (LBBB) or longer QRS duration., Objective: To measure associations between QRS duration and morphology and outcomes among patients receiving a CRT defibrillator (CRT-D) in clinical practice., Design, Setting, and Participants: Retrospective cohort study of Medicare beneficiaries in the National Cardiovascular Data Registry's ICD Registry between 2006 and 2009 who underwent CRT-D implantation. Patients were stratified according to whether they were admitted for CRT-D implantation or for another reason, then categorized as having either LBBB or no LBBB and QRS duration of either 150 ms or greater or 120 to 149 ms., Main Outcomes and Measures: All-cause mortality; all-cause, cardiovascular, and heart failure readmission; and complications. Patients underwent follow-up for up to 3 years, with follow-up through December 2011., Results: Among 24 169 patients admitted for CRT-D implantation, 1-year and 3-year mortality rates were 9.2% and 25.9%, respectively. All-cause readmission rates were 10.2% at 30 days and 43.3% at 1 year. Both the unadjusted rate and adjusted risk of 3-year mortality were lowest among patients with LBBB and QRS duration of 150 ms or greater (20.9%), compared with LBBB and QRS duration of 120 to 149 ms (26.5%; adjusted hazard ratio [HR], 1.30 [99% CI, 1.18-1.42]), no LBBB and QRS duration of 150 ms or greater (30.7%; HR, 1.34 [99% CI, 1.20-1.49]), and no LBBB and QRS duration of 120 to 149 ms (32.3%; HR, 1.52 [99% CI, 1.38-1.67]). The unadjusted rate and adjusted risk of 1-year all-cause readmission were also lowest among patients with LBBB and QRS duration of 150 ms or greater (38.6%), compared with LBBB and QRS duration of 120 to 149 ms (44.8%; adjusted HR, 1.18 [99% CI, 1.10-1.26]), no LBBB and QRS duration of 150 ms or greater (45.7%; HR, 1.16 [99% CI, 1.08-1.26]), and no LBBB and QRS duration of 120 to 149 ms (49.6%; HR, 1.31 [99% CI, 1.23-1.40]). There were no observed associations with complications., Conclusions and Relevance: Among fee-for-service Medicare beneficiaries undergoing CRT-D implantation in clinical practice, LBBB and QRS duration of 150 ms or greater, compared with LBBB and QRS duration less than 150 ms or no LBBB regardless of QRS duration, was associated with lower risk of all-cause mortality and of all-cause, cardiovascular, and heart failure readmissions.

Objectives: We sought to describe the incidence of acute lead dislodgements and the consequences of these events in patients enrolled in the National Cardiovascular Data Registry (NCDR) Implantable Cardioverter-Defibrillator (ICD) Registry., Background: Lead dislodgements are common adverse events in patients undergoing ICD implants. Little is known regarding who is at risk and the consequences of these events., Methods: Patients enrolled between April 2006 and September 2008 were included. Acute lead dislodgement was defined as movement of the lead requiring another procedure for repositioning before discharge., Results: Acute dislodgement occurred in 2,628 of 226,764 patients. Univariate variables associated with dislodgements included older age, female sex, and patients with atrial fibrillation, chronic lung disease, cerebrovascular disease, nonischemic cardiomyopathy, and lower ejection fractions (all p < 0.002). After multivariate adjustment, factors associated with an increased risk for dislodgement included New York Heart Association functional class IV heart failure, atrial fibrillation/flutter, having a cardiac resynchronization therapy-defibrillator device, and procedures performed by physicians trained under alternative pathways. A teaching/training hospital setting was not a factor (p = 0.64). Acute dislodgements had increased odds for other adverse events including cardiac arrest, cardiac tamponade, device infection, pneumothorax, and in-hospital death even after adjustment for potential confounders (all p < 0.0001)., Conclusions: Acute lead dislodgements occur more often in patients with more comorbidities and in patients undergoing implants by nonelectrophysiology-trained implanters. These events were strongly associated with increased odds for in-hospital death., (Copyright © 2010 American College of Cardiology Foundation. Published by Elsevier Inc. All rights reserved.)

BackgroundContemporary data on national trends and outcomes in cardiac resynchronization therapy with defibrillator (CRT-D) recipients following the 2012 updated guidelines has not been studied.ObjectivesThis study assessed the trends in long-term outcomes among CRT-D Medicare-aged recipients implanted in 2011-2015.MethodsPatients aged ≥65 years undergoing de novo CRT-D implantation in the National Cardiovascular Data Implantable Cardiac Defibrillator Registry from 2011-2015 with follow-up through 2017 using Medicare data were included and stratified by year of implant. Patient characteristics, in-hospital outcomes, and outcomes up to 2 years following implant were evaluated.ResultsAmong 53,174 patients (aged 75.6-6.4 years, 29.7% women) implanted with CRT-D from 2011 to 2015, there was an increase in implantations based on guideline-concordant recommendations (81.0% to 84.7%, P < .001). Compared to 2011, in-hospital procedural complications decreased in 2015 (3.9% vs 2.9%; adjusted odds ratio, 0.76, 95% confidence interval, 0.66-0.88, P < .001), driven in part by decreased lead dislodgement (1.4% vs 1.0%). After multivariable adjustment, there was a lower risk of all-cause hospitalization, cardiovascular hospitalization, and mortality at 2-year follow-up in 2015 as compared to 2011, while there were no differences in heart failure hospitalizations at follow-up.ConclusionAmong Medicare beneficiaries receiving CRT-D from 2011 to 2015, there was an increase in implantations based on guideline-concordant recommendations. Furthermore, there has been a reduction in in-hospital complications and long-term outcomes, including cardiovascular hospitalization, all-cause hospitalization, and mortality; however, there has been no difference in the risk of heart failure hospitalization after adjustment.

BackgroundCardiac resynchronization therapy with defibrillator (CRT-D) reduces morbidity and mortality among selected patients with heart failure in clinical trials. The effectiveness of this therapy in clinical practice has not been well studied.Methods and resultsWe compared a cohort of 4471 patients from the National Cardiovascular Data Registry's Implantable Cardioverter-Defibrillator (ICD) Registry hospitalized primarily for heart failure and who received CRT-D between April 1, 2006, and December 31, 2009, to a historical control cohort of 4888 patients with heart failure without CRT-D from the Acute Decompensated Heart Failure National Registry (ADHERE) hospitalized between January 1, 2002, and March 31, 2006. Both registries were linked with Medicare claims to evaluate longitudinal outcomes. We included patients from the ICD Registry with left ventricular ejection fraction ≤35% and QRS duration ≥120 ms who were admitted for heart failure. We used Cox proportional hazards models to compare outcomes with and without CRT-D after adjustment for important covariates. After multivariable adjustment, CRT-D was associated with lower 3-year risks of death (hazard ratio, 0.52; 95% confidence interval, 0.48-0.56; P

Left ventricular (LV) lead implantation is often the most challenging aspect of cardiac resynchronization therapy (CRT) procedures; early studies reported implant failure rates in ∼10% of cases. The purpose of this study was to define rates, reasons for, and factors independently associated with LV lead implant failure. We studied patients with left bundle branch block and ejection fraction ≤ 35% who underwent planned de novo transvenous CRT implantation (2010–2016) and were reported to the National Cardiovascular Data Registry ICD Registry. Independent predictors of LV lead implant failure were determined using logistic regression; age, sex, and variables with a univariable P value of <.15 were considered for inclusion in the model. Of the 111,802 patients who underwent a planned CRT procedure, 3.6% of patients (n = 3979) had LV lead implant failure. Reasons for implant failure included venous access (7.5%), coronary sinus access (64.3%), tributary vein access (13.5%), coronary sinus dissection (7.6%), unacceptable threshold (4.4%), and diaphragmatic stimulation (1.7%). Significant independent predictors of LV lead implant failure included younger age (odds ratio [OR] 1.01; 95% confidence interval [CI] 0.1.01–1.02), female sex (OR 1.38; 95% CI 1.29–1.47), black race (vs white, OR 1.44; 95% CI 1.32–1.57), Hispanic ethnicity (OR 1.23; 95% CI 1.08–1.40), QRS duration (OR 1.055 per 10 ms; 95% CI 1.038–1.072 per 10 ms), obstructive sleep apnea (OR 1.14; 95% CI 1.04–1.24), and implantation by a physician without specialized training (vs electrophysiology trained, OR 1.53; 95% CI 1.34–1.76). LV lead implant failure is uncommon in the current era and is most commonly due to coronary sinus access failure. Predictors of LV lead implant failure included younger age, female sex, black race, Hispanic ethnicity, increased QRS duration, sleep apnea, and absence of electrophysiology training. [ABSTRACT FROM AUTHOR]

Background Patients undergoing implantable cardioverter-defibrillator (ICD) implantations have high rates of long-term device-related complications and reoperations. Whether physician specialty training is associated with differences in long-term outcomes following ICD implantation is unclear. Methods and Results We linked data from the National Cardiovascular Data Registry ICD Registry with Medicare fee-for-service claims to identify physicians who performed ≥10 index ICDs from 2006 to 2009. We used data from the American Board of Medical Specialties to group the specialty of the implanting physician into mutually exclusive categories: electrophysiologists, interventional cardiologists, general cardiologists, thoracic surgeons, and other specialties. Primary outcomes were long-term device-related complications requiring reoperations or hospitalizations and reoperations for reasons other than complications. We compared the cumulative incidence rates and case-mix adjusted rates of long-term outcomes of index ICD implantations across physician specialties. Our analysis had a median follow-up of 47 months and included 107 966 index ICD implantations. Electrophysiologists had the lowest rates of incident long-term device-related complications (14.1%; interventional cardiologists, 15.3%; general cardiologists, 15.4%; thoracic surgeons, 16.4%; other specialists, 15.2%; P<0.001) and reoperations for reasons other than complications (electrophysiologists, 16.7%; interventional cardiologists, 17.0%; general cardiologists, 18.0%; thoracic surgeons, 18.4%; other specialists, 18.0%; P<0.001). Compared with patients whose ICDs were implanted by electrophysiologists, patients with implantations performed by nonelectrophysiologists were at higher risk of having long-term device-related complications (relative risk for interventional cardiologists: 1.16 [95% CI, 1.08-1.25]; general cardiologists: 1.13 [1.08-1.18]; thoracic surgeons: 1.20 [1.06-1.37]; all P<0.001, but not other specialists: 1.08 [0.99-1.17]; P=0.07). Compared to patients with implantations performed by electrophysiologists, patients with implantations performed by general cardiologists and thoracic surgeons were at higher risk of reoperation for noncomplication causes (relative risk for general cardiologists: 1.10 [1.05-1.15]; thoracic surgeons: 1.16 [1.00-1.33]; both P<0.05). Conclusions Patients with ICD implantations performed by electrophysiologists had the lowest risks of having long-term device-related complications and reoperations for noncomplication causes. Consideration of physician specialty before ICD implantation may represent an opportunity to minimize long-term adverse outcomes. [ABSTRACT FROM AUTHOR]

Objectives: The purpose of the study was to define the extent and nature of cardiac resynchronization therapy (CRT) device usage outside consensus guidelines using national data. Background: Recent literature has shown that the application of CRT in clinical practice frequently does not adhere to evidence-based consensus guidelines. Factors underlying these practices have not been fully explored. Methods: From the National Cardiovascular Data Registry''s Implantable Cardiac-Defibrillator Registry, we defined a cohort of 45,392 cardiac resynchronization therapy-defibrillator (CRT-D) implants between January 2006 and June 2008 with a primary prevention indication. We defined “off-label” implants as those in which the ejection fraction was >35%, the New York Heart Association functional class was below III, or the QRS interval duration was <120 ms in the absence of a documented need for ventricular pacing. The relationships between patient, implanting physician, and hospital characteristics with off-label use were explored with multivariable hierarchical logistic regression models. Results: Overall, 23.7% of devices were placed without meeting all 3 implant criteria, most often due to New York Heart Association functional class below III (13.1% of implants) or QRS interval duration <120 ms (12.0%). Atrial fibrillation/flutter, previous percutaneous coronary intervention, and the performance of an electrophysiology study before implant were independently associated with increased odds of off-label use, whereas diabetes mellitus, increasing age, and female sex were associated with decreased odds. Physician training and insurance payer were weakly associated with the likelihood of off-label use. Conclusions: Nearly 1 in 4 patients receiving CRT devices in the study time frame did not meet guideline-based indications. Given the evolving evidence base supporting the use of CRT, these practices require careful scrutiny. [Copyright &y& Elsevier]