Primary Prevention Implantable Cardioverter-defibrillator Research Articles

Abstract 11967: Benefit of Implantable Cardioverter Defibrillator Therapy in Patients With Advanced Renal Impairment: A Competing Risk Analysis From the MADIT Trials

Introduction: The life-saving benefit of the implantable cardioverter defibrillator (ICD) in patients with advanced chronic kidney disease (A-CKD) is still controversial. This is possibly due to a higher risk of dying from non-arrhythmic causes in A-CKD patients, and thereby die prior to receiving therapy from the ICD. We aimed to evaluate the competing risk for ventricular tachycardia/fibrillation (VT/VF) vs. death without prior VT/VF in ICD recipients by renal function. Methods: The study population comprised 3953 patients with an ICD enrolled in the landmark MADIT trials, categorized by renal function into: A-CKD (estimated Glomerular Filtration Rate [eGFR] ≤40 ml/min/1.73 m 2 [N=403]; Moderate CKD (eGFR 41-60 ml/min/1.73 m 2 [N=995]); and No-CKD (eGFR >60 ml/min/1.73 m 2 [N=2555)). Cumulative incidence function curves were used to display the rate of fast VT/VF (>200 bpm) and the competing risk of death without experiencing prior fast VT/VF using the Fine and Gray method. Results: At 4-years of follow-up, patients in the A-CKD group had a significantly lower cumulative incidence of VT/VF compared to patients with Moderate-CKD and No-CKD (13%, 17%, and 20%, respectively; p=0.006 for the overall difference [Figure: left panel]). In contrast, the corresponding 4-year rates of death without experiencing prior fast VT/VF were significantly highest among patients with A-CKD and attenuated among those with Moderate- and No-CKD (28%, 17%, and 9%, respectively; p<0.001 for the overall difference [Figure: right panel]). Conclusion: Our data from 4 landmark primary prevention ICD trials show significant differences in the risk of VT/VF vs the competing risk of death without experiencing prior VT/VF by renal function. This suggests an attenuated benefit of ICD therapy with declining renal function.

Abstract 9521: Improvement of Left Ventricular Ejection Fraction After Surgical Revascularization in Patients Eligible for Implantable Cardioverter Defibrillator

Introduction: Left ventricular ejection fraction (LVEF) ≤35% is the cornerstone criterion for implantable cardioverter-defibrillator (ICD) eligibility. But improvement in LVEF may occur in ICD-eligible patients after coronary artery bypass graft surgery (CABG). Methods: We studied the incidence, predictors, and outcomes of LVEF improvement among patients with LVEF ≤35% who underwent CABG as part of the Surgical Treatment for Ischemic Heart Failure (STICH) trial and had pre- and post-operative (4 months) LVEF assessment using the same cardiac imaging modality. Improvement in LVEF was defined as post-operative EF >35% and >5% absolute improvement from baseline. Results: Of the 427 patients (mean age 62±10 and 50 women), 125 (29.2%) had LVEF improvement from 26.8%±5.8% to 43.3%±6.5%; p<0.001. Improvement in LVEF occurred in 20% and 38% of patients with pre-operative LVEF <25% and 30-35%, respectively (Figure). Post-operative improvement in LVEF was 2.20 times more likely in patients with pre-operative LVEF ≥25% (95% CI 1.41-3.43; p<0.001) than those with pre-operative EF <25%. The odds of post-operative LVEF improvement were 1.96 times higher (95% CI 0.91-4.23, p=0.09) in patients with myocardial viability. After adjusting for age, sex, and pre-operative LVEF, improvement in LVEF was associated with a 42% lower risk of all-cause mortality (HR 0.58, 95% CI 0.35-0.96; p=0.03) and 69% lower risk of heart failure mortality (HR 0.31, 95% CI 0.11-0.87; p=0.03). Conclusions: Nearly 1/3 rd of patients with LVEF ≤35% who underwent CABG had a significant improvement in left ventricular systolic function, obviating the need for primary prevention ICD implantation. Post-operative LVEF improvement was associated with a lower risk of death. These results provide patients and clinicians data on the likelihood of ICD eligibility after CABG and support the practice of reassessment of LVEF after revascularization.

Bluetooth-Enabled Implantable Cardiac Monitors and Two-Way Smartphone Communication for Patients With Hypertrophic Cardiomyopathy

BackgroundSudden cardiac death (SCD) risk stratification in hypertrophic cardiomyopathy (HCM) currently relies on arrhythmic burden quantification by 24 or 48-hour Holter monitoring. Whether this approach adequately captures arrhythmic burden, compared with longer-term continuous monitoring, is unclear. We sought to assess the long-term incidence of nonsustained ventricular tachycardia (NSVT) in HCM patients at low or moderate SCD risk, using implantable cardiac monitors (ICMs) paired with a novel Bluetooth-enabled 2-way communication platform. MethodsThis prospective, single-arm, observational study enrolled 33 HCM patients. Patients were implanted with an Abbott (Chicago, IL) Confirm Rx ICM and monitored using a protocolized care pathway. ResultsA total of 20 patients (60.6%) had ≥ 1 episode of NSVT recorded on the ICM, the majority of whom had previous Holter monitors that did not identify NSVT (60%, n = 12). A total of 71 episodes of NSVT were detected. Median time to first NSVT detection was 76.5 days (range: 0-553 days). A total of 19 patients underwent primary prevention implantable cardioverter defibrillator implantation during an average follow-up of 544 days (range: 42-925 days). A total of 172,112 automatic transmissions were received, and 65 (0.04%) required clinical follow-up. A total of 325 manual transmissions were received and managed. A total of 14 manual transmissions (4.3%) required follow-up, whereas 311 (95.7%) were managed solely with a text message. ConclusionsSurveillance and reporting systems utilizing 2-way communication enabled by novel ICMs are feasible and allow remote management of patients with HCM. Prolonged monitoring with ICMs identified more patients with nonsustained arrythmias than did standard Holter monitoring. In many cases, this information impacted both SCD risk stratification and patient management.

2021 PACES Expert Consensus Statement on the Indications and Management of Cardiovascular Implantable Electronic Devices in Pediatric Patients: Executive Summary.

2021 PACES Expert Consensus Statement on the Indications and Management of Cardiovascular Implantable Electronic Devices in Pediatric Patients: Executive Summary.

Children really are not little adults: What we can take away from the 2021 PACES Expert Consensus Statement on the Indications and Management of Cardiovascular Implantable Electronic Devices

Children really are not little adults: What we can take away from the 2021 PACES Expert Consensus Statement on the Indications and Management of Cardiovascular Implantable Electronic Devices

Cardiac manifestations of fabry disease in female patients: a single centre experience

Abstract Introduction Fabry disease is a lysosomal storage disorder resulting in multisystemic effects due to deposition and accumulation of glycosphingolipids. Although an X linked disorder, it is recognised that female heterozygotes can express clinical manifestations. Cardiac expression in the female Fabry population remains incompletely understood. Data from the Fabry Outcome Survey suggests that up to a quarter of female patients demonstrate left ventricular hypertrophy (LVH) on echocardiography. Although LVH is the most commonly cited cardiac finding, other abnormalities from clinical surveillance can include electrocardiographic abnormalities, fibrosis and elevated troponin levels. Purpose To establish the prevalence and extent of cardiac involvement amongst our cohort of female Fabry patients. Methods Heterozygous females, confirmed by genetic testing, were identified in our single centre Fabry database. Data was collected retrospectively on their 12 lead ECG, high sensitivity troponin I level and echocardiography performed at their most recent cardiac Fabry clinic visit, along with the most recent cardiac magnetic resonance imaging (CMR). Values are expressed as mean ± SD. Results 51 female heterozygotes were identified, ranging from 23 to 83 years (mean age 49.3±15.4). 28 (54.9%) were established on enzyme replacement therapy. On echocardiography LVH of ≥13mm was identified in 14 (27.5%) patients (mean 14.6±1.9 mm). 44 patients had CMR and of these, 17 (38.6%) had findings in keeping with a Fabry cardiomyopathy (34.1% had fibrosis, 15.9% hypertrophy, 13.6% both). Of the 17 patients with abnormalities on CMR, 8 had normal left ventricular wall thickness on echocardiography. All patients had a high sensitivity troponin I measurement and this was above upper reference limits (>40ng/L) in 21 (41.1%) patients in the absence of chest pain. Of 21 patients with abnormal troponin I levels, 9 had normal left ventricular wall thickness on echocardiography. Abnormalities identified on 12 lead ECG are summarised in Table 1. All patients with ECG abnormalities listed in Table 1 had an abnormal troponin and/or abnormal imaging, except for 5 patients who had an isolated short PR interval. 6 patients had a permanent pacemaker and 1 had a primary prevention implantable cardioverter defibrillator. 25 (49%) of the 51 patients were classed as having cardiac involvement based on raised troponin levels and/or abnormal imaging findings. Conclusion Although Fabry disease is traditionally thought to be a male predominant disease, in our cohort nearly half of our female heterozygotes showed evidence of cardiac involvement. The use of CMR, cardiac biomarkers and 12 lead ECG are helpful adjuncts to identify cardiac involvement, which could otherwise be missed if stand-alone echocardiography was used. Timely identification and monitoring of cardiac involvement has clinical implication, especially with regards to prognosis and treatment. Funding Acknowledgement Type of funding sources: None.

Sudden cardiac death risk stratification in hypertrophic cardiomyopathy: discrepancies persist among guidelines

Abstract Background Differing criteria have been provided on sudden cardiac death (SCD) risk stratification in hypertrophic cardiomyopathy (HCM) by current guidelines. Recently, AHA/ACC proposed an algorithm with novel clinical markers. It remains to be established the impact of this new approach. Purpose Evaluate the impact of the 2020 AHA/ACC guideline on the 2014 ESC and 2011 ACCF/AHA criteria regarding SCD risk assessment and primary prevention implantable cardioverter-defibrillator (ICD) in HCM. Methods The database of a HCM center non-referred cohort was accessed for SCD risk profile between March 2007 and March 2020. The agreement for primary prevention ICD recommendations among guidelines was assessed with the Cohen's and Fleiss' Kappa coefficient, P<0.05. SCD or appropriate ICD shock were defined as the primary end-point. Results A total of 100 patients, age 60±13 years, 55 (55%) females, were followed by 5±3 years. The maximal left ventricular (LV) wall thickness was 18±4 mm, 38 (38%) patients showed a family history of SCD, 22 (22%) syncope, 6 (6%) ejection fraction ≤50%, 2 (2%) LV apical aneurysm, 1 (1%) massive LV hypertrophy, 26 (26%) non-sustained ventricular tachycardia, and 23 (23%) extensive late gadolinium enhancement. An ICD was placed in 17 (17%) patients. According to the 2020 AHA/ACC guideline, 57 (57%) patients met class IIa recommendation, 27 (27%) class IIb, and 16 (16%) class III. The 2014 ESC model classified 14 (14%) in class IIa, 18 (18%) in class IIb, and 68 (68%) in class III. The 2011 ACCF/AHA considered 66 (66%) in class IIa, 6 (6%) in class IIb, and 28 (28%) in class III. The Cohen's Kappa was 0.200 (95% CI 0.292–0.107), P=0.0005, between the 2020 AHA/ACC and the 2014 ESC, and 0.520 (95% CI 0.651–0.388), P=0.0005, between the North American approaches. The Fleiss' Kappa was 0.219 (95% CI 0.303–0.135) P=0.0005 among the three guidelines, whereas it reached 0.221 (95% CI 0.334–0.108) for class IIa, 0.244 (95% CI 0.357–0.131) for class IIb and 0.202 (95% CI 0.315–0.089) for class III, P=0.0005. Figure 1 shows the patient's reclassification with the new guideline. The primary end-points occurred in 7 (7%) patients in a median follow-up of 6 (17–0.4) years. All of them were classified as IIa with the 2011 ACCF/AHA guideline, but only 4 (4%) met this class under the 2020 AHA/ACC, and none in the 2014 ESC model. Conclusion A low agreement was found among guidelines, especially between the 2020 AHA/ACC and the 2014 ESC criteria. The North American systems differed moderately, but the new approach has reduced the cases in class IIa and III recommendation for primary prevention ICD. In contrast, the recent 2020 guideline has increased the number of patients in class IIa in relation to the European model, but both strategies have not protected the totality of patients with SCD or appropriate shock. Funding Acknowledgement Type of funding sources: Public hospital(s). Main funding source(s): Hospital de Clínicas de Porto Alegre Figure 1

Development and piloting of four decision aids for implantable cardioverter-defibrillators in different media formats.

Using DAs for preference-sensitive decisions is an evidence-based way to improve patient-centered decisions. Reimbursement mandates have increased the need for DAs in ICD care, although none have been formally evaluated. The objectives were to develop and pilot implantable cardioverter-defibrillator (ICD) decision aids (DAs) for patients considering primary prevention ICDs. Development Phase: An expert panel, including patients and physicians, iteratively developed four DAs: a one-page Option GridTM conversation aid, a four-page in-depth paper tool, a 17-minute video, and an interactive website. Trial Phase: At three sites, patients with heart failure who were eligible for primary prevention ICDs were randomly assigned 2:1 to intervention (received DAs) or control (usual care). We conducted a mixed-methods evaluation exploring acceptability and feasibility. Twenty-one eligible patients enrolled (15 intervention). Most intervention participants found the DAs to be unbiased (67%), helpful (89%), and would recommend them to others (100%). The pilot was feasible at all sites; however, using clinic staff to identify eligible patients was more efficient than chart review. Although the main goals were to measure acceptability and feasibility, intervention participants trended towards increased concordance between longevity values and ICD decisions (71% concordant vs. 29%, p=.06). Participants preferred the in-depth paper tool and video DAs. Access to a nurse during the decision-making window encouraged questions and improved participant-perceived confidence. Participants felt the DAs provided helpful, balanced information that they would recommend to other patients. Further exploration of this larger context of DA use and strategies to promote independent use related to electrophysiology (EP) visits are needed.

Association between ethnicity and degree of improvement in cardiac function following initiation of sacubitril/valsartan.

The aim of this study was to determine the degree of short-term improvement in left ventricular ejection fraction (LVEF), haemodynamics, NT-proBNP and quality of life following initiation of sacubitril/valsartan in black patients when compared with white patients. This was a retrospective, observational, single-centre, hypothesis-generating study of patients with symptomatic heart failure and reduced ejection fraction (HFrEF) treated with guideline recommended therapy, who were transitioned from an ACE inhibitor (ACE-I) or angiotensin receptor blocker (ARB) to sacubitril/valsartan. Our analysis included 83 patients (mean age 57 years) with echocardiography performed before and after transition from ACE-I/ARB to sacubitril/valsartan, after excluding patients with concomitant Cardiac resynchronization therapy implantation. Overall, sacubitril/valsartan was associated with LVEF improvement from 28.8% ± 0.7 to 32.0% ± 1.1% (P = 0.0002), but no reverse remodelling was observed. The association with LVEF improvement was only observed in white patients (n = 46, P = 0.0006), but not in black patients (n = 37, P = 0.1728), and appeared to be associated with reduced blood pressure (baseline vs. 2-week blood pressure 116.5 ± 13.9 vs. 109.4 ± 14.3 mmHg, respectively, in white patients, P = 0.0449). Fifteen patients (18.1%) became ineligible for primary prevention Implantable cardioverter defibrillator implantation. Sacubitril/valsartan was associated with improved LVEF, NT-proBNP concentrations and quality of life in patients with symptomatic HFrEF on guideline recommended therapy. However, in our cohort, improvement of LVEF and quality of life might be attenuated in black patients, which warrants further investigation.

Arrhythmia in Cardiomyopathy: Sex and Gender Differences.

There is emerging evidence for important sex differences in cardiac arrhythmias. In this up-to-date review, we summarise the differences in incidence, aetiology, treatment and prevention of ventricular arrhythmias (VAs) and sudden cardiac death (SCD) in women versus men, in the context of ischaemic and nonischaemic cardiomyopathies. The incidence of ventricular tachyarrhythmia and SCD is significantly lower in women than in men with ischaemic cardiomyopathy, whereas sex differences in nonischaemic cardiomyopathy are less clear. Women who receive a primary prevention implantable cardioverter-defibrillator (ICD) are less likely to receive appropriate activations, compared to men; however, such findings are limited by under-representation of women. Women with ischaemic cardiomyopathy have significantly lower incidence of VA and SCD compared to men and may not derive the same benefit from a primary prevention ICD. However, further clinical ICD studies are needed that ensure adequate female participation, in order to examine sex differences in outcomes in both ischaemic and nonischaemic cardiomyopathies.

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.

Health status measured by Kansas City Cardiomyopathy Questionnaire-12 in primary prevention implantable cardioverter defibrillator patients with heart failure

BackgroundSelf-reported health status as measured by the Kansas City Cardiomyopathy Questionnaire (KCCQ) in patients with primary prevention implantable cardioverter defibrillators (ICDs) has mainly been reported from randomized trials. However, these studies are often limited to short follow-up and are subject to selection bias. The aim of this study was to assess KCCQ-12 in patients with primary prevention ICD due to either ischemic or nonischemic heart failure.MethodsThis cross-sectional observational study included all patients in Region Gävleborg, Sweden, who because of primary prevention due to heart failure, had an ICD or underwent device replacement between 2007 and 2017. After validation using medical records patients were sent and returned the KCCQ-12 by regular mail.ResultsA total of 118 questionnaires were analyzed (response rate 71.1%). The mean age was 70.9 ± 9.8 years, and a minority was female (n = 20, 16.9%). The mean overall summary score was 71.5 ± 22.4, there was no significant difference between ischemic and nonischemic heart failure (69.5 ± 23.1 vs. 74.4 ± 21.3; p = 0.195). Atrial fibrillation at baseline was associated with lower score for the domains Symptom frequency (70.2 ± 23.2 vs. 82.2 ± 19.2; p = 0.006) and Social limitation (62.1 ± 26.0 vs. 75.6 ± 26.6; p = 0.006) as well as the overall summary score (63.9 ± 21.3 vs. 74.8 ± 22.2; p = 0.004).ConclusionIn a real-world setting, primary prevention ICD patients with heart failure report an acceptable disease-specific health status at long-term follow-up. Ischemic and nonischemic etiology showed similar health status whereas atrial fibrillation was associated with worse outcome.

Severity of spleep apnea syndrome and life-threatening tachyarrhythmias in patients with implantable cardioverter defibrillator.

Sleep apnea syndrome (SAS) has been reported to be associated with a higher incidence of ventricular arrhythmias. The aim of this study was twofold: (1) to investigate whether in SAS patients receiving an implantable cardioverter defibrillator (ICD) the severity of SAS was associated with the occurrence of ventricular arrhythmias; (2) to assess whether changes in nocturnal apnoic/hypopnoic episodes may favor the occurrence of life-threatening arrhythmias, that is, sustained ventricular tachycardia (VT)/fibrillation (VF), requiring ICD intervention. We enrolled 46 patients with documented SAS at polysomnography (apnea/hypopnea index [AHI]>5) who also had a left ventricle ejection fraction (LVEF)<35% and, according to primary prevention indications, implanted an ICD (Boston Scientific Incepta) able to daily monitor apnoic/hypopnoic episodes occurring during sleep. Patients were followed at 3-month intervals. At a mean follow-up of 18 months, 21 episodes of sustained VT/FV requiring ICD intervention were documented in eight patients (17.4%). Baseline AHI was significantly higher in patients with compared to those without ICD intervention. ICD interventions, however, were not preceded by any worsening of apnoic/hypopnoic episodes. The respiratory disturbance index (RDI) of the week during the event, indeed, was not different from that recorded during the previous 2weeks (25.4 ± 11, 25.6 ± 10 and 25.1 ± 10, respectively; p=.9). In patients with SAS who received an ICD for primary prevention of sudden death, those with ICD interventions showed a more severe form of the disease at baseline. ICD interventions, however, were not preceded by any significant changes in SAS severity.

B-PO02-057 DEVICE NURSE-LED INTERVENTION TO INCREASE GUIDELINE-CONCORDANT PRIMARY PREVENTION IMPLANTABLE CARDIOVERTER-DEFIBRILLATOR PROGRAMMING

Implantable cardioverter-defibrillators (ICDs) are highly effective in reducing mortality in patients at risk for life-threatening arrhythmias. However, studies have shown that delivery of unnecessary or inappropriate ICD therapies for non-sustained ventricular tachycardia and supraventricular tachycardia (SVT) is associated with increased morbidity and mortality. Thus, professional societies have issued guidelines on appropriate ICD programming for primary prevention of sudden cardiac death. We previously demonstrated that patients with primary prevention ICDs with guideline-concordant (GC) ICD programming had significantly lower ICD therapy rates compared to patients with guideline-discordant (GD) ICD programming. However, the rate of GC programming was very low. This study aims to assess the effect of a device nursing-led intervention on the rate of GC versus GD primary prevention ICD programming at one large academic center. A device nurse-led intervention was deployed in the cardiac device clinic at a large tertiary care center in January 2018. This intervention involved device nurse review of patients’ ICD programming at each clinic visit with alert of the covering electrophysiology provider if programming was GD. Consecutive patients undergoing primary prevention ICD implantation between 2018-2020 were assessed for rates of GC and NGC ICD programming. Kaplan-Meier analysis and Cox proportional hazard models were used to estimate freedom from first ICD therapy and shock. Comparisons were made to a control period before implementation of the intervention (consecutive patients with primary prevention ICD implantation between 2014-2016). A total of 241 patients underwent primary prevention ICD implementation during the study period. Of these, 215 (89.2%) had GC programming. Compared to the control period, rates of GC ICD programming significantly increased (31% of 310 patients versus 89.2% of 241 patients, respectively; p <0.01). A device nursing-led intervention successfully increased the rates of guideline-concordant primary prevention ICD programming at a large tertiary care center.

B-PO03-006 PATIENT EXPERIENCE OF AN IMPLANTED CARDIAC MONITOR FOR HYPERTROPHIC CARDIOMYOPATHY

Hypertrophic cardiomyopathy (HCM) is considered the most common inherited heart disease affecting 1 in 500 individuals. Those with HCM are at increased risk of non-sustained ventricular tachycardia (NSVT) and sudden cardiac death. Guidelines recommend HCM patients undergo arrhythmia monitoring every 1-2 years to determine candidacy for primary prevention implantable cardioverter defibrillators (ICD). A variety of implantable cardiac monitors (ICMs) are currently approved for use with varying technology and interface platforms. Unlike other ICMs, the Abbott Confirm Rx™ ICM has the capability of connecting directly to the individual’s smart phone via Bluetooth technology. This enables real-time transmission of cardiac events, patient-reported symptoms and the potential for two-way communication with care providers enabling direct feedback of alert severity to the patient. The purpose of this study was to explore individuals’ experiences and understand the psychosocial effects of patients with HCM who underwent implantation of the Confirm Rx™ ICM and participated in a prospective trial looking at a novel two-way communication alert system. Using an exploratory qualitative approach, semi-structured interviews were conducted by telephone with 10 participants who received a Confirm Rx™ ICM. Analysis revealed three key themes 1) psychological impact 2) educational needs and 3) technology expectations. Participants reported that receiving feedback from real-time transmissions resulted in improved understanding of symptoms and reduced patient anxiety. Over time, this led to fewer health system encounters. Some participants reported uncertainty regarding when to send manual transmissions, identifying a possible gap in educational needs. Lastly, participants reported the smart phone app interface did not meet expectations with regards to the amount of data displayed to patients, with patients expecting more data available to them. Overall, participants report psychological benefit utilizing a smart phone app to facilitate two-way communication of ICM transmissions. Future directions include addressing gaps in educational needs and technology expectations and deliverables.

B-PO03-169 MYOCARDIAL SCAR BURDEN QUANTIFIED BY CARDIAC MAGNETIC RESONANCE IMAGING IS PREDICTIVE OF VENTRICULAR TACHYCARDIA IN PATIENTS WITH HYPERTROPHIC CARDIOMYOPATHY

Patients with hypertrophic cardiomyopathy (HCM) are at a higher risk of developing ventricular tachycardia (VT) and sudden cardiac death (SCD). Previous studies have demonstrated a correlation between late gadolinium enhancement (LGE) measured by cardiac magnetic resonance imaging (MRI) quantified as % of myocardial mass and VT; however, the predictive value of a more practical and routinely performed semi-quantitative assessment of LGE remains unknown. To determine whether a semi-quantitative assessment of myocardial fibrosis by cardiac MRI (number of myocardial segments with LGE) is predictive of VT in patients with HCM. We identified 65 patients (mean age 47±17, 34% female) with a clinical diagnosis of HCM who had a cardiac MRI prior to an implantable cardioverter defibrillator (ICD) implantation for primary prevention of SCD. VT was defined as appropriate anti-tachycardia pacing or shocks for sustained ventricular arrhythmias. The MRI was analyzed by an experienced radiologist blinded to the clinical data. LGE was assessed by both quantitative (% of total myocardial mass) and semi-quantitative (number of myocardial segments involved) methods. During the follow-up period (median 33 months), seven patients experienced VT. Patients with > 6 myocardial segments with LGE were at higher risk to develop VT (OR: 5.7, p=0.03) which remained significant after adjusting for age, maximum left ventricular wall thickness, left atrial size, maximum left ventricular outflow gradient, history of nonsustained VT, unexplained syncope, and family history of SCD (p=0.03). Similarly, patients with a higher fibrosis burden (LGE >10% myocardial mass) were more likely to develop VT (OR: 8.6, p=0.01) even after adjusting for the abovementioned traditional risk factors (p=0.04). The extent of LGE, assessed by both quantitative and semi-quantitative measures, is strongly associated with ventricular arrhythmias requiring ICD therapy in patients with HCM even after accounting for traditional risk factors. Fibrosis burden as detected by cardiac MRI may serve as an imaging biomarker to improve risk stratification and patient selection for primary prevention ICD implantation in patients with HCM.

Longitudinal Outcomes Associated With Non-Evidence-Based Implantable Cardioverter-Defibrillators Among Medicare Beneficiaries (From the National Cardiovascular Data Registry)

Primary prevention implantable cardioverter-defibrillators (ICDs) in patients with recent myocardial infarction or coronary revascularization and those with newly diagnosed or severe heart failure (HF) are considered non-evidence-based, as defined by pivotal randomized clinical trials. Although non-evidence-based ICDs have been associated previously with greater risk of in-hospital adverse events, longitudinal outcomes are not known. We used Medicare-linked data from the National Cardiovascular Data Registry's ICD Registry to identify patients discharged alive following first-time primary prevention ICD implantations performed between 2010 and 2013. We compared longitudinal outcomes, including all-cause mortality and all-cause hospital readmission among patients receiving non-evidence-based versus evidence-based ICDs, up to 4.75 years after implantation, using multivariable time-to-event analyses. Of 71,666 ICD implantations, 9,609 (13.4%) were classified as non-evidence-based. Compared to patients receiving evidence-based ICDs, non-evidence-based ICD recipients had greater mortality risk at 90 days (HR=1.44, CI: 1.37 - 1.52, p <0.0001) and at 1 year (HR=1.19, CI: 1.15 - 1.24, p <0.0001), but similar mortality risk at 3 years (HR=1.03, CI: 0.98 - 1.08, p=0.2630). Risk of all-cause hospitalization was higher in patients with non-evidence-based ICDs at 90 days (HR=1.17, CI: 1.14 - 1.20, p <0.0001), but the difference diminished at 1 year (HR=1.04, CI 1.00 - 1.07, p=0.0272) and at 3 years (HR=0.94, CI: 0.90 - 0.99, p=0.0105). In conclusion, among patients undergoing primary prevention ICD implantations between 2010 and 2013, those with non-evidence-based ICDs were at increased risk of mortality and readmission during longitudinal follow-up. Differences in the risk of mortality and hospitalization were highest in the first year following device implantation.

Clinical Outcomes of Implantable Cardioverter-Defibrillator in Pediatric Patients - A Korean Multicenter Study.

Implantable cardioverter-defibrillator (ICD) therapy is important for the prevention of sudden cardiac death, but data on clinical outcomes of ICD therapy in Asian pediatric patients are scarce. The aim of this Korean multicenter study was to evaluate the current state and elucidate the clinical outcomes of ICD therapy in children.Methods and Results:Data from 5 pediatric cardiology centers were retrospectively collected from 2007 to 2019. Altogether, 99 patients were enrolled (mean age 13.9±4.1 years). The most common underlying disease was a primary electrical disease (56%). An ICD was implanted for primary prevention in 19%. Appropriate shock occurred in 44% of patients at a median of 1.6 years after implantation. There was no significant difference in the appropriate shock rate between patients with primary and secondary prevention indications (32% vs. 48%, respectively). A total of 33 patients (33%) experienced inappropriate shock, which was associated with primary electrical disease and follow-up duration on multivariate analysis. 17% of patients had ICD-related complications. The utilization rate of ICD for primary prevention was still low in the pediatric population in Korea, but there was a substantial rate of appropriate shock in these patients. Efforts to increase ICD usage to save the lives of high-risk patients and reduce the incidence of inappropriate shock are required.

Prediction of ventricular arrhythmia in phospholamban p.Arg14del mutation carriers-reaching the frontiers of individual risk prediction.

AimsThis study aims to improve risk stratification for primary prevention implantable cardioverter defibrillator (ICD) implantation by developing a new mutation-specific prediction model for malignant ventricular arrhythmia (VA) in phospholamban (PLN) p.Arg14del mutation carriers. The proposed model is compared to an existing PLN risk model.Methods and resultsData were collected from PLN p.Arg14del mutation carriers with no history of malignant VA at baseline, identified between 2009 and 2020. Malignant VA was defined as sustained VA, appropriate ICD intervention, or (aborted) sudden cardiac death. A prediction model was developed using Cox regression. The study cohort consisted of 679 PLN p.Arg14del mutation carriers, with a minority of index patients (17%) and male sex (43%), and a median age of 42 years [interquartile range (IQR) 27–55]. During a median follow-up of 4.3 years (IQR 1.7–7.4), 72 (10.6%) carriers experienced malignant VA. Significant predictors were left ventricular ejection fraction, premature ventricular contraction count/24 h, amount of negative T waves, and presence of low-voltage electrocardiogram. The multivariable model had an excellent discriminative ability {C-statistic 0.83 [95% confidence interval (CI) 0.78–0.88]}. Applying the existing PLN risk model to the complete cohort yielded a C-statistic of 0.68 (95% CI 0.61–0.75).ConclusionThis new mutation-specific prediction model for individual VA risk in PLN p.Arg14del mutation carriers is superior to the existing PLN risk model, suggesting that risk prediction using mutation-specific phenotypic features can improve accuracy compared to a more generic approach.

Cost-effectiveness of implantable cardioverter-defibrillators for primary prevention of sudden cardiac death

Introduction and objectivesImplantable cardioverter-defibrillators (ICD) are a cost-effective alternative for secondary prevention of sudden cardiac death, but their efficiency in primary prevention, especially among patients with nonischemic heart disease, is still uncertain. MethodsWe performed a cost-effectiveness analysis of ICD plus conventional medical treatment (CMT) vs CMT for primary prevention of cardiac arrhythmias from the perspective of the national health service. We simulated the course of the disease by using Markov models in patients with ischemic and nonischemic heart disease. The parameters of the model were based on the results obtained from a meta-analysis of clinical trials published between 1996 and 2018 comparing ICD plus CMT vs CMT, the safety results of the DANISH trial, and analysis of real-world clinical practice in a tertiary hospital. ResultsWe estimated that ICD reduced the likelihood of all-cause death in patients with ischemic heart disease (HR, 0.70; 95%CI, 0.58-0.85) and in those with nonischemic heart disease (HR, 0.79; 95%CI, 0.66–0.96). The incremental cost-effectiveness ratio (ICER) estimated with probabilistic analysis was €19 171/quality adjusted life year (QALY) in patients with ischemic heart disease and €31 084/QALY in those with nonischemic dilated myocardiopathy overall and €23 230/QALY in patients younger than 68 years. ConclusionsThe efficiency of single-lead ICD systems has improved in the last decade, and these devices are cost-effective in patients with ischemic and nonischemic left ventricular dysfunction younger than 68 years, assuming willingness to pay as €25 000/QALY. For older nonischemic patients, the ICER was around €30 000/QALY.