Implantable Cardioverter-defibrillator Therapy Research Articles

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.

Sex differences among subcutaneous defibrillator (S-ICD) recipients: a propensity-matched, multicenter, international analysis from the i-SUSI project.

Women have been historically underrepresented in implantable cardioverter defibrillator (ICD) trials. No data on sex differences regarding subcutaneous-ICDs (S-ICD) carriers have been described. Aim of our study was to investigate sex-related differences among unselected S-ICD recipients. Consecutive patients enrolled in the multicenter, international i-SUSI registry were analyzed. Comparisons between sexes were performed using a 1:1 propensity matching adjusted analysis for age, body mass index (BMI), left ventricular function and substrate. The primary outcome was the rate of appropriate shocks during follow-up. Inappropriate shocks and other device-related complications were deemed secondary outcomes. A total of 1698 patients were extracted from the iSUSI registry; 399 (23.5%) were females. After propensity matching, two cohorts of 374 patients presenting similar baseline characteristics were analyzed. Despite similar periprocedural characteristics and a matched BMI, women resulted at lower risk of conversion failure as per PRAETORIAN score (73.4% vs 81.3%, p = 0.049). Over a median follow-up time of 26.5 [12.7-42.5] months, appropriate shocks were more common in the male cohort (rate/year 3.4%vs1.7%; log-rank p = 0.049), while no significant differences in device-related complications (rate/year: 6.3% vs 5.8%; log-rank p = 0.595) and inappropriate shocks (rate/year: 4.3%vs3.1%; log-rank p = 0.375) were observed. After controlling for confounders, sex remained significantly associated with the primary outcome (aHR 1.648; CI 0.999-2.655, p = 0.048), while not resulting predictor of inappropriate shocks and device-related complications. In a propensity-matched cohort of S-ICD recipients, women are less likely to experience appropriate ICD therapy, while not showing higher risk of device related-complications.

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 ischemic cardiomyopathy and chronic total occlusion of an infarct-related coronary artery (IRA-CTO) are at a particularly high risk of implantable cardioverter-defibrillator (ICD) therapy occurrence. 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, multicenter, randomized trial including ischaemic patients with ejection fraction ≤40%, no documented 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.

Evaluating the predictive value of late gadolinium enhancement assessed by cardiac magnetic resonance on sudden cardiac death in patients selected for implantable cardioverter defibrillator and cardiac resynchronization therapy implantation: a systematic review and meta-analysis.

Late gadolinium enhancement (LGE) assessed by cardiovascular magnetic resonance (CMR) can evaluate myocardial scar associated with a higher risk of sudden cardiac death (SCD), which can guide the selection between cardiac resynchronization therapy with or without a defibrillator (CRT-P/CRT-D). Our aim was to investigate the association between LGE and SCD risk in patients with CRT using the LGE-CMR technique. We performed a systematic literature search using four databases. The target population was CRT candidates. The primary endpoint was SCD. The risk of bias was assessed using the QUIPS tool. Fifteen eligible articles were included with a total of 2494 patients, of whom 27%, 56%, and 19% had an implantable cardioverter defibrillator (ICD), CRT-D, and CRT-P, respectively. Altogether, 54.71% of the cohort was LGE positive, who had a 72% higher risk for SCD (HR 1.72; 95% CI 1.18-2.50) compared to LGE negatives. In non-ischemic patients, the proportion of LGE positivity was 46.6%, with a significantly higher risk for SCD as compared to LGE negatives (HR 2.42; 95% CI 1.99-2.94). The subgroup of CRT-only patients showed no difference between the LGE-positive vs. negative candidates (HR 1.17; 95% CI 0.82-1.68). Comparable SCD risk was observed between articles with short- (OR 7.47; 95% CI 0.54-103.12) vs. long-term (OR 6.15; 95% CI 0.96-39.45) follow-up time. LGE-CMR positivity was associated with an increased SCD risk; however, in CRT candidates, the difference in risk reduction between LGE positive vs. negative patients was statistically not significant, suggesting a role of reverse remodeling. LGE-CMR before device implantation could be crucial in identifying high-risk patients even in non-ischemic etiology.

Sex Differences in Outcomes of Patients with an Implantable Cardioverter-Defibrillator for the Secondary Prevention of Sudden Cardiac Death.

Background: In patients with an implantable cardioverter-defibrillator (ICD) for secondary prevention, sex differences may exist in clinical outcomes. We sought to investigate sex differences in appropriate ICD therapy, appropriate and inappropriate shock, and all-cause mortality in this patient population. Methods: A total of 257 patients who received an ICD for a secondary prevention indication in the University Medical Centre Groningen (UMCG) between 1 January 2012 and 31 December 2018 were retrospectively included in a consecutive manner. Appropriate ICD therapy, comprising shock and antitachycardia pacing (ATP) for ventricular fibrillation (VF) or ventricular tachycardia (VT), was the primary outcome. Results: The patient population included 257 patients, of whom 45 (18%) were women and 212 (82%) were men. The median of the age was 64 (interquartile range (IQR) 53-72) years. During follow-up (median duration 6.2 (IQR 4.8-7.8) years), first appropriate device therapy took place in 10 (22%) patients for women and 85 (40%) patients for men. Female sex was negatively associated with the rate of appropriate ICD therapy, univariably (hazard ratio (HR) 0.48 [95% confidence interval (CI) 0.25-0.93]; p = 0.030) and multivariably (HR 0.44 [95% CI 0.20-0.95]; p = 0.036). Conclusions: Women with secondary prevention ICDs were less likely than men to receive appropriate ICD therapy.

Predicting Post-Infarct Ventricular Tachycardia by Integrating Cardiac MRI and Advanced Computational Reentrant Pathway Analysis

BackgroundImplantable cardiac defibrillator (ICD) implantation can protect against sudden cardiac death (SCD) after a myocardial infarction. However, improved risk stratification for device requirement is still needed. ObjectiveTo improve assessment of post-infarct ventricular electro-pathology and prediction of appropriate ICD therapy by combining late gadolinium enhancement (LGE) and advanced computational modelling. MethodsADAS LV and custom-made software was used to generate 3D patient-specific ventricular models in a prospective cohort of post-infarct patients (n=40) having undergone LGE imaging pre-ICD implantation. Corridor metrics and 3D surface features were computed from LGE images. The Virtual Induction and Treatment of Arrhythmias (VITA) framework was applied to patient-specific models to comprehensively probe the vulnerability of the scar substrate to sustaining reentrant circuits. Imaging and VITA metrics, related to the numbers of induced VTs and their corresponding round trip times (RTTs), were compared with ICD therapy during follow-up. ResultsPatients with an event (n=17) had a larger interface between healthy-scar and higher VITA metrics. Cox-regression demonstrated a significant independent association with an event: interface (HR 2.79; 1.44-5.44, p < .01), unique VTs (HR 1.67; CI 1.04–2.68, p = .03), mean RTT (HR 2.14; CI 1.11–4.12, p = .02), maximum RTT (HR 2.13; CI 1.19–3.81, p = .01). ConclusionDetailed quantitative analysis of LGE based scarmaps, combined with advanced computational modeling, is able to accurately predict ICD therapy and could facilitate early identification of high-risk patients in addition to LVEF.

The axillary vein puncture for implantable cardiac defibrillator implantation: 14 years of experience. Analysis of the results

BackgroundAxillary vein puncture (AVP) is a valid alternative to Subclavan vein puncture for leads insertion in cardiac implantable electronic device implantation, that may reduce acute and delayed complications. Very few data are available about ICD recipients.A simplified AVP technique is described. MethodsAll the patients who consecutively underwent “de novo” ICD implantation, from March 2006 to December 2020 at the University of Verona, were considered.Leads insertion was routinely performed through an AVP, according to a simplified technique. Outcome and complications have been retrospectively analyzed. ResultsThe study population consisted of 1711 consecutive patients. Out of 1711 patients, 38 (2.2%) were excluded because they were implanted with Medtronic Sprint Fidelis lead.Out of 1673 ICD implantations, 963 (57.6%) were ICD plus cardiac resynchronization therapy, 434 (25.9%) were dual-chamber defibrillators, and 276 (16.5%) were single-chamber defibrillators, for a total of 3879 implanted leads. The AVP success rate was 99.4%. Acute complications occurred in 7/1673 (0.42%) patients. Lead failure (LF) occurred in 20/1673 (1.19%) patients. Comparing the group of patients with lead failure with the group without LF, the presence of three leads inside the vein was significantly associated with LF, and the multivariate analysis confirmed three leads in place as an independent predictor of LF. ConclusionAVP, according to our simplified technique, is safe, effective, has a high success rate, and a very low complication rate. The incidence of LF was exceptionally low.The advantages of AVP are maintained over time in a population of ICD recipients.

Cardiac implantable electronic devices and bloodstream infections: management and outcomes.

Bloodstream infection (BSI) of any cause may lead to device infection in cardiac implantable electronic device (CIED) patients. Aiming for a better understanding of the diagnostic approach, treatment, and outcome, patients with an implantable cardioverter defibrillator (ICD) and cardiac resynchronization therapy and defibrillator (CRT-D) hospitalized with BSI were investigated. This is a single-centre, retrospective, cohort analysis including consecutive ICD/CRT-D patients implanted between 2012 and 2021. These patients were screened against a list of all hospitalized patients having positive blood cultures consistent with diagnosed infection in any department of a local public hospital. The total cohort consisted of 515 patients. Over a median follow-up of 59 months (interquartile range 31-87 months), there were 47 BSI episodes in 36 patients. The majority of patients with BSI (92%) was admitted to non-cardiology units, and in 25 episodes (53%), no cardiac imaging was performed. Nearly all patients (85%) were treated with short-term antibiotics, whereas chronic antibiotic suppression therapy (n = 4) and system extraction (n = 3) were less frequent. Patients with BSI had a nearly seven-fold higher rate (hazard ratio 6.7, 95% confidence interval 3.9-11.2; P < .001) of all-cause mortality. Diagnostic workup of defibrillator patients with BSI admitted to a non-cardiology unit is often insufficient to characterize lead-related endocarditis. The high mortality rate in these patients with BSI may relate to underdiagnosis and consequently late/absence of system removal. Efforts to increase an interdisciplinary approach and greater use of cardiac imaging are necessary for timely diagnosis and adequate treatment.

Cost effectiveness of implantable cardioverter defibrillators for 1.5 primary prevention of sudden cardiac arrest in China: an analysis from the Improve SCA study

Objectives Implantable cardioverter defibrillator (ICDs) for primary prevention (PP) of sudden cardiac arrest (SCA) is underutilized in developing countries. The Improve SCA study has identified a subset of 1.5 primary prevention (1.5PP) patients with a higher risk of SCA and a significant mortality benefit from ICD therapy. From the perspective of China’s healthcare system, we evaluated the cost-effectiveness of ICD therapy vs. no ICD therapy among1.5PP patients with a view of informing clinical and policy decisions. Methods A published Markov model was adjusted and verified to simulate the course of the disease and describe different health states of 1.5PP patients. The patient characteristics, mortality, utility and complication estimates were obtained from the Improve SCA study and other literature. Cost inputs were sourced from government tender prices, medical service prices and clinical experts’ surveys in 9 Chinese public hospitals. For both ICD and no ICD therapy, the total medical costs and quality-adjusted life-years (QALYs) were modelled over a lifetime horizon and the incremental cost-effectiveness ratio (ICER) was calculated. Deterministic and probabilistic sensitivity analyses were performed to assess the uncertainty of the model parameters. We used the willingness-to-pay (WTP) threshold recommended by China Guidelines for Pharmacoeconomic Evaluations, one to three times of China’s GDP per capita (CNY85,698-CNY 257,094) in 2022 Chinese Yuan. Results The incremental cost effectiveness ratio (ICER) of ICD therapy compared to no ICD therapy is 139,652 CNY/QALY, which is about 1-2 times China’s GDP per capita. The probability that ICD therapy is cost effective was 92.1%. Results from sensitivity analysis supported the findings of the base case. Conclusions ICD therapy compared to no ICD therapy is cost-effective for the 1.5PP patients in China.

Comparing adolescent- and adult-onset unexplained cardiac arrest: Results from the Dutch Idiopathic VF Registry

BackgroundCurrent cohorts of patients with idiopathic ventricular fibrillation (IVF) primarily include adult-onset patients. Underlying causes of sudden cardiac arrest vary with age; therefore, underlying causes and disease course may differ for adolescent-onset vs adult-onset patients. ObjectiveThe purpose of this study was to compare adolescent-onset with adult-onset patients having an initially unexplained cause of VF. MethodsThe study included 39 patients with an index event aged ≤19 years (adolescent-onset) and 417 adult-onset patients from the Dutch Idiopathic VF Registry. Data on event circumstances, clinical characteristics, change in diagnosis, and arrhythmia recurrences were collected and compared between the 2 groups. ResultsIn total, 42 patients received an underlying diagnosis during follow-up (median 7 [2–12] years), with similar yields (15% adolescent-onset vs 9% adult-onset; P = .16). Among the remaining unexplained patients, adolescent-onset patients (n = 33) had their index event at a median age of 17 [16–18] years, and 72% were male. The youngest patient was aged 13 years. In comparison with adults (n = 381), adolescent-onset patients more often had their index event during exercise (P <.01). Adolescent-onset patients experienced more appropriate implantable cardioverter-defibrillator (ICD) therapy during follow-up compared with adults (44% vs 26%; P = .03). Inappropriate ICD therapy (26% vs 17%; P = .19), ICD complications (19% vs 14%; P = .41), and deaths (3% vs 4%; P = 1) did not significantly differ between adolescent-onset and adult-onset patients. ConclusionIVF may occur during adolescence. Adolescent-onset patients more often present during exercise compared with adults. Furthermore, they are more vulnerable to ventricular arrhythmias as reflected by a higher incidence of appropriate ICD therapy.

Implantable cardioverter defibrillators for primary prevention in cardiomyopathies

BackgroundImplantable cardioverter defibrillators (ICD) are often used as primary prevention strategy for sudden cardiac death (SCD) in young individuals. This study analyzed appropriate therapies, complications and inappropriate shocks in the real-world Indian population. MethodsAll patients in the cardiomyopathy cohort under follow up who had ICD implanted as a primary prevention strategy were studied. The objective was to assess the incidence of appropriate ICD therapies, inappropriate therapies and complications. ICD was interrogated and stored electrograms analyzed. Underlying arrhythmia or conditions resulting in appropriate or inappropriate ICD therapy were studied. Correlation and regression studies was done to assess for the predictors of appropriate therapy. ResultsFifty patients were followed up for a mean follow-up duration of 4.4 ± 3.1 years with total follow up of 220.2 patient years. Appropriate ICD therapy was delivered in 16 out of 50 (32%) patients, with 65 appropriate therapies (median 2 per patient, range: 0–20). Inappropriate therapy delivered in 7 of the 50 (14%) patients, with 44 inappropriate therapies (median 5 per patient, range: 0–20). Complications occurred in 8 of the 50 (16%) patients. Overall, the rate of appropriate therapy was 29.5 per 100 patient years, that of inappropriate therapy was 19.9 per 100 patient years and the rate of complications was 3.6 per 100 patient years. ConclusionsWhen implanted for primary prevention in patients with cardiomyopathies over a mean period of 4.4 ± 3.1 years, appropriate ICD therapy was delivered in 32% patients. However, inappropriate therapy (14% patients) and complications (16% patients) were also common.

Impact of atrial fibrillation on 1-year outcome in patients with implantable cardioverter defibrillator or cardiac resynchronization therapy with defibrillator: results from the German DEVICE Registry.

Atrial fibrillation (AF) is a cardiac arrhythmia frequently documented in patients requiring implantable cardioverter defibrillators (ICDs) and/or cardiac resynchronization therapy with defibrillator (CRT-D). Patients with diagnosed AF at the point of ICD or CRT-D implantation may have an impaired follow-up outcome. The German DEVICE I-II registry is a nationwide prospective multicentre database of patients implanted with ICD and CRT-D with clinical follow-up data. We analysed a 1-year follow up of implanted patients with AF and with sinus rhythm (SR). A total of 4,929 ICD/CRT patients are included in the present analysis: 946 (19.2%) were in AF and 3,983 (80.8%) were SR at time of device implantation. AF patients had a significantly more comorbid profile including older age {72 [interquartile range (IQR), 66-77] vs. 66 (IQR, 56-73) years; P<0.001}, and higher rate of patients with left ventricular ejection fraction <30% (68.2% vs. 61.0%; P<0.001), peripheral artery disease (4.5% vs. 2.7%; P=0.002), diabetes (33.6% vs. 25.5%; P<0.001), hypertension (58.4% vs. 51.1%; P<0.001) and renal failure (22.6% vs. 15.3%; P<0.001). The intra-hospital complication rate was 4.3% in the AF and 3.6% in the SR group (P=0.38). In 1-year follow-up AF patients experienced a significantly higher rate of defibrillator shocks (25% vs. 15.3%; P<0.001). One-year estimated mortality was 10.8% in the AF and 5.9% in the SR group (P<0.001), while estimated 1-year major adverse cardiac and cerebrovascular events (MACCE) rate was 11.2% vs. 7.0% (P<0.001). The effects of AF on electrical shocks and mortality persisted after adjusting for age, sex, advanced New York Heart Association (NYHA) class, severely impaired left ventricular ejection fraction (LVEF), coronary artery disease (CAD), chronic obstructive pulmonary disease (COPD), diabetes mellitus (DM), chronic renal failure (CRF), QRS duration, and type of indication for electronic device implantation. Our clinical data on an extended cohort of contemporary patients confirm the significant impact of AF, and its associated comorbidities, upon mortality and major adverse events after implantation of ICD/CRT.

Mitral Annular Disjunction in Idiopathic Ventricular Fibrillation Patients: Just a Bystander or a Potential Cause?

Previously, we demonstrated that inferolateral mitral annular disjunction (MAD) is more prevalent in patients with idiopathic ventricular fibrillation (IVF) than in healthy controls. In the present study, we advanced the insights into the prevalence and ventricular arrhythmogenicity by inferolateral MAD in an even larger IVF cohort. This retrospective multicentre study included 185 IVF patients (median age 39 [27, 52] years, 40% female). Cardiac magnetic resonance images were analysed for mitral valve and annular abnormalities and late gadolinium enhancement. Clinical characteristics were compared between patients with and without MAD. MAD in any of the 4 locations was present in 112 (61%) IVF patients and inferolateral MAD was identified in 24 (13%) IVF patients. Mitral valve prolapse (MVP) was found in 13 (7%) IVF patients. MVP was more prevalent in patients with inferolateral MAD compared with patients without inferolateral MAD(42% vs. 2%, p < 0.001). Proarrhythmic characteristics in terms of a high burden of premature ventricular complexes (PVC) and non-sustained ventricular tachycardia (VT) were more prevalent in patients with inferolateral MAD compared to patients without inferolateral MAD (67% vs. 23%, p < 0.001 and 63% vs 41%, p = 0.046, respectively). Appropriate implantable cardioverter defibrillator therapy during follow-up was comparable for IVF patients with or without inferolateral MAD (13% vs. 18%, p = 0.579). A high prevalence of inferolateral MAD and MVP is a consistent finding in this large IVF cohort. The presence of inferolateral MAD is associated with a higher PVC burden and non-sustained VTs. Further research is needed to explain this potential interplay.

Ventricular Arrhythmias and Hemodynamic Collapse During Acute Coronary Syndrome- Increased Risk for Sudden Cardiac Death?

In acute phase of acute coronary syndrome (ACS), ventricular tachycardia (VT) and/or ventricular fibrillation (VF) leading to resuscitation are not considered to be associated with increased long-term sudden cardiac death (SCD) because the cause - acute ischemia - is believed to be reversible.Aim of this study was to investigate whether ventricular arrhythmias leading to sudden cardiac arrest during ACS associate with the risk of incident SCD in patients with normal or mildly impaired left ventricular ejection fraction (LVEF). This study is based on a retrospective analysis of all 8,062 consecutive ACS patients undergoing coronary angiography with baseline LVEF ≥40% between 2007-2018 (follow-up until December 31st, 2021). The primary outcome was SCD equivalent life-threatening ventricular arrhythmias (LTVA) composing of true SCDs, aborted SCDs by successful resuscitation or appropriate ICD therapy. The risk of sudden LTVA was estimated with multivariate subdistribution hazard model using other deaths as competing events. Two-hundred and thirteen (n=211, 2.6%) patients suffered acute phase VF/VT leading to resuscitation and survived to discharge and most happened before angiography (80.6%, N=170) and were VF (92.9%, N=196). During a median follow-up of 7.6 years, 3.9% (N=316) of all the patients had LTVA (10.0% in VF/VT group vs 3.8% in other patients). VF/VTs during ACS associated with an increased risk for future SCD (HR 3.07; 95% CI 1.94-4.85, p<0.001). Most LTVAs occurred in patients without ICDs. VF/VT in ACS associates with remarkably high long-term risk for SCD in patients with LVEF ≥40%.

The impact of supraventricular arrhythmias on the outcomes of guideline-compliant implantable cardioverter defibrillator programming.

Several implantable cardioverter defibrillators (ICD) programming strategies are applied to minimize ICD therapy, especially unnecessary therapies from supraventricular arrhythmias (SVA). However, it remains unknown whether these optimal programming recommendations only benefit those with SVAs or have any detrimental effects from delayed therapy on those without SVAs. This study aims to assess the impact of SVA on the outcomes of ICD programming based on 2015 HRS/EHRA/APHRS/SOLAECE expert consensus statement and 2019 focused update on optimal ICD programming and testing guidelines. Consecutive patients who underwent ICD insertion for primary prevention were classified into four groups based on SVA status and ICD programming: (1) guideline-concordant group (GC) with SVA, (2)GC without SVA, (3) nonguideline concordant group (NGC) with SVA, and (4)NGC without SVA. Cox proportional hazard models were analyzed for freedom from ICD therapies, shock, and mortality. Seven hundred and seventy-two patients (median age, 64 years) were enrolled. ICD therapies were the most frequent in NGC with SVA (24.0%), followed by NGC without SVA (19.9%), GC without SVA (11.6%), and GC with SVA (8.1%). Guideline concordant programming was associated with 68% ICD therapy reduction (HR 0.32, p = .007) and 67% ICD shock reduction (HR 0.33, p = .030) in SVA patients and 44% ICD therapy reduction in those without SVA (HR 0.56, p = .030). Programming ICDs in primary prevention patients based on current guidelines reduces therapy burden without increasing mortality in both SVA and non-SVA patients. A greater magnitude of reduced ICD therapy was found in those with supraventricular arrhythmias.

Use of class IC antiarrhythmic drugs in patients with structural heart disease and implantable cardioverter defibrillator.

Due to suspected pro-arrhythmic effects and increased mortality associated with class-IC antiarrhythmic drugs (AADs) in previous trials, AAD therapy in structural heart disease (SHD) is mainly restricted to amiodarone. In the presence of diagnostic and therapeutic advancements in cardiovascular medicine, it remains unclear if previous studies adequately reflect contemporary patients. In clinical practice, class-IC-AADs are occasionally used in individual cases, particularly in patients with an implantable cardioverter defibrillator (ICD). This study retrospectively investigated outcome in ICD-carriers with SHD in whom class-IC-AADs were used as an individualized therapy due to failure, side effects, or unacceptable risk of alternative therapeutic options. Fifty patients from four tertiary centers were included (median age 48.5years; 52% female). The most common underlying SHD were dilated (42%) or ischemic cardiomyopathy (26%) (median LVEF = 45%). Indications for AAD were sustained ventricular arrhythmias (VA) (58%), symptomatic premature ventricular contractions (26%), or atrial arrhythmias (16%). Median follow-up was 27.8months. Freedom from sustained VA was 72%, and freedom from ICD therapy was 80%. In 19 patients (38%), AAD therapy was terminated. The most common reason was insufficient efficacy (n = 8). Pro-arrhythmia was suspected in three patients. Five patients died during follow-up (10.0%), two of cardiovascular cause (4.0%). In a multicenter cohort of ICD-carriers with SHD, class-IC-AADs were associated with a low rate of pro-arrhythmic effects or cardiovascular mortality. The majority of patients remained free from sustained VA during a follow-up of > 2years. Further efforts should be made to evaluate the safety of class-IC-AADs in SHD patients receiving contemporary cardiovascular therapy.

Do Implantable Cardioverter-Defibrillators Prevent Sudden Cardiac Death in End-Stage Renal Disease Patients on Dialysis?

Chronic kidney disease patients appear to be predisposed to heart rhythm disorders, including atrial fibrillation/atrial flutter, ventricular arrhythmias, and supraventricular tachycardias, which increase the risk of sudden cardiac death. The pathophysiological factors underlying arrhythmia and sudden cardiac death in patients with end-stage renal disease are unique and include timing and frequency of dialysis and dialysate composition, vulnerable myocardium, and acute proarrhythmic factors triggering asystole. The high incidence of sudden cardiac deaths suggests that this population could benefit from implantable cardioverter-defibrillator therapy. The introduction of implantable cardioverter-defibrillators significantly decreased the rate of all-cause mortality; however, the benefits of this therapy among patients with chronic kidney disease remain controversial since the studies provide conflicting results. Electrolyte imbalances in haemodialysis patients may result in ineffective shock therapy or the appearance of non-shockable underlying arrhythmic sudden cardiac death. Moreover, the implantation of such devices is associated with a risk of infections and central venous stenosis. Therefore, in the population of patients with heart failure and severe renal impairment, periprocedural risk and life expectancy must be considered when deciding on potential device implantation. Harmonised management of rhythm disorders and renal disease can potentially minimise risks and improve patients' outcomes and prognosis.

Brugada syndrome in Iran: Insights from a 12-year longitudinal study.

Brugada syndrome (BrS) is characterized by ST-segment elevation in the right precordial leads, which is not explained by ischemia, electrolyte disturbances, or obvious structural heart disease. In present study, we aim to evaluate presentation, long-term outcome, genetic findings, and therapeutic interventions in patients with BrS. Between September 2001 and June 2022, all consecutive patients with diagnosis of BrS were enrolled in the present study. All patients gave written informed consent for the procedure, and the local ethical committee approved the study. Of the 76 cases, 79% were proband and 21% were detected during screening after diagnosis of BrS in a family member. Thirty-three (43%) patients had a typical spontaneous electrocardiogram (ECG) pattern. Thirty percent of the patients were symptomatic; symptomatic patients were more likely to have spontaneous type 1 Brugada ECG pattern in their ECGs (p = .01), longer PR interval (p = .03), and SCN5A mutation (p = .01) than asymptomatic patients. The mean PR interval was considerably longer in men than women (p = .034). SCN5A mutation was found in 9 out of 50 (18%) studied patients. Fifteen percent received appropriate implantable cardioverter-defibrillator (ICD) therapy and inappropriate ICD interventions were observed in 17%. Presentation with aborted SCD or arrhythmic syncope was the only predictor of adverse outcome in follow-up (odds ratio: 3.1, 95% confidence interval: 0.7-19.6, p = .001). Symptomatic patients with BrS are more likely to present with spontaneous type 1 Brugada ECG pattern, longer PR interval, and pathogenic mutation in SCN5A gene. Appropriate ICD interventions are more likely in symptomatic patients and those with SCN5A mutation.

Is it safe to give birth with an activated implantable cardioverter-defibrillator: A multicentre observational study.

Data and guidelines are lacking, so implantable cardioverter-defibrillators (ICDs) are often deactivated during labour to prevent inappropriate shocks. This study aimed to ascertain the safety of an activated ICD during labour. An observational study was performed. Dutch hospitals. A total of 41 childbirths were included of 26 patients who gave birth between February 2009 and November 2018 after receiving an ICD in our tertiary hospital. Five of these childbirths were attended by the research team between December 2018 and August 2020, during which the ICD remained active. Groups were made based on ICD status during labour. Patients who gave birth with an activated ICD at least once were stratified to the activated ICD group. Patients' files were checked and patients received a questionnaire about childbirth perceptions and treatment preferences. The differences in ordinal data resulting from the questionnaire were calculated using a chi-square or Fisher's exact test. Primary outcome was inappropriate ICD therapy and occurrence of ventricular arrhythmias requiring treatment. During the 41 childbirths, no inappropriate shocks or ventricular arrhythmias occurred during labour. All patients in the activated ICD group (n = 13) preferred this setting, while 8 of the 13 patients in the deactivated ICD group preferred activation (p = 0.002). Reasons included avoiding hemodynamic monitoring, magnet placement, or labour induction to facilitate technician availability. This study shows no evidence that labour and birth in women with an activated ICD are unsafe, as there were no ventricular arrhythmias or inappropriate therapy. In addition, most patients prefer an activated ICD during labour.