Primary Prevention Implantable Cardioverter-defibrillator Research Articles

PO-04-226 RISK OF VENTRICULAR RECURRENT TACHYARRHYTHMIA IN PATIENTS RECEIVING PRIMARY PREVENTION IMPLANTABLE CARDIOVERTER-DEFIBRILLATORS

Implantable cardioverter-defibrillators (ICDs) have demonstrated efficacy in reducing mortality attributable to sustained ventricular tachyarrhythmia (VTA) and have been used for primary prevention of sudden death. However, patients with primary prevention ICDs remain at risk for first and recurrent VTA, which are associated with increased morbidity and mortality. Currently, there are limited data on factors associated with recurrent VTA after the occurrence of a first episode in this population. Improved risk stratification may help tailor advanced therapies, such as catheter ablation or antiarrhythmic medications, to patients at a high risk for recurrence. The objective of this study was to quantify the risk for recurrent VTA after the occurrence of a first VTA episode among patients with a primary prevention ICD. The population comprised patients enrolled in five landmark ICD trials (MADIT-II, MADIT-Risk, MADIT-CRT, MADIT-RIT, RAID) who experienced a first episode of VTA (defined as ventricular tachycardia [VT] ≥170 bpm or ventricular fibrillation [VF]) after ICD implantation (N=789). The primary endpoint was recurrent VTA after a first episode. All-cause mortality associated with recurrent VTA was a secondary endpoint. Among 789 study patients who experienced a first VTA after ICD implantation, mean age was 63 ± 11 years, 17% were women, 64% had ischemic cardiomyopathy, and mean left ventricular ejection fraction (EF) was 24 ± 7%. Kaplan Meier analysis showed the risk of recurrent VTA after a first episode was very high (60% at 3 years [Figure - A]). Findings were consistent regardless of baseline risk factors, including age, sex, NYHA Class, EF. Furthermore, the burden of multiple VTA episodes after a first episode was also high (average of 3.6 episodes per patient at 3 years [Figure B]). Recurrent VTA was associated with a significant two-fold increased risk of subsequent death (HR=2.15, 95% CI 1.40-3.32, p=0.001 [Figure - C]). Among primary prevention ICD recipients who experience a first VTA, the burden of recurrent VTA and subsequent mortality increase is very high regardless of baseline risk factors. Intensification of therapies, including early catheter ablation, should be considered in primary prevention ICD recipients who experience a first VTA.

PO-05-203 RISK OF APPROPRIATE ICD THERAPY IN PATIENTS WITH IMPROVED EF>35% AFTER INITIAL PRIMARY PREVENTION IMPLANT

Implantable cardioverter defibrillator (ICD) replacement in patients with heart failure with improved ejection fraction (HFimpEF, EF>35%) at the time of generator change is controversial. Assess the risk of appropriate ICD intervention (aICDi, anti-tachycardia pacing or shocks) in patients with HFimpEF >35%. Databases were searched for studies reporting patients who received ICD for primary prevention and HFimpEF, and aICDi including Ovid MEDLINE, EMBASE, Web of Science, and Google Scholar. The search was not restricted to time or publication status. The minimal follow up duration was one year. HFimpEF was defined as left ventricular reversed remodeling (LVRR, see Figures) with EF >35%. A total of 25 studies and 6,452 patients (3,061 with improved EF vs 3,391 with EF <35% during follow up) were included; mean follow up was 43 months (ranging between 12 to 74 months). Mean age was 63.5 and 75% were males. HFimpEF was associated with a lower risk of aICDi (OR 0.43, 95% CI 0.3-0.61; P<0.01; annual rate 5.1 vs. 10.3%). Subgroup analysis in HFimpEF patients who had not received aICDi before generator change showed a lower subsequent risk of VA and SCD (OR 0.26, 95% CI 0.12-0.59; P<0.01; annual rate 1.6 vs. 4.8%). Figures (A, B) HFimpEF is associated with reduced risk for aICDi in patients with primary prevention ICDs. HFimpEF patients who had not received aICDi before generator change had even lower subsequent risk, but the 5-year risk of arrhythmia recurrence is still 8%.

MP-453089-1 DIGOXIN AND RISK OF VENTRICULAR TACHYARRHYTHMIA AND DEATH IN ICD RECIPIENTS

Digoxin continues to be used in patients with heart failure with reduced ejection fraction (HFrEF), especially among those with atrial fibrillation (AF) with difficult to control ventricular response. However, some studies have shown digoxin use to be associated with adverse outcomes including increased mortality. There are limited data on whether digoxin use is associated with increased risk of ventricular tachycardia/ventricular fibrillation (VT/VF) in implantable cardioverter defibrillator (ICD) recipients. We sought to assess whether digoxin use would be associated with increased risk of VT/VF in patients with HFrEF who were implanted with a primary prevention ICD in landmark clinical trials. Our study cohort consisted of patients with an ICD or cardiac resynchronization therapy-defibrillator (CRT-D) who were enrolled in the four landmark MADIT trials. Propensity score for digoxin at baseline was developed using a wide variety of baseline clinical measures with a logistic regression model stepwise variable selection approach. All potential variables which met a significance level <0.10 were included in the propensity score model. Additionally, a multivariate proportional hazards regression model was developed for the endpoint of VT/VF. This multivariate model was used along with propensity score quintile stratification for the endpoints of VT/VF, death and VT/VF/death. At baseline, 1155 of 4499 patients were on digoxin (26%). Propensity score variables are shown in Table 1. From statistical models using both multivariate adjustment and propensity score quintile stratification, patients prescribed digoxin exhibited a statistically significant 28% increased risk of VT/VF [HR 1.28 (1.10-1.50); p=0.002; Figure 1A], 38% increased risk of the composite of VT/VF or death [HR 1.38 (1.21-1.58); p<0.0001; Figure 1B]; and a 64% increased risk of death [HR 1.64; (1.32-2.04); p<0.0001]. Our findings suggest that digoxin use is associated with a significant increased risk of ventricular tachyarrhythmic events and death among ICD recipients. This adds to the growing evidence that digoxin use is associated with adverse outcomes in certain groups of patients and suggest a need for reconsideration on use of digoxin in HFrEF patients with an ICD.

PO-03-230 LEFT VENTRICULAR FUNCTION IN SUDDEN CARDIAC DEATH DUE TO ISCHEMIC AND NONISCHEMIC HEART DISEASE

Sudden cardiac death (SCD) remains a major public health problem. Severe left ventricular (LV) dysfunction (EF ≤ 35%) increases the risk of SCD and is the most important indication for prophylactic implantable cardioverter defibrillator (ICD). Previous studies have shown that subjects with EF ≤ 35% represent a minority of all SCD cases. However, it has been unclear whether ischemic and nonischemic cardiac diseases present with different LVEF prior to SCD. We sought to evaluate the spectrum of LVEF among SCD victims with ischemic and nonischemic etiologies. Our study population is drawn from the Fingesture study, which has prospectively collected autopsy and clinical data from consecutive SCD victims from Northern Finland between 1998 and 2017. The cause of death was verified to be of cardiac origin in a medicolegal autopsy in all cases. Cases with ischemic SCD had evidence of coronary artery disease and ischemic cardiomyopathy at autopsy. Electronic health records were examined to identify subjects who underwent evaluation for LV function before SCD. LV function was categorized by quantitative assessment of LVEF as normal (EF ≥ 50%), reduced (50% > EF > 35%), and severely reduced (EF ≤ 35%). In all cases, echocardiography was unrelated to the SCD event. Left ventricular assessment was available in 717 SCD victims. The majority of subjects (n=449, 62.7%) had normal LVEF prior to SCD. The prevalence of reduced LVEF was 21.9%, while severely reduced LVEF was found only in 110 subjects (15.4%). Men were more likely to have LV dysfunction than women (45.9% vs 29.6%; p<0.001). In addition, LVEF was found to be severely reduced more commonly in men compared to women (17.4% vs 10.9% respectively; p<0.001). In SCD victims with ischemic and nonischemic heart disease, LV dysfunction was equally common (37.7% vs 36% respectively; p=0.72). The prevalence of severely reduced LVEF was also similar between ischemic SCD and nonischemic SCD (15.1% vs. 16.3%, respectively; p=0.72). Only one third of SCD cases had ventricular dysfunction and only one in seven had severely reduced LVEF prior to their SCD event, suggesting that only a minority of SCD victims meet the current criteria for primary prevention ICD. We found no difference in the spectrum of LVEF between ischemic and nonischemic heart diseases. However, women were found to have preserved LV function more often than men, highlighting the importance of developing novel SCD risk stratification tools beyond LVEF.

Sudden Cardiac Death in Ischaemic Cardiomyopathy and the Primary Prevention ICD: Time for a More a Personalised Approach?

Guidelines recommend primary prevention implantable cardioverter defibrillator (PPICD) for left ventricular ejection fraction (LVEF) <35% only after 3 months of optimal medical therapy (OMT) or 6 weeks after acute MI with persistent LVEF dysfunction. A 73-year-old woman presented with decompensated heart failure secondary to ischaemic cardiomyopathy. Severe coronary disease with sufficient dysfunctional myocardial segments on cardiac MRI suggested potential benefit from revascularisation. Following discussion with the heart team, she underwent percutaneous coronary intervention (PCI). PPICD implantation was deferred as per guideline recommendations. However, 20 days post-PCI, the patient died from malignant ventricular arrhythmia captured on a Holter monitor. This case demonstrates that some high-risk patients may not receive a potentially life-saving PPICD if guidelines are stringently adhered to. We highlight evidence that LVEF alone is of limited value in a risk assessment of arrhythmogenic death, and postulate that a more personalised ICD prescription should be considered using scar characteristics on cardiac MRI to prompt upstream ICD implantation in high-risk patients.

Role of N-terminal pro-B type natriuretic peptide as a predictor of poor outcomes in patients with HFrEF receiving primary prevention implantable cardioverter-defibrillator therapy: a systematic review and dose–response meta-analysis

IntroductionSeveral studies have demonstrated that combining left ventricular ejection fraction and New York Heart Association functional class is insufficient for predicting risk of appropriate implantable cardioverter-defibrillator (ICD) shock in primary...

Late gadolinium enhancement and the risk of ventricular arrhythmias and sudden death in NYHA class I patients with non-ischaemic cardiomyopathy.

To compare the risk of ventricular arrhythmias (VA) and sudden death (SD) between New York Heart Association (NYHA) class I and NYHA class II-III patients with non-ischaemic cardiomyopathy (NICM). Observational retrospective cohort study including patients with NICM who underwent cardiac magnetic resonance at two hospitals. The primary endpoint included appropriate implantable cardioverter defibrillator (ICD) therapies, sustained ventricular tachycardia, resuscitated cardiac arrest and SD. The secondary endpoint included heart failure (HF) hospitalizations, heart transplant, left ventricular assist device implant or HF death. Overall, 698 patients were included, 33% in NYHA class I. During a median follow-up of 31 months, the primary endpoint occurred in 57 patients (8%), with no differences between NYHA class I and NYHA class II-III cases (7% vs. 9%, p=0.62). Late gadolinium enhancement (LGE) was the only independent predictor of the primary outcome both in NYHA class I and NYHA class II-III patients. LGE+ NYHA class I patients had a similar cumulative incidence of the primary endpoint as compared to LGE+ NYHA class II-III (p=0.92) and a significantly higher risk as compared to LGE- NYHA class II-III cases (p < 0.001). The risk of the secondary endpoint was significantly higher in patients in NYHA class II-III as compared to those in NYHA class I (hazard ratio 3.2, p=0.001). Patients with NICM in NYHA class I are not necessarily at low risk of VA and SD. Actually, LGE+ NYHA class I patients have a high risk. NYHA class I patients with high-risk factors, such as LGE, could benefit from primary prevention ICD at least as much as those in NYHA class II-III with the same risk factors.

Cardioverter-defibrillator reduces mortality risk in eligible ischemic and non-ischemic cardiomyopathy patients: Sub-analysis of the multi-center Improve SCA study

Background & ObjectiveDespite the burden of sudden cardiac arrest (SCA) worldwide, implantable cardioverter-defibrillators (ICDs) are underutilized, particularly in Asia, Latin America, Eastern Europe, the Middle East, and Africa. The Improve SCA trial demonstrated that primary prevention (PP) patients in these regions benefit from an ICD or a cardiac resynchronization therapy defibrillator (CRT-D). We aimed to compare the rate of device therapy and mortality among ischemic and non-ischemic cardiomyopathy (ICM and NICM) PP patients who met guideline indications for ICD therapy and had an ICD/CRT-D implanted. MethodsImprove SCA was a prospective, non-randomized, non-blinded multicenter trial that enrolled patients from the above-mentioned regions. All-cause mortality and device therapy were examined by cardiomyopathy (ICM vs NICM) and implantation status. Cox proportional hazards methods were used, adjusting for factors affecting mortality risk. ResultsOf 1848 PP NICM patients, 1007 (54.5%) received ICD/CRT-D, while 303 of 581 (52.1%) PP ICM patients received an ICD/CRT-D. The all-cause mortality rate at 3 years for NICM patients with and without an ICD/CRT-D was 13.1% and 18.3%, respectively (HR 0.51, 95% CI 0.38–0.68, p < 0.001). Similarly, all-cause mortality at 3 years in ICM patients was 13.8% in those with a device and 19.9% in those without an ICD/CRT-D (HR 0.54, 95% CI 0.33–.0.88, p = 0.011). The time to first device therapy, time to first shock, and time to first antitachycardia pacing (ATP) therapy were not significantly different between groups (p ≥ 0.263). ConclusionsIn this large data set of patients with a guideline-based PP ICD indication, defibrillator device implantation conferred a significant mortality benefit in both NICM and ICM patients. The rate of appropriate device therapy was also similar in both groups. Clinical trial registrationClinicalTrials.gov ID: NCT02099721.

Growth Differentiation Factor-15 Predicts Mortality and Heart Failure Exacerbation But Not Ventricular Arrhythmias in Patients With Cardiomyopathy.

Background Heart failure (HF) has been increasing in prevalence, and a need exists for biomarkers with improved predictive and prognostic ability. GDF-15 (growth differentiation factor-15) is a novel biomarker associated with HF mortality, but no serial studies of GDF-15 have been conducted. This study aimed to investigate the association between GDF-15 levels over time and the occurrence of ventricular arrhythmias, HF hospitalizations, and all-cause mortality. Methods and Results We used a retrospective case-control design to analyze 148 patients with ischemic and nonischemic cardiomyopathies and primary prevention implantable cardioverter-defibrillator (ICD) from the PROSe-ICD (Prospective Observational Study of the ICD in Sudden Cardiac Death Prevention) cohort. Patients had blood drawn every 6 months and after each appropriate ICD therapy and were followed for a median follow-up of 4.6 years, between 2005 to 2019. We compared serum GDF-15 levels within ±90 days of an event among those with a ventricular tachycardia/fibrillation event requiring ICD therapies and those hospitalized for decompensated HF. A comparator/control group comprised patients with GDF-15 levels available during 2-year follow-up periods without events. Median follow-up was 4.6 years in the 148 patients studied (mean age 58±12, 27% women). The HF cohort had greater median GDF-15 values within 90 days (1797 pg/mL) and 30 days (2039 pg/mL) compared with the control group (1062 pg/mL, both P<0.0001). No difference was found between the ventricular tachycardia/fibrillation subgroup within 90 days (1173 pg/mL, P=0.60) or 30 days (1173 pg/mL, P=0.78) and the control group. GDF-15 was also significantly predictive of mortality (hazard ratio, 3.17 [95% CI, 2.33-4.30]). Conclusions GDF-15 levels are associated with HF hospitalization and mortality but not ventricular arrhythmic events.

Management of heart failure in patients with kidney disease-updates from the 2021 ESC guidelines.

The wide overlap between the syndromes of chronic kidney disease (CKD) and chronic heart failure (HF) means that familiarity with the 2021 European Society of Cardiology guidelines is of importance to nephrologists. The common risk factors for the two syndromes together with the adverse cardiac structural remodelling associated with CKD means that many kidney disease patients experience breathlessness and fall within the HF phenotypes categorized in the guidelines. The management of HF is evolving rapidly leading to significant changes in the latest guideline iteration. The 2021 guidelines have changed from the 2016 version firstly by an increased focus on identifying the three phenotypes of HF to guide appropriate evidence-based management. Secondly, a new and simplified treatment algorithm for HF with reduced ejection fraction involving the rapid sequential initiation and up-titration of four 'pillars' of drug treatment-angiotensin-converting enzyme inhibitors or angiotensin-neprilysin inhibitors, beta blockers, mineralocorticoid receptor antagonists and now, thanks to convincing trial data, sodium-glucose co-transporter 2 inhibitors. Thirdly, guidelines for device therapy have been changed with down-graded advice on indications for primary prevention implantable cardioverter defibrillator therapy for patients with non-ischaemic HF and for cardiac resynchronization therapy with left bundle branch block (LBBB) and a QRS duration <150ms. There are updated treatment plans for HF associated with non-cardiovascular comorbidities including CKD.

Age and the Risk of Ventricular Tachyarrhythmia in Patients With an Implantable Cardioverter-Defibrillator

BackgroundThe benefit of implantable cardioverter-defibrillators (ICDs) in elderly patients is controversial. ObjectivesThe aims of this study were to evaluate the risk for ventricular tachyarrhythmia (VTA) and ICD shocks by age groups and to assess the competing risk for VTA and death without prior VTA. MethodsThe study included 5,170 primary prevention ICD recipients enrolled in 5 landmark ICD trials (MADIT [Multicenter Automatic Defibrillator Implantation Trial] II, MADIT-Risk, MADIT-CRT [MADIT Cardiac Resynchronization Therapy], MADIT-RIT [MADIT Reduce Inappropriate Therapy], and RAID [Ranolazine in High-Risk Patients With Implanted Cardioverter-Defibrillator]). Fine and Gray regression analysis was used to evaluate the risk for fast VTA (ventricular tachycardia ≥200 beats/min or ventricular fibrillation) vs death without prior fast VTA in 3 prespecified age groups: <65, 65 to <75, and ≥75 years. ResultsThe cumulative incidence of fast VTA at 3 years was similar for patients <65 years of age and those 65 to <75 years of age (17% vs 15%) and was lowest among patients ≥75 years of age (10%) (P < 0.001). Multivariate Fine and Gray analysis showed a 40% lower risk for fast VTA in patients ≥75 years of age (HR: 0.60; 95% CI: 0.46-0.78; P < 0.001) compared with patients <65 years of age. In patients ≥75 years of age, a risk reversal was observed whereby the risk for death without prior fast VTA exceeded the risk for developing fast VTA. A history of nonsustained ventricular tachycardia, male sex, and the presence of nonischemic cardiomyopathy were identified as predictors of fast VTA in patients ≥75 years of age. ConclusionsPatients ≥75 years of age have a significantly lower risk for VTA and ICD shocks compared with younger patients. Aging is associated with a higher risk for death compared with the risk for fast VTA, the reverse of what is seen in younger patients.

Implantable cardioverter-defibrillators for primary and secondary prevention of sudden cardiac death in clinical practice: analysis of the clinical and anamnestic characteristics of patients according to the Kuzbass registry

Aim. To study clinical and anamnestic data of patients with implantable cardioverterdefibrillators (ICD) for primary or secondary prevention of sudden cardiac death (SCD) based on the data from the Kuzbass ICD registry.Methods. Retrospective analysis of demographic, clinical and anamnestic data from the “Kuzbass Registry of Patients with Implanted Cardioverter-Defibrillator”, which includes 286 patients admitted at the Kuzbass Cardiology Center in 2015–2019, was carried out.Results. The age of patients included in the registry was 59 (53; 66) years, 239 (83.6%) were men; all patients were diagnosed with heart failure. ICD for primary prevention of SCD was prescribed in 171 (63.6%) patients (group 1) and for secondary prevention in 98 (36.4%) patients (group 2). The groups were comparable in age, sex, main nosology (coronary artery disease), left ventricular ejection fraction (31.4 (26; 35) and 30 (10; 68)%, p = 0.389). Compared with the group 2, the group 1 had fewer working patients, higher incidence of heart defects, severe heart failure, higher incidence of paroxysmal supraventricular tachycardia (68.7% versus 44.8%, p = 0.001), and higher rates of revascularization (48, 9% and 31.7%, respectively, p = 0.006). Before ICD implantation for heart failure, 210 (73.4%) patients were receiving renin angiotensin aldosterone system inhibitors, 259 (90.6%) – beta-blockers, 167 (58.4%) – mineralocorticoid receptor antagonists. There were no differences in prescribed treatment between the groups. Only 137 (47.9%) patients, 86 (47.3%) patients in the group 1 and 51 (49.0%) patients in the group 2 received triple neurohormonal blockade. Remote monitoring was used only within the framework of research programs.Conclusion. The primary cohort of patients with ICD is the primary SCD prevention group. Regardless of the type of SCD prevention, the underlying disease is coronary artery disease. Current guidelines for optimal drug therapy and myocardial revascularization are not always followed prior to ICD implantation. The creation of registries of patients with ICD is an effective way to identify existing problems in ICD patient selection and to optimize follow-up and treatment.

Implantable Cardioverter Defibrillator for the Primary Prevention of Sudden Cardiac Death among Patients With Cancer

Data are limited regarding the characteristics and outcomes of patients with cancer who are found eligible for primary defibrillator therapy. We performed a single-center retrospective analysis of patients with preexisting cancer diagnoses who become eligible for a primary prevention implantable cardioverter defibrillator (ICD) or cardiac resynchronization therapy (CRT) defibrillator. Multicenter Automatic Defibrillator Implantation Trial-ICD (MADIT-ICD) benefit scores were calculated. The study included 75 cancer patients at a median age of 73 (interquartile range 64, 81) years at heart failure diagnosis. Active cancer was present in 51%. Overall, 55% of the cohort had coronary artery disease and 37% were CRT eligible. We found that 48%, 49%, and 3% of cohorts had low, intermediate, and high MADIT-ICD Benefit scores, respectively. Only 27% of patients underwent primary defibrillator implantation. Using multivariate analysis, indication for CRT and intermediate/high MADIT-ICD Benefit categories were found as independent predictors for implantation (odds ratio 8.42 p <0.001 and odds ratio 3.74 p=0.040, respectively). During a median follow-up of 5.3 (interquartile range 4.5, 7.2) years, one patient (5%) with a defibrillator had appropriate shock therapy and 2 patients (10%) had bacteremia. Of 13 patients with CRT defibrillator-implants, one patient was admitted for heart failure exacerbation (8%). Using a time-varying covariate model, we did not observe statistically significant differences in the survival of patients with cancer implanted versus those not implanted with primary defibrillators (hazard ratio 0.521, p=0.127). In conclusion, although primary defibrillator therapy is underutilized in patients with cancer, its relative benefit is limited because of competing risk of nonarrhythmic mortality. These findings highlight the need for personalized cardiologic and oncologic coevaluation.

Inter-American Society of Cardiology (CIFACAH-ELECTROSIAC) and Latin-American Heart Rhythm Society (LAHRS): multidisciplinary review on the appropriate use of implantable cardiodefibrillator in heart failure with reduced ejection fraction

BackgroundOur main objective was to present a multidisciplinary review on the epidemiology of sudden cardiac death (SCD) and the tools that could be used to identify malignant ventricular arrhythmias (VAs) and to perform risk stratification. In addition, indications and contraindications for the use of implantable cardioverter defibrillator (ICD) in general and in special populations including the elderly and patients with chronic kidney disease (CKD) are also given.MethodsAn expert group from the Inter American Society of Cardiology (IASC), through their HF Council (CIFACAH) and Electrocardiology Council (ElectroSIAC), together with the Latin American Heart Rhythm Society (LAHRS), reviewed and discussed the literature regarding the appropriate use of an ICD in people with heart failure (HF) with reduced ejection fraction (HFpEF). Indications and contraindications for the use of ICD are presented in this multidisciplinary review.ResultsNumerous clinical studies have demonstrated the usefulness of ICD in both primary and secondary prevention of SCD in HFpEF. There are currently precise indications and contraindications for the use of these devices.ConclusionsIn some Latin American countries, a low rate of implantation is correlated with low incomes, but this is not the case for all Latin America. Determinants of the low rates of ICD implantation in many Latin American countries are still a matter of research. VA remains one of the most common causes of cardiovascular death associated with HFrEF and different tools are available for stratifying the risk of SCD in this population.

Hospital utilisation and the costs associated with complications of ICD implantation in acontemporary primary prevention cohort.

Implantation of an implantable cardioverter defibrillator (ICD) is standard care for primary prevention of sudden cardiac death. However, ICD-related complications are increasing as the population of ICD recipients grows. ICD-related complications in anational DO-IT Registry cohort of 1442 primary prevention ICD patients were assessed in terms of additional use of hospital care resources and costs. During amedian follow-up of 28.7months (IQR 25.2-33.7) one or more complications occurred in 13.5% of patients. Acomplication resulted in asurgical intervention in 53% of cases and required on average 3.65 additional hospital days. The additional hospital costs were €6,876 per complication or €8,110 per patient, to which clinical re-interventions and additional hospital days contributed most. Per category of complications, infections required most hospital utilisation and were most expensive at an average of €22,892. The mean costs were €5,800 for lead-related complications, €2,291 for pocket-related complications and €5,619 for complications due to other causes. We estimate that the total yearly incidence-based costs in the Netherlands for hospital management of ICD-related complications following ICD implantation for primary prevention are €2.7million. Complications following ICD implantation are related to asubstantial additional need for hospital resources. When performing cost-effectiveness analyses of ICD implantation, including the costs associated with complications, one should be aware that real-world complication rates may deviate from trial data. Considering the economic implications, strategies to reduce the incidence of complications are encouraged.

Abstract 14643: Benefits and Risks of Single- vs. Dual- Chamber Implantable Cardioverter Defibrillators for Primary Prevention of Sudden Cardiac Death

Introduction: Implantable cardioverter defibrillator (ICD) is the more effective and safer treatment for the primary prevention of sudden cardiac death. It remains unclear whether dual-chamber ICD offers the clinical benefits over single-chamber ICD without increasing complications. Hypothesis: The study aimed to evaluate the benefits and risks of dual-chamber ICD compared with single-chamber ICD for primary prevention of sudden cardiac death in clinical practice. Methods: Using the Korean National Health Insurance Service database from January 2008 to December 2019, we include patients with primary prevention ICD and no documented indication for pacing. The propensity score matching method was used to balance covariates across single- and dual-chamber ICDs. Primary outcomes were all-cause mortality, hospitalization of heart failure, and hospitalization of cardiovascular cause. Results: Among 1,929 patients, 1,098 (56.9%) received a single-chamber ICD and 831 (43.1%) received a dual-chamber ICD. In 752 pairs of patients after propensity matching baseline characteristics were balanced between the 2 groups (median age 62 years; male 72%). Over a mean follow-up of 2.7±2.4 years, 1- and 5-year all-cause mortality (5.5% vs. 5.6%, P=0.910; 19.4% vs. 19.3%, P=0.948), 1- and 5-year hospitalization for cardiovascular cause (14.9% vs. 14.9%, P=1.000; 23.9% vs. 22.6%, P=0.542), and 1- and 5-year hospitalization for heart failure (10.8% vs. 8.6%, P=0.163; 16.8% vs. 14.0%, P=0.133) were similar in both groups. However, cardiac tamponade in the rates of device-related complications was 0.1% in the single-chamber ICD vs. 1.1% in dual-chamber ICD groups (P=0.013). Conclusions: In the real-world population receiving a primary prevention ICD, dual-chamber ICD was associated with higher rates of cardiac tamponade than single-chamber ICD. One and five-year rates of all-cause mortality and hospitalization did not differ significantly between the two groups.

Abstract 12086: Predicting Long-Term Survival After De Novo Cardioverter-Defibrillator Implantation for Primary Prevention

Introduction: Current guidelines recommend the use of implantable cardioverter-defibrillators (ICDs) for primary prevention of arrhythmia in patients with reduced ejection fraction cardiomyopathy. Little is known about the long-term outcomes of patients with ICDs in clinical practice. Objective: To develop a risk prediction model for 10-year survival after ICD implantation for primary prevention. Methods: In this population-based registry of all ICD patients across 18 centers in Ontario, CA, 5097 patients receiving ICD implant for primary prevention from February 2007 to March 2011 were followed for up to 10 years. Patients were randomly split 2:1 into derivation and internal validation cohorts to develop and validate a prognostic model using Cox regression and predictors measured at initial ICD evaluation. Results: Mean age was 65.3 years (SD 11.0), 664 patients were female (19.5%) and 2344 patients (69.0%) had ischemic cardiomyopathy for primary disease indication. 10-year survival was 45.7% (95% CI 44.0%-47.4%).The final prediction model included age, sex, disease indication, comorbidities and biomarkers at the time of ICD assessment ( Table 1 ). This model had good discrimination in derivation (AUC 0.80; 95% CI 0.78-0.81) and validation samples (0.79, 95% CI 0.77-0.81) and good calibration. Sensitivity analyses showed that the addition of device type, provider factors (implantation site, implanter volume, physician main specialty), sex-related interaction terms, and frailty scores did not significantly improve the prediction model. Conclusion: A combination of demographic and patient factors determined at baseline device evaluation enabled the prediction of 10-year survival in patients undergoing ICD for primary prevention in the clinical practice. Our findings may help identify and monitor individuals at risk of long-term mortality and may be useful in targeting future prevention strategies to enhance longevity in this high-risk population.

Abstract 9500: Patients’ Perspectives Regarding Generator Exchanges of Implantable Cardioverter-Defibrillators

Background: Shared decision-making (SDM) is mandated for patients receiving primary prevention implantable cardioverter-defibrillators (ICD). Less attention has been paid to ICD generator exchange (GE) decisions. At the time of GE, patients’ risk of sudden cardiac death (SCD), risk of procedural complications, quality of life, or prognosis may have changed. This study was designed to explore how patients view GE decisions. Methods: In-depth interviews about perspectives regarding GE decisions were conducted with patients who had primary prevention ICDs implanted at Emory Healthcare from 2013-2021. Patients were also presented a hypothetical scenario where their ICD battery was depleted but their risk of SCD over 5 years at the time of battery depletion varied (10%, 5%, 1%). Patients were asked about their willingness to undergo GE under each of these conditions. Transcribed interview text was qualitatively coded using a multilevel template analytic method. Results: Fifty patients were interviewed, of whom 19 had a prior GE, 16 had no prior ICD therapies and 14 had improved left ventricular ejection fraction. Overall, even with low SCD risk, patients’ willingness to undergo a GE remained high (Figure). If their doctor recommended deferring GE, 15/49 patients still would not defer a GE. Many patients reported not relying on risk/benefit estimates to make GE decisions. Most also reported deferring the decision to their doctor, and many exhibited significant therapeutic inertia. One patient stated, “since I’m already wired for it⋯wouldn’t make sense to disregard it.” Conclusion: Strong default preferences push patients towards a GE. Risk stratifying patients for SCD at the time of GE may facilitate SDM and may reduce GE in very low-risk patients. However, even at 1% risk of SCD, which would not meet thresholds for ICD therapy, most patients would choose GE. This highlights provision of risk information alone seems unlikely to drive substantially different GE decisions.

Abstract 9972: Sex-Related Differences and the Influence of Pregnancy on Cardiac Outcomes in Adults With a Systemic Right Ventricle and Biventricular Physiology

Introduction: Transposition of the great arteries (TGA) with a systemic right ventricle (sRV) and biventricular physiology is associated with increased morbidity and mortality. There is a paucity of data regarding sex-related differences in outcomes in the context of a sRV. Moreover, pregnancy has been associated with deterioration of sRV function in short-term post-partum follow-up, but the long-term impact remains largely unknown. Methods and Results: A retrospective cohort study was conducted on 214 adults, age 44.7±12.3 years, with a sRV and biventricular physiology followed for a median of 13 years at an adult congenital heart disease center. No sex-related difference was identified in the prevalence of atrial or ventricular arrhythmias, permanent pacemaker implantation, hospitalization for heart failure, systemic atrio-ventricular valve intervention, heart transplant, or cardiac death. Among the 82 (38.3%) women, age 44.0±12.5 years, 43 (52.4%) had at least one full-term pregnancy. Women had a lower prevalence of moderate to severe sRV dysfunction than men (21% vs 42.6%, p=0.001) despite similar ages. Beta-blockers (p=0.008), furosemide (p=0.012), and mineralocorticoid receptor antagonists (p=0.028) were less frequently prescribed to women than men. Women had fewer implantable cardioverter-defibrillators (ICDs) for primary prevention than men (3.7% vs 13.6%, p=0.016), with no difference in the prevalence of secondary prevention ICDs (1.2% vs 2.3%, p=1). The four women with a prohibitive maternal mortality risk (modified WHO class IV) complied with recommendations to avoid pregnancy. After excluding these 4 women, no differences regarding frequency of adverse cardiac events, age at the time of event, and proportion with moderate or severe sRV dysfunction were observed in women with (N=43) and without (N=35) pregnancies during 14 years of follow-up. Conclusions: Women with TGA and a sRV had a lower prevalence of moderate to severe systemic ventricular dysfunction than men, along with a lower proportion of primary prevention ICDs. Following risk assessment and counselling with contraindication of pregnancy in the highest risk subgroup, pregnancy had no impact on long-term cardiac outcomes.

Guideline-Directed Medical Therapy Before and After Primary Prevention Implantable Cardioverter Defibrillator Implantation in New Zealand (ANZACS-QI 66).

Guidelines recommend angiotensin converting enzyme inhibitors (ACEi)/angiotensin receptor blockers (ARB)/angiotensin receptor neprilysin inhibitors (ARNI); beta blockers; and mineralocorticoid receptor antagonists (MRA) in patients with symptomatic heart failure and reduced left ventricular ejection fraction before consideration of primary prevention implantable cardioverter defibrillator (ICD). This study aims to investigate dispensing rates of guideline-directed medical therapy (GDMT) before and after primary prevention ICD implantation in New Zealand. All patients receiving a primary prevention ICD between 2009 and 2018 were identified using nationally collected data on all public hospital admissions in New Zealand. This was anonymously linked to national pharmaceutical data to obtain medication dispensing. Medications were categorised as low dose (<50% of target dose), 50-99% of target dose or target dose based on international guidelines. Of the 1,698 patients identified, ACEi/ARB/ARNI, beta blockers and MRA were dispensed in 80.2%, 83.6% and 45.4%, respectively, prior to ICD implant. However, ≥50% target doses of each medication class were dispensed in only 51.8%, 51.8% and 34.5%, respectively. Only 15.8% of patients were receiving ≥50% target doses of all three classes of medications. In the 1,666 patients who survived 1 year after ICD implant, the proportions of patients dispensed each class of medications remained largely unchanged. Dispensing of GDMT was suboptimal in patients before and after primary prevention ICD implantation in New Zealand, and only a minority received ≥50% target doses of all classes of medication. Interventions are needed to optimise use of these standard evidence-based medications to improve clinical outcomes and avoid unnecessary device implantation.