Primary Prevention Implantable Cardioverter-defibrillator Research Articles

Left ventricular ejection fraction and myocardial fibrosis in survivors of ventricular fibrillation and ventricular tachycardia

Abstract Background Primary prevention implantable cardioverter defibrillator (ICD) therapy is indicated in patients with a LVEF<35%. Increasing evidence suggests that LVEF is a poor predictor or ventricular arrhythmias, such as ventricular tachycardia (VT) or fibrillation (VF). Methods Patients hospitalized for VF (55.4%) or VT with hemodynamic compromise underwent late gadolinium enhancement cardiovascular magnetic resonance (CMR). Patients with congenital heart disease, channelopathies, hypertrophic cardiomyopathy, arrhythmogenic right ventricular cardiomyopathy and chemotherapy-induced cardiomyopathy were excluded. Results Among patients (n=111, aged 62.1 ± 14.6 years [mean ± SD]) hospitalized for VF (55.4%) or VT with hemodynamic compromise (44.5%) only 29/111 (43.6%) had a history of cardiac disease. At the index hospitalization, an ischemic cause was identified in 69.3%, a non-ischemic cause in 24.8% and no cause emerged in 5.9%. The LVEF (39.1 ± 17.2%) was ≤35% in 55.4% and >35% in 44.6%. Myocardial fibrosis was present in 85.1% (LVEF≤35%: 91.1%; LVEF>35%: 77.8%; p = 0.0619). Conclusions A large proportion of sustained VT or VF survivors would not have previously met LVEF primary prevention criteria for ICD therapy. In this 'ICD treatment gap', myocardial fibrosis was more prevalent than a LVEF≤35%. Further studies are needed to determine whether myocardial scar rather than LVEF≤35% should be used as an indication for primary prevention ICD therapy.

Sex differences in hospitalization for ventricular arrhythmia after a first myocardial infarction in patients without indication for implantable cardioverter-defibrillator implantation

Abstract Background Ventricular arrhythmias (VAs) represent a serious complication of myocardial infarction (MI). Incidence rate of VAs and sudden cardiac death is commonly reported to be lower in women than in men after MI (1,2). While data regarding SCD and VAs after MI in patients with implantable cardioverter defibrillator (ICD) are well described, data regarding the incidence of readmissions for VA in patients without ICD implantation criteria after a first MI are scarce, as well as the impact of sex on their occurrence. Objective This study aims to investigate the impact of sex on VA occurrences in post-MI patients without ICD implantation criteria. Methods This study was conducted using the French national health data system using electronic codes for procedures (CCAM) and hospitalizations data (PMSI). The study population consisted of patients discharged after a first MI and without criteria for ICD implantation. Results Between January 2014 and January 2015, 137,736 patients were hospitalized in France with a diagnosis of first MI and were followed using CCAM and PMSI codes. Among the 112,465 alive at discharge, 6838 patients were excluded due to criteria for the implantation of an ICD for primary or secondary prevention. Of the remaining 105,629 patients, 1600 (1.51%) were rehospitalized for VA with a median delay of 505 days (IQR 110-1208). Men had almost twice the risk of VA than women after initial discharge for MI (OR 1.88, 95% CI 1.65-2.14; p<0.0001). Among the 72,103 men included, 1240 (1.72%) were rehospitalized for VA with a median delay of 514 days (IQR 107-1212). Factors independently associated with VA in men were previous atrial fibrillation (OR 1.91, 95% CI 1.66 - 2.21, p<0.0001), previous vascular disease (OR 1.28, 95% CI 1.10 - 1.50, p=0.002), absence of coronary angioplasty (OR 1.28, 95% CI 1.10 - 1.50, p=0.002), previous diabetes (OR 1.19, 95% CI 1.04 - 1.36, p=0.012), previous hypertension (OR 1.19, 95% CI 1.05 - 1.34, p=0.007), previous or in-hospital congestive heart failure (OR 1.47, 95% CI 1.03-2.08, p=0.032 and OR 1.65, 95% CI 1.32-2.07, p<0.0001), and age (patients between 60 and 79 yo being at the higher risk of VA compared to <60 and >80yo patients, p=0.002 and <0.0001 respectively). Among the 33,526 women included, 360 (1.07%) were rehospitalized for VA with a median (IQR) delay of 461 days (116-1159) after MI. Factors independently associated with VA were previous atrial fibrillation (OR 1.68, 95% CI 1.30 - 2.18, p<0.0001), previous vascular disease (OR 1.37, 95% CI 1.01 - 1.84, p=0.041), and age (patients between 60 and 79 yo being at the higher risk of VA compared to >80yo patients, p=0.001). Conclusion The risk of readmission for VAs after a first MI is significantly lower in women compared to men, with distinct predictive factors. These findings suggest that sex-specific VA risk stratification and management strategies may be warranted after an initial MI.Sexe influence on post-MI VAs occurence

Plasmatic NT-proBNP is strongly associated with atrial fibrillation in patients without severely reduced left ventricular ejection fraction in an ICD collective

Abstract Background and objectives Atrial fibrillation is common in patients with chronic heart failure and associated with poor outcome in these patients. Plasmatic NT-proBNP represents the gold standard biomarker for chronic heart failure. Further, a recent analysis showed a strong association of plasmatic NT-proBNP and atrial fibrillation (AFib). Aim of the study was to assess the association of plasmatic NT-proBNP depending on left ventricular ejection fraction (LVEF) in a cohort of patients with implantable cardioverter defibrillator (ICD). Methods 412 patients were included in the study. Blood samples were used to assess plasmatic NT-proBNP. Follow-up was performed after 45 months. LVEF was estimated by echocardiography according to Simpsons’ method. At enrollment, a 12-lead electrocardiogram was performed (sinus rhythm (SR, n = 306), atrial fibrillation (AFib, n = 79)). Patients were divided into two subgroups by LVEF of 40%. Results Patients suffering from severely reduced LVEF ≤ 40% showed significant higher age, higher rates of chronic kidney disease, diabetes, coronary artery disease, primary prevention ICD indication, coronary artery disease, dilatative cardiomyopathy and plasmatic NT-proBNP compared to patients with LVEF > 40% (each p < 0.05). There were no differences regarding hypertension and occurrence of AFib between patients with LVEF ≤ 40% compared to patients with LVEF < 40% (each p = n.s.). In ROC analysis there was a significantly higher AUC in patients with LVEF > 40% (AUC: 0.87, IQR 0.82-0.92) compared to patients with severely reduced LVEF ≤ 40% (AUC: 0.72, IQR 0.64-0.80) regarding plasmatic NT-proBNP and prediction of AFib (p < 0.002). In patients with LVEF > 40% plasmatic NT-proBNP was shown as significant predictor regarding existence of atrial fibrillation in binary logistic regression analysis, beside age (p < 0.05). Diabetes, hypertension, serum creatinine, coronary artery disease and primary prevention ICD indication were no significant predictors (p = n.s.). In patients with LVEF ≤ 40% plasmatic NT-proBNP was not shown as significant predictor regarding existence of atrial fibrillation in binary logistic regression analysis. Conclusion Elevated levels of plasmatic NT-proBNP are strongly associated with the prevalence of atrial fibrillation in patients without severely reduced LVEF in a cohort of ICD patients.

Plasmatic NT-proBNP is strongly associated with atrial fibrillation in patients with Implantable cardioverter defibrillator

Abstract Background and objectives Atrial fibrillation is common in patients with chronic heart failure and associated with poor outcome in these patients. Plasmatic NT-proBNP represents the gold standard biomarker for chronic heart failure. Further, recent studies showed prognostic impact of urinary NT-proBNP. Aim of the study was to assess the association of plasmatic as well as urinary NT-proBNP and atrial fibrillation in a cohort of patients with implantable cardioverter defibrillator (ICD). Methods 412 patients were included in the study. Fresh spot urine and blood samples were used to assess urinary as well as plasmatic NT-proBNP. Urinary NT-proBNP was normalized to urinary creatinine. Follow-up was performed after 45 months. Heart rhythm history was evaluated and a 12-lead electrocardiogram was performed at enrollment (sinus rhythm (SR, n = 306), atrial fibrillation (AFib, n = 79)). Results Patients suffering from atrial fibrillation showed significant higher age, reduced left ventricular ejection fraction (LVEF), higher rates of chronic kidney disease, hypertension and urinary as well as plasmatic NT-proBNP compared to patients with sinus rhythm (each p < 0.05). There were no differences regarding Diabetes, primary prevention ICD indication, coronary artery disease and dilatative cardiomyopathy (each p = n.s.). In ROC analysis, plasmatic NT-proBNP showed promising predictive values regarding AFib (AUC: 0.80, IQR 0.76-0.85, p < 0.001) as well as urinary NT-proBNP (AUC: 0.76, IQR 0.71-0.81, p < 0.001). There was no significant difference between plasmatic and urinary NT-proBNP according to ROC analysis (p = n.s.). Plasmatic NT-proBNP was shown as a significant predictor regarding existence of atrial fibrillation in binary logistic regression analysis, beside age (p < 0.05). Diabetes, hypertension, serum creatinine, LVEF, coronary artery disease and primary prevention ICD indication were no significant predictors (p = n.s.). Urinary NT-proBNP was not shown as a significant predictor regarding existence of atrial fibrillation in binary logistic regression analysis (p = n.s.). Conclusion Elevated levels of plasmatic NT-proBNP are strongly associated with the prevalence of atrial fibrillation in a cohort of ICD patients.

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.

Competing Risks for Monomorphic versus Non-Monomorphic Ventricular Arrhythmias in Primary Prevention Implantable Cardioverter Defibrillator Recipients: Global Electrical Heterogeneity and Clinical Outcomes (GEHCO) Study.

Ablation of monomorphic ventricular tachycardia (MMVT) has been shown to reduce shock frequency and improve survival. We aimed to compare cause-specific risk factors of MMVT and polymorphic ventricular tachycardia (PVT)/ventricular fibrillation (VF) and to develop predictive models. The multicenter retrospective cohort study included 2,668 patients (age 63.1±13.0 y; 23% female; 78% white; 43% nonischemic cardiomyopathy, left ventricular ejection fraction 28.2±11.1%). Cox models were adjusted for demographic characteristics, heart failure severity and treatment, device programming, and ECG metrics. Global electrical heterogeneity was measured by spatial QRS-T angle (QRSTa), spatial ventricular gradient elevation (SVGel), azimuth, magnitude (SVGmag), and sum absolute QRST integral (SAIQRST). We compared the out-of-sample performance of the lasso and elastic net for Cox proportional hazards and the Fine-Gray competing risk model. During a median follow-up of 4 years, 359 patients experienced their first sustained MMVT with appropriate ICD therapy, and 129 patients had their first PVT/VF with appropriate ICD shock. The risk of MMVT was associated with wider QRSTa (HR 1.16; 95%CI 1.01-1.34), larger SVGel (HR 1.17; 95%CI 1.05-1.30), and smaller SVGmag (HR 0.74; 95%CI 0.63-0.86) and SAIQRST (HR 0.84; 95%CI 0.71-0.99). The best-performing 3-year competing risk Fine-Gray model for MMVT (ROC(t)AUC 0.728; 95%CI 0.668-0.788) identified high-risk (> 50%) patients with 75% sensitivity, 65% specificity, and PVT/VF prediction model had ROC(t)AUC 0.915 (95%CI 0.868-0.962), both satisfactory calibration. We developed and validated models to predict the competing risks of MMVT or PVT/VF that could inform procedural planning and future RCTs of prophylactic VT ablation.

Is It Time to Consider a “Time-Out” Before Primary Prevention Implantable Cardioverter-Defibrillator in Currently or Recently Hospitalized Older Patients with Heart Failure?

Trajectories of mortality after primary implantable cardioverter-defibrillator (ICD) placement for older heart failure (HF) patients during or soon after acute hospitalization have not been assessed. To compare trajectories of mortality after primary ICD placement during or soon after acute cardiac or non-cardiac hospitalization. We identified older HF patients with primary ICD using 20% Medicare data (2008-2018). Placement settings were: 1) 'current-H' during current hospitalization, 2) 'recent-H' within 90 days of hospitalization, or 3) 'chronic stable'. Hospitalization was categorized cardiac vs. non-cardiac. Interval mortality and hazard ratios (HRs) using Cox regression were estimated at 0-30 days, 31-90 days, and 91-365 days after ICD placement. Of 61,710 patients (mean age 76; 35% female; 85% White), 19%, 25%, and 56% had ICDs in 'current-H', 'recent-H', and 'chronic stable' settings. Mortality rates (per 100 person-years) were highest during 0-30 days with 38(34-42) and 22(19-24) for 'current-H' and 'recent-H', which declined to 21(20-22) and 16(15-17) during 91-365 days, respectively. Compared to 'chronic stable', HRs were greatest during 0-30 days post-ICD placement ('current-H' = 5.5[4.5-6.8], 'recent-H' = 3.4[2.8-4.2]) and decreased during 91-365 days ('current-H' = 2.0[1.8-2.1], 'recent-H' = 1.6[1.5-1.7]). HR pattens were similar for cardiac and non-cardiac hospitalization. Primary ICD placement during or soon after hospitalization for any reason was associated with worse mortality with diminishing risks after 90 days. Hospitalization likely identifies a sicker population in whom early mortality with or without ICD may be higher. Our results support careful consideration regarding ICD placement during the 90 days following hospitalization.

Safety, efficacy, and reliability evaluation ofa novel small-diameter defibrillation lead: Global LEADR pivotal trial results

BackgroundImplantable cardioverter-defibrillators last longer, and interest in reliable leads with targeted lead placement is growing. The OmniaSecure defibrillation lead is a novel, small-diameter, catheter-delivered lead designed for targeted placement, based on the established SelectSecure SureScan MRI Model 3830 lumenless pacing lead platform. ObjectiveThis trial assessed safety and efficacy of the OmniaSecure defibrillation lead. MethodsThe worldwide LEADR pivotal clinical trial enrolled patients indicated for de novo implantation of a primary or secondary prevention implantable cardioverter-defibrillator or cardiac resynchronization therapy defibrillator, all of whom received the study lead. The primary efficacy end point was successful defibrillation at implantation per protocol. The primary safety end point was freedom from study lead–related major complications at 6 months. The primary efficacy and safety objectives were met if the lower bound of the 2-sided 95% credible interval was >88% and >90%, respectively. ResultsIn total, 643 patients successfully received the study lead, and 505 patients have completed 12-month follow-up. The lead was placed in the desired right ventricular location in 99.5% of patients. Defibrillation testing at implantation was completed in 119 patients, with success in 97.5%. The Kaplan-Meier estimated freedom from study lead–related major complications was 97.1% at 6 and 12 months. The trial exceeded the primary efficacy and safety objective thresholds. There were zero study lead fractures and electrical performance was stable throughout the mean follow-up of 12.7 ± 4.8 months (mean ± SD). ConclusionThe OmniaSecure lead exceeded prespecified primary end point performance goals for safety and efficacy, demonstrating high defibrillation success and a low occurrence of lead-related major complications with zero lead fractures.

The Spatial Ventricular Gradient is Associated with Inducibility of Ventricular Arrhythmias During Electrophysiology Study

Myocardial electrical heterogeneity is critical for normal cardiac electromechanical function, but abnormal/excessive electrical heterogeneity is proarrhythmic. The spatial ventricular gradient (SVG), a vectorcardiographic measure of electrical heterogeneity, has been associated with arrhythmic events over long-term follow-up, but its relationship with short-term inducibility of ventricular arrhythmias (VAs) is unclear. Determine associations between SVG and inducible VAs during electrophysiology study (EPS). Retrospective study of adults without prior sustained VA, cardiac arrest, or implantable cardioverter-defibrillator (ICD), who underwent ventricular stimulation for evaluation of syncope, non-sustained VT, and/or risk-stratification prior to primary prevention ICD implantation. 12-lead ECGs were converted into vectorcardiograms and SVG magnitude (SVGmag) and direction (azimuth and elevation) were calculated. Odds of inducible VA were regressed using logistic models. Among 143 patients (median age 66, 80% male, median LVEF 47%, 52% myocardial infarction), 34 (23.8%) had inducible VAs. Inducible patients had lower median LVEF (38 vs 50%, p<0.0001), smaller SVGmag (29.5 vs 39.4mV*ms, p=0.0099), and smaller cosine SVG azimuth (cosSVGaz) (0.64 vs 0.89, p=0.0007). When LVEF, SVGmag, and cosSVGaz were dichotomized at their medians, there was a 39-fold increase in adjusted odds (p=0.002) between patients with all low LVEF, SVGmag, and cosSVGaz (65% inducible), compared to patients with all high LVEF, SVGmag, and cosSVGaz (4% [n=1] inducible). After multivariable adjustment, SVGmag, cosSVGaz, and sex, but not LVEF or other characteristics, remained associated with inducible VAs. Assessment of electrical heterogeneity via SVG, which reflects abnormal electrophysiological substrate, adds to LVEF and identifies patients at high and low risk of inducible VA at EPS.

Impact of preventive substrate catheter ablation on implantable cardioverter-defibrillator interventions in patients with ischaemic cardiomyopathy and infarct-related coronary chronic total occlusion.

Primary prevention patients with ischaemic cardiomyopathy and chronic total occlusion of an infarct-related coronary artery (CTO) are at a particularly high risk of implantable cardioverter-defibrillator (ICD) therapy occurrence. The trial was designed to evaluate the efficacy of preventive CTO-related substrate ablation strategy in ischaemic cardiomyopathy patients undergoing primary prevention ICD implantation. The PREVENTIVE VT study was a prospective, multicentre, randomized trial including ischaemic patients with ejection fraction ≤40%, no documented ventricular arrhythmias (VAs), and evidence of scar related to the coronary CTO. Patients were randomly assigned 1:1 to a preventive substrate ablation before ICD implantation or standard therapy with ICD implantation only. The primary outcome was a composite of appropriate ICD therapy or unplanned hospitalization for VAs. Secondary outcomes included the primary outcome's components, the incidence of appropriate ICD therapies, cardiac hospitalization, electrical storm, and cardiovascular (CV) mortality. Sixty patients were included in the study. During the mean follow-up of 44.7 ± 20.7 months, the primary outcome occurred in 5 (16.7%) patients undergoing preventive substrate ablation and in 13 (43.3%) patients receiving only ICD [hazard ratio (HR): 0.33; 95% confidence interval (CI): 0.12-0.94; P = 0.037]. Patients in the preventive ablation group also had fewer appropriate ICD therapies (P = 0.039) and the electrical storms (Log-rank: P = 0.01). While preventive ablation also reduced cardiac hospitalizations (P = 0.006), it had no significant impact on CV mortality (P = 0.151). Preventive ablation of the coronary CTO-related substrate in patients undergoing primary ICD implantation is associated with the reduced risk of appropriate ICD therapy or unplanned hospitalization due to VAs.

Impact of a Chronic Total Coronary Occlusion on the Incidence of Appropriate Implantable Cardioverter-Defibrillator Shocks and Mortality: A Substudy of the Dutch Outcome in ICD Therapy (DO-IT)) Registry.

Chronic total coronary occlusions (CTO) substantially increase the risk for sudden cardiac death. Among patients with chronic ischemic heart disease at risk for sudden cardiac death, an implantable cardioverter defibrillator (ICD) is the favored therapy for primary prevention of sudden cardiac death. This study sought to investigate the impact of CTOs on the risk for appropriate ICD shocks and mortality within a nationwide prospective cohort. This is a subanalysis of the nationwide Dutch-Outcome in ICD Therapy (DO-IT) registry of primary prevention ICD recipients in The Netherlands between September 2014 and June 2016 (n=1442). We identified patients with chronic ischemic heart disease (n=663) and assessed available coronary angiograms for CTO presence (n=415). Patients with revascularized CTOs were excluded (n=79). The primary end point was the composite of all-cause mortality and appropriate ICD shocks. Clinical follow-up was conducted for at least 2 years. A total of 336 patients were included, with an average age of 67±9 years, and 20.5% was female (n=69). An unrevascularized CTO was identified in 110 patients (32.7%). During a median follow-up period of 27 months (interquartile range, 24-32), the primary end point occurred in 21.1% of patients with CTO (n=23) compared with 11.9% in patients without CTO (n=27; P=0.034). Corrected for baseline characteristics including left ventricular ejection fraction, and the presence of a CTO was an independent predictor for the primary end point (hazard ratio, 1.82 [95% CI, 1.03-3.22]; P=0.038). Within this nationwide prospective registry of primary prevention ICD recipients, the presence of an unrevascularized CTO was an independent predictor for the composite outcome of all-cause mortality and appropriate ICD shocks.

Long-term reliability of the phospholamban (PLN) p.(Arg14del) risk model in predicting major ventricular arrhythmia: a landmark study.

Recently, a genetic variant-specific prediction model for phospholamban (PLN) p.(Arg14del)-positive individuals was developed to predict individual major ventricular arrhythmia (VA) risk to support decision-making for primary prevention implantable cardioverter defibrillator (ICD) implantation. This model predicts major VA risk from baseline data, but iterative evaluation of major VA risk may be warranted considering that the risk factors for major VA are progressive. Our aim is to evaluate the diagnostic performance of the PLN p.(Arg14del) risk model at 3-year follow-up. We performed a landmark analysis 3 years after presentation and selected only patients with no prior major VA. Data were collected of 268 PLN p.(Arg14del)-positive subjects, aged 43.5 ± 16.3 years, 38.9% male. After the 3 years landmark, subjects had a mean follow-up of 4.0 years (± 3.5 years) and 28 (10%) subjects experienced major VA with an annual event rate of 2.6% [95% confidence interval (CI) 1.6-3.6], defined as sustained VA, appropriate ICD intervention, or (aborted) sudden cardiac death. The PLN p.(Arg14del) risk score yielded good discrimination in the 3 years landmark cohort with a C-statistic of 0.83 (95% CI 0.79-0.87) and calibration slope of 0.97. The PLN p.(Arg14del) risk model has sustained good model performance up to 3 years follow-up in PLN p.(Arg14del)-positive subjects with no history of major VA. It may therefore be used to support decision-making for primary prevention ICD implantation not merely at presentation but also up to at least 3 years of follow-up.

Multicenter prospective observational study to clarify the current status and clinical outcome in Japanese patients who have an indication for implantable cardioverter defibrillator (ICD) or wearable cardioverter defibrillator (WCD) (TRANSITION JAPAN‐ICD/WCD study): Rationale and design of a prospective, multicenter, observational, comparative study

AbstractBackgroundDespite the positive impact of implantable cardioverter defibrillators (ICDs) and wearable cardioverter defibrillators (WCDs) on prognosis, their implantation is often withheld especially in Japanese heart failure patients with reduced left ventricular ejection fraction (HFrEF) who have not experienced ventricular tachycardia (VT) or ventricular fibrillation (VF) for uncertain reasons. Recent advancements in heart failure (HF) medications have significantly improved the prognosis for HFrEF. Given this context, a critical reassessment of the treatment and prognosis of ICDs and WCDs is essential, as it has the potential to reshape awareness and treatment strategies for these patients.MethodsWe are initiating a prospective multicenter observational study for HFrEF patients eligible for ICD in primary and secondary prevention, and WCD, regardless of device use, including all consenting patients. Study subjects are to be enrolled from 31 participant hospitals located throughout Japan from April 1, 2023, to December 31, 2024, and each will be followed up for 1 year or more. The planned sample size is 651 cases. The primary endpoint is the rate of cardiac implantable electronic device implementation. Other endpoints include the incidence of VT/VF and sudden death, all‐cause mortality, and HF hospitalization, other events. We will collect clinical background information plus each patient's symptoms, Clinical Frailty Scale score, laboratory test results, echocardiographic and electrocardiographic parameters, and serial changes will also be secondary endpoints.ResultsNot applicable.ConclusionThis study offers invaluable insights into understanding the role of ICD/WCD in Japanese HF patients in the new era of HF medication.

Implantable Cardioverter Defibrillator Tachycardia Therapies: Past, Present and Future Directions.

Implantable cardioverter defibrillators (ICDs) have a long history and have progressed significantly since the 1980s. They have become an essential part of the prevention of sudden cardiac death, with a proven survival benefit in selected patient groups. However, with more recent trials and with the introduction of contemporary heart failure therapy, there is a renewed interest and new questions regarding the role of a primary prevention ICD, especially in patients with heart failure of non-ischaemic aetiology. This review looks at the history and evolution of ICDs, appraises the traditional evidence for ICDs and looks at issues relating to patient selection, risk stratification, competing risk, future directions and a proposed contemporary ICD decision framework.

Are We Implanting Too Many Primary-Prevention Implantable Cardioverter-Defibrillators?

Canadian Cardiovascular Society/Canadian Heart Failure Society guidelines recommend optimizing patients with heart failure with reduced ejection fraction (HFrEF) on guideline directed medical therapy (GDMT) prior to implanting primary prevention implantable cardioverter defibrillators (ICDs). However, often GDMT is suboptimal at the time of ICD implantation, and is associated with reduced survival. Furthermore, with evidence for declining sudden cardiac death (SCD) rates in patients with cardiomyopathy, there is a need for better risk stratification to determine the indication for ICD.1 This raises concern for potentially unnecessary ICD implantation in this population, and efforts are needed to address this issue in clinical practice.

Distinguishing Primary Prevention From Secondary Prevention Implantable Cardioverter Defibrillators Using Administrative Health and Cardiac Device Registry Data

BackgroundAdministrative health data and cardiac device registries can be used to empirically evaluate outcomes and costs after implantable cardioverter defibrillator (ICD) implantation. These datasets often have incomplete information on the indication for implantation (primary vs secondary prevention of sudden cardiac death). MethodsWe used 16 years of population-based cardiac device registry and administrative health data from British Columbia, Canada, to derive and internally validate statistical models that predict the likely indication for ICD implantation. We used chart review data as the reference standard for ICD indication in the Cardiac Device Registry database (CDR; 2004-2012 [Cardiac Services BC]) and nonmissing indication as the reference standard in the Heart Information System registry database (HEARTis; 2013-2019 [Cardiac Services BC]). We created 3 logistic regression prediction models in each database: one using only registry data, one using only administrative data, and one using both registry and administrative data. We assessed the predictive performance of each model using standard metrics after optimism correction with 200 bootstrap resamples. ResultsModels that used registry data alone demonstrated excellent predictive performance (sensitivity ≥ 89%; specificity ≥ 87%). Models that used only administrative data performed well (sensitivity ≥ 84%; specificity ≥ 70%). Models that used both registry and administrative data showed modest gains over those that used registry data alone (sensitivity ≥ 90%; specificity ≥ 89%). ConclusionsAdministrative health data and cardiac device registry data can distinguish secondary prevention ICDs from primary prevention ICDs with acceptable sensitivity and specificity. Imputation of missing ICD indication might make these data resources more useful for research and health system monitoring.

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.

Implantable loop recorder in Brugada syndrome: Insights from a single-center experience

BackgroundThis study aimed to investigate the characteristics and outcomes of patients diagnosed with Brugada syndrome (BrS) who underwent implantable loop recorder (ILR) insertion during routine clinical activity. MethodsWe conducted a comprehensive screening of all consecutive patients diagnosed with BrS at our institution. We analyzed baseline clinical characteristics, arrhythmic findings, and outcomes. ResultsOut of 147 BrS patients, 42 (29 %) received an ILR, 13 (9 %) underwent implantable cardioverter-defibrillator (ICD) placement, and 92 patients (63 %) continued regular cardiological follow-up. Patients who received an ILR had a higher prevalence of suspected arrhythmic syncope (43 % vs. 22 %, p = 0.012) and tended to be younger (median age 38 years, interquartile range 30–52, vs. 43 years, 35–55, p = 0.044) with a higher presence of SCN5A gene mutations (17 % vs. 6 %, p = 0.066) compared to those who continued regular follow-up. Additionally, compared to patients with an ICD, those with an ILR had a significantly lower frequency of positive programmed ventricular stimulation (0 % vs. 91 %, p < 0.001). During a median follow-up period of 14.7 months (4.7–44.8), no deaths occurred among the patients with ILR. Eight individuals (19 %) were diagnosed with arrhythmic findings through continuous ILR monitoring, primarily atrial fibrillation, and asystolic pauses. The median time from insertion to the occurrence of these events was 8.7 months (3.6–46.4). No adverse events related to ILR were reported. ConclusionContinuous monitoring with ILR may facilitate the timely detection of non-malignant rhythm disorders in BrS patients with risk factors but without an indication for primary prevention ICD implantation.

MRI Assessment of Myocardial Deformation for Risk Stratification of Major Arrhythmic Events in Patients With Non-Ischemic Cardiomyopathy Eligible for Primary Prevention Implantable Cardioverter Defibrillators.

Implantable cardioverter-defibrillator (ICD) intervention is an established prophylactic measure. Identifying high-benefit patients poses challenges. To assess the prognostic value of cardiac magnetic resonance imaging (MRI) parameters including myocardial deformation for risk stratification of ICD intervention in non-ischemic cardiomyopathy (NICM) while accounting for competing mortality risk. Retrospective and prospective. One hundred and fifty-nine NICM patients eligible for primary ICD (117 male, 54 ± 13 years) and 49 control subjects (38 male, 53 ± 5 years). Balanced steady state free precession (bSSFP) and three-dimensional phase-sensitive inversion-recovery late gadolinium enhancement (LGE) sequences at 1.5 T or 3 T. Patients underwent MRI before ICD implantation and were followed up. Functional parameters, left ventricular global radial, circumferential and longitudinal strain, right ventricular free wall longitudinal strain (RV FWLS) and left atrial strain were measured (Circle, cvi42). LGE presence was assessed visually. The primary endpoint was appropriate ICD intervention. Models were developed to determine outcome, with and without accounting for competing risk (non-sudden cardiac death), and compared to a baseline model including LGE and clinical features. Wilcoxon non-parametric test, Cox's proportional hazards regression, Fine-Gray competing risk model, and cumulative incidence functions. Harrell's c statistic was used for model selection. A P value <0.05 was considered statistically significant. Follow-up duration was 1176 ± 960 days (median: 896). Twenty-six patients (16%) met the primary endpoint. RV FWLS demonstrated a significant difference between patients with and without events (-12.5% ± 5 vs. -16.4% ± 5.5). Univariable analyses showed LGE and RV FWLS were significantly associated with outcome (LGE: hazard ratio [HR] = 3.69, 95% CI = 1.28-10.62; RV FWLS: HR = 2.04, 95% CI = 1.30-3.22). RV FWLS significantly improved the prognostic value of baseline model and remained significant in multivariable analysis, accounting for competing risk (HR = 1.73, 95% CI = 1.12-2.66). In NICM, RV FWLS may provide additional predictive value for predicting appropriate ICD intervention. 2 TECHNICAL EFFICACY: Stage 5.

Analysis of electrotherapy in patients with implantable cardioverter-defibrillator for primary prevention of sudden cardiac death according to remote monitoring data

Aim: To determine the factors associated with development of justified and inappropriate implantable cardioverter-defibrillator (ICD) activations in patients at high risk of sudden cardiac death based on the remote monitoring systemMaterial and Methods. We analyzed remote monitoring data from 2014 to 2022 in 132 patients with ICD for primary prevention of sudden cardiac death (SCD). Patients were divided into 2 groups 1 – patients with persistent paroxysmal tachyarrhythmias; 2 – patients without persistent paroxysms of ventricular tachycardia (VT) / ventricular fibrillation (VF). In case of inappropriate shocks, the causes and possible predictors of their development were analyzed.Results. Of 132 patients, 62 (46.9%) patients appeared to have persistent VT/VF. It was found that the probability of detecting persistent paroxysms of VT/VF decreased with a history of revascularization (p = 0.030) and increased in the absence of amiodarone therapy (p = 0.012), with increasing age (p = 0.035), with decreasing left ventricular ejection fraction (LVEF) less than 35% (p = 0.016). 71 arrhythmic episodes (17.9%) in 27 (20.4%) patients were considered as false detection of tachyarrhythmias. Analyzing the causes of inappropriate electrotherapy, different types of supraventricular tachyarrhythmias in the zone of VT detection (85.9%), including atrial fibrillation (25.4%), in smaller percentage of cases there was discovered T-wave detection 4.2%, noise on the electrode – 2.8%, 7.1% – double counter due to the operation of the cardiac contractility modulation device. When analyzing factors associated with the development of false detection, reliable results were obtained with regard to the presence of a history of atrial fibrillation (p = 0.036), implanted single-chamber ICD (p = 0.028).Conclusion. The development of persistent ventricular tachyarrhythmias was noted in 47% of patients with ICD as a part of primary prevention of sudden cardiac death, and 20.4% had the development of inappropriate detection and electrotherapy. Predictors of their occurrence have been identified, which can be used as development of strategies for shock minimization.