Implantable Cardioverter-defibrillator Utilization Research Articles

Regional disparities and risk factors of mortality among patients at high risk of sudden cardiac death in emerging countries: a nonrandomized controlled trial

BackgroundComprehensive data on patients at high risk of sudden cardiac death (SCD) in emerging countries are lacking. The aim was to deepen our understanding of the SCD phenotype and identify risk factors for death among patients at high risk of SCD in emerging countries.MethodsPatients who met the class I indication for implantable cardioverter-defibrillator (ICD) implantation according to guideline recommendations in 17 countries and regions underrepresented in previous trials were enrolled. Countries were stratified by the WHO regional classification. Patients were or were not implanted with an ICD at their discretion. The outcomes were all-cause mortality and SCD.ResultsWe enrolled 4222 patients, and 3889 patients were included in the analysis. The mean follow-up period was 21.6 ± 10.2 months. There were 433 (11.1%) instances of all-cause mortality and 117 (3.0%) cases of SCD. All-cause mortality was highest in primary prevention (PP) patients from Southeast Asia and secondary prevention (SP) patients from the Middle East and Africa. The SCD rates among PP and SP patients were both highest in South Asia. Multivariate Cox regression modelling demonstrated that in addition to the independent predictors identified in previous studies, both geographic region and ICD use were associated with all-cause mortality in patients with high SCD risk. Primary prophylactic ICD implantation was associated with a 36% (HR = 0.64, 95% CI 0.531–0.802, p < 0.0001) lower all-cause mortality risk and an 80% (HR = 0.20, 95% CI = 0.116–0.343, p < 0.0001) lower SCD risk.ConclusionsThere was significant heterogeneity among patients with high SCD risk in emerging countries. The influences of geographic regions on patient characteristics and outcomes were significant. Improvement in increasing ICD utilization and uptake of guideline-directed medical therapy in emerging countries is urgent.Trial registrationClinicalTrials.gov, NCT02099721.

Implantable cardioverter defibrillator use in arrhythmogenic right ventricular cardiomyopathy in North America and Europe.

Implantable cardioverter-defibrillators (ICDs) are critical for preventing sudden cardiac death (SCD) in arrhythmogenic right ventricular cardiomyopathy (ARVC). This study aims to identify cross-continental differences in utilization of primary prevention ICDs and survival free from sustained ventricular arrhythmia (VA) in ARVC. This was a retrospective analysis of ARVC patients without prior VA enrolled in clinical registries from 11 countries throughout Europe and North America. Patients were classified according to whether they received treatment in North America or Europe and were further stratified by baseline predicted VA risk into low- (<10%/5 years), intermediate- (10%-25%/5 years), and high-risk (>25%/5 years) groups. Differences in ICD implantation and survival free from sustained VA events (including appropriate ICD therapy) were assessed. One thousand ninety-eight patients were followed for a median of 5.1 years; 554 (50.5%) received a primary prevention ICD, and 286 (26.0%) experienced a first VA event. After adjusting for baseline risk factors, North Americans were more than three times as likely to receive ICDs {hazard ratio (HR) 3.1 [95% confidence interval (CI) 2.5, 3.8]} but had only mildly increased risk for incident sustained VA [HR 1.4 (95% CI 1.1, 1.8)]. North Americans without ICDs were at higher risk for incident sustained VA [HR 2.1 (95% CI 1.3, 3.4)] than Europeans. North American ARVC patients were substantially more likely than Europeans to receive primary prevention ICDs across all arrhythmic risk strata. A lower rate of ICD implantation in Europe was not associated with a higher rate of VA events in those without ICDs.

Disparities in Referral and Utilization of Implantable Cardioverter-Defibrillators for Primary Prevention of Sudden Cardiac Death.

Implantable cardioverter-defibrillators (ICDs) reduce mortality in patients with reduced left ventricular ejection fraction (LVEF). We investigated sex disparities in a contemporary Canadian population for utilization of primary prevention ICDs. This was a retrospective cohort study on patients with reduced LVEF admitted to hospitals from 2010 to 2020 in Nova Scotia (population= 971,935). There were 4406 patients eligible for ICDs: 3108 (71%) men and 1298 (29%) women. The mean follow-up time was 3.9 ± 3.0 years. Rates of coronary disease were similar between men and women (45.8% vs 44.0%; P= 0.28), but men had lower LVEF (26.6 ± 5.9% vs 27.2 ± 5.8%; P= 0.0017). The referral rate for ICD was 11% (n= 487), with 13% of men (n= 403) and 6.5% of women (n= 84) referred (P < 0.001). The ICD implantation rate in the population was 8% (n= 358), with 9.5% of men (n= 296) and 4.8% of women (n= 62) (P < 0.001) receiving the device. Men were more likely than women to receive an ICD (odds ratio 2.08, 95% confidence interval 1.61-2.70; P < 0.0001)). There was no significant difference in mortality between men and women (P= 0.2764). There was no significant difference in device therapies between men and women (43.8% vs 31.1%; P= 0.0685). A significant disparity exists in the utilization of primary prevention ICDs between men and women in a contemporary Canadian population.

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.

MP-453089-11 DIFFERENCES IN UTILIZATION OF PRIMARY PREVENTION IMPLANTABLE CARDIOVERTER DEFIBRILLATORS IN ARRHYTHMOGENIC RIGHT VENTRICULAR CARDIOMYOPATHY ACROSS NORTH AMERICA AND EUROPE

Implantable cardioverter-defibrillators (ICDs) are critical for preventing sudden cardiac death (SCD) in patients with arrhythmogenic right ventricular cardiomyopathy (ARVC), but differences in their utilization across North America and Europe are unknown. To identify cross-national differences in both utilization of primary prevention ICDs and survival free from ventricular arrhythmia (VA) in patients with ARVC. This was a retrospective analysis of ARVC patients without prior sustained VA enrolled in clinical registries in 11 countries throughout Europe and North America. Patients were classified according to whether they received treatment in North America or Europe. They were further stratified by their calculated 5-year VA risk (low: <10%/5y, intermediate: 10-25%/5y, high: >25%/5y) using the ARVC risk calculator (ARVCrisk.com). Differences in rates of ICD implantation and VA-free survival were assessed using the Kaplan-Meier method and log-rank testing. Differences in VA-free survival were also assessed in the subset of patients without ICD. 1,098 patients were followed for a median of 5.1 years, during which time 554 (50.5%) received a primary prevention ICD. Patients treated in Europe were more likely to be probands (61.5% vs 52.0%, p=0.002) and were diagnosed at older ages (42 vs. 32 years, p<0.001). Baseline 5-year VA risk was similar (19.5% vs 19.4, p-value 0.71). North Americans were twice as likely to receive primary prevention ICDs (13.6%/year vs. 6.4%/year, p<0.001) and had shorter times from diagnosis to ICD implantation (83 days vs. 243 days, p<0.001). Overall, 285 patients (25.9%) experienced a first sustained VA event. Rates of VA were higher in North Americans compared to Europeans (6.0%/year versus 4.2%/year, p<0.001); this increase was driven primarily by higher rates of appropriate ICD therapy in North Americans (70.7% vs 59.3% of events). In sub-analysis of patients without ICD, North Americans had higher rates of VA events than Europeans (3.4%/year vs 2.4%/year, p=0.01). When stratified by baseline VA risk, North Americans received significantly more ICDs at all risk strata despite similar rates of VA events in low and intermediate risk patients (Figure). North American ARVC patients were significantly more likely to receive primary prevention ICDs across all risk strata than their European counterparts. However, a lower rate of primary prevention ICD implantation in Europe was not associated with a higher rate of adverse VA outcomes.

The Relevance of Preventive Implantable Cardioverter-Defibrillators (ICDs) in Non-Ischemic Cardiomyopathy in the Presence of Effective Quadruple Therapy for Heart Failure: A Review of Contemporary Medical Literature.

Cardiomyopathy is a disease of the cardiomyocytes that affects their structural function, leading to heart failure (HF). Non-ischemic cardiomyopathy (NICM) includes a subtype of dilated cardiomyopathy (DCM), restrictive cardiomyopathy (RCM), and hypertrophic cardiomyopathy (HCM). These types of cardiomyopathies have no coronary artery vessel involvement. The most common cause of NICM is DCM. In the ischemic cardiomyopathy (ICM) subtype, the utilization of implantable cardioverter-defibrillators (ICDs) has been effective in the prevention of sudden cardiac death (SCD). However, the relevance of ICDs in patients with NICM having an ejection fraction (EF) ≤35%, who are also receiving effective quadruple therapy (i.e., angiotensin-converting enzyme (ACE) inhibitors or angiotensin receptor blockers (ARB), beta-blockers, mineralocorticoid receptor antagonists, and sodium-glucose cotransporter-2 (SGLT2) inhibitors)for HF has been a topic of debate.The purpose of this review is to analyze the benefits of preventive ICDs in NICM patients on adequate quadruple therapy for HF. The current guidelines recommend ICD implantation in patients with NICM who have a left ventricular ejection fraction of ≤35%, come under the New York Heart Association (NYHA) class II or III, andare in sinus rhythm with optimal medical therapy. The evidence supporting this recommendation islimited. Numerous clinical studies and meta-analyses have been conducted to look into this issue. While some have discovered a substantial decrease in mortality with the implantation of an ICD in patients with NICM, others have not found significant changes.Thereby, further investigations are required to define the function of ICDs in this population.

HeartFailure Burden by Autopsy, Guideline-Directed Medical Therapy, and ICD Utilization Among Sudden Deaths.

Studies of heart failure with reduced ejection fraction (HFrEF) and preserved ejection fraction (HFpEF) report high sudden cardiac death (SCD) rates but presume cardiac cause. Underlying causes, guideline-directed medical therapy (GDMT), and implantable cardioverter-defibrillator (ICD) use in community sudden deaths with heart failure (HF) are unknown. This study aims to assess the burden of HF, GDMT, and ICD use among autopsied sudden deaths in the POST SCD (Postmortem Systematic Investigation of Sudden Cardiac Death) study, a countywide postmortem study of all presumed SCDs. Incident WHO-defined (presumed) SCDs for individuals of ages 18 to 90 years were autopsied via prospective surveillance of consecutive out-of-hospital deaths in San Francisco County from February 1, 2011, to March 1, 2014. Sudden arrhythmic deaths (SADs) had no identifiable nonarrhythmic cause (eg, pulmonary embolism), and are thus considered potentially rescuable with ICD. Of 525 presumed SCDs, 100 (19%) had HF. There were 85 patients with known HF (31 HFpEF, 54 HFrEF) and 15 with subclinical HF (postmortem evidence of cardiomyopathy and pulmonary edema without HF diagnosis). SADs comprised 56% (293 of 525) of all presumed SCDs, and 69% (69 of 100) of HF SCDs. The rates were similar in HFrEF (40 of 54 [74%]) and HFpEF (19 of 31 [61%], P=0.45). Four SAD patients (4%) had ICDs, 3 of which experienced device failure. Twenty-eight SCDs had ejection fraction≤35%: 22 (79%) with arrhythmic and 6 (21%) with noncardiac causes. Of the 22 SAD patients, 8 (36%) had no identifiable barrier to ICD referral. Complete use of GDMT in HFrEF was 6%. One in 5 community sudden deaths had HF; two-thirds had autopsy-confirmed arrhythmic causes. ICD prevention criteria captured only 8% (22 of 293) of all SAD cases countywide; GDMT and ICD use remain important targets for HF sudden death prevention.

Utilization, Outcomes and Costs of Implantable Cardioverter Defibrillators in Italy: A Population-Based Analysis Using Healthcare Administrative Databases

Introduction: The high cost of treatment with an implantable cardioverter defibrillator (ICD) requires continuous monitoring of its real effectiveness and appropriateness. The aim of this study was to evaluate epidemiological and economic impacts of ICD therapy in Lombardy, the most populated Italian region. Materials and Methods: We extracted data from DENALI, a data warehouse that organizes healthcare administrative databases concerning about ten million people covered by the Lombardy Health System (LHS). We estimated annual rates of first implant and of first replacement from 2000 to 2008. The cohort of patients who underwent a first ICD implantation between 2005 and 2007 was followed from discharge to December 31, 2008 in order to evaluate mean annual total healthcare cost per-capita, mortality and device replacement. Results: We identified 12,732 first implants and 4,833 replacements performed from 2000 to 2008 and we estimated the annual rates: first ICD implants increased from 55 to 236 (per million person-years), and the first replacement rates increased with a peak in 2005. A first ICD implantation cost €23,934 (standard deviation 4,986) on average and the LHS bore a further mean annual cost of €5,760 (95% confidence interval 5,592-5,931) percapita during follow-up: 17% due to drugs, 12% to outpatient visits and 71% to hospitalizations. Conclusions: The results confirm the increase in ICD utilization in Italy, especially in the Lombardy region, and its high economic burden. Age and comorbidities of ICD recipients should be considered in assessing care since they influence survival outcome. Moreover, this study shows how healthcare administrative databases could be useful to understand the impact of a health intervention in large unselected populations.

Utilization of Implantable Cardioverter-Defibrillators in Patients With Heart Transplant (from National Inpatient Sample Database)

Heart transplant (HT) recipients represent a unique and vulnerable population in whom medium and long-term outcomes are significantly affected by the risk of arrhythmias and sudden cardiac death. The use of implantable cardioverter-defibrillators (ICDs) in this population remains debated. A retrospective analysis of the National Inpatient Sample data between 2009 and 2018 was conducted. Hospitalization data on patients who underwent HT, or who had a preexisting HT, and who received a new ICD were included (excluding the preexisting ICD). Outcomes assessed included inpatient mortality, length of stay, and inflation-adjusted costs. We explored temporal trends in ICD placement and mean length of stay, and predictors of ICD placement. Between 2009 and 2018, 22,673 hospitalizations were recorded for HT, during which patients either received a concurrent new ICD placement (n=70 [0.31%]) or no new ICD placement (n=22,603 [99.7%]). During the same period, 146,555 admissions were recorded in patients with a history of HT. ICD placement in patients with a preexisting HT was associated with significantly higher inflation-adjusted costs ($55,680.7 vs $17,219.2; p<0.001). Predictors of ICD placement in preexisting patients with HT included cardiac arrest during hospitalization (odds ratio [OR]:14.3 [3.5 to 58.6]), drug abuse (OR:6.0 [1.3 to 27.1]), and previous PCI (OR:6.0 [2.1 to 17.3]). In conclusion, ICD placement in patients with HT history was associated with significantly higher inflation-adjusted costs. In patients with HT history, factors predicting ICD placement included cardiac arrest at hospitalization, previous PCI, and drug abuse.

EP News: Allied Professionals

Using a multinational registry, Nauffal et al (Eur Heart J 2021;42:3932, PMID 34491319) sought to determine whether there are differences between centers in the United States (US) and those outside the US (non-US) in the utilization of implantable cardioverter-defibrillators (ICDs) and outcome in patients with hypertrophic cardiomyopathy (HCM). The Sarcomeric Human Cardiomyopathy Registry is an association of 8 US and 5 non-US tertiary care centers collecting and maintaining data on patients with HCM, including baseline clinical data, changes in clinical data over time, and data on longitudinal follow-up and outcome.

Worldwide differences in primary prevention implantable cardioverter defibrillator utilization and outcomes in hypertrophic cardiomyopathy.

Risk stratification algorithms for sudden cardiac death (SCD) in hypertrophic cardiomyopathy (HCM) and regional differences in clinical practice have evolved over time. We sought to compare primary prevention implantable cardioverter defibrillator (ICD) implantation rates and associated clinical outcomes in US vs. non-US tertiary HCM centres within the international Sarcomeric Human Cardiomyopathy Registry. We included patients with HCM enrolled from eight US sites (n = 2650) and five non-US (n = 2660) sites and used multivariable Cox-proportional hazards models to compare outcomes between sites. Primary prevention ICD implantation rates in US sites were two-fold higher than non-US sites (hazard ratio (HR) 2.27 [1.89-2.74]), including in individuals deemed at high 5-year SCD risk (≥6%) based on the HCM risk-SCD score (HR 3.27 [1.76-6.05]). US ICD recipients also had fewer traditional SCD risk factors. Among ICD recipients, rates of appropriate ICD therapy were significantly lower in US vs. non-US sites (HR 0.52 [0.28-0.97]). No significant difference was identified in the incidence of SCD/resuscitated cardiac arrest among non-recipients of ICDs in US vs. non-US sites (HR 1.21 [0.74-1.97]). Primary prevention ICDs are implanted more frequently in patients with HCM in US vs. non-US sites across the spectrum of SCD risk. There was a lower rate of appropriate ICD therapy in US sites, consistent with a lower-risk population, and no significant difference in SCD in US vs. non-US patients who did not receive an ICD. Further studies are needed to understand what drives malignant arrhythmias, optimize ICD allocation, and examine the impact of different ICD utilization strategies on long-term outcomes in HCM.

The mortality analysis of primary prevention patients receiving a cardiac resynchronization defibrillator (CRT-D) or implantable cardioverter-defibrillator (ICD) according to guideline indications in the improve SCA study.

In primary prevention (PP) patients the utilization of implantable cardioverter-defibrillators (ICD) and cardiac resynchronization therapy-defibrillators (CRT-D) remains low in many geographies, despite the proven mortality benefit. The objective of this analysis was to examine the mortality benefit in PP patients by guideline-indicated device type: ICDand CRT-D. Improve sudden cardiac arrest was a prospective, nonrandomized, nonblinded multicenter trial that enrolled patients from regions where ICD utilization is low. PP patient's CRT-D or ICD eligibility was based upon the 2008 ACC/AHA/HRS and 2006 ESC guidelines. Mortality was assessed according to guideline-indicated device type comparing implanted and nonimplanted patients. Cox proportional hazards methods were used, adjusting for known factors affecting mortality risk. Among 2618 PP patients followed for a mean of 20.8 ± 10.8 months, 1073 were indicated for a CRT-D, and 1545 were indicated for an ICD. PP CRT-D-indicated patients who received CRT-D therapy had a 58% risk reduction in mortality compared with those without implant (adjusted hazard ratio [HR]: 0.42, 95% confidence interval [CI]: 0.28-0.61, p < .0001). PP patients with an ICD indication had a 43% risk reduction in mortality with an ICD implant compared with no implant (adjusted HR: 0.57, 95% CI: 0.41-0.81, p = .002). This analysis confirms the mortality benefit of adherence to guideline-indicated implantable defibrillation therapy for PP patients in geographies where ICD therapy was underutilized. These results affirm that medical practice should follow clinical guidelines when choosing therapy for PP patients who meet the respective defibrillator device implant indication.

The Pacemaker and Implantable Cardioverter-Defibrillator Registry of the Italian Association of Arrhythmology and Cardiac Pacing - Annual report 2019

The pacemaker (PM) and implantable cardioverter-defibrillator (ICD) Registry of the Italian Association of Arrhythmology and Cardiac Pacing (AIAC) monitors the main epidemiological data in real-world practice. The survey for the 2019 activity collects information about demographics, clinical characteristics, main indications for PM/ICD therapy and device types from the Italian collaborating centers. The Registry collects prospectively national PM and ICD implantation activity on the basis of European cards. PM Registry: data about 22 889 PM implantations were collected (19 621 first implants and 3268 replacements). The number of collaborating centers was 173. Median age of treated patients was 81 years (75 quartile I; 87 quartile III). ECG indications included atrioventricular conduction disorders in 33.3% of first PM implants, sick sinus syndrome in 16.4%, atrial fibrillation plus bradycardia in 11.6%, other in 38.7%. Among atrioventricular conduction defects, third-degree atrioventricular block was the most common type (18.3% of first implants). Use of single-chamber PMs was reported in 25.5% of first implants, of dual-chamber PMs in 67.1%, of PMs with cardiac resynchronization therapy (CRT) in 1.5%, and of single lead atrial-synchronized ventricular stimulation (VDD/R PMs) in 5.8%. ICD Registry: data about 17 328 ICD implantations were collected (12 129 first implants and 5199 replacements). The number of collaborating centers was 425. Median age of treated patients was 71 years (62 quartile I; 77 quartile III). Primary prevention indication was reported in 83.1% of first implants, secondary prevention in 16.9% (cardiac arrest in 5.9%). A single-chamber ICD was used in 26.1% of first implants, dual-chamber ICD in 28.0% and biventricular ICD in 45.9%. The PM and ICD Registry appears fundamental for monitoring PM and ICD utilization on a large national scale with rigorous examination of demographics and clinical indications. The PM Registry showed stable electrocardiographic and symptom indications, with an important prevalence of dual-chamber pacing. The use of CRT-PM regards a very limited number of patients. The ICD Registry documented a large use of prophylactic and biventricular ICD, reflecting a favorable adherence to trials and guidelines in clinical practice. In order to increase and optimize the cooperation of Italian implanting centers, online data entry (https://www.aiac.it/riprid) should be adopted at large scale.

Association between insurance status and in-hospital outcomes in patients with out-of-hospital ventricular fibrillation arrest.

BackgroundLack of health insurance is associated with adverse clinical outcomes; however, the association between health insurance status and in‐hospital outcomes after out‐of‐hospital ventricular fibrillation (OHVFA) arrest is unclear.HypothesisLack of health insurance is associated with worse in‐hospital outcomes after out‐of‐hospital ventricular fibrillation arrest.MethodsFrom January 2003 to December 2014, hospitalizations with a primary diagnosis of OHVFA in patients ≥18 years of age were extracted from the Nationwide Inpatient Sample. Patients were categorized into insured and uninsured groups based on their documented health insurance status. Study outcome measures were in‐hospital mortality, utilization of implantable cardioverter defibrillator (ICD), and cost of hospitalization. Inverse probability weighting adjusted binary logistic regression was performed to identify independent predictors of in‐hospital mortality and ICD utilization and linear regression was performed to identify independent predictors of cost of hospitalization.ResultsOf 188 946 patients included in the final analyses, 178 005 (94.2%) patients were insured and 10 941 (5.8%) patients were uninsured. Unadjusted in‐hospital mortality was higher (61.7% vs. 54.7%, p < .001) and ICD utilization was lower (15.3% vs. 18.3%, p < .001) in the uninsured patients. Lack of health insurance was independently associated with higher in‐hospital mortality (O.R = 1.53, 95% C.I. [1.46–1.61]; p < .001) and lower utilization of ICD (O.R = 0.84, 95% C.I [0.79–0.90], p < .001). Cost of hospitalization was significantly higher in uninsured patients (median [interquartile range], p‐value) ($) (39 650 [18 034‐93 399] vs. 35 965 [14 568.50‐96 163], p < .001).ConclusionLack of health insurance is associated with higher in‐hospital mortality, lower utilization of ICD and higher cost of hospitalization after OHVFA.

Associations Between Female Sex, Sarcomere Variants, and Clinical Outcomes in Hypertrophic Cardiomyopathy.

The impact of sex on phenotypic expression in hypertrophic cardiomyopathy (HCM) has not been well characterized in genotyped cohorts. Retrospective cohort study from an international registry of patients receiving care at experienced HCM centers. Sex-based differences in baseline characteristics and clinical outcomes were assessed. Of 5873 patients (3788 genotyped), 2226 (37.9%) were women. At baseline, women were older (49.0±19.9 versus 42.9±18.4 years, P<0.001) and more likely to have pathogenic/likely pathogenic sarcomeric variants (HCM patients with a sarcomere mutation; 51% versus 43%, P<0.001) despite equivalent utilization of genetic testing. Age at diagnosis varied by sex and genotype despite similar distribution of causal genes. Women were 3.6 to 7.1 years older at diagnosis (P<0.02) except for patients with MYH7 variants where age at diagnosis was comparable for women and men (n=492; 34.8±19.2 versus 33.3±16.8 years, P=0.39). Over 7.7 median years of follow-up, New York Heart Association III-IV heart failure was more common in women (hazard ratio, 1.87 [CI, 1.48-2.36], P<0.001), after controlling for their higher burden of symptoms and outflow tract obstruction at baseline, reduced ejection fraction, HCM patients with a sarcomere mutation, age, and hypertension. All-cause mortality was increased in women (hazard ratio, 1.50 [CI, 1.13-1.99], P<0.01) but neither implantable cardioverter-defibrillator utilization nor ventricular arrhythmia varied by sex. In HCM, women are older at diagnosis, partly modified by genetic substrate. Regardless of genotype, women were at higher risk of mortality and developing severe heart failure symptoms. This points to a sex-effect on long-term myocardial performance in HCM, which should be investigated further.

Abstract 16484: Primary Prevention Implantable Cardioverter Defibrillator Utilization for Hypertrophic Cardiomyopathy in US vs Non-US: Findings From the Share Registry

Introduction: Risk stratification for sudden cardiac death (SCD) in hypertrophic cardiomyopathy (HCM) has evolved with notable differences in international practice trends and US vs European guidelines. Hypothesis: Utilization of primary prevention implantable cardioverter defibrillators (ICD) is higher in the US. Methods: We examined rates of primary prevention ICD implantation in 5,063 HCM patients in the international SHaRe registry from 2000 - 2020 (NUS=2,390; Nnon-US=2,673). Using multiple logistic regression we compared probability of ICD implantation for US vs non-US sites adjusting for standard SCD risk factors (Figure 1A). Interaction tests were performed to identify risk factors differentially associated with ICD implantation in US vs non-US sites after 2014 when the European Society of Cardiology (ESC) risk score was introduced. Results: The odds of ICD implantation were 3-fold higher in US sites [ORUS/non-US=3.11 (2.54 -3.81)] (Figure 1A). Odds remained similar after adjustment for ESC risk score [OR =3.17 (2.57 -3.91)]. Implantation rates were higher in the US throughout the study period with a notable drop in rates in both US and non-US sites after 2014 and a reduction in the magnitude of the difference in ICD utilization between US and non-US sites (ORUS/non-US (&lt;2014) =4.20 (3.05-5.78) vs. ORUS/non-US (≥2014)=2.55 (1.89-3.44); pinteraction&lt;0.001) (Figure 1B). Non-sustained ventricular tachycardia was a stronger predictor of ICD implantation in US sites [ORUS=4.9 (3.4-7.0) vs ORnon-US= 2.1 (1.2-3.6); pinteraction=0.005], whereas, left atrial diameter (&gt; 40 mm) was a stronger predictor in non-US sites [ORNon-US=2.9 (2.1-4.0) vs ORUS=1.3 (1-1.6); pinteraction &lt;0.001]. Conclusions: ICD utilization rates vary globally. In this study, primary prevention ICD utilization rates were 3-fold higher in the US despite adjustment for standard SCD risk factors. Further studies are needed to evaluate outcomes of these practice differences.

Implantable Cardioverter Defibrillator Utilization and Mortality Among Patients ≥65 Years of Age With a Low Ejection Fraction After Coronary Revascularization

The purpose of this analysis was to assess implantable cardioverter-defibrillator (ICD) utilization and its association with mortality among patients ≥65 years of age after coronary revascularization. Patients in the National Cardiovascular Database Registry Chest Pain-Myocardial Infarction (MI) Registry who presented with MI from January 2, 2009 to December 31, 2016, had a left ventricular ejection fraction ≤35% and underwent in-hospital revascularization (10,014 percutaneous coronary intervention (PCI) and 1,647 coronary artery bypass grafting (CABG)) were linked with Medicare claims to determine rates of 1-year ICD implantation. The association between ICD implantation and 2-year mortality was assessed. Of 11,661 included patients, an ICD was implanted in 1,234 (10.6%) within 1 year of revascularization (1,063 (10.6%) PCI and 171 (10.4%) CABG). Among PCI-treated patients, in-hospital ventricular arrhythmia (adjusted hazard ratio [aHR] 1.60, 95% confidence interval [CI] 1.34 to 1.92), 2-week cardiology follow-up (aHR 1.48, 95% CI 1.29 to 1.70), readmission for heart failure (aHR 3.21, 95% CI 2.73 to 3.79), and readmission for MI (aHR 2.18, 95% CI 1.66 to 2.85) were positively associated with ICD implantation. Among CABG-treated patients, in-hospital ventricular arrhythmia (aHR 2.33, 95% CI 1.39 to 3.91), and heart failure readmission (aHR 3.14, 95% CI 1.96 to 5.04) were positively associated with ICD implantation. Women were less likely to receive an ICD, regardless of the revascularization strategy. ICD implantation was associated with lower 2-year all-cause mortality (aHR 0.74, 95% CI 0.63 to 0.86). In conclusion, only 1 in 10 Medicare patients with low ejection fraction received an ICD within 1 year after revascularization. Contact with the healthcare system after discharge was associated with higher likelihood of ICD implantation. ICD implantation was associated with lower mortality following revascularization for MI.

Seventeen-year trend (2001–2017) in pacemaker and implantable cardioverter-defibrillator utilization based on hospital discharge database data: An analysis by age groups

AimsTo analyze temporal trends (2001 -2017) of Pacemakers (PM) and Implantable Cardioverter-Defibrillators (ICD) procedures in Italy, according to the national Hospital Discharge Database (HDD). MethodsFrequency and implant rate (IR) in the Italian population were analyzed by age groups (<50, 50–79, ≥80 years). ResultsFrom 2001 (2009 for Cardiac Resynchronization Therapy-Defibrillator – CRT-D) to 2017, first PM implants (1stPM) increased from 36,823 (637/million inhabitants) to 49,716 (820/million), ICD implants from 3,141 (54/million) to 24,255 (400/million) and CRT-D from 2,915 (49/million, 16.5% of ICD) to 8,595 (142/million, 35.4% of ICD).ICD implants due to ventricular tachycardia or ventricular fibrillation decreased from 55.6% to 13.5% and from 15.9% to 4.5% respectively, while the proportion increased among patients with heart failure (from 22.9% to 46.8%), hypertension (from 11.1% to 15.0%), diabetes (from 6.5% to 10.9%), and renal insufficiency (from 4.4% to 7.6%). Both PM and ICD procedures markedly increased in patients ≥80 years old. However, while IR for ICDs increased from 82/million to 1,038/million inhabitants, IR of 1stPM only changed from 6,111/million to 6,212/million as the population in this age group nearly doubled in Italy. ConclusionSince 2001, the increase of 1stPM in Italy was mainly due to the ultra-octogenarian population growth. No differences were observed for IR in each PM age group, while the absolute number and IR increased in all groups (especially ≥80 years old) for ICDs and CRT-Ds. An increase in comorbidities and a reduction in implants for secondary prevention were observed in the ICD population.

Cost-Effectiveness of Implantable Cardioverter-Defibrillators in Children with Cardiac Conditions Associated with Risk for Sudden Cardiac Death.

Children at high risk for sudden cardiac death (SCD) receive implantable cardioverter-defibrillators (ICD) for prevention, but the cost effectiveness of ICDs in children at intermediate risk is unclear. Our objective was to create a cost-effectiveness model to compare costs and outcomes in children at risk of SCD, with and without ICD. Utilizing hypertrophic cardiomyopathy as the proxy disease, a theoretical cohort of 8150 children was followed for 69years. Model inputs were derived from the literature, with an incremental cost-effectiveness ratio (ICER) willingness-to-pay threshold of $100,000/quality-adjusted life year (QALY) used to delineate cost effectiveness. Outcomes included prevalence of severe neurological morbidity (SNM), SCD, cost, and QALYs. In children at intermediate risk of SCD (4-6% over 5years), ICD resulted in 56 fewer cases of SNM, 2686 fewer deaths. In children at high risk (> 6% over 5years), ICD placement resulted in 74 fewer cases of SNM and 3663 fewer deaths from cardiac causes. The costs of ICD were higher, but placement was cost effective with an ICER of $3009 per QALY in intermediate risk children, but ICD therapy was a dominant strategy in high-risk children. Sensitivity analysis demonstrated ICD placement was cost-effective until the annual probability of SCD was < 0.22%. The model was robust over a wide range of values. For children at risk of SCD, prophylactic ICD implantation is cost effective, resulting in improved outcomes and increased QALYs, despite increased costs. These findings highlight the economic benefits of ICD utilization in this population.

Implantable Cardioverter Defibrillator Use in Males with Duchenne Muscular Dystrophy and Severe Left Ventricular Dysfunction.

Duchenne muscular dystrophy (DMD) is characterized by myocardial fibrosis and left ventricular (LV) dysfunction. Implantable cardioverter defibrillator (ICD) use has not been characterized in this population but is considered for symptomatic patients with severe LV dysfunction (SLVD) receiving guideline-directed medical therapy (GDMT). We evaluated ICD utilization and efficacy in patients with DMD. Retrospective cohort study of DMD patients from 17 centers across North America between January 2, 2005 and December 31, 2015. ICD use and its effect on survival were evaluated in patients with SLVD defined as ejection fraction (EF) < 35% and/ or shortening fraction (SF) < 16% on final echocardiogram. SLVD was present in 57/436 (13.1%) patients, of which 12 (21.1%) died during the study period. Of these 12, (mean EF 20.9 ± 6.2% and SF 13.7 ± 7.2%), 8 received GDMT, 5 received steroids, and none received an ICD. ICDs were placed in 9/57 (15.8%) patients with SLVD (mean EF 31.2 ± 8.5% and SF 10.3 ± 4.9%) at a mean age of 20.4 ± 6.3years; 8/9 received GDMT, 7 received steroids, and all were alive at study end; mean ICD duration was 36.1 ± 26.2months. Nine ICDs were implanted at six different institutions, associated with two appropriate shocks for ventricular tachycardia in two patients, no inappropriate shocks, and one lead fracture. ICD use may be associated with improved survival and minimal complications in DMD cardiomyopathy with SLVD. However, inconsistent GDMT utilization may be a significant confounder. Future studies should define optimal indications for ICD implantation in patients with DMD cardiomyopathy.