Implantable Cardioverter Defibrillator Research Articles

A manual synchronous low energy shock impedance as a predictor of successful defibrillation testing during subcutaneous ICD implantation.

Guidelines recommend defibrillation testing (DFT) during subcutaneous implantable cardioverter-defibrillator (S-ICD) implantation. Implant position, patient characteristics and device factors, such as shock impedance, influence defibrillation success. To evaluate the shock impedance, a manual synchronous 10J shock (low energy synchronous shock [LESS]) can be delivered, without the need to induce ventricular fibrillation (VF). To compare LESS and DFT impedance values and to evaluate the diagnostic accuracy of LESS impedance for predicting a successful DFT during S-ICD implantation. Consecutive S-ICD implantations were included. Shock impedances were compared by paired t-tests. Univariate analysis was performed to investigate factors associated with successful DFT. A prediction model of successful DFT based on LESS impedance was assessed by logistic regression. Receiver operating characteristic (ROC) curve, area under the ROC curve and the Hosmer-Lemeshow tests were used to evaluate the accuracy of LESS impedance. Sixty patients were included (52±14years; 69% male). LESS and DFT impedance values were highly correlated (r2=0.97, p<.01). Patients with a failed first shock had higher body mass index (BMI) (30±3vs. 25.7±4.3, p=.014), higher mean LESS (120±35Ω vs. 86.±23Ω, p=.0013) and DFT impedance (122±33Ω vs. 87±24Ω, p=.0013). ROC analysis showed that LESS impedance had a good diagnostic performance in predicting a successful conversion test (AUC 84% [95% CI: 0.72-0.92]) with a cutoff value of <94Ω to identify a successful DFT (sensitivity 71%, specificity 73%). LESS impedance values without the need to induce VF can intraoperatively predict a successful DFT.

Gender Disparity of Automatic Implantable Cardioverter-Defibrillator Placement for Primary Prevention: National Inpatient Sample Analysis.

Automatic implantable cardioverter-defibrillators (AICDs) for the primary prevention of sudden cardiac death have become standard care for patients with systolic heart failure (sHF) and ejection fraction ≤35%. While the prevalence of sHF and rates of hospitalization are higher in men, one would expect equivalent rates of implantation in women. We used the Healthcare Cost and Utilization Project's National Inpatient Sample (NIS) from 2009 to 2018 to identify patient visits with sHF and AICD implantation. The comorbidities and outcomes were compared based on gender. There were 15,247,854 inpatient admissions for sHF, of which 60.3% were males (95% CI: 60.1%-60.4%) and 39.8% females (95% CI: 39.7%-39.9%). Approximately 2% of patients (294,726) underwent the insertion of an AICD for primary prevention: 72.3% males (95% CI: 71.9%-72.7%) and 27.72% females (95% CI: 27.3%-28.1%). There was no significant difference in age (p = 0.29), length of stay (p = 0.09), and inpatient mortality (p = 0.18). In this study, women accounted for approximately 40% of patients admitted with the diagnosis of sHF; however, they accounted for less than 30% of patients who underwent the insertion of an AICD. Further research is needed to better understand this gender disparity and identify reasons for the lower rates of AICD placement in women.

Connected to the cloud at time of death: a case report

BackgroundOur case report provides the first clinical evaluation of autopsy practices for a patient death that occurs on the cloud. We question how autopsy practices may require adaptation for a death that presents via the ‘Internet of Things’, examining how existing guidelines capture data related to death which is no longer confined to the patient's body.Case presentationThe patient was a British man in his 50s, who came to the attention of the medical team via an alert on the cloud-based platform that monitored his implanted cardioverter defibrillator (ICD). The patient had a background of congenital heart disease, with previous ventricular fibrillation cardiac arrest, for which the ICD had been implanted two years earlier. Retrospective analysis of the cloud data demonstrated a gradually decreasing nocturnal heart rate over the previous three months, falling to a final transmission of 24 beats per minute (bpm). In the patient post-mortem the ICD was treated as medical waste, structural tissue changes precluded the effective evaluation of device hardware, potential issues related to device software were not investigated and the cause of death was assigned to underlying heart failure. The documentation from the attending law enforcement officials did not consider possible digital causes of harm and relevant technology was not collected from the scene of death.ConclusionThrough this patient case we explore novel challenges associated with digital deaths including; (1) device hardware issues (difficult extraction processes, impact of pathological tissue changes), (2) software and data limitations (impact of negative body temperatures and mortuary radio-imaging on devices, lack of retrospective cloud data analysis), (3) guideline limitations (missing digital components in autopsy instruction and death certification), and (4) changes to clinical management (emotional impact of communicating deaths occurring over the internet to members of family). We consider the implications of our findings for public health services, the security and intelligence community, and patients and their families. In sharing this report we seek to raise awareness of digital medical cases, to draw attention to how the nature of dying is changing through technology, and to motivate the development of digitally appropriate clinical practice.

Peripartum management of cardiac arrhythmias: a narrative review

Cardiac arrhythmias are responsible for a significant portion of cardiovascular disease among pregnant people. As the incidence of arrhythmias in pregnancy continues to increase, anesthesiologists who care for obstetric patients should be experts managing arrhythmias in pregnancy. This article examines the most common arrhythmias encountered in pregnancy, including risk factors, diagnosis, and management strategies. Peripartum monitoring and labor analgesia recommendations are discussed. Additionally, management of cardioversion, management of pacemakers and implantable cardioverter-defibrillators, and advanced cardiac life support in the setting of pregnancy is reviewed.

Abstract Mo082: Polygenic Assessment for Atrial Fibrillation Liability Predicts Ventricular Arrhythmia Risk

Background: The risks for atrial and ventricular arrhythmias are increased with cardiomyopathy. Currently, left ventricular dysfunction is the major determinate of implantable cardioverter-defibrillator (ICD) placement despite left ventricular ejection fraction only having an odds ratio of 2.9 for subjects with an LVEF &lt;35% with sensitivity and specificity that suggests many patients are inappropriately receiving or not receiving a device. Additional testable variables would aid in arrhythmia risk stratification. There is growing evidence that atrial dysfunction is both a cause and consequence of ventricular disease. Atrial fibrillation (AFib) is the most common atrial arrhythmia and is highly heritable suggesting a strong genetic basis, and AFib occurs at increased frequency with cardiomyopathies. Genome-wide association studies (GWAS) identify &gt;100 loci that contribute to AFib, and signals from GWAS can be used to develop polygenic risk scores (PRS). Subjects in the top 3% of one AFib PRS were found to have ~2 fold greater risk for AFib (OR 1.7-4.6). Hypothesis: The genetic pathways represented in an AFib PRS account for a portion of arrhythmia risk associated with cardiomyopathy and can be exploited to predict ventricular arrhythmia risk. Approach: As part of an AHA Arrhythmia and Sudden Death Strategically Funded Research Network, we assembled a cohort with varying risk for sudden cardiac death ranging from low-risk individuals with non-ischemic cardiomyopathy without arrhythmia to higher risk individuals who underwent ICD placement for aborted sudden death and sudden death. Whole genome sequencing was completed 1043 individuals across the arrhythmia risk spectrum. Results: We examined an AFib PRS to define ventricular outcomes in the cohort. Of the 440 participants with disease, 81% had cardiomyopathy, 8% channelopathy and 7% idiopathic arrest. We found the AFib PRS stratified subjects without significant ventricular arrhythmia risk from subjects with known ventricular arrhythmia (p=0.03), indicating that the AFib PRS includes components that are important markers of ventricular dysfunction. Conclusions: The AFib PRS is a useful tool to stratify ventricular arrhythmia risk.

Abstract Tu060: Unveiling Arrhythmogenic Right Ventricular Dysplasia In Pregnancy

Introduction: Arrhythmogenic right ventricular dysplasia (ARVD) is a rare autosomal dominant disease, caused by desmosomal gene mutations, and characterized by fibrofatty replacement of right ventricular (RV) myocardium with left ventricular (LV) involvement in advanced stages. It is mostly diagnosed between the second and forth decades of life and can present with ventricular tachycardia and arrhythmic sudden death. Here we present a case of ARVD diagnosis in a female in her forth pregnancy. Case description: A 28-year-old female, on her 27 th week of gestation (G4P3) was admitted to the hospital with preterm premature rupture of membranes. She also endorsed intermittent chest pressure, palpitations and shortness of breath. Her vital signs were stable, and electrocardiogram (ECG) revealed normal sinus rhythm with frequent premature ventricular contractions (PVCs) and T wave inversions in leads V1- V3. Laboratory studies showed normal troponin and D-dimer levels, and slightly elevated brain natriuretic peptide 240 pg/mL. Patient notably had frequent runs of monomorphic non-sustained ventricular tachycardia (NSVT) arising from RV apical territory, with left bundle branch morphology on telemetry. An echocardiogram revealed a dilated right atrium and RV with hypokinesis of RV; LV size and function were normal. Overall, patient met the revised task force diagnostic criteria for ARVD based on PVC morphology, abnormal ECG and dilated and hypokinetic RV. She had no sustained or hemodynamically unstable VT, no history of syncope or family history of sudden cardiac death and did not meet class I indication for implantable cardioverter defibrillator. She was started on oral metoprolol succinate 25 mg daily with which her arrhythmias significantly improved. She was recommended a cardiac magnetic resonance imaging and genetic testing for confirmation and to assess familial implications. Conclusion: Recognition of ARVD during pregnancy is challenging given the overlapping symptoms of normal pregnancy-related changes. Hormonal surge and sympathetic drive may have driven the increased frequency of NSVT in our patient and beta blocker was effective in managing these. Early recognition and tailored management are crucial to ensure the well-being of both the mother and the fetus. A close follow-up is necessary to understand the long-term implications for the patient and potential genetic predisposition in the family.

Arrhythmic prognosis according to left ventricular systolic dysfunction severity in cardiac sarcoidosis

BackgroundCurrent guidelines present varying classes of recommendations for implantable cardioverter-defibrillator (ICD) utilization in patients with cardiac sarcoidosis (CS) and left ventricular ejection fraction (LVEF) <50%. ObjectiveThe purpose of this study was to investigate the ventricular arrhythmia risk in CS patients with ICDs and varying degrees of left ventricular systolic dysfunction. MethodsThe study included CS patients with an ICD and LVEF <50% at index evaluation. The primary outcome was survival free of sustained ventricular tachycardia (VT)/ventricular fibrillation (VF) after ICD implantation and was assessed comparatively for LVEF ≤35% vs 36%–49% and for primary vs secondary prevention ICD indication. ResultsThe study included 61 patients (median age 57 years; 61% male) with LVEF 36%–49% (n = 23) or LVEF ≤35% (n = 38). An ICD was implanted for secondary prevention in 24% and 44% of the LVEF ≤35% and 36%–49% groups, respectively (P = .11). The primary outcome did not differ between the 2 groups in univariable analysis (LVEF ≤35% vs 36%–49%: hazard ratio [HR] 0.85; 95% confidence interval [CI] 0.39–1.82; P = .67). In multivariable analysis, secondary prevention ICD indication was the only significant predictor of incident sustained VT/VF (HR 2.86; 95% CI 1.23–6.67; P = .015). Mean sustained VT/VF event burden was higher in the secondary compared with the primary prevention ICD patients (0.47 vs 0.11 events per patient-year; P = .005) but did not differ significantly between LVEF ≤35% and 36%–49% patients. ConclusionCS patients with ICD indications and LVEF 36%–49% carry similarly high arrhythmic risk as those with LVEF ≤35%. Patients with secondary prevention ICDs have the highest overall risk.

A Systematic Review and Meta-Analysis of Catheter Ablation Versus Anti-arrhythmic Drugs for Treatment of Ventricular Arrhythmia.

Catheter ablation (CA) and anti-arrhythmic drugs (AADs) minimize implanted cardioverter-defibrillator (ICD) shocks in individuals with ischemic cardiomyopathy and an ICD, while the best strategy is still unknown. CA has been proposed as a potentially effective means of reducing the occurrence of ICD events in a number of studies; however, there were insufficient relevant dates from randomized controlled trials. A meta-analysis and systematic review of randomized controlled trials were carried out to evaluate the efficacy of CA for the prevention of VA in patients with ischemic heart disease. Cardiovascular mortality, an unscheduled hospitalization due to increasing heart failure, appropriate ICD shock, or serious treatment-related consequences comprised the composite primary outcome. AADs were examined in six trials (n = 1564; follow-up = 15 ± 8 months), while CA was evaluated in four trials (n = 682; follow-up = 12 ± 6 months). Both CA (odds ratio (OR) 0.65, 95% confidence interval (CI) 0.47-0.82, p = 0.001) and AADs (OR 0.76, 95% CI 0.32-0.84, p = 0.034) significantly reduced the number of suitable ICD interventions, with no discernible difference between the two treatment approaches. AADs were observed to reduce incorrect ICD interventions (OR 0.38, p = 0.001), but CA did not. During follow-up, there was no correlation seen between reduced mortality and either CA or AAD. When compared to AAD, CA decreased the composite endpoint of cardiovascular death, adequate ICD shock, heart failure-related hospitalization, or severe treatment-related consequences in ICD patients with ischemic cardiomyopathy and symptomatic VT.

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

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

Failure to treat ventricular tachycardia or ventricular fibrillation by implantable cardioverter-defibrillators

BackgroundNormally functioning implantable cardioverter-defibrillators (ICDs) with intact lead systems occasionally fail to deliver therapy for ventricular tachycardia/fibrillation (VT/VF) or deliver it only after clinically significant delays (failure-to-treat). ObjectiveWe aimed to investigate ICD failure-to-treat VT/VF in a large patient cohort. MethodsWe searched the US Food and Drug Administration's online Manufacturer and User Facility Device Experience (MAUDE) database from 2019 to 2023 for manufacturer-verified reports in which normally functioning ICDs failed to treat VT/VF. ResultsWe identified 854 reports classified as deaths (n = 96 [11.2%]), injuries (n = 585 [68.5%]), or malfunctions (n = 173 [20.4%]) for normally functioning ICDs. The most common causes were misclassification as supraventricular tachycardia (SVT) or atrial fibrillation (AF; 54.8%), undersensing (21.1%), and failure to satisfy programmed rate/duration criteria (8.7%). Most events caused by misclassification as SVT/AF (89.5%) and failure to satisfy rate/duration criteria (70.3%) were VT; most caused by undersensing were either VF (54.4%) or not specified as VT or VF (19.4%). Undersensing caused 65.6% of deaths, although it represented only 21.1% of reports. In the United States, the number of reports increased faster than that of ICD patients. ConclusionIn the largest reported series of failure-to-treat VT/VF by normally functioning ICDs, the most common cause was misclassification of VT as SVT/AF; the most common cause of death was undersensing of VF. Although relatively few patients with normally functioning ICDs experience failure-to-treat VT/VF, the absolute number of verified MAUDE reports suggests that more work is needed to quantify the magnitude of the problem, to identify root causes, and to develop solutions.

Assessing the impact and safety of implantable cardioverter defibrillators in treating catecholaminergic polymorphic ventricular tachycardia: a systematic review and meta-analysis protocol

BackgroundWhile the guidelines acknowledge the anticipated benefits of using an implantable cardioverter defibrillator (ICD) in individuals with catecholaminergic polymorphic ventricular tachycardia (CPVT). However, the potential adverse effects have received less...

Cardiac Arrhythmias and Their Management: An In-Depth Review of Current Practices and Emerging Therapies.

Cardiac arrhythmias encompass a range of conditions characterized by abnormal heart rhythms, affecting millions globally and significantly contributing to morbidity and mortality. This review provides a comprehensive analysis of the current practices and emerging therapies in managing cardiac arrhythmias, covering their definition, classification, epidemiology, and the critical importance of effective management. It explores the pathophysiology underlying various arrhythmias, including the mechanisms of arrhythmogenesis, such as re-entry, automaticity, and triggered activity. The review details the latest diagnostic tools, including ECG, Holter monitoring, and electrophysiological studies, and discusses the clinical presentation of different arrhythmias, from supraventricular to ventricular types and bradyarrhythmias. We examine current pharmacological and non-pharmacological treatment strategies, such as antiarrhythmic drugs, catheter ablation, and device therapy, highlighting their efficacy and limitations. Furthermore, the review delves into emerging therapies, including advanced catheter ablation techniques, novel antiarrhythmic agents, gene therapy, and innovative device technologies like leadless pacemakers and subcutaneous implantable cardioverter-defibrillators (ICDs). Special considerations for managing arrhythmias in diverse populations, including pediatrics, the elderly, and pregnant women, are discussed. Additionally, the review explores future directions in arrhythmia management, emphasizing personalized medicine, artificial intelligence applications, and the integration of advanced technologies in diagnosis and treatment. By synthesizing current knowledge and prospects, this review aims to enhance understanding and promote advancements in the field, ultimately improving patient outcomes with cardiac arrhythmias.

Long-term adherence to a wearable for continuous behavioural activity measuring in the SafeHeart implantable cardioverter defibrillator population.

Wearable health technologies are increasingly popular. Yet, wearable monitoring only works when devices are worn as intended, and adherence reporting lacks standardization. In this study, we aimed to explore the long-term adherence to a wrist-worn activity tracker in the prospective SafeHeart study and identify patient characteristics associated with adherence. This study enrolled 303 participants, instructed to wear a wrist-worn accelerometer day and night for 6 months. Long-term adherence was defined as valid days (≥22 h of wear time) divided by expected days, and daily adherence as mean hours of wear time per 24 h period. Optimal, moderate, and low long-term and daily adherence groups were defined as long-term adherence above or below 95 and 75% and daily adherence above or below 90 and 75%. Regression models were used to identify patient characteristics associated with long-term adherence. In total, 296 participants [median age 64 years; interquartile range (IQR) 57-72; 19% female] were found eligible, yielding 44 003 days for analysis. The median long-term adherence was 88.2% (IQR 74.6-96.5%). A total of 83 (28%), 127 (42.9%), and 86 (29.1%) participants had optimal, moderate, and low long-term adherence, and 163 (55.1%), 87 (29.4%), and 46 (15.5%) had optimal, moderate, and low daily adherence, respectively. Age and smoking habits differed significantly between adherence levels, and increasing changeover intervals improved the degree of long-term adherence. Long-term adherence to a wearable activity tracker was 88.2% over a 6-month period. Older age and longer changeover interval were positively associated with long-term adherence. This serves as a benchmark for future studies that rely on wearable devices. The National Trial Registration number: NL9218 (https://onderzoekmetmensen.nl/).

Effect of posture on position of subcutaneous implantable cardioverter-defibrillator

BackgroundThe PRAETORIAN score was developed as an alternative for defibrillation testing after subcutaneous implantable cardioverter-defibrillator implantation to assess 3 aspects of implant position on a bidirectional chest radiograph. The score is validated on a standard standing chest radiograph with arms elevated in the lateral view. ObjectiveWe aimed to evaluate the effect of different anatomic positions on the PRAETORIAN score. MethodsThirty patients with a subcutaneous implantable cardioverter-defibrillator underwent standard posterior-anterior and lateral chest radiography, including additional lateral views in 2 positions: standing with arms down and supine with arms alongside the body. PRAETORIAN score and weighted κ coefficient were calculated for each position. ResultsIn 8 of 30 patients, the PRAETORIAN score was ≥90 in standard position. The agreement in PRAETORIAN score was substantial (κ = 0.677) for the position with the arms down and fair (κ = 0.399) for the supine position. With the arms down, the PRAETORIAN score decreased in 10 patients (33%), 4 of whom changed to a lower risk category. In supine position, the PRAETORIAN score decreased in 16 patients (53%), 7 of whom changed to a lower risk category, 1 from high to low risk. ConclusionA supine or arms-down position during chest radiography can result in lower PRAETORIAN scores and underestimation of associated risk on defibrillation testing failure. This emphasizes the importance of correct anatomic positioning (arms up) during chest radiography when the PRAETORIAN score is used.

Brugada Syndrome and Sudden Cardiac Death: An Electrocardiographic History.

A 22-year-old male with a history of anti-neutrophil cytoplasmic antibody vasculitis, renal transplant, hypertension, and no known family history of sudden cardiac death suffered a witnessed cardiac arrest. An initial rhythm strip recorded by emergency medical services revealed ventricular fibrillation. Return of spontaneous circulation was achieved after three rounds of cardiopulmonary resuscitation, defibrillation, and intravenous epinephrine. The patient was brought to the emergency department and admitted to the intensive care unit. He was diagnosed with Brugada syndrome, and an automatic implantable cardioverter-defibrillator (AICD) was placed after discharge. Brugada syndrome is characterized electrocardiographically by ≥2 millimeters (mm) ST-segment elevation in leads V1-V2 with either "coved type" (type 1) or "saddleback" (type 2) ST-segment morphology, or ≤2mm ST-segment elevation in V1-V2 with either "coved" or "saddleback" morphology (type 3). The absence of these patterns on isolated electrocardiograms (ECG) does not exclude the diagnosis, as dynamic fluctuations in ECG patterns are well-documented and can be induced by various physiologic stressors. This case provides an uncommon, complete electrocardiographic history of Brugada syndrome, from out-of-hospital cardiac arrest to AICD placement and depicts dynamic fluctuations between Brugada patterns and normal ECGs. This highlights the importance of serial ECGs in diagnosis, as sudden cardiac death is often the first or only presentation of Brugada syndrome.

Clonal haematopoiesis is associated with major adverse cardiovascular events in patients with hypertrophic cardiomyopathy.

The heterogeneous phenotype of hypertrophic cardiomyopathy (HCM) is still not fully understood. Clonal haematopoiesis (CH) is emerging as a cardiovascular risk factor potentially associated with adverse clinical events. The prevalence, phenotype and outcomes related to CH in HCM patients were evaluated. Patients with HCM and available biospecimens from the Peter Munk Cardiac Centre Cardiovascular Biobank were subjected to targeted sequencing for 35 myeloid genes associated with CH. CH prevalence, clinical characteristics, morphological phenotypes assessed by echocardiogram and cardiac magnetic resonance and outcomes were assessed. All patients were evaluated for a 71-plex cytokines/chemokines, troponin I and B-type natriuretic peptide analysis. Major adverse cardiovascular events (MACE) were defined as appropriate implantable cardioverter-defibrillator shock, stroke, cardiac arrest, orthotopic heart transplant and death. Among the 799 patients, CH was found in 183 (22.9%) HCM patients with sarcomeric germline mutations. HCM patients with CH were more symptomatic and with a higher burden of fibrosis than those without CH. CH was associated with MACE in those HCM patients with sarcomeric germline mutations (adjusted hazard ratio [HR] 6.89, 95% confidence interval [CI] 1.78-26.6; p = 0.005), with the highest risk among those that had DNMT3A, TET2 and ASXL1 mutations (adjusted HR 5.76, 95% CI 1.51-21.94; p = 0.010). Several cytokines (IL-1ra, IL-6, IL-17F, TGFα, CCL21, CCL1, CCL8, and CCL17), and troponin I were upregulated in gene-positive HCM patients with CH. These results indicate that CH in patients with HCM is associated with worse clinical outcomes. In the absence of CH, gene-positive patients with HCM have lower rates of MACE.

Association Between Right Bundle Branch Block and Ventricular Arrhythmia in Patients With Cardiac Sarcoidosis

BackgroundVentricular arrhythmia (VA) is a life-threatening condition associated with cardiac sarcoidosis (CS). Right bundle branch block (RBBB) is a common conduction disorder in CS; however, its association with VA remains unknown. ObjectivesThis study aimed to investigate the relationship between RBBB and VA in patients with CS. MethodsThis was a post hoc analysis of ILLUMINATE-CS (Illustration of the Management and Prognosis of Japanese Patients with Cardiac Sarcoidosis), a multicenter, retrospective, and observational study that evaluated the clinical characteristics and prognosis of CS. Eligible patients were divided into two groups based on the presence or absence of RBBB at the time of diagnosis. The primary outcome was serious ventricular arrhythmia events (SVAEs), defined as a combination of sudden cardiac death and documented ventricular fibrillation, sustained ventricular tachycardia, or appropriate implantable cardioverter-defibrillator therapy. ResultsOverall, 312 patients were studied, with 155 (49.7%) patients presenting with RBBB (RBBB group). Patients in the RBBB group had a higher prevalence of basal interventricular septum (IVS) thinning and prominent late gadolinium enhancement in the basal IVS on cardiac magnetic resonance imaging than those in the non-RBBB group. During a median follow-up of 3.0 years (IQR: 1.6-6.0 years), 66 patients experienced SVAE. In multivariable Cox regression analysis, the RBBB group was independently associated with a higher incidence of SVAEs (HR: 1.93 [95% CI: 1.14-3.28]; P = 0.015). ConclusionsIn patients with CS, RBBB was an independent predictor of SVAEs, which might reflect the specific scar distribution that is predominant in the IVS.

SMART Pass automatic deactivation of subcutaneous implantable cardioverter-defibrillators

BackgroundThe SMART Pass algorithm for subcutaneous implantable cardioverter-defibrillator prevents inappropriate shocks due to oversensing. The mechanisms and significance of SMART Pass deactivation remain unclear. ObjectiveThe objective of this study was to assess whether SMART Pass deactivation is associated with inappropriate shocks and to elucidate the underlying mechanism. MethodsWe retrospectively investigated 115 patients who underwent subcutaneous implantable cardioverter-defibrillator implantation between 2016 and 2021. SMART Pass deactivation and inappropriate shocks during follow-up were assessed. The QRS amplitudes of the subcutaneous (S-ECG) and 12-lead electrocardiogram (ECG) at the time of implantation (pre) and SMART Pass deactivation (post) were measured. The patients were divided into the SP-ON group with SMART Pass consistently on and the SP-OFF group with the experience of SMART Pass deactivation. ResultsThree of 12 patients in the SP-OFF group experienced inappropriate shocks during a median follow-up of 1094 (interquartile range, 887–1502) days compared with 4 of 87 patients in the SP-ON group. Pre- and post–S-ECG QRS amplitudes were significantly lower in the SP-OFF group than in the SP-ON group (both P < .05), despite similar 12-lead ECG QRS amplitude in both groups. A significant temporary drop in the QRS amplitude of the S-ECG led to SMART Pass deactivation (pre–QRS amplitude vs amplitude at deactivation, P = .015; 95% CI, 0.3–1.9). ConclusionThe rate of inappropriate shocks was numerically higher after SMART Pass deactivation. A low QRS amplitude in S-ECG was a potential risk factor for SMART Pass deactivation. Careful follow-up and suitable management are required for managing patients with risks of SMART Pass deactivation.

Cardiac implantable electronic devices in pregnancy: A position statement.

The aim of this document is to provide guidance for the management of women and birthing people with a permanent pacemaker (PPM) or implantable cardioverter defibrillator (ICD). Cardiac devices are becoming more common in obstetric practice and a reference document for contemporary evidence-based practice is required. Where evidence is limited, expert consensus has established recommendations. The purpose is to improve safety and reduce the risk of adverse events relating to implanted cardiac devices during pregnancy, birth and the postnatal period.

Brugada syndrome, early repolarization syndrome/j-wave syndromes, and a subtype of idiopathic ventricular fibrillation: microstructural cardiomyopathies

Brugada Syndrome is an inherited cardiac channelopathy with a high incidence of ventricular fibrillation and sudden cardiac death in patients with structurally normal hearts. Diagnosis is based on a characteristic electrocardiographic pattern (coved type ST-segment elevation ≥2 mm followed by a negative T-wave in ≥1 in the right precordial leads V1-V2) combined with an absence of gross structural abnormalities and several other criteria. The cornerstone of BrS diagnosis and definition, is its characteristic ECG pattern that can be present spontaneously or unmasked by drugs. This entity was described by the Brugada brothers in 1992 and belongs to a group of diseases known as inherited primary arrhythmia syndromes. The prevalence varies among regions and ethnicities, affecting mostly males. Despite several genes identified, SCN5A seems to be the most affected gene related BrS (≈ 30% of patients). The current main therapy is an implantable cardioverter-defibrillator, but radiofrequency catheter ablation has been recently reported as an effective new treatment.