Benefit Of Implantable Cardioverter-defibrillator Research Articles

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%.

New York Heart Association functional class and implantable cardioverter-defibrillator in non-ischaemic heart failure with reduced ejection fraction: Extended follow-up of the DANISH trial.

Current guidelines recommend implantable cardioverter-defibrillator (ICD) therapy in patients with heart failure, a left ventricular ejection fraction of ≤35%, and New York Heart Association (NYHA) class II-III. However, the evidence regarding the benefit of primary prevention ICD is less consistent in patients with NYHA class III. We investigated the long-term effects of primary prevention ICD implantation according to NYHA class in an extended follow-up study of the DANISH trial. The DANISH trial randomized 1116 patients with non-ischaemic heart failure with reduced ejection fraction (HFrEF) to ICD implantation or usual care. Outcomes were analysed according to NYHA class at baseline (NYHA class II and III/IV). The primary outcome was all-cause mortality. Of the 1116 patients randomized in the DANISH trial, 597 (53.5%) were in NYHA class II at baseline, 505 (45.3%) in NYHA class III, and 14 (1.3%) in NYHA class IV. During a median follow-up of 9.5 years, NYHA class III/IV, compared with NYHA class II, were associated with a greater long-term rate of all-cause mortality (hazard ratio [HR] 1.52, 95% confidence interval [CI] 1.20-1.93) and cardiovascular death (HR 1.95 [1.47-2.60]). ICD implantation, compared with usual care, did not reduce the long-term rate of all-cause mortality (all participants: HR 0.89 [95% CI 0.74-1.08]; NYHA class II: HR 0.85 [0.64-1.13]; NYHA class III/IV: HR 0.89 [0.69-1.14]; pinteraction = 0.78) or cardiovascular death (all participants: HR 0.87 [95% CI 0.70-1.09]; NYHA class II: HR 0.78 [0.54-1.12]; NYHA class III/IV: HR 0.89 [0.67-1.19]; pinteraction = 0.58), irrespective of NYHA class. Similarly, NYHA class did not modify the beneficial effects of ICD implantation on sudden cardiovascular death (all participants: HR 0.60 [95% CI 0.40-0.92]; NYHA class II: HR 0.73 [0.40-1.36]; NYHA class III/IV: HR 0.52 [0.29-0.94]; pinteraction = 0.39). In patients with non-ischaemic HFrEF, ICD implantation, compared with usual care, did not reduce the overall mortality rate, but it did reduce sudden cardiovascular death, regardless of baseline NYHA class. ClinicalTrials.gov NCT00542945.

An international multicenter cohort study on implantable cardioverter-defibrillators for the treatment of symptomatic children with catecholaminergic polymorphic ventricular tachycardia

BackgroundCatecholaminergic polymorphic ventricular tachycardia (CPVT) may cause sudden cardiac death (SCD) despite medical therapy. Therefore, implantable cardioverter-defibrillators (ICDs) are commonly advised. However, there are limited data on the outcomes of ICD use in children. ObjectiveThe purpose of this study was to compare the risk of arrhythmic events in pediatric patients with CPVT with and without ICD. MethodsWe compared the risk of SCD in patients with RYR2 (ryanodine receptor 2) variants and phenotype-positive symptomatic patients with CPVT with and without ICD who were younger than 19 years and had no history of sudden cardiac arrest at phenotype diagnosis. The primary outcome was SCD; secondary outcomes were composite end points of SCD, sudden cardiac arrest, or appropriate ICD shocks with or without arrhythmic syncope. ResultsThe study included 235 patients, 73 with ICD (31.1%) and 162 without ICD (68.9%). Over a median follow-up of 8.0 years (interquartile range 4.3–13.4 years), SCD occurred in 7 patients (3.0%), of whom 4 (57.1%) were noncompliant with medications and none had an ICD. Patients with ICD had a higher risk of both secondary composite outcomes (without syncope: hazard ratio 5.85; 95% confidence interval 3.40–10.09; P < .0001; with syncope: hazard ratio 2.55; 95% confidence interval 1.50–4.34; P = .0005). Thirty-one patients with ICD (42.5%) experienced appropriate shocks, 18 (24.7%) inappropriate shocks, and 21 (28.8%) device-related complications. ConclusionSCD events occurred only in the no ICD group and in those not on optimal medical therapy. Patients with ICD had a high risk of appropriate and inappropriate shocks, which may be reduced with appropriate device programming. Severe ICD complications were common, and risks vs benefits of ICDs need to be considered.

Mortality Benefit Among Primary Prevention Implantable Cardioverter-Defibrillator Recipients on Contemporary Heart Failure Treatment

BackgroundPast clinical trials have shown the benefit of implantable cardioverter-defibrillators (ICDs) for reducing sudden cardiac death in at-risk patients. However, heart failure management and ICD technology have changed since these trials were first published. An updated assessment of ICD mortality benefit is needed. ObjectivesThe purpose of this study was to compare mortality rates between patients with a primary prevention (PP) indication for an ICD who did or did not receive an ICD using a contemporary, real-world data set. MethodsData was obtained from a large electronic health record data set covering patients in the United States from 2012 through 2020 who had a PP indication for an ICD and survived at least 1-year postindication. ResultsA total of 25,296 patients were identified as having a PP indication for ICD implantation, of which 2,118 (8.4%) were treated with an ICD within a year. Treated patients were younger than nontreated patients (age 63.4 years vs 66.1 years) with a smaller proportion of women (25.0% vs 36.7%). After 4-to-1 propensity matching, treated patients had similar clinical characteristics to nontreated patients. A Cox proportional hazard model estimated a 24.3% lower risk of all-cause mortality in patients when treated vs not treated with an ICD (HR: 0.757; 95% CI: 0.678-0.835; P <0.001). There was no detectable difference in ICD benefit between patients with ischemic and nonischemic heart disease (P = 0.50). ConclusionsICD treatment of patients with a PP indication is associated with improved mortality even in the context of evolving adjunctive HF treatment, consistent with earlier landmark trials.

Whether to implant a defibrillator or not? The Possibility of Using the MADIT-ICD Benefit Score Calculator in Real Practice

To study the predictive capabilities of the MADIT-ICD Benefit Score calculator in assessing the benefit of implantable cardioverter defibrillator (ICD) placement for the primary prevention of sudden cardiac death (SCD). This study included 388 patients with NYHA II-IV functional class chronic heart failure (CHF) with a left ventricular ejection fraction (LVEF) ≤35 % who underwent ICD placement for the primary prevention of SCD. Patients were followed up for two years to record the endpoints of first-time paroxysmal sustained ventricular tachyarrhythmia (VT) or non-arrhythmic death. According to the results of calculation with the MADIT-ICD Benefit Score calculator, 276 (71 %) patients had a high risk of VT (score ≥7) and 150 (39 %) had a high risk of non-arrhythmic death (score ≥3). 336 (94%) patients would benefit from an ICD: 148 (38 %) with a high level of probability and 218 (56 %) with a medium level of probability. According to the incidence of endpoints, VT episodes predominated in the low-ICD benefit group (36%), while the high-ICD benefit group had a relatively high incidence of non-arrhythmic death (12%). The results obtained for a cohort of Russian patients with CHF and reduced LVEF indicated that the use of the MADIT-ICD Benefit Score in routine clinical practice does not improve the stratification of SCD risk compared to the traditional approach to selecting patients with CHF for ICD based on the LVEF value.

Mortality benefit of implantable cardioverter-defibrillators for primary prevention of sudden cardiac death: a real-world analysis

Abstract Background Nearly 1,000 people suffer an out-of-hospital sudden cardiac arrest daily in the United States, with only 10% surviving when treated by emergency medical services. Implantable cardioverter-defibrillators (ICDs) are a proven first-line treatment in limiting sudden cardiac death, but the evidence has become dated. We sought to assess the survival benefit of ICDs in a contemporary population. Purpose Using a real-world database, we aimed to determine the current impact of ICDs on mortality in primary prevention patients. Methods Data were obtained from a de-identified electronic health record database. We included patients that met ICD primary prevention indication (PPI) implantation criteria between 2012 and 2019, had one year of available data before the PPI, and survived for at least one year post-PPI. Patients were split into 2 groups based on ICD implant status (implanted vs not implanted) within one year after PPI. The primary endpoint was the overall mortality rate, beginning at one-year post-PPI. Propensity matching was performed to account for baseline differences between patients that did and did not receive an ICD, and all-cause mortality rates were compared using the Kaplan-Meier method and Cox proportional hazard model. Results A total of 25,296 patients were identified as having a PPI for ICD implantation, of which 2,118 (8.4%) were implanted with an ICD within a year. Implanted patients were younger than non-implanted patients (63.4 vs 66.1 years) and had a smaller proportion of females (25.0% vs 36.7%). After 4 to 1 propensity matching, patients who did not have an ICD implanted had a mean age of 63.6 years and were 25.1% female. In the matched cohort, the 5-year all-cause mortality rate was 37.6% (CI: 33.2%-41.7%) in PPI patients who received an ICD and 44.9% (CI: 42.8%-47.0%) in those that did not receive an ICD. A Cox proportional hazard model revealed a 25.3% lower risk of all-cause mortality in PPI patients implanted with an ICD compared to PPI patients without an ICD (HR: 0.747; CI: 0.670-0.834; p&amp;lt;0.001 [Figure 1]). Conclusion In a large cohort of PPI patients that survived at least one year after indication, those implanted with an ICD during that year had a 25.3% lower risk of all-cause mortality than similar patients who did not receive an ICD, consistent with landmark trials. Thus, ICD implantation continues to be associated with a reduction in all-cause mortality in PPI patients at risk for sudden cardiac death.

Abstract 15327: Clinical Outcomes of Methamphetamine-Associated Cardiomyopathy Compared to Ischemic Cardiomyopathy: A Single Institution Retrospective Longitudinal Study

Background: Methamphetamine-associated cardiomyopathy (MAC) leads to significant morbidity and mortality. The benefit of implantable cardioverter-defibrillator (ICD) in this population is poorly characterized. Aims: To evaluate ICD use and outcomes in patients with MAC compared to ischemic cardiomyopathy (ICM). Methods: Electronic health record (EHR) was queried for all heart failure hospitalizations using ICD-9 codes between 2011 and 2019. Patients with an EF ≤ 35% were included. The MAC cohort was derived from this population and defined by ICD-9 code or positive urine toxicology and compared to ICM cohort. Baseline characteristics and outcomes were extracted from the EHR. MACE was defined as death, ventricular tachycardia, cardiac arrest, rehospitalization, atrial fibrillation (AF) or stroke. Results: The study included 294 patients in the MAC group and 373 patients in the ICM group. MAC patients were younger (56 vs 61 years, p&lt;0.001) compared to ICM (table 1). Readmission rates for heart failure at one year were similar (13% vs 11.2%, p=ns). Significantly fewer patients with MAC had ICD for primary prevention (15.0% vs 27.9%, p&lt;0.001). Mortality and AF were lower in MAC compared to ICM, however VT (2.38% vs 5.09%, p=0.072) and cardiac arrest (6.1% vs 7.8%, p=0.408) were similar between the two groups. MACE outcomes were worse in the ICM cohort (38.3% vs 21.1%, p=0.012) than MAC. In the MAC cohort, ICD presence was associated with 56.82% incidence of MACE compared to 40.00% without ICD (OR = 1.97, CI 1.032-3.77, p = 0.040) mainly due to higher AF hospitalization (22% vs 8%, p=0.01). Conclusion: ICM patients had higher mortality and atrial fibrillation compared to MAC. ICD implantation for primary prevention was not associated with reduced mortality, however this cohort had higher AF hospitalization. We need further studies to assess the benefit of ICD in MAC.

The Uncertain Benefit from Implantable Cardioverter-Defibrillators in Nonischemic Cardiomyopathy: How to Guide Clinical Decision-Making?

Life-threatening dysrhythmias remain a significant cause of mortality in patients with nonischemic cardiomyopathy (NICM). Implantable cardioverter-defibrillators (ICD) effectively reduce mortality in patients who have survived a life-threatening arrhythmic event. The evidence for survival benefit of primary prevention ICD for patients with high-risk NICM on guideline-directed medical therapy is not as robust, with efficacy questioned by recent studies. In this review, we summarize the data on the risk of life-threatening arrhythmias in NICM, the recommendations, and the evidence supporting the efficacy of primary prevention ICD, and highlight tools that may improve the identification of patients who could benefit from primary prevention ICD implantation.

Evaluation of MADIT-II Risk Stratification Score Among Nationwide Registry of Heart Failure Patients With Primary Prevention Implantable Cardiac Defibrillators or Resynchronization Therapy Devices

Current guidelines advocate prophylactic Implantable Cardioverter Defibrillator (ICD) for all symptomatic heart failure (HF) patients with low LVEF. Since many patients will never use their device, a score delineating subgroups with differential ICD benefit is crucial. We aimed to Evaluate MADIT II-based Risk Stratification Score (MRSS) feasibility to delineate ICD survival benefit among nationwide registry of HF patients with prophylactic ICDs. Accordingly, all Israeli HF patients with prophylactic ICD/CRTDs were categorized into MRSS-based risk-subgroups. Study endpoints included overall mortality, sustained ventricular arrhythmia (VA), and a competing risk of VA (potential preventable arrhythmic death, where ICD could benefit survival) versus non-arrhythmic death. Potential ICD survival benefit was estimated by the area between these cumulative incidence curves. Among 2,177 HF patients implanted prophylactic device, 189 patients (8.7%) had VA and 316 (14.5%) died during median Follow-up (F/U) of 2.9 years. MRSS risk-subgroups were significantly associated with overall mortality (p < 0.001) and weakly with VA (p 0.3). Competing risk analysis of VA versus non-arrhythmic death revealed significantly shorter duration (p < 0.001) and smaller magnitude of ICD survival benefit with increased risk subgroups, yielding estimated 76, 60, 38, and 0 life-days gained from prophylactic ICD implant during 5-year F/U for the MRSS low, intermediate, high, and very-high risk subgroups, respectively (p for trend< 0.05). In conclusion, MRSS use among nationwide registry of ischemic and non-ischemic cardiomyopathy patients, revealed subgroups with differing ICD survival benefit, suggesting it could help evaluate prophylactic ICD survival benefit.

Analysis of risk stratification and prevention of sudden death in pediatric patients with hypertrophic cardiomyopathy: Dilemmas and clarity.

Hypertrophic cardiomyopathy (HCM) has been considered the most common cause of sudden death (SD) in the young. However, introduction of implantable cardioverter-defibrillators (ICDs) in HCM has proved highly effective and the mainstay of preventing SD in children, adolescents, and adults by terminating malignant ventricular tachyarrhythmias. Nevertheless, ICD decision making is generally regarded as more difficult in pediatrics, and the strategy for selecting ICD patients from this population remains without consensus. Prospective studies in HCM children and adolescents have shown the American Heart Association/American College of Cardiology traditional major risk marker strategy to be reliable with >90% sensitivity in selecting patients for SD prevention. International data in >2000 young HCM patients assembled over 20 years who were stratified by major risk markers showed ICDs effectively prevented SD in 20%. Alternatively, novel quantitative risk scoring initiatives provide 5-year risk estimates that are potentially useful as adjunctive tools to facilitate discussion of prophylactic ICD risks vs benefit but are as yet unsupported by prospective outcome studies. Risk scoring strategies are characterized by reasonable discriminatory statistical power (C-statistic 0.69-0.76) for identifying patients with SD events but with relatively low sensitivity, albeit with specificity comparable with the risk marker strategy. While some reticence for obligating healthy-appearing young patients to lifelong device implants is understandable, underutilization of the ICD in high-risk children and adolescents can represent a lost opportunity for fulfilling the long-standing aspiration of SD prevention. This review provides a critical assessment of the current strengths and weaknesses of SD risk stratification strategies in young HCM patients in an effort to clarify clinical decision making in this challenging subpopulation.

Survival, ventricular arrhythmia, and implantable cardioverter-defibrillator usefulness in toxic cardiomyopathy due to substance abuse.

Toxic dilated cardiomyopathy (T-DCM) due to substance abuse is now recognized as a potential cause of severe left ventricular dysfunction. The burden of ventricular arrhythmias (VA) and the role of a prophylactic implantable cardioverter-defibrillator (ICD) are not well documented in this population. We aim to assess the usefulness of ICD implantation in a T-DCM cohort. Patients younger than 65 years with a left ventricular ejection fraction (LVEF)<35% followed at a tertiary center heart failure (HF) clinic between January 2003 and August 2019 were screened for inclusion. The diagnosis of T-DCM was confirmed after excluding other etiologies, and substance abuse was established according to the DSM-5 criteria. The composite primary endpoints were arrhythmic syncope, sudden cardiac death (SCD), or death of unknown cause. The secondary endpoints were the occurrence of sustained VA and/or appropriate therapies in ICD carriers. Thirty-eight patients were identified, and an ICD was implanted in 19 (50%) of these patients, only one for secondary prevention. The primary outcome was similar between the two groups (ICD vs. non-ICD; p=1.00). After a mean follow-up of 33±36 months, only two VA episodes were reported in the ICD group. Three patients received inappropriate ICD therapies. One ICD implantation was complicated with cardiac tamponade. Twenty-three patients (61%) had an LVEF ≥35% at 12 months. VA are infrequent in the T-DCM population. The prophylactic ICD benefit was not observed in our cohort. The ideal timing for potential prophylactic ICD implantation in this population needs further studies.

Implantable cardioverter defibrillator for primary prevention in patients with non-ischemic cardiomyopathy in the era of novel therapeutic agents- meta-analysis.

Evidence regarding the mortality benefit of implantable cardioverter defibrillator (ICD) non-ischemic dilated cardiomyopathy (NIDCM) is inconsistent. The most recent randomized study, the DANISH trial, did not find improved outcomes with ICD. However, based on previous studies and meta-analyses, current guidelines still highly recommend ICD implantation in NIDCM patients. The introduction of novel medications for heart failure improved the clinical outcome dramatically. We aimed in this study to evaluate the effect of Angiotensin Receptor-Neprilysin Inhibitors (ARNi) and sodium-glucose transport protein 2 inhibitors (SGLT2i) on the mortality benefit of ICD in NIDCM. We used a previous metanalysis algorithm and added an updated comprehensive literature search in PubMed for randomized control trials that examined the mortality benefit of ICD in NIDCM vs. optimal medical treatment. The primary outcome included death from any cause. We did a meta-regression analysis to search for a single independent factor affecting mortality. Using previous data, we evaluated the theoretical effect of ICD implementation on patients treated with SGLT2 inhibitors and ARNi. No new articles were added to the results of the previous meta-analysis. 2,622 patients with NIDCM from 5 cohort studies published between 2002 and 2016 were included in the analysis. 50% of them underwent ICD implantation for primary prevention of sudden cardiac death, and 50% did not. ICD was associated with a significantly decreased risk for death from any cause compared to control (OR = 0.79, 95%CI: 0.66-0.95, p = 0.01, I2 = 0%). The theoretical addition of ARNi and the SGLT2 inhibitor dapagliflozin did not change the significant mortality effect of ICD (OR = 0.82, 95%CI: 0.7-0.9, p = 0.001, I2 = 0%) and (OR = 0.82, 95%CI: 0.7-0.9, p = 0.001, I2 = 0%). A meta-regression revealed no association between death from any cause and left bundle branch block (LBBB), use of amiodarone, use of angiotensin-converting enzyme inhibitors (ACEi) or angiotensin receptor blockers, year initiated enrollment, and the year ended enrollment (R2 = 0.0). In patients with NIDCM, the addition of ARNi and SGLT2i did not affect the mortality advantages of ICD for primary prevention. https://www.crd.york.ac.uk/prospero/, identifier: CRD42023403210.

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

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

The Effect of Continuous Care Program on the Self-Efficacy of Patients with Implantable Cardioverter Defibrillator: A Randomized Control Trial.

The majority of cardiac disorders resulting from ventricular dysrhythmias are fatal. The Implantable Cardioverter Defibrillator (ICD) is one of the most common treatments of ventricular dysrhythmias. Despite the benefits of ICD in preserving life, patients with ICD experience adverse physical, psychological, and social consequences. This study investigated the effects of the continuous care program on self-efficacy in patients with ICD. The present study was a randomized clinical trial. Based on the inclusion criteria, 80 patients attending an educational cardiovascular center in Tehran during 2017-2018, were randomly assigned to two intervention and control groups (40 in each). The intervention included the continuous care program, an educational session, and a follow-up program undertaken for the patients receiving the ICD. The control group received routine care. Self-efficacy was then measured by ICD (SE-ICD and OE-ICD) questionnaires and compared between the two groups. The results showed no difference between the two groups before the intervention (p > 0.05). However, there was a significant difference in the mean self-efficacy score between the two groups after the intervention, being significantly higher in the intervention group (t77 = 4.9, p < 0.001). The results of the present study indicated that providing a continuous care program can increase self-efficacy in patients with ICD and can be used as an effective model in the nursing care of patients with ICD.

ICD harm and benefit: risk scores applied to the Swedish ICD-treated LQTS population

Objectives. The use of implantable cardioverter defibrillators (ICDs) in long QT syndrome (LQTS) patients is essential in high-risk patients. However, it is sometimes used in patients without high-risk profiles for whom the expected benefit may be lower than the risk of ICD harm. Here, we evaluated ICD benefit and harm by assessing risk according to risk scores and pre-ICD clinical characteristics. Design. We studied 109 Swedish LQTS patients drawn from the Swedish ICD and Pacemaker Registry with data collected from medical records. In addition to clinical characteristics, we used two risk scores to assess pre-ICD risk, and evaluated ICD benefit and harm. Results. Twenty percent of all patients received ≥1 appropriate shock with a first appropriate shock incidence rate of 4.3 per 100 person-years. A long QTc (≥550 ms) and double mutations were significantly associated with appropriate shock. Low risk scores among patients without pre-ICD aborted cardiac arrest were not significantly associated with low risk of first appropriate shock. The incidence rates of a first inappropriate shock and first complication were 3.0 and 7.6 per 100 person-years, respectively. Conclusion. Our findings on ICD harm emphasize the importance of careful individual pre-ICD consideration. When we applied two risk scores to patients without pre-ICD aborted cardiac arrest, we could not validate their ability to identify patients with low risk of appropriate shocks and patients who were assessed as having a low risk still received appropriate shocks. This further supports the complexity of risk stratification and the difficulty of using risk scores.

Efficacy and safety of the ICD in patients with catecholaminergic polymorphic ventricular tachycardia

Abstract Background Catecholaminergic Polymorphic Ventricular Tachycardia (CPVT) is a potentially fatal genetic arrhythmia syndrome and, despite optimal beta-blocker (BB) therapy, patients often experience life-threatening arrhythmic events (LAE). The role of implantable cardioverter defibrillators (ICD) on reducing mortality in patients with CPVT is debated. Purpose 1) To assess the survival benefit of ICD in the overall CPVT population; 2) to investigate the benefit-to-harm ratio in the population of CPVT patients carriers of ICD. Methods We followed-up consecutive patients with genetically-proven CPVT, treated with optimal BB mono-therapy. The probability of surviving at the occurrence of a first LAE (defined as: sudden cardiac death, aborted cardiac arrest or hemodynamically non-tolerated ventricular tachycardia) during BB mono-therapy was compared between ICD carriers and non-ICD carriers. In the cohort of ICD carriers, we assessed the rate of a first major complication (i.e., a complication requiring surgical intervention) and we calculated the benefit-to-harm ratio of ICD (defined as rate of appropriate shocks on LAE over rate of major complications). Results We enrolled 228 CPVT patients with a pathogenic RYR2 (n=216) or CASQ2 (n=12) mutation, of whom 87 (38%) had an ICD implanted. Overall, during 1,558 person-years of follow-up, 31/228 (14%) patients experienced a first LAE on BB mono-therapy (annual LAE rate 2.0%, 95% CI: 1.4–2.8%). Of the 31 individuals who experienced an LAE, 21 patients had an ICD when the LAE occurred, and all survived after ICD intervention. Of the remaining 10 patients who were not carriers of an ICD, 6/10 (60%) survived after external defibrillation or spontaneous arrhythmia termination, while 4/10 (40%) died suddenly. The probability of surviving at the occurrence of a first LAE in BB mono-therapy was thirty-fold higher (Odds Ratio: 30.0, 95% CI: 1.4–629.0; p=0.029) in patients with an ICD, as compared to patients without an ICD. Overall, 15/87 (17%) patients with an ICD experienced a first major complication over 602 person-years of follow-up (2.5% per year, 95% CI: 1.4%-4.1%). Importantly, no patient died for a pro-arrhythmic effect or complications related to ICD. Comparing the rate of major complications to the rate of appropriate ICD shocks on LAE (LAE rate 4.7% per year, 95% CI: 3.1–7.0%), the benefit-to-harm ratio was 1.9, thus favouring the benefit of ICD therapy. Conclusions In our population, ICD therapy conferred a significant survival benefit in patients with CPVT at the occurrence of a first LAE. Overall, the benefit of ICD implant outweighed the harm, as shown by almost two times greater benefit-to-harm ratio. This study provides evidence supporting ICD implantation in patients with high-risk CPVT. Funding Acknowledgement Type of funding sources: Public grant(s) – National budget only. Main funding source(s): Ricerca Corrente Funding Scheme of the Italian Ministry of Health

Guideline-Directed Medical Therapy andthe Risk of Death in Primary Prevention Defibrillator Recipients.

Contemporary guideline-directed medical therapy (GDMT) confers a significant mortality benefit for patients with heart failure with reduced ejection fraction (HFrEF), as compared to GDMT prevalent at the time of landmark primary prevention implantable cardioverter-defibrillator (ICD) trials. The impact of modern era GDMT on survival in this population is unknown. This study sought to investigate the impact of number of GDMT medications prescribed for HFrEF on all-cause mortality in recipients of primary prevention ICD. A cohort of 4,972 recipients with primary prevention ICD (n=3,210) or cardiac resynchronization therapy-defibrillator (CRT-D) (n=1,762) was studied. The association of number of GDMT medications prescribed at the time of device implantation and all-cause mortality at 2 years post implantation was examined. In our primary prevention cohort, 5%, 20%, 52%, and 23% of patients were prescribed 0, 1, 2, or 3-4 GDMT medications, respectively. After risk adjustment for age, sex, ejection fraction, body mass index, the Elixhauser comorbidity score, the type of cardiomyopathy, and the year of device implantation, each additional GDMT conferred a reduction in the risk of death of 36% in recipients of ICD (HR: 0.64; P< 0.001) and 30% in recipients of CRT-D (HR:0.70; P< 0.001). A higher number of prescribed GDMT medications is associated with an incremental 1-year survival inrecipients of primary prevention ICD with or without CRT. Initiation of maximum number of tolerated GDMT medications should therefore be the goal for all patients with HFrEF. In the setting of robust GDMT, the risk versus benefit of a primary prevention ICD warrants re-examination in future studies.

Prevention of sudden death in heart failure with reduced ejection fraction: do we still needan implantable cardioverter-defibrillator for primary prevention?

Sudden death is a devastating complication of heart failure (HF). Current guidelines recommend an implantable cardioverter-defibrillator (ICD) for prevention of sudden death in patients with HF and reduced ejection fraction (HFrEF) specifically those with a left ventricular ejection fraction ≤35% after at least 3 months of optimized HF treatment. The benefit of ICD in patients with symptomatic HFrEF caused by coronary artery disease has been well documented; however, the evidence for a benefit of prophylactic ICD implantation in patients with HFrEF of non-ischaemic aetiology is less strong. Angiotensin-converting enzyme inhibitors or angiotensin receptor blockers, beta-blockers (BB), and mineralocorticoid receptor antagonists (MRA) block the deleterious actions of angiotensin II, norepinephrine, and aldosterone, respectively. Neprilysin inhibition potentiates the actions of endogenous natriuretic peptides that mitigate adverse ventricular remodelling. BB, MRA, angiotensin receptor-neprilysin inhibitor (ARNI) have a favourable effect on reduction of sudden cardiac death in HFrEF. Recent data suggest a beneficial effect of sodium-glucose cotransporter 2 inhibitors (SGLT2i) in reducing serious ventricular arrhythmias and sudden cardiac death in patients with HFrEF. So, in the current era of new drugs for HFrEF and with the optimal use of disease-modifying therapies (BB, MRA, ARNI and SGLT2i), we might need to reconsider the need and timing for use of ICD as primary prevention of sudden death, especially in HF of non-ischaemic aetiology.

Implantable cardioverter defibrillators in patients with orthotopic heart transplant: A multicenter case series.

Sudden cardiac death (SCD) is common after orthotopic heart transplant (OHT). No clear guidelines for implantable cardioverter defibrillator (ICD) implantation in OHT patients at high risk for SCD currently exist. To assess the safety, efficacy, and benefit of ICDs and resynchronization therapy post-OHT. We also provide a systematic review of previous reports. A retrospective multicenter cohort study within the United States. Patients with ICD post-OHT between 2000 and 2020 were identified. We analyzed 16 patients from 4 centers. The mean standard-deviation (SD) age was 43 (18) years at OHT and 51 (20) years at ICD implantation. The mean (SD) duration from OHT to ICD implantation was 9 (5) years. The mean (SD) left ventricular ejection fraction (LVEF) was 35% (17%). There were 2 (13%) postprocedural complications: 1 hematoma and 1 death. Mean (SD) follow-up was 24 (23) months. Survival rate was 63% (10/16) at 1 year and 56% (9/16) at 2 years, with 6/7 of those who died having LVEF < 35% at the time of the ICD implantation. Patients were more likely to receive appropriate therapy if their ICD was implanted for secondary (5/8) rather than primary (0/8) prevention (p = .007). Of those who did, 4 patients survived to 30 days post-ICD therapy. Severe CAV was not associated with the rate of appropriate therapy. Beneficial outcomes were observed when ICDs were implanted for secondary prevention only, and in patients with higher baseline LVEF. We also observed benefits with resynchronization therapy.

The MADIT-ICD benefit score helps to select implantable cardioverter-defibrillator candidates in cardiac resynchronization therapy.

The aim of this study is to evaluate whether the MADIT-ICD benefit score can predict who benefits most from the addition of implantable cardioverter-defibrillator (ICD) to cardiac resynchronization therapy (CRT) in real-world patients with heart failure with reduced ejection fraction (HFrEF) and to compare this with selection according to a multidisciplinary expert centre approach. Consecutive HFrEF patients who received a CRT for a guideline indication at a tertiary care hospital (Ziekenhuis Oost-Limburg, Genk, Belgium) between October 2008 and September 2016, were retrospectively evaluated. The MADIT-ICD benefit groups (low, intermediate, and high) were compared with the current multidisciplinary expert centre approach. Endpoints were (i) sustained ventricular tachycardia (VT) or ventricular fibrillation (VF) and (ii) non-arrhythmic mortality. Of the 475 included patients, 165 (34.7%) were in the lowest, 220 (46.3%) in the intermediate, and 90 (19.0%) in the highest benefit group. After a median follow-up of 34 months, VT/VF occurred in 3 (1.8%) patients in the lowest, 9 (4.1%) in the intermediate, and 13 (14.4%) in the highest benefit group (P < 0.001). Vice versa, non-arrhythmic death occurred in 32 (19.4%) in the lowest, 32 (14.6%) in the intermediate, and 3 (3.3%) in the highest benefit group (P = 0.002). The predictive power for ICD benefit was comparable between expert multidisciplinary judgement and the MADIT-ICD benefit score: Uno's C-statistic 0.69 vs. 0.69 (P = 0.936) for VT/VF and 0.62 vs. 0.60 (P = 0.790) for non-arrhythmic mortality. The MADIT-ICD benefit score can identify who benefits most from CRT-D and is comparable with multidisciplinary judgement in a CRT expert centre.