Implantable Cardioverter-defibrillator Placement Research Articles

Abstract 4135273: Frailty increases the risk of in-hospital mortality and post-procedural complications in patients undergoing Cardiac Implantable Electronic Devices placement

Background: Heart failure with reduced ejection fraction (HFrEF) often necessitates the use of cardiac implantable electronic devices (CIED) such as cardiac resynchronization therapy defibrillators (CRT-D) or implantable cardioverter-defibrillators (ICD). These devices are proven to reduce mortality, prevent hospitalizations, and improve symptoms and quality of life. Frailty, characterized by an age-associated decline in physiological reserve, significantly impacts outcomes in these patients. This study uses the Hospital Frailty Risk Score (HFRS) to assess the effect of frailty on mortality and post-procedural complications in HFrEF patients undergoing CIED implantation. Hypothesis: Frail patients with HFrEF have worse in-hospital outcomes after CIED placement Methods: We conducted a retrospective cohort study using the 2020 National Inpatient Sample database from the Healthcare Utilization Project. Our population included patients aged 18 years or older with HFrEF who underwent CRT-D or ICD placement, identified using ICD-10 procedure codes. The primary risk factor was frailty, classified by an HFRS score of ≥5 (frail) or <5 (not frail). The primary outcome was in-hospital mortality, and the secondary outcome was the composite of post-procedural complications. Multivariate regression analysis was used to estimate the odds ratio. Results: Out of 24,809 patients who underwent ICD or CRT-D placement, 48.8% were frail. Non-Frail patients had lower mean age compared to Frail patients (66.2 vs 67.3 years old, p=0.003). In-hospital mortality was 1.1%, and 7% experienced post-procedural complications. In-hospital mortality was higher in frail patients compared to non-frail patients (2% vs 0.3%, p<0.001). In the multivariate analysis, frail patients had higher odds of in-hospital mortality compared to the non-frail group subset (OR=5.97; 95% CI: 2.77-12.88, p<0.001). Additionally, frailty was associated with higher odds of post-procedural complications (OR=1.28; 95% CI: 1.01-1.63, p<0.001), increased length of stay (5 vs 11.6 days, p<0.001), and total hospital charges (215,668 vs 324,474 , p<0.001). Conclusion: Frailty significantly increases the risk of in-hospital mortality and post-procedural complications in HFrEF patients. This highlights the importance of considering frailty as part of a pre-procedural risk stratification assessment and tailoring management strategies to improve outcomes for these high-risk patients.

No improvement in atrial arrhythmia rates in patients on baroreflex activation therapy

Abstract Background Atrial arrhythmias encompass a wide range of abnormal cardiac rhythms including atrial fibrillation, atrial flutter, and atrial tachycardia. Patients with heart failure with reduced ejection fraction (HFrEF) have increased risk of atrial arrhythmias, ultimately leading to increased morbidity. Baroreflex Activation Therapy (BAT) employs an implantable device to increase parasympathetic nervous system activity by stimulating the carotid baroreceptors thereby reducing afterload and heart failure symptoms. In our prior study, BAT therapy has been shown to reduce hospitalization rates in patients with HFrEF. However, the effects of BAT on atrial arrhythmia has never been studied. Objective In this study, we analyzed the effects of BAT on atrial arrhythmia rates in patients with HFrEF. Methods Patients with HFrEF with BAT therapy for at least 12-months at a hospital were retrospectively studied. Inclusion criteria includes implantable cardioverter-defibrillator (ICD) placement of at least 12-months pre- and post-BAT therapy. Additionally, patients diagnosed with atrial arrhythmias prior to the study timeline were excluded. Atrial arrhythmia rates 6 and 12-months pre-BAT therapy and 6 and 12-months post-BAT therapy were compared. Atrial arrhythmia episodes were recorded through ICD interrogation every 1-3 months in the clinic. Of the 31 identified patients on BAT therapy, 11 patients fit the inclusion criteria. For the 11 patients in the study, 3 identified as female and 8 identified as male, 6 identified as white, 4 identified as Hispanic, and 1 identified as African-American with a mean age of 59.8 ± 17.4 years. The average left ventricular ejection fraction pre-BAT therapy was 23.8 ± 10.8%. Results The mean average atrial arrhythmia rates for 6-month pre-BAT therapy and 6-month post-BAT therapy were 0.12/month ± 0.40 and 1.32/month ± 2.76 respectively (p=0.18), suggesting no differences in atrial arrhythmia rates at 6-months with BAT therapy. The mean average atrial arrhythmia rates for 12-month pre-BAT therapy and 12-month post-BAT therapy were 0.11/month ± 0.35 and 2.40/month ± 5.84 respectively (p=0.22), suggesting no differences in atrial arrhythmia rates at 12-months with BAT therapy. Conclusion Although BAT therapy has been shown to decrease hospitalization rates, BAT therapy is not associated with decreased atrial arrhythmia rates at 6 months and 12 months.

Implantable cardioverter defibrillators among elderly survivors of out-of-hospital cardiac arrest

Abstract Background Survivors of out-of-hospital cardiac arrest (OHCA) with a shockable rhythm are at increased risk of cardiac arrest, and clinical practice guidelines recommend placement of an implantable cardioverter defibrillator (ICD) in the absence of a reversible cause and an expected meaningful survival of at least one year. Contemporary data on the prevalence of secondary prevention ICD placement among OHCA survivors remain limited. Purpose Examine patterns of secondary prevention ICD implantation in survivors of OHCA due to a shockable rhythm in a large national registry. Methods Using 2013-2019 data from the Cardiac Arrest Registry to Enhance Survival (CARES) linked to Medicare files, we identified 3,226 patients aged >65 years who survived to discharge following OHCA due to an initial shockable rhythm from January 1, 2013 to December 31, 2019. Patients with severe neurological disability, prior history of cancer, and those discharged to hospice were excluded. We calculated cumulative prevalence of ICD implantation at discharge, 90 days, and 6 months post cardiac arrest. Multivariable hierarchical regression models with random hospital effects were used to determine the adjusted association of patient characteristics with ICD implantation and quantify the extent of variation in ICD implantation across sites, using a median odds ratio (OR) and 95% confidence interval (CI). Results Patients’ mean age was 72.2 years; 23.5% were women, 10% were Black and 4% Hispanic. Among 3,226 OHCA patients, 997 (30.9%) received an ICD before discharge; 1,266 (39.2%) received an ICD within 90 days of cardiac arrest, and 1,287 (39.9%) received an ICD by 6 months. After adjusting for differences in demographics and co-morbidities, the odds of receiving an ICD at discharge were significantly lower in patients aged 85 years and older, women, patients with prior history of stroke or diabetes, patients who presented with acute myocardial infarction (P<0.05 for all). There was no significant difference in ICD implantation by race and ethnicity (P=0.94) (Table 1). Even after adjusting for patient demographics, co-morbidities, and presentation with acute myocardial infarction, there was large variation in hospital rate of ICD implantation at discharge, with a median odds ratio of 1.65 (95% CI 1.41-1.86). Conclusion Fewer than 1 in 3 patients with OHCA due to a shockable rhythm are discharged with a secondary prevention ICD. Although implantation of ICD was associated with patient variables, there was no difference in ICD implantation by race and ethnicity. There was large variation across hospitals in ICD implantation even after adjusting for patient variables highlighting an opportunity for improving post-arrest management of cardiac arrest survivors.

Performance of the 2020 ACC/AHA and 2023 ESC risk stratification scales for primary prevention of sudden cardiac death in a Latin American population with hypertrophic cardiomyopathy

Abstract Background Identifying patients with hypertrophic cardiomyopathy (HCM) who are at high risk of sudden cardiac death (SCD) is essential for managing this condition. The American Heart Association/American College of Cardiology (AHA/ACC) and European Society of Cardiology (ESC) guidelines help assess and stratify the risk of determining which patients would benefit from primary prevention with an implantable cardioverter-defibrillator (ICD). Objective The study aims to evaluate the performance of the 2020 AHA/ACC and 2023 ESC risk stratification scales (AHA/ACC-rss; ESC-rss) for the primary prevention of SCD in Latin-American patients diagnosed with HCM. Methods A retrospective cohort of HCM from a single-center was analyzed. The inclusion criteria were individuals aged 16 years or older, without a history of SCD, and who had not undergone any treatment such as myomectomy or septal ablation with alcohol (Figure 1). The primary outcome was the identification of SCD or an equivalent event (successful resuscitation after cardiac arrest or appropriate therapy from the ICD). Results One hundred twenty patients were included (mean age 46.2 years old) and the mean follow-up duration was 61.1 months. From the total sample, 10 patients (8.3%) experienced an equivalent SCD event; 7 patients (5.8%) were ICD-protected and 3 (2.5%) required external defibrillation. The ESC-rss showed a greater area under the ROC curve (AUC, 0.79; 95% CI 0.62-0.94 vs AUC, 0.63; 95% CI 0.49-0.78) and specificity (85%; 95% CI 63-92 vs 51%; 95% CI 37.3-64.5). Sensitivity was similar between both scales (AHA/ACC-rss: 77%; 95% CI 50-100 vs ESC-rss: 73%; 95% CI 43-100). Remarkably, 2.5% of the patients who experienced an equivalent of SCD were incorrectly identified as low-risk individuals by either the AHA/ACC-rss, ESC-rss, or both (Table 1). Conclusion The SCD risk stratification recommended by the ESC-rss demonstrated a more effective identification of Latin American patients with HCM for ICD placement because the area under the curve was more significant than those of the AHA/ACC-rss. This single-center study highlights the need for a multicenter prospective study in Latin America.

Results of endoscopic electrode removal surgery in patients with cardiovascular implantable electronic devices

Introduction: The increasing popularity of permanent pacemakers and implantable cardioverter defibrillators (ICDs) has improved the quality of life and long-term prognosis of cardiovascular patients. However, there is also an increase in infections of cardiac implantable devices (CIEDs). The infection rate after the first implant is 4.82/1000 people, and after the device replacement is 12.12/1000. With the development of endoscopic techniques, a method of thoroughly treating infections of cardiac implantable devices is opened without increasing the severity of the patient’s condition. Method: Cross-sectional study, 08 patients with pacemaker infection underwent endoscopic surgery at the Cardiovascular Center, E Hospital from January 2020 to July 2024. Result: In 08 patients, the male ratio is mainly 06 patients, the oldest age was 85 years old and the youngest is 25 years old. There are 07 cases with permanent pacemaker implantation, 1 case of ICD placement Brugada syndrome. All cases have bacterial cultures: 05 patients have Staphylococcus aureus and 03 cases have cultured Staphylococcus epidermidis. All patients have pacemaker examination and underwent endoscopic surgery to remove the electrode. The average surgical time is 68,71± 18.3 minutes (97-40), in which 01 case has only electrode probe infection, the remaining cases has both the pacemaker and electrode probe infection. Most stable cases are discharged from hospital with an average time of 16,2± 7,8 days (11-30), 01 severe case due to sepsis in a patient with heart failure EF: 30%, kidney failure, diabetes, hypertension has to stay in treatment for additional 30 days. Conclusion: Endoscopic electrode removal surgery in patients with pacemaker infection initially achieved good results, with low complications and mortality, but a larger number of patients and long-term follow-up and evaluation are needed.

The Utility of Baseline Characteristics and [123I]MIBG Cardiac Adrenergic System Scintigraphy in Qualifying Patients with Post-Infarction Heart Failure for Implantable Cardioverter-Defibrillator (ICD) Placement.

Background: Post-infarction heart failure with reduced ejection fraction (HFrEF) patients often face persistent risks of sudden cardiac arrest leading to sudden cardiac death. While implanting a cardioverter-defibrillator (ICD) can enhance prognosis, complications and costs limit its widespread use. Current patient qualification criteria, relying on imperfect parameters, require refinement. The impairment of the cardiac adrenergic system in heart failure is associated with ventricular arrhythmias. The goal of the study was to assess the utility of cardiac adrenergic system scintigraphy in qualifying patients for ICD placement. Methods: In this prospective study of 85 post-infarction HFrEF patients at a single center, clinical assessments, laboratory tests, echocardiography, [123I]MIBG scintigraphy, and ICD implantation were performed. Scintigraphy involved planar chest images and evaluating the heart-to-mediastinum ratio (H/M) and washout rate (WO). SPECT imaging assessed [123I]MIBG uptake in 17 left ventricular segments to calculate the summed difference score (SDS). Results: During a median of 4-year follow-up, 22% of patients experienced appropriate ICD interventions, and 25% of patients died or underwent heart transplantation. The mean values of analyzed parameters did not significantly differ between groups. In the univariate analysis, younger age and moderately impaired left ventricular ejection fraction (LVEF) were correlated with more frequent ICD interventions. In comparison, older age and elevated NT-proBNP levels were associated with death or heart transplantation. Additionally, the univariate analysis identified SDS-15' as a prognostic factor for death/heart transplant. The multivariate analysis identified predictors for ICD interventions, including younger age, an EF of 30% or greater, and a larger left ventricular end-diastolic diameter. In contrast, older age and an LVEF of less than 25% were significant predictors of death or heart transplantation. Conclusions: Scintigraphic parameters did not effectively predict ICD interventions or death/heart transplantation, though the summed difference score demonstrated potential as a prognostic factor. Younger age with moderately impaired EF correlated with frequent ICD interventions, while in older age, EF < 25% predicted death or transplantation. Further investigation is needed for patients with borderline EF values.

8288 Navigating Diagnostic Challenges of Amiodarone Induced Thyrotoxicosis in a Psychiatrically Complex Patient within a Community Hospital Setting

Abstract Disclosure: M.S. Shah: None. K.P. Sanu: None. S. Humayon: None. R. Chawla: None. N.K. Bains: None. This case delves into the intricate diagnostic and therapeutic journey of a 64-year-old male who presented to a community hospital with psychosis. Medical history was pertinent for ventricular arrhythmias treated with amiodarone 400 mg once daily, bipolar disorder with medication non-compliance and heart failure with reduced ejection fraction status post automatic implantable cardioverter-defibrillator placement. Collaboration with the patient's family revealed a history of repeated hospitalizations for similar presentations as well as recent weight loss. The challenge lay in distinguishing between manic episodes and other potential underlying medical causes. The patient's recent weight loss and amiodarone use prompted a thyroid panel, revealing a TSH of 0.01 mlU/L (n = 0.27 to 4.20 mIU/L), free T4 of &amp;gt;7.77ng/dL (n = 0.93 to 1.70 ng/dL), and free T3 of &amp;gt;7.51ng/dL (n = 2.00 to 4.40 pg/mL). Inadequate facilities for a radioactive iodine uptake (RAIU) scan and thyroid doppler ultrasound heightened the diagnostic challenge, making the history and physical exam pivotal in steering the course of this patient's care. The Burch-Wartofsky score was found to be elevated at 30 due to delirium and abdominal pain reported in the emergency department. Amiodarone use for over two years with no prior history of thyroid dysfunction, along with the absence of a goiter or thyroid antibodies suggestive of Graves disease heightened the suspicion for amiodarone-induced thyrotoxicosis type 2 (AIT type 2). Due to the lack of RAIU scan and thyroid ultrasound to better differentiate between AIT type 1 and type 2, the patient was treated with methimazole and prednisone along with an antipsychotic medication regimen. The discontinuation of antipsychotic medications became necessary due to QTc prolongation and subsequent defibrillator discharge. The patient's further improvement without psychiatric medications highlighted the success of the tailored treatment strategy, emphasizing the importance of accurate diagnosis in patients with psychiatric comorbidities. The patient’s relatively rapid clinical response also aids in differentiating AIT type 1 from type 2. This case brings awareness to the importance of a comprehensive history and physical exam, particularly in the setting of a community hospital with limited diagnostic resources. Despite the inability to obtain history directly from the patient and having diagnostic constraints, the judicious use of available resources and clinical acumen led to the diagnosis of Amiodarone-induced thyrotoxicosis type 2. Clinicians should keep a broad differential to avoid confirmation bias in treating psychiatric patients with a complex medical history. This case serves as a testament to the importance of a holistic approach to patient care and the need for ongoing advancements in diagnostic capabilities within community healthcare settings. Presentation: 6/2/2024

Performance and Safety of the Extravascular Implantable Cardioverter-Defibrillator Through Long-Term Follow-Up: Final Results From the Pivotal Study.

Substernal lead placement of the extravascular implantable cardioverter-defibrillator (EV ICD) permits both defibrillation at thresholds similar to those seen with transvenous ICDs and effective antitachycardia pacing (ATP), while avoiding the vasculature and associated complications. The global Pivotal study has shown the EV ICD system to be safe and effective through 6 months, but long-term experience has yet to be published. We aim to report the performance and safety of the EV ICD system throughout the study. The EV ICD Pivotal study was a prospective, global, single-arm, pre-market clinical study. Individuals with a class I or IIa indication for a single-chamber ICD per guidelines were enrolled. Freedom from major system- or procedure-related complications, as well as appropriate and inappropriate therapy rates, were assessed through 3 years using the Kaplan-Meier method. Anti-tachycardia pacing success was calculated using simple proportions. An implant was attempted in 316 patients [25.3% female, 53.8±13.1 years old, 81.6% primary prevention, LVEF 38.9%±15.4%]. Of 299 patients with a successful implant, 24 experienced 82 spontaneous arrhythmic episodes that were appropriately treated with either ATP only (38, 46.3%), shock only (34, 41.5%), or both (10, 12.2%) for a Kaplan-Meier-estimated rate of first any appropriate therapy of 9.2% at 3 years. Antitachycardia pacing was successful in 77.1% (37/48) of episodes, and ATP usage significantly increased from discharge to last follow-up visit (P<0.0001). Shock therapy was successful in 100% (27/27) of discrete, spontaneous ventricular arrhythmias. The inappropriate shock rates at 1 and 3 years were 9.8% and 17.5%, respectively, with P-wave oversensing the predominant cause. No major intraprocedural complications were reported and the estimated freedom from system- or procedure-related major complications was 91.9% at 1 year and 89.0% at 3 years. The most common major complications were lead dislodgement (10 events; n=9 patients, 2.8%), postoperative wound or device pocket infection (n=8, 2.5%), and device inappropriate shock delivery (n=4, 1.3%). Twenty-four system revisions were performed as a result of major complications related to the EV ICD system or procedure. From implant to study completion, the EV ICD Pivotal study demonstrated that a single integrated system with an extravascular lead placed in the substernal space maintains high ATP success, effective defibrillation, and a consistent safety profile.

Implantable Cardioverter-Defibrillators Among Older Survivors of Out-of-Hospital Cardiac Arrest.

Although current guidelines recommend implantable cardioverter-defibrillator (ICD) placement in survivors of out-of-hospital cardiac arrest, contemporary data on secondary-prevention ICDs in survivors of out-of-hospital cardiac arrest remain limited. Using 2013 to 2019 CARES (Cardiac Arrest Registry to Enhance Survival) linked to Medicare, we identified 3226 patients aged ≥65 years with an initial shockable rhythm who survived to discharge without severe neurological disability. Multivariable hierarchical regression models were used to examine the association between patient variables and ICD placement and quantify hospital variation in ICD implantation. The mean age was 72.2 years, 23.5% were women, 10% were Black individuals, and 4% were Hispanic individuals. Overall, 997 (30.9%) patients received an ICD before discharge, 1266 (39.2%) at 90 days, and 1287 (39.9%) within 6 months. Older age (≥85 years), female sex, history of diabetes, calendar year, and presentation with acute myocardial infarction were associated with lower odds of ICD implantation, but race or ethnicity was not associated with ICD implantation. Among 297 hospitals, the median proportion of survivors receiving ICD at discharge was 28.6% (interquartile range, 20%-50%). The relative odds of ICD implantation varied by 62% across hospitals (median odds ratio, 1.62 [95% CI, 1.38-1.82]) after adjusting for case mix. Fewer than 1 in 3 survivors of out-of-hospital cardiac arrest due to a shockable rhythm received a secondary-prevention ICD before discharge. Although patient variables were associated with ICD implantation, there was no difference by race or ethnicity. Even after adjusting for patient case mix, ICD implantation varied markedly across hospitals.

Metabolome analysis in patients with heart failure and implantable cardioverter defibrillators.

Heart failure (HF) is a complex, heterogeneous syndrome with several comorbidities, often life-threatening and requires urgent therapy. In HF, metabolic alterations that can be assessed using comprehensive plasma, and tissue profiling will help establish new biomarkers and therapeutic targets. Metabolomic analysis of sudden death in HF cases remains unresolved. We prospectively evaluated 19 patients who underwent implantable cardioverter defibrillator (ICD) placement for the primary prevention of sudden cardiac death (SCD). Metabolomic analysis was performed using plasma samples before ICD implantation. Ventricular arrhythmia (VA)/SCD was defined as VA with an appropriate ICD therapy or SCD. During a median follow-up of 29months (range, 13-35months), four patients developed VA and one patient developed SCD. Using metabolomic analysis, arginine, lysine, and valine were significantly reduced in patients with VA/SCD (n = 5) compared with those without VA/SCD (n = 14). The molecules involved in energy metabolism might be associated with VA/SCD, thus requiring further investigation as a predictive value of metabolomic analysis of VA/SCD.

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.

A novel tool for arrhythmic risk stratification in desmoplakin gene variant carriers.

Pathogenic desmoplakin (DSP) gene variants are associated with the development of a distinct form of arrhythmogenic cardiomyopathy known as DSP cardiomyopathy. Patients harbouring these variants are at high risk for sustained ventricular arrhythmia (VA), but existing tools for individualized arrhythmic risk assessment have proven unreliable in this population. Patients from the multi-national DSP-ERADOS (Desmoplakin SPecific Effort for a RAre Disease Outcome Study) Network patient registry who had pathogenic or likely pathogenic DSP variants and no sustained VA prior to enrolment were followed longitudinally for the development of first sustained VA event. Clinically guided, step-wise Cox regression analysis was used to develop a novel clinical tool predicting the development of incident VA. Model performance was assessed by c-statistic in both the model development cohort (n = 385) and in an external validation cohort (n = 86). In total, 471 DSP patients [mean age 37.8 years, 65.6% women, 38.6% probands, 26% with left ventricular ejection fraction (LVEF) < 50%] were followed for a median of 4.0 (interquartile range: 1.6-7.3) years; 71 experienced first sustained VA events {2.6% [95% confidence interval (CI): 2.0, 3.5] events/year}. Within the development cohort, five readily available clinical parameters were identified as independent predictors of VA and included in a novel DSP risk score: female sex [hazard ratio (HR) 1.9 (95% CI: 1.1-3.4)], history of non-sustained ventricular tachycardia [HR 1.7 (95% CI: 1.1-2.8)], natural logarithm of 24-h premature ventricular contraction burden [HR 1.3 (95% CI: 1.1-1.4)], LVEF < 50% [HR 1.5 (95% CI: .95-2.5)], and presence of moderate to severe right ventricular systolic dysfunction [HR 6.0 (95% CI: 2.9-12.5)]. The model demonstrated good risk discrimination within both the development [c-statistic .782 (95% CI: .77-.80)] and external validation [c-statistic .791 (95% CI: .75-.83)] cohorts. The negative predictive value for DSP patients in the external validation cohort deemed to be at low risk for VA (<5% at 5 years; n = 26) was 100%. The DSP risk score is a novel model that leverages readily available clinical parameters to provide individualized VA risk assessment for DSP patients. This tool may help guide decision-making for primary prevention implantable cardioverter-defibrillator placement in this high-risk population and supports a gene-first risk stratification approach.

Ventriculo-arterial (VA) coupling and fQRS as new selection criteria for primary prevention ICD placement

For decades, left ventricular ejection fraction (LVEF < 35%) has been a mainstay for identifying heart failure (HF) patients most likely to benefit from an implantable cardioverter defibrillator (ICD). However, LVEF is a poor predictor of sudden cardiac death (SCD) and ignores 50% of HF patients with mildly reduced and preserved LVEF. The current international guidelines for primary prophylaxis ICD therapy are inadequate. Instead of LVEF, which is not a good measure of LV contractility or hemodynamic characterization, we hypothesize ventriculo-arterial (VA) coupling combined with fragmented QRS (fQRS) will improve risk stratification and patient suitability for an ICD. Quantifying cardiac and aortic mechanics, and predicting active arrhythmogenic substrate, from varying fQRS morphologies, may help to stratify ischemic and non-ischemic patients with different functional capacities and predisposition for lethal arrhythmias. We propose HF patients with a low physiological reserve may not benefit from ICD therapy, whereas those patients with higher reserves and extensive arrhythmogenic substrate may benefit. Our hypothesis combining VA coupling with fQRS changes has the potential to widen HF patient participation (low and high LVEF) and advance personalized medicine for HF patients at high risk of SCD.

Disparities in the implantation of secondary prevention implantable cardioverter defibrillator in the United States.

The annual incidence of sudden cardiac death is over 300,000 in the United States (US). Historically, inpatient implantation of secondary prevention implantable cardioverter defibrillator (ICD) has been variable and subject to healthcare disparities. To evaluate contemporary practice trends of inpatient secondary prevention ICD implants within the US on the basis of race, sex, and socioeconomic status (SES). The study is a retrospective analysis of the National Inpatient Sample from 2016 to 2020 of adult discharges with a primary diagnosis of ventricular tachycardia (VT), ventricular flutter, and fibrillation (VF). Adjusted ICD implantation rates based on race, sex, and SES and associated temporal trends were calculated using multivariate regression. A total of 193,600 primary VT/VF discharges in the NIS were included in the cohort, of which 57,895 (29.9%) had ICD placement. There was a significant racial and ethnic disparity in ICD placement for Black, Hispanic, Asian, and Native American patients as compared to White patients; adjusted odds ratio (aOR): 0.86 [p<.01], 0.90 [p = .03], 0.81[p<.01], 0.45 [p<.01], respectively. Female patients were also less likely to receive an ICD compared to male patients (aOR: 0.75, p<.01). Disparities in ICD placement remained stable over the study period (ptrend ≥.05 in all races, both sexes and income categories). Racial, sex, and SES disparities persisted for secondary prevention ICD implants in the US. An investigation into contributing factors and subsequent approaches are needed to address the modifiable causes of disparities in ICD implantation as these trends have not improved compared to historic data.

Arrhythmogenic Right Ventricular Dysplasia: A Comprehensive Review of Pathophysiology, Diagnosis, and Management Strategies

Arrhythmogenic Right Ventricular Dysplasia (ARVD) is a rare inherited heart disorder characterized by fibrofatty replacement of the right ventricular myocardium, leading to ventricular arrhythmias and an increased risk of sudden cardiac death. This review aims to provide a comprehensive overview of ARVD, including its pathophysiology, clinical manifestations, diagnostic criteria, and management strategies. The pathogenesis of ARVD involves genetic mutations affecting proteins of the cardiac desmosome, leading to myocardial cell death and fibrofatty replacement. Clinical presentation varies widely, ranging from asymptomatic individuals to those with palpitations, syncope, or sudden cardiac arrest. Diagnosis is challenging and relies on a combination of clinical, electrocardiographic, imaging, and histopathologic findings. Management involves risk stratification for sudden cardiac death, lifestyle modifications, antiarrhythmic medications, and, in select cases, implantable cardioverter-defibrillator placement or catheter ablation.

Clinical performance and safety of a two-lead cardiac resynchronization therapy system with a floating atrial sensing dipole

Abstract Background The incidence of complications after implantable cardioverter-defibrillator (ICD) and cardiac resynchronisation therapy (CRT-D) implantations is dependent on the number of implanted leads. The majority of CRT-D patients have unimpaired sinus node function and do not require atrial pacing. A two-lead CRT-D system with a floating atrial sensing dipole mounted on the right ventricular lead ((CRT-DX) allows dual chamber tachyarrhythmia detection, and atrio-ventricular sequential pacing with a reduced amount of implanted material. Purpose This study investigated the clinical efficacy and safety of the CRT-DX system. Methods This multicentre, single-arm study observed patients after de novo implantation of a CRT-DX system for 12 months. Patients were eligible for the study when chronotropic competence was proven by heart rates ≥100 bpm during exercise, premature ventricular contractions rate of &amp;lt; 5%/h and absence of atrioventricular block ≥ II. Intraoperatively measured p-wave amplitude of ≥ 1 mV was recommended. The primary safety endpoint was the additional implantation of a right atrial (RA) lead after the initial implantation. As indicators of efficacy, we report the changes in left ventricular ejection fraction (LVEF) and New York Heart Association (NYHA) class over the follow-up period. Results Overall, 110 patients were implanted with the complete CRT-DX system. Mean age of study participants was 62 ± 12 years and 77 (70%) were male. The underlying heart disease was non-ischemic in 66 (60%) patients and 103 (93%) had a left bundle branch block. NYHA class was II in 60 (54.5%) and III in 50 (45.5%) patients. ICD placement was performed in 13 (11.8%) patients for the secondary prevention of sudden cardiac death. A total of 104 patients completed the follow-up, 2 patients died, 1 had the system explanted for infection, 2 withdrew consent and 1 was lost to follow-up. The primary endpoint of RA lead implantation was met in 2 (1.8%) participants (Figure 1). One patient required atrial pacing and one patient, who had shown a p-wave amplitude &amp;lt; 1 mV at implantation, lost atrial sensing. The mean RA sensing amplitude remained stable during follow-up (4.6 ± 1.8 mV, 4.9 ± 1.8 mV and 4.6 ± 1.8 mV at 1, 6 and 12 months, respectively; Figure 2). The LVEF improved by 14.7% ± 11.0%, from 26.3% ± 6.9% to 40.8% ± 10.7% (p &amp;lt; 0.00001). Changes in NYHA class were available in 87 patients with 35 (40.2%) improved by one class and 13 (14.9 %) by two classes. Thirty-four (39.1%) had no change and 5 (5.7%) worsened by one class (global p &amp;lt; 0.00001). Conclusion The two-lead CRT-DX system showed a low requirement of subsequent RA lead implantations (1.8%) and stable RA sensing amplitudes. Our results suggest a CRT response similar to that of conventional three-lead CRT-D systems. CRT-DX systems appear to be a feasible alternative for patients with chronotropic competence.Kaplan-Meier curve for primary endpointDaily mean RA sensing amplitude

Isolated left ventricular non-compaction: clinical characterisation of a teenage male

Isolated Left Ventricular Non-compaction (LVNC) is a type of cardiomyopathy that usually has a genetic origin. Its diagnosis is based on findings such as deep intertrabecular recesses or sinusoids and ventricular trabeculations communicating with the left ventricular cavity. LVNC was first clinically recognised almost four decades back, yet its diagnostic and management challenges persist. In this report, we present the case of an 18-year-old boy, who presented at the National Institute of Cardiovascular Diseases, Karachi, in March 2023, with complaints of dizziness, pedal oedema, and shortness of breath. Echocardiography revealed signs suggestive of LVNC, which were confirmed conclusively on Cardiovascular Magnetic Resonance (CMR) (NC/C ratio&gt;2.4). The patient underwent implantable cardioverter defibrillator (ICD) placement, was discharged after a smooth post-procedure recovery, and is doing well on follow-ups. ---Continue

Long-term prognostic role of pre-ICD implantation magnetic resonance: a longitudinal cohort study

Abstract Background While it's has already been demonstrated that cardiovascular mortality increases in patients with reduced ejection fraction (EF), there is no evidence that this parameter identifies with high sensitivity those who will experience sudden cardiac death (SCD). Cardiac magnetic resonance (CMR), through myocardial scar characterization, could enhance risk stratification for arrhythmic events in such patients. Purpose The study's objective was to identify factors, independent of EF, capable of stratifying arrhythmic risk in a population of patients undergoing implantable cardioverter-defibrillator (ICD) placement. Methods This is an observational, retrospective, longitudinal, cohort study. Demographic, clinical, and radiological data were collected for all patients undergoing ICD implantation between 2014 and 2021. Deaths from all causes and significant arrhythmic events (non-sustained ventricular tachycardia, sustained ventricular tachycardia, ventricular fibrillation) were recorded during routine device controls and remote monitoring. To define the prognostic value of various factors was performed an univariate Kaplan-Meier analysis in relation to the composite primary endpoint, consisting of ventricular arrhythmias [VA] and all-cause mortality. Results Among 700 patients (82% males, mean age 69 ± 13 years) who underwent ICD implantation (46% single-chamber, 15% dual-chamber, 36% cardiac resynchronization therapy, 3% subcutaneous ICD) pre-implantation CMR was available in 354 of the total, with 69% of them implanted for primary prevention and 52% with non-ischemic cardiomyopathy. Late gadolinium enhancement (LGE) was present in 67% of them; and 30% of these patients had it in fewer than 5 segments. At the end of the mean 8-year follow-up, 30.6% of patients died. Patients with LGE showed increased all-cause mortality and incidence of VA compared to those without LGE (HR=2.17 [1.78-2.60]; p&amp;lt;0.05); this data was mainly driven by the difference in mortality, as the incidence of VA alone did not exhibit significant variation between the two groups (HR=0.7 [0.65-1.02]; p=0.23). In patients with fewer than 5 cardiac segments involved by LGE, the risk of all-cause death and significant VA was higher than in those with more than 5 segments involved (HR=2.46 [2.09-9.07]; p&amp;lt;0.05). Conclusions The presence of LGE emerged as a significant prognostic factor for both arrhythmic events and overall mortality. This suggests the possibility that assessing myocardial fibrosis serves as a comprehensive predictor of the patient's future clinical outcome, extending beyond merely predicting arrhythmic events. Notably, the relevance of LGE is heightened when observed in fewer than 5 segments, indicating a focal substrate, making it a crucial prognostic factor for anticipating arrhythmic events. In patients with reduced EF, pre-implantation CMR proves valuable in effectively stratifying arrhythmic risk and all-cause mortality.

Long-term follow-up of patients with Brugada syndrome: Foremost risk factors associated with overall arrhythmic events.

Brugada syndrome (BS) is characterized by ST segment elevation in right precordial leads (V1-V3), ventricular tachycardia (VT), ventricular fibrillation (VF), and sudden cardiac death (SCD) in individuals without structural heart disease. The aim of this study is to contribute to the controversial issue of finding the most valuable marker that can predict poor prognosis during follow-up in patients with a diagnosis of BS. A total of 68 patients diagnosed with BS or had Brugada-type ECG change between January 1997 and July 2012 at the Department of Cardiology of Başkent University Faculty of Medicine, Ankara, Turkey, were included in this cohort study. Patients were screened every 6 months for arrhythmia-related syncope, SCD, appropriate and inappropriate defibrillation (shock), AF development and death; collectively defined as "arrhythmic events" and were the primary endpoints. Patients with and without arrhythmic events were compared. The mean age was 34.9 ± 12.2 years (9-71 years), and 52 (76.5%) patients were male. Mean follow-up was 49.6 ± 37.6 months (4-188 months). Univariate analysis showed that male sex (P = .004), type 1 electrocardiographic pattern (P = .008), SCD (P = .036), VT/VF history (P = .046), requirement for electrophysiological studies (P = .034), implantable cardioverter-defibrillator placement (P = .014) were found to demonstrate significant differences in patients with and without arrhythmic events. In multivariable analyzes, spontaneous type 1 ECG presence (HR = 8.54, 95% CI: 0.38-26.37; P = .003) and VT/VF history (HR = 9.21, 95% CI: 0.004-1.88; P = .002) were found to be independently associated with arrhythmic events. We found the presence of spontaneous type 1 ECG and a history of VT/VF to be associated with increased likelihood of overall arrhythmic events in BS. Given the higher risk of poor prognosis, we recommend additional measures in patients with BS who have these features.

Is it time to consider a “time-out” before primary prevention implantable cardioverter-defibrillator placement in currently or recently hospitalized older patients with heart failure?

BackgroundTrajectories of mortality after primary prevention implantable cardioverter-defibrillator (ICD) placement for older patients with heart failure during or soon after acute hospitalization have not been assessed. ObjectiveThe purpose of this study was to compare trajectories of mortality after primary prevention ICD placement during or soon after acute cardiac or non-cardiac hospitalization. MethodsWe identified older patients with heart failure undergoing primary prevention ICD placement using 20% Medicare data (2008–2018). Placement settings were as follows: (1) Current-H—during current hospitalization, (2) Recent-H—within 90 days of hospitalization, or (3) Chronic stable. Hospitalization was categorized as cardiac vs non-cardiac. Interval mortality rates and hazard ratios (HRs) using Cox regression were estimated at 0–30, 31–90, and 91–365 days after ICD placement. ResultsOf the 61,710 patients (mean age 76 years; 35% female; 85% white), 19% (11,947), 25% (15,147), and 56% (34,616) had ICDs in Current-H, Recent-H, and Chronic stable settings. Mortality rates (per 100 person-years) were highest during 0–30 days, with 38 (34–42) and 22 (19–24) for Current-H and Recent-H, which declined to 21 (20–22) and 16 (15–17) during 91–365 days, respectively. Compared to Chronic stable, HRs were highest during 0–30 days post–ICD placement (5.5 [4.5–6.8] for Current-H and 3.4 [2.8–4.2] for Recent-H) and decreased during 91–365 days (2.0 [1.8–2.1] for Current-H and 1.6 [1.5–1.7] for Recent-H). HR pattens were similar for cardiac and non-cardiac hospitalizations. ConclusionPrimary prevention ICD placement during or soon after hospitalization for any reason was associated with worse mortality with diminishing risks after 90 days. Hospitalization likely identifies a sicker population in whom early mortality with or without ICD may be higher. Our results support careful consideration regarding ICD placement during the 90 days after hospitalization.