Implantable Cardioverter-defibrillator Interventions Research Articles

Longitudinal validation of the phospholamban (PLN) p.Arg14del risk model

Abstract Background/Introduction Recently, a variant-specific prediction model for PLN p.Arg14del variant carriers was developed to predict individual malignant ventricular arrhythmia (VA) risk to inform decision-making for primary prevention implantable cardioverter defibrillator (ICD) implantation. This model predicts malignant VA risk from data at diagnosis, but iterative evaluation of malignant VA risk may be warranted considering that the risk factors for malignant VA are progressive. Purpose To evaluate the diagnostic performance of the PLN p.Arg14del risk model. Methods/Results Date were collected of 278 PLN p.Arg14del variant carriers at 3 year follow-up. This was considered the new baseline for the survival analysis. Patients with history of malignant VA at both baseline and during the first 3 years after baseline were excluded. At 3 year patients were aged 40.1±18.0 year and 40.7% was male. Median left ventricular ejection fraction (LVEF) was 53% and percentage with microvoltages was 10.3. During a median follow-up of 4 years (Interquartile range 1.8–6.5) 31 (11%) carriers experienced malignant VA, defined as sustained VA, appropriate ICD intervention, or (aborted) sudden cardiac death. Reevaluation of the predictors with the 3 year follow-up data revealed hazard rates that were similar to those in the original PLN p.Arg14del risk model; LVEF per 1% decrease (hazard ratio (HR) 1.10 [95% confidence interval (CI), 1.06–1.12]; p<0.001), premature ventricular contraction count/24h (HR 1.51 [95% CI, 1.15–1.98]; p=0.003) and the presence of low-voltage electrocardiogram (HR 12.24 [95% CI, 5.21–28.8); p<0.001). Negative T waves did not remain significant as a predictor. The 5-year malignant VA risk was calculated for each variant carrier, after multiple imputation for dealing with incomplete cases, by applying the PLN p.Arg14del risk model to the 3 year follow-up data. Afterwards the cohort was divided into tertiles of predicted risk. This clearly demonstrated the lowest risk tertile having a low malignant VA rate and the highest risk tertile having a high malignant VA rate, which resulted in an optimism-corrected C-statistic of 0.85 (95% CI 0.78–0.92). Conclusion The PLN p.Arg14del risk model is valid at 3 year follow-up in PLN p.Arg14del variant carriers with no history of malignant VA and can therefore be used to inform decision-making for primary prevention ICD implantation not merely at diagnosis, but also during follow-up and can be seen as a type of validation in a cohort where no other large cohort is present to perform external validation. Funding Acknowledgement Type of funding sources: Private grant(s) and/or Sponsorship. Main funding source(s): 1. PSIDER: From pluripotent stem cells to prime editing gene therapy for inheritedcardiomyopathies. ZOn-MW.2. PREDICT2: Predicting sudden cardiac arrest. The Dutch Heart Foundation.

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

Risk stratification in Arrhythmogenic Right Ventricular Cardiomyopathy: the impact of genotype on the 2019 ARVC risk calculator

Abstract Introduction Arrhythmogenic Right Ventricular Cardiomyopathy (ARVC) is associated with sudden cardiac death (SCD). The 2019 ARVC risk model has been proposed as a method to quantify arrhythmic risk, but the impact of genotype its performance has not been addressed. Purpose To study arrhythmic outcomes in patients with ARVC and the performance of the 2019 ARVC risk model in predefined genetic subgroups. Methods This is an international, retrospective observational cohort study on consecutively evaluated patients with ARVC recruited from 17 centres in 7 countries. Inclusion criteria were: (i) a definite diagnosis of ARVC according to the 2010 Task Force Criteria; (ii) no history of sustained ventricular arrhythmia (VA) prior to first assessment at the participating centre; (iii) a follow up period of ≥1 month; (iv) age of diagnosis ≥14 years. Sustained ventricular arrhythmia (sustained ventricular tachycardia, appropriate implantable cardioverter defibrillator intervention, aborted SCD, or SCD) comprised the primary outcome (VA). Discriminative ability was assessed by Uno's concordance index (c-statistic) and calibration with the calibration plot slope. Fine-Gray regression was used to model the impact of clinical predictors on the arrhythmic outcome, in the context of competing risks (heart transplantation and non-arrhythmic death). The cumulative probability and 95% confidence intervals (95% CI) for the occurrence of an outcome were estimated using the Aalen-Johansen estimate in order to take into account competing risks. Results The study cohort comprised 554 ARVC patients. During a median follow-up of 6.0 [3.1,12.5] years, 100 patients (18%) experienced VA (Figure). Risk estimates for VA using the 2019 ARVC risk model showed good discriminative ability (c-statistic 0.75 (95% CI 0.70–0.81)) but with overestimation of risk (slope 0.46 (95% CI 0.33–0.63)). The ARVC risk model was compared in 4 gene groups: PKP2 (n=118, 21%); DSP (n=79, 14%); other desmosomal (n=59, 11%); and gene elusive (n=160, 29%). Discrimination and calibration were highest for PKP2 [c-statistic 0.83 (95% CI 0.75–0.91); calibration slope 0.67 (95% CI 0.40–1.04)] and lowest for the gene elusive group [c-statistic 0.65 (95% CI 0.57–0.74); calibration slope 0.26 (95% CI 0.06–0.49)]. Univariable analyses revealed variable performance of individual clinical risk markers in the different gene groups (see heatmap of hazard ratios and statistical significance in Figure). For example, RV dimensions and systolic function are significant risk markers in PKP2 but not in DSP patients and the opposite is true of LV systolic function (Figure). Conclusion The 2019 ARVC risk model performs reasonably well in gene positive ARVC, (particularly for PKP2) but is more limited in gene elusive patients. Genotype specific risk factors should be considered in ARVC patients. Funding Acknowledgement Type of funding sources: Foundation. Main funding source(s): British Heart Foundation

NT-proBNP is superior to novel plasma biomarkers for predicting adverse outcome in arrhythmogenic right ventricular cardiomyopathy

Abstract Background/Introduction Arrhythmogenic right ventricular cardiomyopathy is a heritable heart muscle disease characterized by progressive substitution of the myocardium with fibrous and fatty tissue, which is the substrate for ventricular arrhythmia, systolic dysfunction and heart failure. Determining the optimal time for heart transplantation is challenging and, therefore, finding risk factors for disease progression is needed. Purpose The purpose of the study was to evaluate the role of markers of myocardial fibrosis sST2, Gal-3, MMP-2 and MMP-9, as well as NT-proBNP and hsTnT, in predicting major adverse outcomes in ARVC. Moreover, we aimed to identify other risk factors for developing end-stage heart failure. Methods We included 91 patients with the definite diagnosis of ARVC according to the 2010 Task Force Criteria (59 males, mean age of 47±16 years). Patients were interviewed for their medical history, electrocardiography and echocardiography were performed and plasma levels of selected biomarkers were measured. Thereafter, subjects were followed for the occurrence of the composite endpoint of death or heart transplantation (HTx) and major arrhythmic events defined as ventricular fibrillation, sustained ventricular tachycardia or appropriate implantable cardioverter-defibrillator intervention. Results During the median follow-up of 36,4 months [29,8–41,2], 13 subjects (14%) reached the composite endpoint of death or HTx and 27 subjects (30%) experienced major arrhythmic event. Among the studied biomarkers, significantly higher levels of sST2, MMP-2, NT-proBNP and hsTnT were found in patients who achieved the composite endpoint. The remaining prognostic factors are shown in Table 1. In the multivariate analysis, three factors turned out to be significant: higher NT-proBNP levels (the cut-off point ≥890.3 pg/m), greater right ventricular end-diastolic area (the cut-off point ≥39.0 cm2) and history of atrial tachycardia. Kaplan-Meyer survival analysis depending on the number of predictors is presented in Figure 1. None of the biomarkers predicted major arrhythmic events. Conclusions NT-proBNP ≥890.3 pg/ml, RV area ≥39.0 cm2 and history of atrial tachycardia are independent risk factors for death or HTx in ARVC. Among the studied biomarkers, higher levels of sST2, MMP-2, NT-proBNP and hsTnT were observed in patients who reached the composite endpoint. Biomarkers had no value in predicting ventricular arrhythmias. Funding Acknowledgement Type of funding sources: Public hospital(s). Main funding source(s): National Institute of Cardiology, Warsaw, Poland

Coronary artery disease is a stronger predictor of mortality than left ventricular ejection fraction among newly diagnosed patients with heart failure

Abstract Background Heart failure (HF) prevalence remains high and prognosis is poor despite improvements in both medical treatment and implantation of primary prophylactic implantable cardioverter-defibrillator (ICD) and cardiac resynchronisation therapy (CRT) devices. At present, classification of HF and treatment algorithms are determined by the left ventricular ejection fraction (LVEF). However, in patients with LVEF <50% and newly diagnosed HF, evidence remains sparse as to whether LVEF per se or presence of CAD provide independent prognostic information on mortality. Methods Using the Western Denmark Heart Registry, we identified newly diagnosed patients with HF and LVEF 10–49% undergoing first-time coronary angiography (CAG) from 2003 to 2016 referred due to HF. Patients were stratified by LVEF (10–35% vs. 36–49%, according as to whether primary prophylactic ICD and CRT treatment should be considered) and presence of coronary artery disease (CAD). Maximum follow-up was 10 years. We estimated 10-year cumulative incidence of death and calculated hazard ratios (HR) adjusted for relevant comorbidities and risk factors. Results Of 154,186 Western Danish residents undergoing CAG, 3,620 patients had HF and LVEF 10–49%. Among these, 2,780 (77%) patients had LVEF 10–35% and 840 (23%) patients had LVEF 36–49%. CAD was present in 1,592 (44%) patients. There was a potential association in 10-year mortality when comparing patients with HF and LVEF 36–49% to those with LVEF 10–35% (37.3% vs. 42.1%, HR 1.15; 95% CI 0.99–1.34) (Figure 1A), with point estimates of mortality ranging from being 1% reduced to 24% increased. This result was not strongly influenced by the presence of CAD (HR 1.11; 95% CI 0.91–1.35) or absence of CAD (HR 1.24; 95% CI 0.97–1.57) (Figure 1B). There was no trend between LVEF categorized by 5-percentiles and mortality (p for trend = 0.24) (Table 1). In contrast, CAD was more strongly associated with increased 10-year mortality (55.0% vs. 31.5%, HR 1.43; 95% CI 1.25–1.64) irrespective of LVEF (Figure 1B). Conclusion Among newly diagnosed patients with HF and LVEF 10–49%, presence of CAD impacts mortality substantially more than LVEF per se. These results emphasize that assessment of CAD is pivotal for prognostication of newly diagnosed patients with HF and LVEF 10–49%. Funding Acknowledgement Type of funding sources: None.

FACTORS INFLUENCING PATIENT DECISION AID USE FOR IMPLANTABLE CARDIOVERTER-DEFIBRILLATOR DECISIONS IN THREE CANADIAN ACADEMIC HOSPITALS

FACTORS INFLUENCING PATIENT DECISION AID USE FOR IMPLANTABLE CARDIOVERTER-DEFIBRILLATOR DECISIONS IN THREE CANADIAN ACADEMIC HOSPITALS

Apical aneurysm formation in apical hypertrophic cardiomyopathy: Pilot study with cardiac magnetic resonance

BackgroundThe dynamic changes and apical aneurysm formation in apical hypertrophic cardiomyopathy (HCM) have not been specifically described. This study aimed to describe these changes to better understand the progression of apical HCM. Methods and resultsSeventy-two patients with apical HCM who underwent at least two cardiac magnetic resonance (CMR) examinations were retrospectively included in this study. The mean interval between the first and last CMR examinations was 50.1 ± 26.8 months (ranging from 4 to 118 months). Compared with the initial values, the left atrial diameter, maximum left ventricular wall thickness and late gadolinium enhancement extent significantly increased (all P < 0.05), while the left ventricular ejection fraction significantly decreased (P < 0.05), at the latest CMR examination. More importantly, the dynamic process of apical aneurysm formation in apical HCM was observed in a subset of patients, which may follow these four stages: starting with systolic apical cavity obliteration, then broadening of the apical slit in systole, further developing into an apical outpouching, and finally forming an apical aneurysm. Eleven patients experienced adverse cardiovascular events, including new-onset or progressive atrial fibrillation (n = 7), hospitalization with heart failure (n = 3) and implantable cardioverter defibrillator intervention (n = 1), at the time of the latest CMR examination. ConclusionsIn the progression of apical HCM, cardiac structure and function will change accordingly. Apical aneurysm formation in apical HCM is a chronic and continuous dynamic process that may follow a 4-step pathway of disease progression.

Stereotactic body radioablation therapy as an immediate and early term antiarrhythmic palliative therapeutic choice in patients with refractory ventricular tachycardia.

BackgroundStereotactic body radioablation therapy (SBRT) has recently been introduced with the ability to provide ablative energy noninvasively to arrhythmogenic substrate while reducing damage to normal cardiac tissue nearby and minimizing patients’ procedural risk. There is still debate regarding whether SBRT has a predominant effect in the early or late period after the procedure. We sought to assess the time course of SBRT’s efficacy as well as the value of using a blanking period following a SBRT session.MethodsEight patients (mean age 58 ± 14 years) underwent eight SBRT sessions for refractory ventricular tachycardia (VT). SBRT was given using a linear accelerator device with a total dose of 25 Gy to the targeted area.ResultsDuring a median follow-up of 8 months, all patients demonstrated VT recurrences; however, implantable cardioverter-defibrillator (ICD) and anti-tachycardia pacing therapies were significantly reduced with SBRT (8.46 to 0.83/per month, p = 0.047; 18.50 to 3.29/per month, p = 0.036, respectively). While analyzing the temporal SBRT outcomes, the 2 weeks to 3 months period demonstrated the most favorable outcomes. After 6 months, one patient was ICD therapy-free and the remaining patients demonstrated VT episodes.ConclusionsOur findings showed that the SBRT was associated with a marked reduction in the burden of VT and ICD interventions especially during first 3 months. Although SBRT does not seem to succeed complete termination of VT in long-term period, our findings support the strategy that SBRT can be utilized for immediate antiarrhythmic palliation in critically ill patients with otherwise untreatable refractory VT and electrical storm.

Impact of coronavirus disease 19 outbreak on arrhythmic events and mortality among implantable cardioverter defibrillator patients followed up by remote monitoring: a single center study from the Veneto region of Italy.

The 2020 severe acute respiratory syndrome coronavirus 2 outbreak entailed reduced availability of traditional (in-office) cardiology consultations. Remote monitoring is an alternative way of caring that may potentially mitigate the negative effects of the epidemic to the care of cardiovascular diseases. We evaluated the outcome of implantable cardioverter defibrillator (ICD) carriers followed up remotely in 2020 (epidemic period) versus 2019 (control). We included all patients with an ICD who remained remotely monitored from the beginning to the end of each year. The combined end point included: new-onset atrial fibrillation; sustained ventricular tachycardia >170 bpm without ICD intervention; appropriate ICD intervention (either shock or antitachycardia pacing); any-cause death. Multiple events in the same patients were counted separately if occurring ≥48 h apart. In 2020, 52 end points occurred in 37 of 366 (10%) ICD carriers [0.14/patient (95% confidence interval [CI] = 0.11-0.19)] versus 43 end points in 32 of 325 (10%) ICD carriers in 2019 [0.13/patient (95% CI = 0.10-0.18) P = 0.75]. There was no difference between the distribution of any individual end point in 2020 versus 2019 although a nonsignificant mortality increase was observed (from 2.8% to 4.6%, P = 0.19). The lowest weekly event rate occurred during the national lock down in spring 2020 but a similar trend occurred also in 2019 suggesting that the effect may not be linked to social distancing measures. We did not observe an increase in a combined end point including arrhythmic events and mortality in ICD carriers who were remotely monitored in 2020, compared to 2019, despite the negative impact of the coronavirus disease 2019 outbreak on the healthcare system.

Influence of diabetes on mortality and ICD therapies in ICD recipients: a systematic review and meta-analysis of 162,780 patients

BackgroundThe influence of diabetes on the mortality and risk of implantable cardioverter defibrillator (ICD) therapies is still controversial, and a comprehensive assessment is lacking. We performed this systematic review and meta-analysis to address this controversy.MethodsWe systematically searched the PubMed, Embase, Web of Science and Cochrane Library databases to collect relevant literature. Fixed and random effects models were used to estimate the hazard ratio (HR) with 95% CIs.ResultsThirty-six articles reporting on 162,780 ICD recipients were included in this analysis. Compared with nondiabetic ICD recipients, diabetic ICD recipients had higher all-cause mortality (HR = 1.45, 95% CI 1.36–1.55). The subgroup analysis showed that secondary prevention patients with diabetes may suffer a higher risk of all-cause mortality (HR = 1.89, 95% CI 1.56–2.28) (for subgroup analysis, P = 0.03). Cardiac mortality was also higher in ICD recipients with diabetes (HR = 1.68, 95% CI 1.35–2.08). However, diabetes had no significant effect on the risks of ICD therapies, including appropriate or inappropriate therapy, appropriate or inappropriate shock and appropriate anti-tachycardia pacing (ATP). Diabetes was associated with a decreased risk of inappropriate ATP (HR = 0.56, 95% CI 0.39–0.79).ConclusionDiabetes is associated with an increased risk of mortality in ICD recipients, especially in the secondary prevention patients, but does not significantly influence the risks of ICD therapies, indicating that the increased mortality of ICD recipients with diabetes may not be caused by arrhythmias. The survival benefits of ICD treatment in diabetes patients are limited.

Predictors of late arrhythmic events after generator replacement in Brugada syndrome treated with prophylactic ICD.

IntroductionPredictors of late life-threatening arrhythmic events in Brugada syndrome (BrS) patients who received a prophylactic ICD implantation remain to be evaluated. The aim of the present long-term multicenter study was to assess the incidence and clinical-electrocardiographic predictors of late life-threatening arrhythmic events in BrS patients with a prophylactic implantable cardioverter defibrillator (ICD) and undergoing generator replacement (GR).MethodsThe study population included 105 patients (75% males; mean age 45 ± 14years) who received a prophylactic ICD and had no arrhythmic event up to first GR.ResultsThe median period from first ICD implantation to last follow-up was 155 (128–181) months and from first ICD Implantation to the GR was 84 (61–102) months. During a median follow-up of 57 (38–102) months after GR, 10 patients (9%) received successful appropriate ICD intervention (1.6%/year). ICD interventions included shock on ventricular fibrillation (n = 8 patients), shock on ventricular tachycardia (n = 1 patient), and antitachycardia pacing on ventricular tachycardia (n = 1 patient). At survival analysis, history of atrial fibrillation (log-rank test; P = 0.02), conduction disturbances (log-rank test; P < 0.01), S wave in lead I (log-rank test; P = 0.01) and first-degree atrioventricular block (log-rank test; P = 0.04) were significantly associated with the occurrence of late appropriate ICD intervention. At Cox-regression multivariate analysis, S-wave in lead I was the only independent predictor of late appropriate ICD intervention (HR: 9.17; 95%CI: 1.15–73.07; P = 0.03).ConclusionsThe present study indicates that BrS patient receiving a prophylactic ICD may experience late appropriate intervention after GR in a clinically relevant proportion of cases. S-wave in lead I at the time of first clinical evaluation was the only independent predictor of persistent risk of life-threatening arrhythmic events. These findings support the need for GR at the end of service regardless of previous appropriate intervention, mostly in BrS patients with conduction abnormalities.

Long-Term Outcomes of Pulmonary Vein Isolation in Patients With Brugada Syndrome and Paroxysmal Atrial Fibrillation.

BackgroundPharmacological treatment of atrial fibrillation (AF) in the setting of Brugada syndrome (BrS) is challenging. In addition, patients with BrS with an implantable cardioverter‐defibrillator (ICD) might experience inappropriate shocks for fast AF. Long‐term outcome of pulmonary vein isolation in BrS has not been well established yet, and it is still unclear whether pulmonary vein triggers are the only pathophysiological mechanism of AF in BrS. The aim of the study is to assess the long‐term outcomes in patients with BrS undergoing pulmonary vein isolation for paroxysmal AF compared with a matched cohort of patients without BrS.Methods and ResultsSixty patients with BrS undergoing pulmonary vein isolation with cryoballoon catheter ablation for paroxysmal AF were matched with 60 patients without BrS, who underwent the same procedure. After a mean follow‐up of 58.2±31.7 months, freedom from atrial tachyarrhythmias was achieved in 61.7% in the BrS group and in 78.3% in the non‐BrS group (log‐rank P=0.047). In particular, freedom from AF was 76.7% in the first group and in 83.3% in the second (P=0.27), while freedom from atrial tachycardia/atrial flutter was 85% and 95% (P=0.057). In the BrS group, 29 patients (48.3%) had an ICD and 8 (27.6%) had a previous ICD‐inappropriate shock for fast AF. In the BrS cohort, ICD‐inappropriate interventions for AF were significantly reduced after ablation (3.4% versus 27.6%; P=0.01).ConclusionsPulmonary vein isolation in patients with BrS was associated with higher rate of arrhythmic recurrence. Despite this, catheter ablation significantly reduced inappropriate ICD interventions in BrS patients and can be considered a therapeutic strategy to prevent inappropriate device therapies.

Importance of genotype for risk stratification in arrhythmogenic right ventricular cardiomyopathy using the 2019 ARVC risk calculator.

AimsTo study the impact of genotype on the performance of the 2019 risk model for arrhythmogenic right ventricular cardiomyopathy (ARVC).Methods and resultsThe study cohort comprised 554 patients with a definite diagnosis of ARVC and no history of sustained ventricular arrhythmia (VA). During a median follow-up of 6.0 (3.1,12.5) years, 100 patients (18%) experienced the primary VA outcome (sustained ventricular tachycardia, appropriate implantable cardioverter defibrillator intervention, aborted sudden cardiac arrest, or sudden cardiac death) corresponding to an annual event rate of 2.6% [95% confidence interval (CI) 1.9–3.3]. Risk estimates for VA using the 2019 ARVC risk model showed reasonable discriminative ability but with overestimation of risk. The ARVC risk model was compared in four gene groups: PKP2 (n = 118, 21%); desmoplakin (DSP) (n = 79, 14%); other desmosomal (n = 59, 11%); and gene elusive (n = 160, 29%). Discrimination and calibration were highest for PKP2 and lowest for the gene-elusive group. Univariable analyses revealed the variable performance of individual clinical risk markers in the different gene groups, e.g. right ventricular dimensions and systolic function are significant risk markers in PKP2 but not in DSP patients and the opposite is true for left ventricular systolic function.ConclusionThe 2019 ARVC risk model performs reasonably well in gene-positive ARVC (particularly for PKP2) but is more limited in gene-elusive patients. Genotype should be included in future risk models for ARVC.

A Comparative Study Between Amiodarone and Implantable Cardioverter-Defibrillator in Decreasing Mortality From Sudden Cardiac Death in High-Risk Patients: A Systematic Review and Meta-Analysis.

Sudden cardiac death (SCD) is an unexpected death that occurs within one hour of symptom onset. In the United States, sudden cardiac death is considered the leading cause of natural death, accounting for 325,000 adult patients annually. SCD is more common in adult patients (above the mid-30s) and men. The risk factors that predict SCD are categorized into clinical, sociological, genetic, and psychological. To prevent the occurrence of SCD, several treatment options, especially antiarrhythmic drugs and implantable cardioverter-defibrillator (ICD), have been used.A literature search from 2000 to 2022 was conducted on six electronic databases: PubMed, Cochrane Library, Web of Science, Embase, ScienceDirect, and Google Scholar. The search query used Boolean expressions and keywords such as amiodarone, implantable cardioverter-defibrillator, sudden cardiac death, cardiac arrest, arrhythmic death, and all-cause mortality. The articles identified from the literature search were screened using the eligibility criteria, resulting in eight articles relevant for inclusion in the review. A meta-analysis of data from six of the included studies showed that ICD was more effective in the reduction of SCD rates, with an SCD rate of 5.97% (n = 84/1,408) observed in the ICD group compared with an SCD rate of 11.81% (n = 168/1,423) observed in the amiodarone group. The results also show that ICD was more effective in reducing all-cause mortality compared with amiodarone (odds ratio (OR): 1.36; 95% confidence interval (CI): 1.06-1.74; I2 = 57%; P = 0.03).ICD treatment of high-risk patients was more effective in reducing SCD and all-cause mortality rates compared with amiodarone treatment. There is evidence that amiodarone can be used as an adjuvant treatment option, especially for patients who are not eligible for ICD treatment and those who face more adverse events. Evidence has also shown that using amiodarone with ICD treatment significantly improves survival rates compared to ICD treatment only.

Implantation of Implantable Cardioverter Defibrillators in Kazakhstan.

Background and Objectives:Implantation of implantable cardioverter-defibrillators (ICD) has increased significantly over the past decade. However, limited data exist regarding practices and policies of ICD implantations in Kazakhstan. We aimed to provide an overview of the current use of ICD in Kazakhstan.Methods:Using the Unified Healthcare Information System database of the entire Kazakh adult population, statistical and cost data of ICD implantations in 2017–2019 were evaluated. Cardiologists and electrophysiologists working in cardio surgery centers and departments were asked to go through an online survey focused on subcutaneous-ICD (S-ICD) experience.Results:Implantation of traditional transvenous cardioverter-defibrillators for residents of Kazakhstan is fully reimbursed. A total of 2,263 ICD interventions (2,252 new implantations and 11 reimplantations) were performed across the country during the study period. According to the tariffs approved by the Ministry of Health, the reimbursement cost for one ICD case is about 14,061.80 US dollars. The survey showed that only two hospitals have implanted S-ICDs. Among the main reasons why S-ICD is not widely used in the country the following were named: lack of trained staff (61.1% of respondents); the cost of device and lack of reimbursement (38.7%); and lack of pacing function (27.8%).Conclusion:The number of ICD implantation in Kazakhstan is steadily continuing to grow, although, compared to developed countries, the implantation rate especially for S-ICD remains low. There is a need in deliberate strategies to remove policy barriers for implementation the most innovative cardiac implantable electronic devices implantations such as S-ICD in the country.

Catheter ablation of ventricular tachycardia in patients with structural heart disease

Ventricular cardiac rhythm disorders are potentially life-threatening arrhythmias. Ventricular tachycardia (VT) in patients with structural heart disease carries an increased risk of sudden cardiac death. Interventional radiofrequency catheter ablation is increasingly becoming the focus of treatment for ventricular arrhythmias. So far, no randomized study has been able to demonstrate areduction in mortality; however, depending on the existing cardiomyopathy, interventional VT ablation has proven to be more effective for rhythm stabilization than antiarrhythmic therapy and is subsequently associated with improve quality of life through reduced implantable cardioverter defibrillator (ICD) treatment. The aim of this work is to discuss the pathophysiology, mechanism and treatment of VT with structural heart disease in order to define the role of catheter ablation.

The clinical characteristics of patients admitted to the emergency department because of implantable cardioverter defibrillator shock

Aim: To present the clinical spectrum of the Emergency Department (ED) patients with presumed electrical shocks. Material and methods: The electronic recordings of the patients admitted to the ED of Unversity Hospital in Wroclaw between April 2020 and June 2021 were searched for the words: discharge, electrical storm, syncope, con¬vulsions. The received patients recordings were checked and all patients with electrical shocks from implantable cardioverter defibrillators (ICDs) both real and presumed were included into the study. Patients were divided into three groups: patients hospitalized due to adequate ICD discharges, patients hospitalized for other reason who had adequate interventions in the ICD memory and patients with incorrectly diagnosed ICD interventions. Results: The study group consisted of 26 patients. There was 18 men aged 65.9±10.9 and 8 women aged 68.1±12.4 (p=0.66). A total of 20 patients had electrical shocks confirmed by ICD memory checking and 6 patients had no ICD shocks. Conclusions: ED visits due to discharges of ICDs are rare. The medical history of ICD discharge could be misleading, because some patients interpret different symptoms or acoustic signals of the ICDs as a discharge. The ICD patients with syncope, unconsciousness, history of seizures should have their ICD checked for the possible discharges.

POSA226 Analysis of Requirement of Implantation for Implantable Cardioverter Defibrillator in the Russian Federation

Sudden cardiac death (SCD) is one of the leading causes of death in people of working age. Implantable Cardioverter Defibrillator (ICD) should be considered as the primary means of preventing SCD. The number of ICD in Russia is 19.4 per 1 million people (2 841 implantations in 2019), but in the countries of Western and Eastern Europe this indicator is approximately 10 times higher. This study aims to estimate the number of patients requiring ICD treatment due to SCD-associated diseases in Russia.

564 Controversial role of intracardiac eletrophysiology study in Brugada syndrome: analysis of a single-centre retrospective cohort study

Abstract Aims According to European guidelines, aborted sudden cardiac death (SCD) in Brugada syndrome (BrS) is regarded as a I class recommendation for secondary prevention implantable cardioverter defibrillator (ICD). However, the risk stratification of BrS patients for primary prevention ICD still represents a clinical conundrum. Although intracardiac electrophysiology (EP) study proved useful for the selection of high-risk patients in this setting. Therefore, aim of this study was to assess all clinical and EP variables associated with the induction of VA at EP study and the rate of appropriate/inappropriate ICD interventions and/or clinical SCD events in these patients occurring at follow-up. Methods and results From 2001 to 2021, all EP studies performed in symptomatic/asymptomatic patients (46 ± 14 years, M 88%) with/without family history of SCD spontaneous/drug-induced type I pattern (TIP) on ECG and no spontaneous ventricular arrhythmias were retrospectively considered at our study centre. Clinical variables, BrS pattern, EP study data (including right ventricular site and type of stimulation protocol), and ICD interventions (DC-shocks or Anti-Tachycardia Pacing events, ATP) and/or SCD events occurring at follow-up were all evaluated. EP study was deemed positive for any polymorphic VA induced during programmed ventricular stimulation; non-sustained episodes included. ICD was routinely implanted in all patients with a positive EP study. Follow-up data were detected by the collection of medical and home-monitoring recordings at study-site level. Follow-up data were available in 50 patients (9 ± 6 years on average). Patients were generally young with few cardiovascular comorbidities. SCD history was known in 21 (42%) with a significant number of asymptomatic patients (48%). Br patterns were equally distributed in the investigated population (spontaneous and drug-induced TIP in 52% and 48%, respectively) and AF history was fairly common (16%). In the study population, EP study tested positive in 30 patients (60%): spontaneous TIP (P = 0.0518), few extrastimuli during programmed ventricular stimulation (P = 0.0015), and right ventricular stimulation at the apical site (P ≤ 0.0001) were the only variables to be clearly associated with a positive EP study in the appraised patients. At follow-up, appropriate ICD shocks were documented in 4 out of 30 implanted patients (13%) at generally 5 ± 7 years from EP study evaluation. Although three ICD interventions (75%) occurred in patients with spontaneous TIP, one patient with drug-induced TIP pattern and positive EP study referred to Emergency Department for unrelenting VT storm after roughly 13 years from ICD implantation. Inappropriate ICD interventions for fast rate AF were detected in 10% of cases. Finally, no SCD events were documented at follow up in patients with a negative EP study. Conclusions In a retrospective analysis, EP study proved useful in the risk stratification of SCD in BrS patients. A few ventricular extrastimuli delivered at the right ventricular apex seem sufficient to prompt the induction of life-threatening VA in high-risk BrS patients during EP study. Moreover, in this setting, a negative EP study seems protective against the development of VA/SCD events at follow-up. However, not only is spontaneous TIP associated with an increased risk of arrhythmic death, but a drug-induced TIP, generally regarded as a low-risk condition, might also be associated with a long-term hazard of SCD in these patients.

Oral procainamide as pharmacological treatment of recurrent and refractory ventricular tachyarrhythmias: A single-center experience.

BackgroundAntiarrhythmic therapy for recurrent ventricular arrhythmias in patients who have undergone catheter ablation, and in whom amiodarone and/or beta-blockers were ineffective or contraindicated, is a controversial issue.ObjectiveThe present study sought to evaluate the efficacy and tolerability of oral procainamide in patients with recurrent ventricular arrhythmias when the standard therapy strategy had failed.MethodsAll patients treated with procainamide for recurrent ventricular tachycardia (VT) or ventricular fibrillation (VF) in our institution between January 2010 and May 2019 were enrolled. The primary endpoint was the total number of implantable cardioverter-defibrillator (ICD) interventions after the beginning of procainamide therapy. Secondary endpoints were the total number of VTs and VFs recorded on the ICDs’ controls and discontinuation of therapy. The events occurring during procainamide treatment were compared with a matched-duration period before the initiation of therapy with procainamide. Patients therefore served as self-controls.ResultsA total of 34 consecutive patients (32 male, 94.1%; mean age 74.4 ± 9.7 years) were included in the retrospective analysis. The mean time of procainamide treatment was 12.9 ± 13.7 months (median 9 [2–20] months). The mean dose of procainamide was 1207 ± 487 mg/day. Procainamide therapy significantly decreased ICD interventions (median 5 [0–22.5] vs 15.5 [3–32.25], P < .05). Procainamide also decreased the total number of VT/VF episodes (median 5.5 [0.75–30] vs 19 [7.5–30], P < .05). Only 3 patients (8.8%) presented severe side effects (dyspnea or hypotension), requiring discontinuation of therapy.ConclusionOral procainamide was associated with a significant decrease in ICD therapies and ventricular arrhythmias, showing an acceptable profile of tolerability.