National Cardiovascular Data Registry Implantable Cardioverter-defibrillator Research Articles

Long-Term Outcomes of Subcutaneous Versus Transvenous Implantable Cardioverter Defibrillator Use Among Patients on Maintenance Dialysis

Despite an elevated risk of sudden cardiac death among dialysis patients, implantable cardioverter defibrillators (ICDs) have not been shown to improve mortality and are associated with high complication rates. Subcutaneous (S-)ICDs may reduce the risk of complications for eligible dialysis patients, but safety and benefits versus transvenous (TV-)ICDs are unknown. To compare long-term outcomes between dialysis patients receiving S-ICD versus TV-ICDs. We performed a retrospective analysis of ICD implants among Fee-For-Service Medicare beneficiary dialysis patients in the National Cardiovascular Data Registry ICD Registry. Outcomes were ascertained from Medicare claims data. We compared survival outcomes, hospital admissions, and ICD- associated and dialysis vascular access-associated complications, between eligible S-ICD and single chamber TV-ICD recipients using stabilized inverse probability of treatment weighting. We identified 529 dialysis patients receiving S-ICDs and 842 receiving single chamber TV-ICDs who met the inclusion criteria. S-ICD recipients were younger, more often Black, and had a higher burden of cardiac disease and prior dialysis access interventions. After propensity weighting, there was no difference in the risk of death (HR 1.12, 95% CI 0.96-1.30), hospital admission (HR 1.01, 95% CI 0.88-1.16), bacteremia/sepsis (HR 1.01, 95% CI 0.80-1.26), device reoperation (HR 1.06, 95%CI 0.59-1.89) and subsequent dialysis access interventions (HR 1.12, 95% CI 0.86-1.46). In this representative longitudinal cohort study of dialysis patients, compared with TV-ICD, S-ICD was not associated with decreased risks of death, hospitalization, device complications, and dialysis access interventions.

Utilization and Outcomes of Primary Prevention Implantable Cardioverter-Defibrillators in Patients With Hypertrophic Cardiomyopathy.

Background There is uncertainty about the appropriate use of primary prevention implantable cardioverter-defibrillators (ICDs) among older patients with hypertrophic cardiomyopathy. Methods and Results Patients with hypertrophic cardiomyopathy who received a primary prevention ICD between 2010 and 2016 were identified using the National Cardiovascular Data Registry ICD Registry. Trends in ICD utilization and patient characteristics were assessed over time. Using linked Centers for Medicare and Medicaid Service claims data, Cox proportional hazard models assessed factors associated with mortality and postdischarge hospitalization for cardiac arrest/ventricular arrhythmia. Of 5571 patients with hypertrophic cardiomyopathy, 1511 (27.1%) were ≥65 years old. ICD utilization increased over time in all age groups. There were no changes in the prevalence of risk factors for sudden cardiac death over time. The variables most strongly associated with postdischarge mortality were older age (adjusted hazard ratio (aHR) 1.80 [95% CI, 1.47-2.21]), New York Heart Association class (III/IV versus I/II aHR 2.17 [95% CI, 1.57-2.98]), and left ventricular ejection fraction (left ventricular ejection fraction ≤35% versus >50% aHR 2.34 [95% CI, 1.58-3.48]; left ventricular ejection fraction 36%-50% versus >50% aHR 2.98 [95% CI, 2.02-4.40]), while history of nonsustained ventricular tachycardia (aHR 2.38 [95% CI, 1.62-3.51]) and New York Heart Association class (III/IV versus I/II aHR 1.84 [95% CI, 1.22-2.78]) were strongly associated with hospitalization for ventricular arrhythmia/cardiac arrest. Conclusions Primary prevention ICD utilization in patients with hypertrophic cardiomyopathy increased over time, including among those ≥65 years old. Among older patients, the strongest risk factors for hospitalization for ventricular arrhythmia/cardiac arrest following ICD implantation were history of nonsustained ventricular tachycardia and New York Heart Association class.

Survival Probability and Survival Benefit Associated With Primary Prevention Implantable Cardioverter-Defibrillator Generator Changes.

BackgroundAs patients derive variable benefit from generator changes (GCs) of implantable cardioverter‐defibrillators (ICDs) with an original primary prevention (PP) indication, better predictors of outcomes are needed.Methods and ResultsIn the National Cardiovascular Data Registry ICD Registry, patients undergoing GCs of initial non‐cardiac resynchronization therapy PP ICDs in 2012 to 2016, predictors of post‐GC survival and survival benefit versus control heart failure patients without ICDs were assessed. These included predicted annual mortality based on the Seattle Heart Failure Model, left ventricular ejection fraction (LVEF) >35%, and the probability that a patient's death would be arrhythmic (proportional risk of arrhythmic death [PRAD]). In 40 933 patients undergoing GCs of initial noncardiac resynchronization therapy PP ICDs (age 67.7±12.0 years, 24.5% women, 34.1% with LVEF >35%), Seattle Heart Failure Model–predicted annual mortality had the greatest effect size for decreased post‐GC survival (P<0.0001). Patients undergoing GCs of initial noncardiac resynchronization therapy PP ICDs with LVEF >35% had a lower Seattle Heart Failure Model–adjusted survival versus 23 472 control heart failure patients without ICDs (model interaction hazard ratio, 1.21 [95% CI, 1.11–1.31]). In patients undergoing GCs of initial noncardiac resynchonization therapy PP ICDs with LVEF ≤35%, the model indicated worse survival versus controls in the 21% of patients with a PRAD <43% and improved survival in the 10% with PRAD >65%. The association of the PRAD with survival benefit or harm was similar in patients with or without pre‐GC ICD therapies.ConclusionsPatients who received replacement of an ICD originally implanted for primary prevention and had at the time of GC either LVEF >35% alone or both LVEF ≤35% and PRAD <43% had worse survival versus controls without ICDs.

Trends in Use of Single- vs Dual-Chamber Implantable Cardioverter-Defibrillators Among Patients Without a Pacing Indication, 2010-2018

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. 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. 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. Implantation of a single- or dual-chamber ICD. 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. 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. 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.

Longitudinal Outcomes of Subcutaneous or Transvenous Implantable Cardioverter-Defibrillators in Older Patients

BackgroundThe subcutaneous (S-) implantable cardioverter-defibrillator (ICD) is an alternative to the transvenous (TV-) ICD that is increasingly implanted in younger patients; data on the safety and effectiveness of the S-ICD in older patients are lacking. ObjectivesThe purpose of this study was to compare outcomes among older patients who received an S- or TV-ICD. MethodsThe authors compared S-ICD and single-chamber TV-ICD implants in Fee-For-Service Medicare beneficiaries using the National Cardiovascular Data Registry ICD Registry. Outcomes were ascertained from Medicare claims data. Cox regression or competing-risk models (with TV-ICD as reference) with overlap weights were used to compare death and nonfatal outcomes (device reoperation, device removal for infection, device reoperation without infection, and cardiovascular admission), respectively. Recurrent all-cause readmissions were compared using Anderson-Gill models. ResultsA total of 16,063 patients were studied (age 72.6 ± 5.9 years, 28.4% women, ejection fraction 28.3 ± 8.9%). Compared with TV-ICD patients (n = 15,072), S-ICD patients (n = 991, 6.2% overall) were more often Black, younger, and dialysis dependent and less likely to have history of atrial fibrillation or flutter. In adjusted analyses, there were no differences between device type and risk of all-cause mortality (HR: 1.020; 95% CI: 0.819-1.270), device reoperation (subdistribution [s] HR: 0.976; 95% CI: 0.645-1.479), device removal for infection (sHR: 0.614; 95% CI: 0.138-2.736), device reoperation without infection (sHR: 0.975; 95% CI: 0.632-1.506), cardiovascular readmission (sHR: 1.087; 95% CI: 0.912-1.295), or recurrent all-cause readmission (HR: 1.072; 95% CI: 0.990-1.161). ConclusionsIn a large representative national cohort of older patients undergoing ICD implantation, risk of death, device reoperation, device removal for infection, device reoperation without infection, and cardiovascular and all-cause readmission were similar among S- and TV-ICD recipients.

Hospital Characteristics and Early Enrollment Trends in the American College of Cardiology Voluntary Public Reporting Program

Limited data exist regarding the characteristics of hospitals that do and do not participate in voluntary public reporting programs. To describe hospital characteristics and trends associated with early participation in the American College of Cardiology (ACC) voluntary reporting program for cardiac catheterization-percutaneous coronary intervention (CathPCI) and implantable cardioverter-defibrillator (ICD) registries. This cross-sectional study analyzed enrollment trends and characteristics of hospitals that did and did not participate in the ACC voluntary public reporting program. All hospitals reporting procedure data to the National Cardiovascular Data Registry (NCDR) CathPCI or ICD registries that were eligible for the public reporting program from July 2014 (ie, program launch date) to May 2017 were included. Stepwise logistic regression was used to identify hospital characteristics associated with voluntary participation. Enrollment trends were evaluated considering the date US News & World Report (USNWR) announced that it would credit participating hospitals. Data analysis was performed from March 2017 to January 2018. Hospital characteristics and participation in the public reporting program. By May 2017, 561 of 1747 eligible hospitals (32.1%) had opted to participate in the program. Enrollment increased from 240 to 376 hospitals (56.7%) 1 month after the USNWR announcement that program participation would be considered as a component of national hospital rankings. Compared with hospitals that did not enroll, program participants had increased median (IQR) procedural volumes for PCI (481 [280-764] procedures vs 332 [186-569] procedures; P < .001) and ICD (114 [56-220] procedures vs 62 [25-124] procedures; P < .001). Compared with nonparticipating hospitals, an increased mean (SD) proportion of participating hospitals adhered to composite discharge medications after PCI (0.96 [0.03] vs 0.92 [0.07]; P < .001) and ICD (0.88 [0.10] vs 0.81 [0.12]; P < .001). Hospital factors associated with enrollment included participation in 5 or more NCDR registries (odds ratio [OR],1.98; 95% CI, 1.24-3.19; P = .005), membership in a larger hospital system (ie, 3-20 hospitals vs ≤2 hospitals in the system: OR, 2.29; 95% CI, 1.65-3.17; P = .001), participation in an NCDR pilot public reporting program of PCI 30-day readmissions (OR, 2.93; 95% CI, 2.19-3.91; P < .001), university affiliation (vs government affiliation: OR, 3.85, 95% CI, 1.03-14.29; P = .045; vs private affiliation: OR, 2.22; 95% CI, 1.35-3.57; P < .001), Midwest location (vs South: OR, 1.47; 95% CI, 1.06-2.08; P = .02), and increased comprehensive quality ranking (4 vs 1-2 performance stars in CathPCI: OR, 8.08; 95% CI, 5.07-12.87; P < .001; 4 vs 1 performance star in ICD: OR, 2.26; 95% CI, 1.48-3.44; P < .001) (C statistic = 0.829). This study found that one-third of eligible hospitals participated in the ACC voluntary public reporting program and that enrollment increased after the announcement that program participation would be considered by USNWR for hospital rankings. Several hospital characteristics, experience with public reporting, and quality of care were associated with increased odds of participation.

Risk and predictors of mortality after implantable cardioverter-defibrillator implantation in patients with sarcoid cardiomyopathy

Implantable cardioverter-defibrillators (ICDs) are recommended for patients with cardiac sarcoidosis (CS) with an indication for pacing, prior ventricular arrhythmias, cardiac arrest, or left ventricular ejection fraction <35%, but data on outcomes are limited. Using data from the National Cardiovascular Data Registry ICD Registry between April 1, 2010 and December 31, 2015, we evaluated a propensity matched cohort of CS patients implanted with ICDs versus non-ischemic cardiomyopathies (NICM). We compared mortality using Kaplan-Meier survival curves and Cox proportional hazards models. We identified 1,638 patients with CS and 8,190 propensity matched patients with NICM. The rate of death at 1 and 2 years was similar in patients with CS and patients with NICM (5.2% vs 5.4%, P = 0.75 and 9.0% vs 9.3%, P = 0.72, respectively). After adjusting for other covariates, patients with CS had similar mortality at 2 years after ICD implantations compared with NICM patients (RR 1.03, 95% CI 0.87-1.23). Among patients with CS, multivariable logistic regression identified 6 factors significantly associated with increased 2-year mortality: presence of heart failure (HR 1.92, 95% CI 1.44-3.22), New York Heart Association (NYHA) Class III heart failure (HR 1.68, 95% CI 1.16-2.45), NYHA Class IV heart failure (HR 3.08, 95% CI 1.49-6.39), atrial fibrillation/flutter (HR 1.66, 95% CI 1.17-2.35), chronic lung disease (HR 1.64, 95% CI 1.17-2.29), creatinine >2.0 mg/dL (HR 4.07, 95% CI 2.63-6.30), and paced rhythm (HR 2.66, 95% CI 1.07-6.59). Mortality following ICD implantation was similar in CS patients compared with propensity matched NICM patients. Presence of heart failure, NYHA class, atrial fibrillation/flutter, chronic lung disease, renal dysfunction, and paced rhythm at time of implantation were all predictors of increased 2-year mortality among CS patients with ICDs.

Defibrillation Safety Margin Testing in Patients With Congenital Heart Disease: ResultsFromthe NCDR.

This study analyzed the predictors of defibrillation safety margin (DSM) testing at the time of implantable cardioverter-defibrillator (ICD) insertion and factors associated with inadequate DSM in patients with congenital heart disease (CHD). There are few data about the prevalence and safety of DSM testing in those with CHD. A retrospective analysis was performed of all patients with atrial or ventricular septal defect, tetralogy of Fallot, transposition of the great vessels, Ebstein anomaly, or common ventricle undergoing a transvenous ICD procedure in the National Cardiovascular Data Registry (NCDR) ICD Registry from April 2010 to March 2016, and DSM testing was assessed. Inadequate DSM was defined as a lowest successful energy tested<10J than the maximum output of the ICD generator. Of all ICD recipients (N=7,024), DSM testing was performed in 52.0% (n=3,654). The mean lowest successful energy tested was 20.7 ± 7.3 J. Of those with DSM adequacy data available (n=3,623), an inadequate DSM occurred in 13.8% (n=501). After multivariable adjustment, DSM testing was not associated with in-hospital complications or death (odds ratio [OR]: 1.00; 95% confidence interval [CI]: 0.79 to 1.28) but was associated with lower odds of prolonged hospital stay (>3days) (OR: 0.71; 95%CI: 0.60 to 0.84; p<0.0001). An inadequate DSM was not associated with in-hospital death or complications (OR: 1.27; 95%CI: 0.79 to 2.04) or prolonged hospital stay (OR: 1.34; 95%CI: 0.995 to 1.81). DSM testing is being performed less frequently over time and seems safe in those with CHD. An inadequate DSM was not associated with worse in-hospital outcomes.

Use and Outcomes of Dual Chamber or Cardiac Resynchronization Therapy Defibrillators Among Older Patients Requiring Ventricular Pacing in the National Cardiovascular Data Registry Implantable Cardioverter Defibrillator Registry

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. 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. 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. Implantation of a CRT-D or DC-ICD. 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. 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). 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.

Abstract 16496: Longitudinal Outcomes After Implantation of a Subcutaneous or Transvenous Implantable Cardioverter Defibrillator in Older Patients: A Report From the National Cardiovascular Data Registry

Introduction: The subcutaneous (S-) implantable cardioverter defibrillator (ICD) is an alternative to the transvenous (TV-) ICD that is increasingly implanted in younger patients. However, data on the safety and effectiveness of the S-ICD in older patients are lacking. Methods: We compared S-ICD and single chamber TV-ICD implants in Medicare beneficiaries (≥65yrs) using National Cardiovascular Data Registry ICD Registry data from 9/28/2012 through 12/31/2017. We excluded patients with prior pacemaker or ICD, an indication for pacing or resynchronization, and those undergoing implant in an acute setting. Mortality status was determined using the Medicare master summary beneficiary file. Cox regression analyses with overlap weights were used to compare all-cause mortality. Mean cumulative counts of all-cause readmissions were compared among for Fee for Service beneficiaries. Results: A total of 23,717 patients met inclusion criteria [mean age 72.7±5.8 years, 29% female, 69% ischemic heart disease, 33% atrial arrhythmias, 49% NYHA II, 31.7% NYHA III, ejection fraction (EF) 28±9%, 3% dialysis dependent, 20% with prior ventricular tachycardia]. Compared to TV-ICD patients (n=22,264), S-ICD patients (n=1,453, 6% overall) were more often male, black, diabetic, dialysis dependent and were less likely to have atrial or ventricular arrhythmias or ischemic heart disease. There was no difference in age or EF between the 2 groups. In adjusted analyses, during a median follow-up of 2.3 years (IQR: 1.2 - 3.5), there was no difference between the 2 groups in all-cause mortality (HR 1.04, CI 0.91-1.17, Figure A ) or readmissions (based on overlap of confidence intervals, Figure B ). Conclusions: In a large representative cohort of older patients undergoing ICD implant, all-cause mortality and readmission were similar among S-ICD and TV-ICD recipients. These findings support use of the S-ICD for the prevention of sudden cardiac death in appropriately selected older patients.

Mortality and readmission in non-ischemic compared with ischemic cardiomyopathies after implantable cardioverter-defibrillator implantation

Abstract Background/Introduction Uncertainty remains regarding the benefit of primary prevention ICDs overall in contemporary practice, and particularly in those with NICM compared with ICM. Purpose To evaluate the contemporary risk of death and readmission following following implantable cardioverter-defibrillator (ICD) implantation in patients with non-ischemic cardiomyopathies (NICM) compared with ischemic cardiomyopathies (ICM) in a large nationally representative cohort in the United States. Methods We used data from the American College of Cardiology (ACC) National Cardiovascular Data Registry (NCDR) ICD Registry linked with Medicare claims from April 1, 2010 to December 31, 2013 to establish a cohort of NICM and ICM patients with a left ventricular ejection fraction ≤35% who received a de novo, primary prevention ICD. We compared mortality, all-cause readmission, and heart failure readmission using Kaplan-Meier curves and Cox proportional hazard regressions models. We also evaluated temporal trends in mortality. Results Among 31,044 NICM and 68,458 ICM patients with a median follow up of 2.4 years, one-year mortality was significantly higher in ICM patients (12.3%) compared with NICM (7.9%, p&amp;lt;0.001). The higher mortality in ICM patients remained significant after adjustment for covariates (hazard ratio (HR) 1.40; 95% confidence interval (CI) 1.36 to 1.45), and was consistent in subgroup analyses. These findings were consistent across the duration of the study. ICM patients were also significantly more likely to be readmitted for all causes (adjusted HR 1.15, CI 1.12 to 1.18) and for heart failure (adjusted HR 1.25, CI 1.21 to 1.31). Conclusions The risks of mortality and hospital readmission after primary prevention ICD implantation were significantly higher in patients with ICM compared with NICM, and these findings were consistent across all patient subgroups tested and over the duration of the study. Funding Acknowledgement Type of funding source: None

Comparison of Mortality and Readmission in Non-Ischemic Versus Ischemic Cardiomyopathy After Implantable Cardioverter-Defibrillator Implantation

Data is lacking on the contemporary risk of death and readmission following implantable cardioverter-defibrillator (ICD) implantation in patients with non-ischemic cardiomyopathies (NICM) compared with ischemic cardiomyopathies (ICM) in a large nationally representative cohort. We performed a retrospective cohort study using the National Cardiovascular Data Registry ICD Registry linked with Medicare claims from April 1, 2010 to December 31, 2013. We established a cohort of NICM and ICM patients with a left ventricular ejection fraction ≤35% who received a de novo, primary prevention ICD. We compared mortality and readmission using Kaplan-Meier curves and Cox proportional hazard regressions models. We also evaluated temporal trends in mortality. In 31,044 NICM and 68,458 ICM patients with a median follow up of 2.4 years, 1-year mortality was significantly higher in ICM patients (12.3%) compared with NICM (7.9%, p < 0.001). The higher mortality in ICM patients remained significant after adjustment for covariates (hazard ratio [HR] 1.40; 95% confidence interval [CI] 1.36 to 1.45), and was consistent in subgroup analyses. These findings were consistent across the duration of the study. ICM patients were also significantly more likely to be readmitted for all causes (adjusted HR 1.15, CI 1.12 to 1.18) and for heart failure (adjusted HR 1.25, CI 1.21 to 1.31). In conclusion, the risks of mortality and hospital readmission after primary prevention ICD implantation were significantly higher in patients with ICM compared with NICM which was consistent across all patient subgroups tested and over the duration of the study.

Comparison of left ventricular lead upgrade vs continued medical care among patients eligible for cardiac resynchronization therapy at the time of defibrillator generator replacement: Predictors of left ventricular lead upgrade and associations with long-term outcomes

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. 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. 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. 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). 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.

Periprocedural Risk and Survival Associated With Implantable Cardioverter-Defibrillator Placement in Older Patients With Advanced Heart Failure

Little is known about the utilization rates and outcomes of implantable cardioverter-defibrillator (ICD) and cardiac resynchronization therapy defibrillator (CRT-D) placement among patients with advanced heart failure (HF). To examine utilization rates, patient characteristics, and outcomes of ICD and CRT-D placements among patients with advanced HF. This cohort study was a post hoc analysis of 81 492 Medicare fee-for-service beneficiaries enrolled in the National Cardiovascular Data Registry ICD Registry between January 2010 and December 2014. Inclusion criteria were patients who had received an HF diagnosis, had a left ventricular ejection fraction of 35% or lower, and showed evidence of advanced HF, which was defined as New York Heart Association (NYHA) class IV symptoms, inotrope use within the last 60 days, left ventricular assist device in situ, or orthotopic heart transplant listing. The comparator group included patients with NYHA class II and no HF hospitalization within the last 12 months, no left ventricular assist device, no orthotopic heart transplant listing, and no current or recent inotrope use. All eligible patients underwent first-time ICD or CRT-D placement for primary prevention of sudden cardiac death. Data were analyzed from January 2010 to December 2014. All-cause mortality and periprocedural complications. Of 81 492 Medicare patients, 3343 had advanced HF (4.1%) and 19 424 were in the comparator group (23.8%). Among the advanced HF population, the mean (SD) age of patients was 74 (9) years, and patients were predominantly white individuals (81.5%) and men (71.1%). The all-cause mortality rate at 30 days was 3.1% (95% CI, 2.6%-3.8%) in the advanced HF group vs 0.5% (0.4%-0.6%) in the comparator group (P < .001). In the advanced HF population, the aggregate in-hospital periprocedural complication rate was 3.74% (95% CI, 3.12%-4.44%) vs 1.10% (95% CI, 0.95%-1.25%) in the comparator group (P < .001). Most adverse events in this group were in-hospital fatality (1.82%; 95% CI, 1.40%-2.34%) and resuscitated cardiac arrest (1.05%; 95% CI, 0.73%-1.45%). Patients with NYHA class IV (hazard ratio, 1.40; 95% CI, 1.02-1.93; P = .04), ischemic heart disease (hazard ratio, 1.24; 95% CI, 1.04-1.48; P = .02), or diabetes (hazard ratio, 1.17; 95% CI, 1.04-1.33; P = .01) had a higher risk of death. Among patients undergoing ICD or CRT-D placement for primary prevention of sudden cardiac death, only a small proportion had advanced HF. These patients experienced clinically important periprocedural complication rates associated with in-hospital death and cardiac arrest relative to patients with nonadvanced HF.

Prevalence, predictors and complications with defibrillation threshold testing in pediatric patients: Results from the NCDR

BackgroundThere are little data about the prevalence and safety of DFT testing in pediatric populations. We analyzed the predictors and outcomes of defibrillation threshold (DFT) testing at the time of implantable cardioverter-defibrillator (ICD) implant and factors associated with inadequate defibrillation safety margin (DSM) in pediatric patients. MethodsWe performed a retrospective analysis of initial transvenous ICD implantations in the National Cardiovascular Data Registry (NCDR) ICD Registry of patients ≤21 years. DSM was defined as the lowest successful energy tested <10 J than the maximum output of the ICD. Subjects were followed to hospital discharge. ResultsOf all ICD recipients (n = 3943), DFT testing was performed in 64.0% (n = 2522) though decreased over time. In those with DFT data available (n = 2500), an inadequate DSM occurred in 13.6% (n = 339). After multivariable adjustment, DFT testing was not associated with in-hospital complications or death (OR 0.789, 95% CI 0.579–1.076), but was associated with lower odds of prolonged hospital stay (>3 days) (OR 0.543, 95% CI 0.436–0.677). An inadequate DSM was associated with an increased risk of complications or death (OR 1.893, 95% CI 1.203–2.979) but not with a prolonged hospital stay (OR 1.307, 95% CI 0.878–1.947). ConclusionsIn the largest dataset of DFT testing in pediatric ICD recipients, we found that DFT testing use decreased over time and was not associated with an increase in in-hospital complications in pediatric patients. An inadequate DSM, however, was associated with a higher rate of in-hospital complications or death.

Analysis of Temporal Trends and Variation in the Use of Defibrillation Testing in Contemporary Practice

Defibrillation testing (DFT) is performed during implantable cardioverter-defibrillator (ICD) implantation to assess the capacity of the device to detect and terminate ventricular arrhythmias. However, DFT can result in complications and omission of its use has been shown to be safe. To describe temporal trends and variation in the use of DFT in contemporary practice in the United States. This multicenter cross-sectional study used data from the National Cardiovascular Data Registry ICD Registry. A total of 499 211 patients from 1794 different facilities undergoing first-time ICD implantation from April 2010 to December 2015 were included. Data analysis was performed from May 20, 2015, to August 15, 2019. Defibrillation testing was assessed using the National Cardiovascular Data Registry ICD Registry. Defibrillation testing rates and median odds ratios (MORs) were assessed over time. The MOR represents the odds that a randomly selected patient receiving testing at a hospital with high testing rates would be tested compared with if he or she had received care at a hospital with low testing rates. Of the 499 211 patients from 1794 different facilities included in this analysis, the mean (SD) age of the population was 65.5 (13.4) years and 356 681 patients (71.4%) were men. The use of DFT declined from 71.6% in the first calendar quarter of 2010 to 36.4% in the fourth quarter of 2015 (P < .001). Patients undergoing DFT were more likely than those without testing to have ischemic heart disease (170 569 [58.1%] vs 116 295 [56.6%]), ventricular tachycardia (91 500 [31.2%] vs 58 949 [28.7%]), and less advanced heart failure (New York Heart Association class I and II, 153 188 [52.2%] vs 91 215 [44.4%]) (P < .001 for all). The MOR for the use of defibrillation testing was 3.78 (95% CI, 3.54-4.03) in 2010, increasing to 6.05 (95% CI, 5.61-6.52) in 2015, indicating that by 2015 a randomly selected patient receiving testing at a hospital with high testing rates would have a 6-fold higher odds of being tested than if they had received care at a hospital with low testing rates. Defibrillation testing at the time of ICD placement in the United States may have declined over time; however, institutional variation in its use appears to be marked and increased. This variability in the reduced use of defibrillation testing could reflect differences in individual or institutional cultures of practice.

Association of body mass index with cardiac resynchronization therapy intention and left ventricular lead implantation failure: insights from the NCDR implantable cardioverter-defibrillator registry.

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. We sought to evaluate whether patient body mass index (BMI) was associated with planned use and implantation failure of CRT-D therapy. 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. 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 > 40kg/m2) 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 > 40kg/m2) obesity was associated with higher odds of failed LV lead placement (AOR, 1.35; 95% CI, 1.07-1.72, p = 0.01). Compared with normal weight patients, extremely obese (BMI > 40kg/m2) CRT-D eligible patients were less likely to be prescribed CRT-D and were at higher odds for failed LV lead placement.

Outcomes following implantable cardioverter-defibrillator generator replacement in patients with recovered left ventricular systolic function: The National Cardiovascular Data Registry

Some patients with heart failure (HF) experience recovery of left ventricular (LV) systolic function by the end of their implantable cardioverter-defibrillator (ICD) generator battery life. Outcomes following generator replacement in this setting are poorly understood. We sought to describe outcomes following ICD generator replacement associated with recovery of LV systolic function. We evaluated 26,197 Medicare beneficiaries enrolled in the American College of Cardiology's National Cardiovascular Data Registry ICD Registry who underwent primary prevention ICD generator replacement between 2006 and 2009, stratified by LV ejection fraction (LVEF): reduced (LVEF ≤35%), partially recovered (LVEF >35% and ≤50%), and recovered (LVEF >50%). At the time of generator replacement, 1915 (7.3%) patients had recovered LVEF and 4576 (17.5%) had partially recovered LVEF. Periprocedural events were rare (<1%) in all patients. In patients with reduced LVEF, the incidence of HF readmission and mortality at 3 years was 27.5% and 32.7%, respectively. In comparison, the rates of HF readmission and mortality were lower for patients with partially recovered LVEF (readmission: 15.9%; hazard ratio [HR] 0.66; 95% confidence interval [CI] 0.61-0.72; mortality: 23.0%; HR 0.82; 95% CI 0.76-0.87) and those with recovered LVEF (readmission: 12.2%; HR 0.55; 95% CI 0.48-0.63; mortality: 18.2%; HR 0.72; 95% CI 0.64-0.80). Patients with partially recovered and recovered LVEF have lower risks of mid-term adverse outcomes than do those with reduced LVEF following ICD generator replacement. Approximately 3 in 4 patients continue to have reduced LVEF at the time of generator replacement and are at high risk of HF readmission and mortality. These data highlight the prognostic associations of LVEF in patients undergoing generator replacement as well as the clinical encounter for generator replacement as an opportunity to identify those at increased risk of adverse outcomes.

Device Therapies Among Patients Receiving Primary Prevention Implantable Cardioverter-Defibrillators in the Cardiovascular Research Network.

BackgroundPrimary prevention implantable cardioverter‐defibrillators (ICDs) reduce mortality in selected patients with left ventricular systolic dysfunction by delivering therapies (antitachycardia pacing or shocks) to terminate potentially lethal arrhythmias; inappropriate therapies also occur. We assessed device therapies among adults receiving primary prevention ICDs in 7 healthcare systems.Methods and ResultsWe linked medical record data, adjudicated device therapies, and the National Cardiovascular Data Registry ICD Registry. Survival analysis evaluated therapy probability and predictors after ICD implant from 2006 to 2009, with attention to Centers for Medicare and Medicaid Services Coverage With Evidence Development subgroups: left ventricular ejection fraction, 31% to 35%; nonischemic cardiomyopathy <9 months’ duration; and New York Heart Association class IV heart failure with cardiac resynchronization therapy defibrillator. Among 2540 patients, 35% were <65 years old, 26% were women, and 59% were white. During 27 (median) months, 738 (29%) received ≥1 therapy. Three‐year therapy risk was 36% (appropriate, 24%; inappropriate, 12%). Appropriate therapy was more common in men (adjusted hazard ratio [HR], 1.84; 95% confidence interval [CI], 1.43–2.35). Inappropriate therapy was more common in patients with atrial fibrillation (adjusted HR, 2.20; 95% CI, 1.68–2.87), but less common among patients ≥65 years old versus younger (adjusted HR, 0.72; 95% CI, 0.54–0.95) and in recent implants (eg, in 2009 versus 2006; adjusted HR, 0.66; 95% CI, 0.46–0.95). In Centers for Medicare and Medicaid Services Coverage With Evidence Development analysis, inappropriate therapy was less common with cardiac resynchronization therapy defibrillator versus single chamber (adjusted HR, 0.55; 95% CI, 0.36–0.84); therapy risk did not otherwise differ for Centers for Medicare and Medicaid Services Coverage With Evidence Development subgroups.ConclusionsIn this community cohort of primary prevention patients receiving ICD, therapy delivery varied across demographic and clinical characteristics, but did not differ meaningfully for Centers for Medicare and Medicaid Services Coverage With Evidence Development subgroups.

Centers for Medicare and Medicaid Services' Decision to Reconsider Coverage Indications for ICDs: Where to Now?

Several well-designed and conducted randomized clinical trials (RCTs) have proven the survival benefit of implantable cardioverter defibrillators (ICDs). This benefit has been demonstrated in patients who survive a cardiac arrest due to a ventricular tachyarrhythmia or have sustained ventricular tachycardia not due to a transient or a reversible cause. The survival benefit of ICDs has also been shown in patients with significant systolic dysfunction (left ventricular ejection fraction (LVEF) ≤35%) due to ischemic or non-ischemic cardiomyopathy. The compelling evidence on the benefits of ICDs led the Centers for Medicare and Medicaid services (CMS) to cover secondary and primary prevention ICDs in Medicare beneficiaries. However, for primary prevention ICDs, CMS provides coverage with evidence development that requires clinicians to enter data on primary prevention ICD implants in Medicare beneficiaries into the National Cardiovascular Data Registry (NCDR) ICD Registry.