Candidates For Implantable Cardioverter-defibrillator Research Articles

Risk stratification for a primary prevention ICD: Performance of the MADIT-ICD Benefit Score in contemporary real world patients

Abstract Background We have recently developed the MADIT-ICD Benefit Score to improve risk stratification for primary implantable cardioverter defibrillator (ICD) implantation by assessing the competing risk of life-threatening ventricular tachyarrhythmia (VTA) vs. non-arrhythmic mortality based using simple clinical variables. Patients with a MADIT-ICD Benefit Score of < 50 are more likely to experience non-arrhythmic mortality than life-threatening VTA, and therefore derive limited benefit from a prophylactic ICD. Purpose We aimed to provide data on the performance of the MADIT-ICD Benefit Score in a real world population, comprising patients with HFrEF and either ischemic or nonischemic cardiomyopathy (ICM/NICM) who are treated with contemporary guideline-directed medical therapy (GDMT). Methods The study population comprised 2875 patients who were implanted with a primary prevention ICD and prospectively followed in a large tertiary healthcare system (the University of Rochester Medical Center, including 3 affiliated hospitals in Upstate New York) between 2017 through 2023. Arrhythmic events were captured from device interrogation data, which were blindly adjudicated by 2 electrophysiologists. Results Among the 2875 study patients, mean age was 62 ± 15 years, 1265 (44%) were women, and 1667 (58%) had ICM. Guideline-directed medical therapies, including angiotensin-converting enzyme inhibitors or angiotensin receptor blockers, angiotensin receptor/neprilysin inhibitors, beta-blockers, mineralocorticoid receptor antagonists, and sodium-glucose transport protein 2 (SGLT2) inhibitors, were prescribed to 43%, 36%, 96%, 67% and 32% of study patients, respectively. The 2-year cumulative incidence of VTA, after accounting for the competing risk of death, was 19% vs. 11% in patients with a Score of ≥50 vs. <50, respectively (p<0.001; Figure 1A). Findings regarding ICD shocks were consistent (8% vs. 4%, respectively, p<0.001; Figure 1B) The rate of VTA events at 4 years was directly correlated with increasing quartiles of the MADIT-ICD Benefit Score, while the corresponding rates of non-arrhythmic mortality were inversely correlated with score quartiles (Figure 1C). A similar direct correlation with increasing Benefit Score quartiles was observed when the endpoint of ICD shocks was assessed (Figure 1D). Accordingly, the benefit of the ICD (calculated as the difference between predicted rates of VTA/shock events and corresponding rates of non-arrhythmic mortality) was attenuated with decreasing quartiles of the MADIT-ICD Benefit Score (Figures 1C and 1D; right column). Conclusions We show good performance of the MADIT-ICD Benefit Score in a large cohort of real world ICD recipients who are treated with contemporary GDMT. These data support the use of the MADIT-ICD Benefit Score for improved risk stratification and for shared decision-making in contemporary candidates for a primary prevention ICD.

Prophylactic ICD Survival Benefit Prediction: Review and Comparison between Main Scores.

Current guidelines advocate for the use of prophylactic implantable cardioverter defibrillators (ICDs) for all patients with symptomatic heart failure (HF) with low ejection fraction (EF). As many patients will never use their device and some are prone to device-related complications, scoring systems for delineating subgroups with differential ICD survival benefits are crucial to maximize ICD benefit and mitigate complications. This review summarizes the main scores, including MADIT trial-based Risk Stratification Score (MRSS) and Seattle Heart Failure Model (SHFM), which are based on randomized trials with a control group (HF medication only) and validated on large cohorts of 'real-world' HF patients. Recent studies using cardiac MRI (CMR) to predict ventricular arrhythmia (VA) are mentioned as well. The review shows that most scores could not delineate sustained VA incidence, but rather mortality without prior appropriate ICD therapies. Multiple scores could identify high-risk subgroups with extremely high probability of early mortality after ICD implant. On the other hand, low-risk subgroups were defined, in whom a high ratio of appropriate ICD therapy versus death without prior appropriate ICD therapy was found, suggesting significant ICD survival benefit. Moreover, MRSS and SHFM proved actual ICD survival benefit in low- and medium-risk subgroups when compared with control patients, and no benefit in high-risk subgroups, consisting of 16-20% of all ICD candidates. CMR reliably identified areas of myocardial scar and 'channels', significantly associated with VA. We conclude that as for today, multiple scoring models could delineate patient subgroups that would benefit differently from prophylactic ICD. Due to their modest-moderate predictability, these scores are still not ready to be implemented into clinical guidelines, but could aid decision regarding prophylactic ICD in borderline cases, as elderly patients and those with multiple co-morbidities. CMR is a promising technique which might help delineate patients with a low- versus high-risk for future VA, beyond EF alone. Lastly, genetic analysis could identify specific mutations in a non-negligible percent of patients, and a few of these mutations were found to predict an increased arrhythmic risk.

Wearable defibrillator to improve accuracy in selecting candidates to implantable defibrillator: A real-world experience.

The indication for implantable cardioverter defibrillator (ICD) for sudden cardiac death (SCD) prevention relies mostly on left ventricular ejection fraction (LVEF)≤35%. The use of a wearable cardioverter defibrillator (WCD) in the case of dynamic alterations of LVEF may help avoid an improper early ICD implant when a favourable evolution in the post-acute phase is observed and may help reduce costs. This parallel cohort retrospective study included patients with heart failure with reduced ejection fraction (HFrEF) at high risk of arrhythmias recruited in the acute phase and divided into an early ICD cohort and a WCD cohort for primary prevention during the waiting period established by European Society of Cardiology guidelines. A total of 41 consecutive patients were enrolled: 26 in the WCD group and 15 in the early ICD group. Age, LVEF at baseline, causes of HFrEF and drug therapy in the two cohorts were similar. During the waiting period after the inclusion, three patients (11.5%) in the WCD cohort and four (26.7%) in the early ICD cohort developed relevant ventricular arrhythmias (P=0.22); none of them had subsequent LVEF recovery. At the end of the waiting period, 13 patients (50%) in the WCD group and 7 (46.7%) in the early ICD group experienced LVEF recovery (P=0.84). The average cost per patient at the end of the waiting period was €23934 in the early ICD cohort versus €19167 in the WCD cohort (-19.9%). This cost savings from WCD use appears even higher when projected over a 10year period (-41.2%). WCD may represent a cost-effective strategy to more accurately select candidates for the primary prevention ICD implant among high-risk patients with HFrEF. ICD use provides effective protection from SCD and reduces costs compared with an extensive early ICD implant.

Lack of Prognostic Value of T-Wave Alternans for Implantable Cardioverter-Defibrillator Benefit in Primary Prevention.

New methods to identify patients who benefit from a primary prophylactic implantable cardioverter-defibrillator (ICD) are needed. T-wave alternans (TWA) has been shown to associate with arrhythmogenesis of the heart and sudden cardiac death. We hypothesized that TWA might be associated with benefit from ICD implantation in primary prevention. In the EU-CERT-ICD (European Comparative Effectiveness Research to Assess the Use of Primary Prophylactic Implantable Cardioverter-Defibrillators) study, we prospectively enrolled 2327 candidates for primary prophylactic ICD. A 24-hour Holter monitor reading was taken from all recruited patients at enrollment. TWA was assessed from Holter monitoring using the modified moving average method. Study outcomes were all-cause death, appropriate shock, and survival benefit. TWA was assessed both as a contiguous variable and as a dichotomized variable with cutoff points <47 μV and <60 μV. The final cohort included 1734 valid T-wave alternans samples, 1211 patients with ICD, and 523 control patients with conservative treatment, with a mean follow-up time of 2.3 years. TWA ≥60 μV was a predicter for a higher all-cause death in patients with an ICD on the basis of a univariate Cox regression model (hazard ratio, 1.484 [95% CI, 1.024-2.151]; P=0.0374; concordance statistic, 0.51). In multivariable models, TWA was not prognostic of death or appropriate shocks in patients with an ICD. In addition, TWA was not prognostic of death in control patients. In a propensity score-adjusted Cox regression model, TWA was not a predictor of ICD benefit. T-wave alternans is poorly prognostic in patients with a primary prophylactic ICD. Although it may be prognostic of life-threatening arrhythmias and sudden cardiac death in several patient populations, it does not seem to be useful in assessing benefit from ICD therapy in primary prevention among patients with an ejection fraction of ≤35%.

Long-term Monitoring to Detect Risk of Sudden Cardiac Death in Inherited Arrhythmia Patients

BackgroundRisk stratification in inherited arrhythmia syndromes is challenging. Implantable cardioverter defibrillators (ICDs) are effective in the prevention of sudden cardiac death but are associated with significant complications. We aimed to determine the value of long-term implantable loop recorder (ILR) monitoring to determine risk factors for arrhythmias in inherited arrhythmia patients. MethodsWe conducted a prospective multicentre study between 2015 and 2020 recruiting inherited arrhythmia probands and family members at intermediate arrhythmic risk, with no class 1 indication for ICD implantation. The primary endpoint was the detection by ILR of nonsustained ventricular tachycardia over ≥ 10 consecutive beats. Secondary endpoints included ICD insertion during follow-up, all-cause mortality, and ILR complication rates. ResultsA total of 45 individuals (30 female participants) were enrolled in the study. The most common diagnoses were long-QT syndrome (28%), Brugada syndrome (26%), and arrhythmogenic cardiomyopathy (11%). Following ILR insertion (mean follow-up 633 days; range, 387-969), cardiac symptoms occurred in 19 of 45 patients (42%), 5 of whom had nonsustained ventricular tachycardias (11%), which were symptomatic in 3 individuals. This situation led to ICD implantation based on ILR in 5 of 45 patients (11%). Fifty percent of symptomatic events occurred in ARVC patients. The median time from ILR insertion to ICD implantation was 152 days (interquartile range (25th, 75th percentiles) 55 of 209). No patient experienced sudden cardiac death. ConclusionsILRs enable the detection of high-risk arrhythmic features and facilitate selection of ICD candidates in inherited arrhythmia patients with borderline indications.

Assessment of late gadolinium enhancement in hypertrophic cardiomyopathy improves risk stratification based on current guidelines.

Identifying patients with hypertrophic cardiomyopathy (HCM) who are candidates for implantable cardioverter defibrillator (ICD) implantation in primary prevention for sudden cardiac death (SCD) is crucial. The aim of this study was to externally validate the 2022 European Society of Cardiology (ESC) model and other guideline-based ICD class of recommendation (ICD-COR) models and explore the utility of late gadolinium enhancement (LGE) in further risk stratification. Seven hundred and seventy-four consecutive patients who underwent cardiac magnetic resonance imaging were retrospectively enrolled. Forty-six (5.9%) patients reached the SCD-related endpoint during 7.4 ± 2.5 years of follow-up. Patients suffering from SCD had higher ESC Risk-SCD score (4.3 ± 2.4% vs. 2.8 ± 2.1%, P < .001) and LGE extent (13.7 ± 9.4% vs. 4.9 ± 6.6%, P < .001). Compared with the 2014 ESC model, the 2022 ESC model showed increased area under the curve (.76 vs. .63), sensitivity (76.1% vs. 43.5%), positive predictive value (16.8% vs. 13.6%), and negative predictive value (98.1% vs. 95.9%). The C-statistics for SCD prediction of 2011 American College of Cardiology (ACC)/American Heart Association (AHA), 2014 ESC, 2020 AHA/ACC, and 2022 ESC models were .68, .64, .76 and .78, respectively. Furthermore, in patients without extensive LGE, LGE ≥5% was responsible for seven-fold SCD risk after multivariable adjustment. Whether in ICD-COR II or ICD-COR III, patients with LGE ≥5% and <15% showed significantly worse prognosis than those with LGE <5% (all P < .001). The 2022 ESC model performed better than the 2014 ESC model with especially improved sensitivity. LGE enabled further risk stratification based on current guidelines.

The relationship between the incision line and position of the latissimus dorsi muscle for subcutaneous implantable cardioverter-defibrillator intermuscular implantations.

Intermuscular implantations of subcutaneous implantable cardioverter-defibrillators (S-ICD) have been recommended, but the position of the anterior border of the latissimus dorsi muscle (LDM) has not previously been evaluated in establishing an incision line to facilitate the intermuscular approach. The objective of this study is to evalua the position and trend of the anterior border of the LDM in patients who are candidates for implantable cardioverter-defibrillators. The distance from the back to the anterior border of the LDM (A) and the anterior-posterior width of the chest wall (B) weremeasured on computed tomography retrospectively, and the ratio (=A/B) was used as the position of the anterior border of the LDM. In addition, the variability and factors affecting the values were evaluated. An analysis was performed on 78 patients, and the position of the anterior border of the LDM (=A/B) exhibited a normal distribution, with a mean value of 0.53 ± 0.062 (0.41-0.69). The position of the anterior border of the LDM tended to be more anterior in younger, taller, male, primary prevention, nonheart failure, low brain natriuretic peptide level, and nondiabetic patients. The position of the anterior border of the LDM varied from case to case with variable results. Conventional incisions on the midaxillary line may be inappropriate for intermuscular implantations, and the position of the anterior border of the LDM should be evaluated in each individual case to establish the incision line.

Left ventricular shape remodelling predicts major arrhythmic events in stable coronary artery disease

Abstract Funding Acknowledgements Type of funding sources: Public Institution(s). Main funding source(s): This work was supported by the National Institute for Health Research Biomedical Research Centre at Guy’s and St. Thomas’ Trust and King’s College, the Centre of Excellence in Medical Engineering funded by the Wellcome Trust and Engineering and Physical Sciences Research Council (EPSRC; WT088641/Z/09/Z). M.J.B. is supported by a Medical Research Council New Investigator Grant (MR/N011007/1) and British Heart Foundation (Project grant PG/18/74/34077). This work was supported by EPSRC 2018/19 DTP - EP/R513064/1 grant. This work was supported by a National Heart and Lung Institute Foundation grant awarded to Professor Sanjay Prasad and Dr Richard Jones. Background Arrhythmic risk stratification of patients with stable coronary artery disease (CAD) for defibrillator implantation remains imprecise. Current clinical guidelines center on a basic assessment of adverse cardiac remodelling, an approach with well documented limitations. More advanced analysis of intricate and regional LV remodelling in these patients may shed new insight for enhanced risk prediction of life-threatening arrhythmia in stable CAD. Objective We explored a novel computational 3D LV shape analysis strategy to accurately represent, and quantify, arrhythmogenic LV remodelling patterns in late gadolinium enhancement cardiovascular magnetic resonance images (LGE-CMR) in patients with stable CAD. We assess the utility of our patient-specific 3D LV arrhythmic shape (LVAS) score predicting major arrhythmic event; comparing to the current clinical benchmark of severely reduced LVEF and NYHA functional class. Methods Patients with stable CAD were prospectively recruited into a CMR registry and followed up for a composite endpoint of major arrhythmic events (MAE) consisting of sudden cardiac death (SCD), aborted SCD or haemodynamically unstable VT. Time-to-event data was also recorded. 2D LGE-CMR images were contoured and used as input to an advanced computational shape-analysis approach (Figure 1A). Reconstructed 3D LV shape models were analysed using Principle Component Analysis and Cox-Lasso to characterise the average arrhythmogenic LV shape, which was then used to quantitatively define a patient-specific LV arrhythmic shape (LVAS) score. Results Of 397 patients (mean [SD] LVEF% 45.4 ± 16.0) followed for a median (IQR) of 6 (3) years, 55 (14%) experienced a major arrhythmic event (MAE). The mean (SD) LVEF for patients who experienced MAE was lower than for those that did not (37.1% ± 13.2 vs 46.7% ± 16.0), yet there was no difference in NYHA class. LVAS mean (95% confidence interval [CI]) score was different between event and event-free patients: 2.98 (0.48-6.44) vs 19.83 (10.66-29), P&amp;lt;0.001. On univariate Cox regression analysis both LVAS score (hazard ratio [HR] 2.1, 95% CI 1.6-2.7, P&amp;lt;0.001) and LVEF&amp;lt;35% (HR 2.9, 95% CI 1.6-5.0, P&amp;lt;0.01) were associated with the primary endpoint. NYHA Class &amp;gt;I was not associated with the primary endpoint (HR 1.5, 95% CI 0.8-2.7, P=0.221). In multivariate Cox regression analysis, LVAS remained independently associated with the primary endpoint after adjusting for LVEF&amp;lt;35% and NYHA&amp;gt;Class I: LVAS score HR 2.1, 95% CI 1.5-3.0, P&amp;lt;0.001; LVEF&amp;lt;35% HR 1.0, 95% CI 0.5-2.2, P=0.923; NYHA&amp;gt;Class I HR 1.3, 95% CI 0.7-2.5, P=0.443 (Figure 1 B, C). The addition of the LVAS score increased the C-statistic from 0.6 to 0.75 between models. Conclusion A Left Ventricle Arrhythmic Shape score improved arrhythmic risk stratification compared to guideline-based clinical parameters, highlighting a potentially novel approach to identifying candidates for implantable cardioverter defibrillators in stable CAD.

Machine learning analysis of complex late gadolinium enhancement patterns to improve risk prediction of major arrhythmic events.

Machine learning analysis of complex myocardial scar patterns affords the potential to enhance risk prediction of life-threatening arrhythmia in stable coronary artery disease (CAD). To assess the utility of computational image analysis, alongside a machine learning (ML) approach, to identify scar microstructure features on late gadolinium enhancement cardiovascular magnetic resonance (LGE-CMR) that predict major arrhythmic events in patients with CAD. Patients with stable CAD were prospectively recruited into a CMR registry. Shape-based scar microstructure features characterizing heterogeneous ('peri-infarct') and homogeneous ('core') fibrosis were extracted. An ensemble of machine learning approaches were used for risk stratification, in addition to conventional analysis using Cox modeling. Of 397 patients (mean LVEF 45.4 ± 16.0) followed for a median of 6 years, 55 patients (14%) experienced a major arrhythmic event. When applied within an ML model for binary classification, peri-infarct zone (PIZ) entropy, peri-infarct components and core interface area outperformed a model representative of the current standard of care (LVEF<35% and NYHA>Class I): AUROC (95%CI) 0.81 (0.81-0.82) vs. 0.64 (0.63-0.65), p = 0.002. In multivariate cox regression analysis, these features again remained significant after adjusting for LVEF<35% and NYHA>Class I: PIZ entropy hazard ratio (HR) 1.88, 95% confidence interval (CI) 1.38-2.56, p < 0.001; number of PIZ components HR 1.34, 95% CI 1.08-1.67, p = 0.009; core interface area HR 1.6, 95% CI 1.29-1.99, p = <0.001. Machine learning models using LGE-CMR scar microstructure improved arrhythmic risk stratification as compared to guideline-based clinical parameters; highlighting a potential novel approach to identifying candidates for implantable cardioverter defibrillators in stable CAD.

Can the Norton Scale Score Be Used as an Adjunct Tool for Implantable Defibrillator Patient Selection? A Retrospective Single-Center Cohort Study.

(1) Background: Implantable cardioverter defibrillators (ICDs) have become the standard of care in the prevention of sudden cardiac death, yet studies have shown that competing causes of death may limit ICD benefits. The Norton scale is a pressure ulcer risk score shown to have prognostic value in other fields. The purpose of this study was to assess the use of the Norton scale as an aid for ICD patient selection; (2) Methods: The study was comprised of consecutive patients who underwent defibrillator implantation at Sheba Medical Center between 2008 and 2016. A competing risk analysis was performed to assess the likelihood of death prior to device therapy; (3) Results: 695 patients were included. A total of 59 (8.5%) patients had low admission Norton scale score (ANSS) (≤14), 81 (11.7%) had intermediate ANSS (15−17), and the remainder (79.8%) had high (18−20) ANSS. The cumulative probability of all-cause mortality within one year of ICD implantation in patients with low ANSS was 30%, compared with 20% and 7% among the intermediate- and high-ANSS groups, respectively. Moreover, the one-year mortality rate without ICD therapy in low-ANSS patients was over four-fold compared with that of high-ANSS patients (33% versus 7%, p < 0.0001); (4) Conclusions: The Norton scale could be a useful additional tool in predicting the life expectancy of ICD candidates, thereby improving patient selection.

Prediction of Left Ventricular Ejection Fraction Change Following Treatment With Sacubitril/Valsartan

BackgroundSacubitril/valsartan (Sac/Val) improves left ventricular ejection fraction (LVEF) in heart failure (HF) with reduced ejection fraction regardless of previous treatments. Improvements in LVEF may change eligibility for primary implantable cardioverter-defibrillator (ICD) placement. Awaiting LVEF improvement may expose patients to potential risks for arrhythmic complications. ObjectivesThe authors sought to develop a model predicting LVEF change after Sac/Val therapy. MethodsA total of 416 persons with HF and LVEF of <35% were included in this analysis. Following initiation of Sac/Val, echocardiographic parameters were measured serially for 1 year. A machine learning algorithm was implemented to develop a risk model for predicting the persistence of LVEF of <35% after 1 year and was validated in a separate group of study participants. ResultsBaseline LVEF, left ventricular mass index, HF duration, age, N-terminal pro–B-type natriuretic peptide concentration at baseline and change by day 14, and body mass index were the most significant factors for identifying lack of LVEF improvement to ≥35% after 1 year. In the training and validation cohorts, the areas under the model curve for predicting lack of LVEF improvement were 0.92 and 0.86, respectively. Three categories of likelihood for LVEF of <35% after 1 year of Sac/Val treatment were developed based on the model predictions: 3.8%, 30.1%, and 83.7%. During follow-up, arrhythmia event rates were 0.9%, 2.9%, and 6.7% in these groups, respectively. ConclusionsMany persons with HF with reduced ejection fraction eligible for ICD insertion experience an increase in LVEF to ≥35% after treatment with Sac/Val. Early identification of those less likely to improve their LVEF might allow for more refined selection of primary ICD candidates. (Effects of Sacubitril/Valsartan Therapy on biomarkers, Myocardial Remodeling, and Outcomes [PROVE-HF]; NCT02887183)

Defibrillation Threshold Testing and Long-term Follow-up in Chagas Disease.

Sudden cardiac death is the most common cause of death in chronic Chagas cardiomyopathy (CCC). Because most CCC patients who are candidates for implantable cardioverter-defibrillators (ICD) meet criteria for high defibrillation threshold values, a defibrillator threshold test (DTT) is suggested. We investigated the use of DTT in CCC patients, focusing on deaths related to ICD and arrhythmic events, as well as treatment during long-term follow-up. We retrospectively evaluated 133 CCC patients who received an ICD mainly for secondary prevention. Demographic, clinical, laboratory data, Rassi score, and DTT data were collected, with p < 0.05 considered significant. The mean patient age was 61 (SD, 13) years and 72% were men. The baseline left ventricular ejection fraction was 40 (SD, 15%) and the mean Rassi score was 10 (SD, 4). No deaths occurred during DTT and no ICD failures were documented. There was a relationship between higher baseline Rassi scores and higher DTT scores (ANOVA = 0.007). The mean time to first shock was 474 (SD, 628) days, although shock was only necessary for 28 (35%) patients with ventricular tachycardia, since most cases resolved spontaneously or through antitachycardia pacing. After a mean clinical follow-up of 1728 (SD, 1189) days, 43 deaths occurred, mainly related to progressive heart failure and sepsis. A routine DTT may not be necessary for CCC patients who receive an ICD for secondary prevention. High DTT values seem to be unusual and may be related to high Rassi scores.

Temporal Changes in Beat‐to‐Beat Variability of Repolarization Predict Imminent Nonsustained Ventricular Tachycardia in Patients With Ischemic and Nonischemic Dilated Cardiomyopathy

BackgroundAn increase in beat‐to‐beat variability of repolarization (BVR) predicts arrhythmia onset in experimental models, but its clinical translation is not well established. We investigated the temporal changes in BVR before nonsustained ventricular tachycardia (nsVT) in patients with implantable cardioverter defibrillator (ICD).Methods and ResultsPatients with nsVT on 24‐hour Holter before ICD implantation for ischemic cardiomyopathy (ischemic cardiomyopathy+nsVT, n=43) or dilated cardiomyopathy (dilated cardiomyopathy+nsVT, n=37), matched ICD candidates without nsVT (ischemic cardiomyopathy‐nsVT, n=29 and dilated cardiomyopathy‐nsVT, n=26), and patients without ICD without structural heart disease (n=50) were studied. Digital Holter recordings from these patients were analyzed using a modified fiducial segment averaging technique to detect the QT interval. The nsVT episodes were semi‐automatically identified and QT‐BVR was assessed 1‐, 5‐, and 30‐minutes before nsVT, and at rest (at 3:00 am). Resting BVR was higher in ICD patients compared with controls without structural heart disease. In ICD patients with nsVT, BVR increased significantly 1‐minute pre‐nsVT in ischemic cardiomyopathy (2.21±0.59 ms, versus 5 minutes pre‐nsVT: 1.78±0.50 ms, P<0.001) and dilated cardiomyopathy (2.09±0.57 ms, versus 5‐minutes pre‐nsVT: 1.58±0.51 ms, P<0.001), but not in patients without nsVT. In multivariable Cox regression analysis, pre‐nsVT BVR was a significant predictor for appropriate therapy during follow‐up.ConclusionsBaseline BVR is elevated and temporal changes in BVR predict imminent nsVT events in patients with ICD independent of underlying cause. Real‐time BVR monitoring could be used to predict impending ventricular arrhythmia and allow preventive therapy to be incorporated into ICDs.

Comparison of Frequency of Ventricular Tachyarrhythmia in Men-Versus-Women in Patients with Implantable Cardioverter-Defibrillator for Primary Prevention

Current guidelines do not account for possible sex differences in the risk of ventricular tachyarrhythmia (VTA). We sought to identify specific factors associated with increased risk for VTA in women implanted with a primary prevention implantable cardioverter-defibrillator (ICD). Our study cohort consisted of 4,506 patients with an ICD or cardiac resynchronization therapy-defibrillator who were enrolled in the 4 landmark MADIT studies - MADIT-II, MADIT-RISK, MADIT-CRT and MADIT-RIT (1,075 women [24%]). Fine and Gray regression models were used to identify female-specific risk factors for the primary end point of VTA, defined as ICD-recorded, treated, or monitored, sustained ventricular tachycardia ≥170 beats per minute or ventricular fibrillation. At 3.5 years of follow-up, the cumulative incidence of VTA was significantly lower in women than men (17% vs 26%, respectively; p <0.001 for the entire follow-up). Use of amiodarone at enrollment, Black race, and history of previous myocardial infarction without previous revascularization was found to be independent risk factors of VTA in women. Of these factors, only Black race was associated with a statistically significant risk increase in men. At 3.5 years, the cumulative incidence of VTA in women with one or more of these risk factors was 27% compared with 14% in women with none of the risk factors (hazard ratio [confidence interval]=2.08 [1.49 to 2.91]). In conclusion, our study, comprising 4 landmark ICD clinical trials, shows that sex and race have the potential to be used for improved risk stratification of patients who are candidates for primary prevention ICD.

The validity of current implantable cardioverter-defibrillator guidelines in a real-world population of adults with congenital heart disease: A single-center experience

AimsSudden cardiac death (SCD) is a major cause of mortality in adults with congenital heart disease (ACHD). The role of implantable cardioverter-defibrillator (ICDs) in preventing SCD has been established, however, robust, clinical evidence-based guidelines are lacking in ACHD. The aim of this study was to evaluate the ICD guidelines in ACHD patients. Methods and ResultsA total of 131 ACHD patients (male: n = 96 (73.3%), mean age: 42.8 ± 14.7 years, mean follow-up: 40.9 ± 28.3 months) undergoing ICDs implantation between 2010 and 2017 were reviewed. Sixty-nine patients (52.6%) received ICDs for a primary prevention indication. 122 (93.3%) patients had congenital heart disease of moderate to severe complexity. CRT-D (implantable cardiac resynchronization defibrillator) was implanted in 55 (42.0%) patients. During follow-up, 23 patients (17.6%) received appropriate ICD therapy. According to the current guideline (PACES/HRS 2014), 84 (64.1%), 8 (6.1%), and 39 (29.8%) could be classified as Class Ⅰ, Class Ⅱa, and Class Ⅱb indication, respectively. Compared to patients with Class Ⅱa and IIb indication, those with Class Ⅰ indication received more appropriate therapy (P = 0.030). Multivariate analysis showed that age (per 10-years decrease; P = 0.015, HR 1.254 CI; 1.045–1.505) and creatinine (per 100-μmol/L increase; P = 0.019, HR 1.555 CI; 1.076–2.247) were associated with appropriate therapy. ConclusionImplantation of ICDs for preventing SCD based on current guidelines is reasonable. For patients with a borderline indication, younger age and renal dysfunction may aid in the selection of ICDs candidates.

CinE caRdiac magneTic resonAnce to predIct veNTricular arrhYthmia (CERTAINTY)

Better models to identify individuals at low risk of ventricular arrhythmia (VA) are needed for implantable cardioverter-defibrillator (ICD) candidates to mitigate the risk of ICD-related complications. We designed the CERTAINTY study (CinE caRdiac magneTic resonAnce to predIct veNTricular arrhYthmia) with deep learning for VA risk prediction from cine cardiac magnetic resonance (CMR). Using a training cohort of primary prevention ICD recipients (n = 350, 97 women, median age 59 years, 178 ischemic cardiomyopathy) who underwent CMR immediately prior to ICD implantation, we developed two neural networks: Cine Fingerprint Extractor and Risk Predictor. The former extracts cardiac structure and function features from cine CMR in a form of cine fingerprint in a fully unsupervised fashion, and the latter takes in the cine fingerprint and outputs disease outcomes as a cine risk score. Patients with VA (n = 96) had a significantly higher cine risk score than those without VA. Multivariate analysis showed that the cine risk score was significantly associated with VA after adjusting for clinical characteristics, cardiac structure and function including CMR-derived scar extent. These findings indicate that non-contrast, cine CMR inherently contains features to improve VA risk prediction in primary prevention ICD candidates. We solicit participation from multiple centers for external validation.

Development of a risk stratification score based on social predictors in patients undergoing implantable cardioverter defibrillator

Abstract Introduction The implantable cardioverter defibrillator (ICD) has been shown to be effective in reducing cardiovascular mortality in selected patients with cardiomyopathy in primary and secondary prevention. However, as it is an invasive and costly procedure, it is necessary to identify the patients who most benefit from this therapy. The evaluation of a multidisciplinary team for CRT candidates can contribute to the improvement of results. Objective Development of a risk score based on social predictors in patients undergoing ICD implantation. Methods Prospective cohort conducted between January 2017 and September 2019 with patients who underwent ICD implantation in primary and secondary prevention. Patients were evaluated before implantation of the device by a multidisciplinary team that analyzed four social predictors for an unfavorable outcome (low medication adherence, presence of psychosocial risks, low family income and low level of education). The social score was calculated by the simple arithmetic sum of the number of predictors present in each patient. Variables with a possible association (p&amp;lt;0.1) with mortality in 1 year of follow-up were used in the multivariate model by Cox regression. Results 205 patients were evaluated with a mean follow-up of 416.5 (± 271.6) days. 140 (68.3%) were male, with an mean age of 54.6 years (± 14.6) and an mean LVEF of 43.8% (± 18.5). Most patients 160 (78.0%) were referred for secondary prevention, with Chagas disease being the most prevalent cause of cardiomyopathy 113 (55.1%). Mortality at 1 year was 32 (15.6%). In the multivariate analysis, with the inclusion of the variables: age, secondary prevention, Chagas' disease, LVEF &amp;lt;40% and social score; only the highest score on the social score and LVEF &amp;lt;40% were independently associated with 1-year mortality, RR: 1.5, IC 1.2–2.0; p=0.003 and RR: 4.1, CI 1.2–14.2; p=0.02, respectively. Mortality increased significantly as the score on the social score increased: 6.0% for a score of 0, 7.5% for 1 point; 21.7% for 2 points; 25.0% for 3 points and 29.0% for 4 points; p=0.006, Log-Rank (Figure 1). Conclusion The social score can represent a simple prognostic tool that can be usefully used in candidates for ICD. The use of a multidisciplinary team to evaluate patients who are candidates for ICD can help to correctly identify patients who can benefit most from therapy. Funding Acknowledgement Type of funding sources: None. Figure 1

Out of Hospital Sudden Death in a Rural Population: Low Rates of ICD Underutilization Among Decedents.

Implantable cardioverter defibrillators (ICDs) reduce mortality in patients at risk for life-threatening arrhythmias. Implantation of ICDs in rural or economically disadvantaged populations is suspected to be low. This study examined Out of Hospital Premature Natural Death (OHPND) and electronic medical record (EMR) data to identify rates of non-implantation of ICDs among decedents in eastern North Carolina. OHPND cases in 2016 were identified using mortality data and matched with EMRs. Those meeting criteria for ICD implantation based on chart review were adjudicated by two electrophysiologists to determine whether they qualified for implantation. Comorbidity burden was established using Charlson's Comorbidity Index (CCI). Out of 1316 OHPND cases, 967 (73.4%) had EMR records. Chart review identified 70 (7.2%) potential ICD candidates with a LVEF ≤35 of which 5 (7.1%) did not meet criteria because LVEF subsequently improved. Of the remaining 65 patients, 32 (49.2%) already received an ICD, and 33 patients (50.7%) met criteria but had not received one. Reasons for non-implantation included: limited life expectancy secondary to comorbidities, principally chronic kidney disease (CKD) (N=11, 17%), physician non-adherence to guidelines (N=9, 14%), loss to follow-up (N=7, 11%), patient refusal (N=5, 8%), and death before commencing medical therapy (N=1, 2%). Among our cohort of 967 individuals who died unexpectedly, nine (0.9%) patients may have avoided death with an ICD. This study using decedent data shows low rates of ICD-underutilization in a rural population and emphasizes the role of advanced comorbidities such as CKD in ICD-underutilization.

Preemptive cardiac resynchronization therapy to prevent cardiac arrest in peripartum cardiomyopathy: a case report

Select patients with peripartum cardiomyopathy are candidates for implantable cardioverter-defibrillator (ICD) or cardiac resynchronization therapy (CRT) due to the increased risk for life threatening arrhythmias and sudden death. We present a case of peripartum cardiomyopathy awaiting CRT placement who suffered cardiac arrest during the surgical dilation and curettage (D&amp;C) procedure for pregnancy termination.

Arrhythmic risk stratification by cardiac magnetic resonance tissue characterization: disclosing the arrhythmic substrate within the heart muscle.

Sudden cardiac death (SCD) is a pivotal health problem worldwide. The identification of subjects at increased risk of SCD is crucial for the accurate selection of candidates for implantable cardioverter defibrillator (ICD) therapy. Current strategies for arrhythmic stratification largely rely on left ventricular (LV) ejection fraction (EF), mostly measured by echocardiography, and New York Heart Association functional status for heart failure with reduced EF. For specific diseases, such as hypertrophic and arrhythmogenic cardiomyopathy, some risk scores have been proposed; however, these scores take into account some parameters that are a partial reflection of the global arrhythmic risk and show a suboptimal accuracy. Thanks to a more comprehensive evaluation, cardiac magnetic resonance (CMR) provides insights into the heart muscle (the so-called tissue characterization) identifying cardiac fibrosis as an arrhythmic substrate. Combining sequences before and after administration of contrast media and mapping techniques, CMR is able to characterize the myocardial tissue composition, shedding light on both intracellular and extracellular alterations. Over time, late gadolinium enhancement (LGE) emerged as solid prognostic marker, strongly associated with major arrhythmic events regardless of LVEF, adding incremental value over current strategy in ischemic heart disease and non-ischemic cardiomyopathies. The evidence on a potential prognostic role of mapping imaging is promising. However, mapping techniques require further investigation and standardization. Disclosing the arrhythmic substrate within the myocardium, CMR should be considered as part of a multiparametric approach to personalized arrhythmic stratification.