Implantable Cardioverter-defibrillator Therapy Research Articles

The Impact of Coronary Ischemia Assessment on Outcomes in Those With Scar-Dependent Ventricular Tachycardia.

Guidance and outcomes of coronary ischemia assessment (IA) in those with structural heart disease (SHD), presenting with monomorphic ventricular tachycardia (MMVT) is unclear. To assess the impact of IA on arrhythmic and non-arrhythmic outcomes in those with SHD. Patients presenting with MMVT over a 6-year period to a tertiary center were retrospectively analyzed. Propensity score-matched analysis was performed comparing those undergoing IA to those who did not. The primary endpoint was a composite of VT recurrence, appropriate ICD therapy, heart failure hospitalization, and death. Secondary analysis of the individual components of the composite was performed. Kaplan-Meier, univariate and multivariate analysis was performed to compare the two groups and derive predictors of poor outcomes. Two hundred and seventeen patients (57.6% ICM) were analyzed. 55.8% underwent IA. Following propensity score-matching, 120 patients remained. At 12 months, freedom from the primary endpoint was 68.3% of those undergoing IA versus 43.3% who did not, p < 0.001, multivariate HR 0.56 (0.34-0.92). This was driven by a reduction in all-cause mortality, with a 12-month survival of 98.3% in those undergoing IA versus 86.5% in those not undergoing IA (p < 0.01). Coronary intervention was associated with a significantly higher event-free 12-month survival compared to those who did not undergo intervention (82.4% vs 51.5%, respectively, p = 0.01). Patients with SHD presenting MMVT who undergo an IA have significantly improved freedom from VT recurrence, appropriate ICD therapies, HF hospitalization, and death compared to those who do not, driven by a reduction in mortality.

Abstract 4121624: Ambulatory Inotropic Support in Patients with Stage D Heart Failure Does Not Increase ICD Therapies

Background: Ambulatory inotropic infusions can be used as a palliative therapy (PT) or bridge to advanced therapies in end-stage heart failure (ESHF) patients, many of whom have implantable cardioverter defibrillators (ICDs). Research Questions: How often do patients receive ICD therapies after initiation of outpatient inotropic support and how often is defibrillation inactivated? Methods: We conducted a retrospective review of all patients discharged from an academic tertiary medical center with a new prescription for inotropic therapy between November 2017 and March 2023. Clinical data, Palliative Care consultation, and ICD interrogations before and after inotrope initiation were extracted from the electronic health record. Results: The cohort comprised 45 patients discharged on new inotropic support, including 22 (49%) with intent of PT and 23 (51%) as a bridge to advanced therapies (Figure). Among PT patients, 15 (68%) had an ICD in place with only 4 having ICD therapies deactivated at discharge. Only 2 additional PT patients had a documented discussion regarding ongoing ICD therapies. By 1 year, 4 (18%) PT patients were transitioned to hospice and 13 (59%) had died, with only 1 additional patient having ICD deactivation. Of 28 patients discharged on inotropic infusions with ICD therapies on (both PT and bridge patients), only 4 patients had ICD therapies turned off later and no ICD shocks were reported for the year following initiation of inotropic support. Conclusion: In a series of 45 patients initiated on inotropic support for PT or bridge to advanced therapies, the majority (77%) had an active ICD, but therapies were rarely delivered. Notably, there were very few documented discussions regarding ICD therapies in PT patients even with specialty Palliative Care consultation. In patients with ESHF initiated on inotropic support as PT, most patients chose to leave ICD therapies in place. For those patients, there was a low rate of ICD therapies delivered.

Abstract 4122247: Impact of serum chloride levels for ventricular arrhythmias in patients with heart failure undergoing cardiac resynchronization therapy

Background: As previous reports of ventricular arrhythmia (VA) as a prognostic marker of mortality in heart failure (HF) patients included those with implantable cardioverter defibrillator (ICD) and cardiac resynchronization therapy (CRT) devices, little is known about the risk factors of VA among patients undergoing cardiac resynchronization therapy (CRT), especially those without previous VA. The prognostic role of electrolyte abnormalities has been highlighted in HF patients. This study evaluated the impact of serum chloride levels for VA and all-cause death in patients with HF who underwent CRT without VA before CRT implantation. Methods: From the retrospective cohort of 397 HF patients (age 63+/-13, male 74%) who undergoing CRT implantation between 2010 and 2020, this study enrolled 175 patients (82% implanted CRT with a defibrillator) without a previous history of VA (sustained ventricular tachycardia (VT) of ventricular fibrillation (VF)). We studied the impact of serum chloride levels before CRT implantation. The primary endpoint was defined as VA, VA with ICD therapy and sudden cardiac death. The secondary endpoint was all-cause mortality. Results: During median follow-up of 35 months, 53 patients (30%) experienced VA. Patients with VA had a tendency toward high LVESV (172ml vs. 150ml, p&lt;0.09) and low left ventricular ejection fraction (26 vs. 29, p&lt;0.09), and significantly reduced rate of angiotensin converting enzyme inhibitors or angiotensin receptor blockers (30% vs. 70%, p&lt;0.05) at the time of CRT implantation. The rate of CRT responders was significantly higher in patients without VA than with VA (59% vs. 40%, p&lt;0.05). The cut-off value of chloride for VA was determined to be 102mEq/l using receiver operating characteristic analysis. The patients with chloride ≤102mEq/l had significantly higher rates of VA (41% vs. 25%, log-rank p&lt;0.05) and mortality (33% vs. 18%, log-rank p&lt;0.05) (Figure). By multivariate cox analysis, the level of chloride had an independent predictive value of VA in patients with CRT (hazard ratio [HR] 1.08 per 1mEq/l decrease, 95% confidence interval [CI] 1.00-1.16, p&lt;0.05) (Table). Conclusions: The chloride level had a predictive value for VA after CRT implantation in HF patients without previous VA. The management of electrolytes, including chloride, might be important for preventing fatal arrhythmia in patients with HF undergoing CRT implantation.

Abstract 4147606: The Risk of Cardiac Events Associated with Psychiatric Drugs in Patients with Long QT Syndrome.

Introduction: Long QT syndrome (LQTS) is a potentially life-threatening genetic heart disease. Patients with LQTS may also have co-existent mental health illnesses that may benefit from psychiatric medications. However, because many of these medications have QT-prolonging potential (www.crediblemeds.org), many of these patients receive suboptimal mental health care. Objective: To evaluate the frequency, management, and incidence of breakthrough cardiac events (BCEs) in patients with LQTS and concomitant mental health issues treated with psychiatric medications. Methods: A retrospective review was conducted on patients cared for in Mayo Clinic's Windland Smith Rice Genetic Heart Rhythm Clinic between 2000 and 2024 focusing on patients with LQTS and a concomitant psychiatric diagnosis requiring medication with known, possible or conditional risk of torsades de pointes (TdP). Electronic medical records were reviewed for data. BCEs were defined as LQTS-triggered syncope, seizures, appropriate ICD therapy, sudden cardiac arrest (SCA), or sudden cardiac death (SCD). Patients with missing information were excluded. Results: Overall, 195 /1899 LQTS patients [10%, 86 (43%) with LQT1, 83 (42%) with LQT2, and 16 (8%) with LQT3] had a concomitant psychiatric diagnosis requiring medication [150 female (76%), mean age at diagnosis 27 ± 18 years, median follow-up time 6.6 years (IQR 2.9-13)]. The most common psychiatric conditions were depression (71%), anxiety (62%), and ADHD (9%). The mean duration of therapy was 3.36 +/- 3.48 years and the most common medications used were fluoxetine (26%), sertraline (14%), and escitalopram (11%). There was no significant difference in QTc after starting the first psychiatric medication when compared to baseline (473 ± 33 vs 474 ± 35 ms, p=0.6). Prior to their LQTS diagnosis and while therefore untreated, 61/195 (31%) had at least 1 LQTS-associated cardiac event. This occurred in the setting of a psychiatric drug in 7 patients (11%). Following LQTS diagnosis and treatment, 14/195 patients (7%) have experienced a non-lethal BCE of which only 3/14 (21%) while on psychiatric medications. Conclusions: Although avoidance of medications with known QT-prolonging potential is prudent, attention to patient’s overall well-being besides just their LQTS must be given. After correct diagnosis and treatment, LQTS patients with concomitant mental health issues may be safely and effectively treated with medications known to prolong QTc.

Risk stratification for ventricular tachyarrhythmia in patients with nonischemic cardiomyopathy.

The implantable cardioverter defibrillator reduces mortality among patients with heart failure (HF) due to ischemic heart disease. Clinical trial data have called into question the benefit of an ICD in patients with HF due to nonischemic cardiomyopathy (NICM). We developed a risk stratification score for ventricular tachyarrhythmia (VTA) among patients with NICM receiving a primary prevention ICD. The study population comprised 1515 patients with NICM who were enrolled in the landmark MADIT trials. Fine and Gray analysis was used to develop a model to predict the occurrence of VTAs and ICD therapies while accounting for the competing risk of non-arrhythmic mortality. External validation was carried out in the RAID Trial population. Four risk factors associated with increased risk for VTA were identified: male sex, left ventricular ejection fraction ≤25%, no indication for cardiac resynchronization therapy with a defibrillator (CRT-D), and Black race. A score was generated based on this model, and patients were stratified into low (N = 390), intermediate (N = 728), and high-risk (N = 387) groups. The 5-year cumulative incidences of VTA were 15%, 24%, and 42%, respectively. Application of score groups for the secondary endpoints of Fast VT or VF and Appropriate ICD Shock revealed similar findings. Recurrent event analysis yielded consistent results. The AUC in the validation cohort for the endpoint of Appropriate ICD Shock was 69.3. Our study shows that patients with NICM can be risk stratified using demographic and clinical variables and may be used when evaluating such patients for a primary prevention ICD.

Abstract 4137113: The Effectiveness of Cardiac Resynchronization Therapy in Patients with Cardiac Sarcoidosis: A Retrospective Analysis

Background: Cardiac sarcoidosis (CS) manifests in a wide range of clinical presentations, including conduction system abnormalities, ventricular arrhythmias, and systolic heart failure. Although cardiac resynchronization therapy (CRT) has shown efficacy in treating select nonischemic cardiomyopathy patients, its specific impact on CS patients remains less explored. This study aimed to evaluate the outcomes of CRT therapy in CS patients, focusing on implantable cardioverter defibrillator (ICD) therapies, heart failure (HF) hospitalizations and mortality. Methods: We retrospectively reviewed all patients with a clinical or histological diagnosis of CS who underwent device implantation (ICD or Permanent Pacemaker (PPM)) with or without CRT therapy at Johns Hopkins Hospital between 2004 and 2024. Baseline characteristics and echocardiographic parameters were assessed. Heart failure hospitalizations, the frequency of ATP (Anti-Tachycardia Pacing) or ICD shocks, and all-cause mortality were also evaluated as the outcomes. Results: The study included 212 patients (40.1% female, average age 52.8 ± 11.1 years). Eighty-five patients underwent CRT implantation (82 CRT-D and 3 CRT-P), whereas the rest received either an ICD or a PPM without CRT therapy. Most CRT devices (58.82%) were upgrades from an initial PPM or ICD. Over a follow-up of 6.15 ± 4.43 years, 27 (12.74%) patients were hospitalized for heart failure (HF), 86 (40.56%) experienced ATP or ICD shocks, and 17 (8.02%) died. The composite outcome was observed in 103 patients (48.5%), with no significant differences between CRT and non-CRT groups ( P = .51). Survival analysis indicated significantly reduced freedom from HF hospitalizations in the CRT group compared to non-CRT group ( P = .01). However, ATP/ICD shocks did not have a significant difference. CRT recipients showed an improvement in left ventricular ejection fraction (LVEF) from 35.3 ± 12.6% to 38.9 ± 13.6% at 6 months ( P = .01). Non-recipients showed no significant change in LVEF ( P = .43). Conclusions: Over an average six-year follow-up period, CRT upgrade does not appear to affect ATP/ICD shock and mortality in CS patients, although it is associated with significantly higher rates of heart failure (HF) hospitalizations compared to CS patients with an ICD or PPM alone. These findings underscore the complex response of CS patients to CRT, highlighting the need for further research to optimize treatment strategies within this subgroup.

Preventive catheter ablation for ventricular arrhythmias in patients with end-stage heart failure referred for heart transplantation evaluation: Rationale for and design of the CASTLE-VT trial.

Timely referrals for transplantation and left ventricular assist device (LVAD) play a key role in favourable outcomes in patients with advanced heart failure (HF). Cardiovascular mortality, driven by sudden cardiac death, is the main reason for dying while waiting for heart transplantation (HTx). The purpose of the Preventive Catheter Ablation for ventricular arrhythmiaS in patients with end-sTage heart faiLure rEferred for heart transplantation eValuaTion (CASTLE-VT) trial is to test the hypothesis that prophylactic catheter ablation of arrhythmogenic ventricular scar tissue will reduce mortality, need for LVAD implantation, and urgent HTx in patients with end-stage HF related to ischaemic cardiomyopathy (ICM). CASTLE-VT is a randomized evaluation of prophylactic ablative treatment of arrhythmogenic ventricular scar in patients referred for HTx evaluation and diagnosed with ICM. Ablation will be performed with the use of a substrate-based approach in which the myocardial scar is mapped and ablated while the heart remains predominantly in sinus rhythm. The primary endpoint is the composite of all-cause mortality, worsening of HF requiring prioritized transplantation or LVAD implantation. The main secondary study endpoints are all-cause mortality, cardiovascular mortality, incidence of implantable cardioverter-defibrillator (ICD) therapy, hospitalizations, quality of life, time to first ICD therapy, number of device-detected ventricular tachycardia/ventricular fibrillation episodes, left ventricular function, and exercise tolerance. CASTLE-VT will randomize 160 patients with a follow-up period of 2 years. CASTLE-VT will determine whether prophylactic catheter ablation of arrhythmogenic ventricular scar tissue reduces mortality in patients with end-stage HF who are referred for HTx evaluation.

Desmoplakin Cardiomyopathy in Pediatric Patients: A Distinct, Underrecognized Cohort of Arrhythmogenic Cardiomyopathy.

DSP cardiomyopathy is a distinct subset of arrhythmogenic cardiomyopathy, reported primarily in adults, that has predominantly left ventricular involvement and features of myocarditis. Clinical characteristics, risk stratification, and management of pediatric patients with DSP variants are not well known. We sought to identify phenotypic features and prognosis of pediatric patients with DSP pathogenic or likely pathogenic variants. Multicenter, retrospective study of patients <21 years of age with DSP variants from 6 tertiary pediatric hospitals. Thirty-four patients, including 10 probands with clinical disease and 24 genotype-positive phenotype-negative patients, were included in the study. The majority of probands were initially diagnosed with myocarditis (50%) and had biventricular (60%) or left ventricular predominant (40%) disease. Chest pain was the most common symptom at presentation (30%), and all had troponin elevation. Probands with homozygous or compound heterozygous DSP variants were likely to present at an early age (<13 years) with symptoms of heart failure, severe biventricular involvement, and dermatologic abnormalities. Low-voltage QRS was the most prominent ECG abnormality. Of those who underwent implantable cardioverter defibrillator implantation, 50% received appropriate implantable cardioverter defibrillator therapy and were found to have significant biventricular involvement in addition to severe left ventricular dysfunction with an ejection fraction <35%. DSP cardiomyopathy in children and adolescents has varied phenotypic manifestations based on age and genotype and often can be diagnosed as myocarditis. Severe left ventricular dysfunction and biventricular involvement may be associated with a higher likelihood of malignant ventricular tachyarrhythmia.

Predictor of wasted implantable cardioverter defibrillator for secondary prevention

Abstract Background ICD is the first line treatment to prevent sudden cardiac death from recurrence of VT/VF. However, patients with organic heart disease have many comorbidities, and some patients die without history of appropriate ICD therapy in lifetime. Purpose The aim of this study is to examine the predictors of death without appropriate ICD therapy in lifetime, among ICD patients for secondary prevention with organic heart disease. Methods We enrolled consecutive patients implanted with ICD/CRT-D for secondary prevention between 2000 and 2022. We excluded patients without organic heart disease, and alive patients without history of appropriate ICD therapy. Inappropriate candidate (Wasted-group) for defibrillator was defined as the patient who died without history of appropriate ICD therapy or died within one year from appropriate ICD therapy. Appropriate candidate (Appropriate-group) was defined as the patient who had been alive over one year from appropriate ICD therapy (Wasted-group:36, Appropriate-group:131). Results During a follow-up of 8.3 ± 5.3 years, a total of 93 (56%) patients died, including 6 (4%) patients died within one year from ICD/CRT-D implantation. Among the 36 patients of Wasted-group, 28 patients died without history of appropriate ICD therapy. Higher age, ischemic cardiomyopathy, non-ARVC, a past history of VF, diabetes mellitus, and higher serum creatinine was the predictor of Wasted-group (P&amp;lt;0.05). Wasted ICD risk score was constructed with the summation of these predictors for predicting candidates of Wasted-group. When the Wasted ICD risk score was ≥3, positive predictive value and negative predictive value were 39.7% and 89.4%, respectively (AUC=0.77, P&amp;lt;0.001). Conclusion Patients with a Wasted ICD risk score &amp;lt;3 is likely to receive appropriate ICD therapy in lifetime. Therefore, Wasted ICD risk score might be useful to decide to need for ICD therapy, regarding elderly patients who would be hesitant to have ICD implanted.Wasted ICD risk score

Prospective assessment of risk factors for appropriate ICD intervention in patients with ischemic cardiomyopathy: results of PARCADIA trial

Abstract Background There is still a big unmet need for better risk stratification tools to identify patients at high risk for sudden cardiac death in the era of primary prevention ICD therapy. Scar burden on late gadolinium enhancement (LGE) cardiac magnetic resonance (CMR) imaging may be a risk marker for the prediction of ventricular arrhythmia in post-myocardial infarction (MI) patients. Purpose The aim of the PARCADIA trial was to assess whether scar characteristics, determined via LGE-CMR, or other baseline risk markers are associated with appropriate ICD therapy. Methods In this prospective, multi-center, clinical trial, we enrolled post-MI patients with an indication for de novo primary prevention ICD. Main exclusion criteria were indication for cardiac resynchronization therapy and NYHA class IV. Prior to the ICD implantation, LGE-CMR was performed to analyze the amount of scar tissue (LGE core mass + grey zone mass) and LV function / volumes. A 24h Holter recording was performed to collect information on potential triggers like premature ventricular beats (PVB) and sympathetic-vagal balance based on heart rate variability (HRV). Follow-ups were performed in-office every 6 months, including remote monitoring. Appropriate ICD therapy was used as primary endpoint and adjudicated by a clinical event committee. Results 199 patients were enrolled at 5 investigational sites in Europe. Patients mean age was 64.3 years, with a mean LVEF of 27.7 %, timing from the index MI was 9.1 years, and 42.7% received a primary PCI on index MI. After a median follow-up duration of 47.7 months, 23.1% of patients received appropriate ICD therapy. In 135 patients (67.8%), quality of LGE-CMR was sufficient for detailed analysis. The mean LGE core mass (20.5 vs. 19,7 g) and grey zone mass (10.5 vs. 11.4 g) was not different in patients with or without appropriate ICD therapy, also not when corrected for LV mass. However, LVEF (28.5 vs. 32.9 %) was lower, while diastolic myocardial mass (141 vs. 125 g), and end-diastolic volume (265.0 vs. 226.7 ml) were significantly higher in patients with appropriate ICD therapy. On 24h Holter the mean PVB burden (3695 vs. 1643 beats), and non-sustained ventricular tachycardia (12 vs. 0.9), were higher in patients with appropriate ICD therapy, while the HRV (96.1 vs. 113.1 SDNN) was lower. In univariate analysis the variables LVEF, timing to index MI, primary PCI on index MI, PVB burden and HRV appeared to be predictors for appropriate ICD intervention, while in multivariate analysis LVEF and PVB burden remained predictive. Conclusion In post-MI patients with appropriate ICD therapy, scar burden was not different from patients without appropriate ICD therapy. Only LVEF and PVB burden were independent predictors of increased arrhythmogenicity. Improved CMR analysis on scar characteristics (conduction channels) to identify potential arrhythmogenic regions might be the topic for future research.

Role of ventricular tachycardia cycle length in the outcomes after catheter ablation or antiarrhythmic drugs in the SURVIVE-VT trial

Abstract Background It has been suggested that antiarrhythmic drugs (AAD) are less effective and safe in slow ventricular tachycardia (VT) due to their effect on conduction velocity, which could stabilize reentry. Conversely, catheter ablation aims to disrupt the VT circuit. Because of the distinct mechanisms of action of AAD and catheter ablation on the VT circuit, VT cycle length (VT-CL) may play a crucial role in determining their therapeutic efficacy. Therefore, VT-CL could be important in selecting VT treatment. Purpose The aim of this study was to assess the impact of VT-CL on outcomes following catheter ablation or antiarrhythmic drugs in AAD-naïve patients with ischemic cardiomyopathy presenting with VT. Methods This is a post hoc analysis of the previously published Substrate Ablation vs Antiarrhythmic Drug Therapy for Symptomatic Ventricular Tachycardia (SURVIVE-VT) trial. In summary, 144 patients with ischemic cardiomyopathy and symptomatic VT were randomized to receive either catheter ablation (N=71) or AAD (N=73) as first-line therapy. We analyzed VT recurrence, implantable cardioverter-defibrillator (ICD) therapies, and the incidence of slow/incessant VT/VT storm using Cox proportional hazard models, with treatment and VT-CL interaction terms, adjusted for age. Missing VT-CL data for five patients were imputed using the median value. Results In patients with chronic ischemic heart disease and VT treated with either AAD or catheter ablation, a significant interaction was observed between clinical VT-CL and treatment effect on VT recurrence (p=0.016 for the interaction). Specifically, slower VT cycle lengths were associated with higher rates of VT recurrence (hazard ratio per 10 ms [HR] 1.094, 95% confidence interval [CI] 1.015, 1.179; p=0.037) in patients treated with AAD, while no significant effect was observed in those undergoing catheter ablation (see Figure 1). Survival freedom from VT recurrence in patients with VT-CL ≥300ms was significantly higher in patients treated with catheter ablation (78.8% vs 58.1%, log-rank p=0.044, see Figure 2). As expected, VT-CL was significantly associated with a higher risk of slow/incessant VT/VT storm (HR per 10 ms 1.115, 95% CI 1.017-1.222, p=0.047) but was not associated with ICD therapies (HR per 10 ms 1.082, 95% CI 0.994-1.178, p=0.102). Conclusion VT-CL significantly influences treatment outcomes, with slower VT cycles associated with an increased risk of VT recurrence in patients treated with AAD, but not in those undergoing catheter ablation. Therefore, VT-CL should be taken into consideration when selecting the optimal therapy for patients with ischemic cardiomyopathy and VT.Figure 1Figure 2

All-cause mortality and incidence of appropriate therapy from a primary preventive implantable cardioverter defibrillator in patients with non-ischemic dilated cardiomyopathy

Abstract Background The DANISH study published in 2016 indicated limited benefit of primary prevention implantable cardioverter-defibrillator (ICD) in patients with non-ischemic dilated cardiomyopathy (niDCM). We aimed to investigate the long-term outcome and incidence of ICD therapy in patients with niDCM implanted on primary prevention indication during 2014-2022. Methods A total of 116 patients with niDCM were prospectively included for primary prevention ICD implantation between 2014 and 2022 in the multicenter IMPROVE study (clinical trials NCT02286908). All patients were examined with electrocardiogram, echocardiography and blood sampling at inclusion. The primary outcome was all-cause mortality, and the secondary outcome was appropriate ICD therapy. Outcomes were compared in patients included from 2014 to end of 2016 (DCM2014-16, n=49) and from 2017-2022 (DCM2017-22, n=67). Results At inclusion, patients in DCM2017-22 were younger (54 years [interquartile range (IQR) 44-68] vs. 64 years [IQR 55-70], p=0.001), had higher left ventricular ejection fraction (LVEF) (33% [IQR 25-38] vs. 24% [IQR 21-31], p&amp;lt;0.001) and less frequently received cardiac-resynchronization therapy defibrillator (6% vs. 29%, p=0.001) compared to DCM2014-16. Over a median 4.4-year follow-up, the all-cause mortality was 14%, of which 10% occurred in the DCM2017-22 patients (2.6 events/100 person-years), and 18% in the DCM2014-16 patients (4.0 events/100 person-years), p=0.38. There was no difference in appropriate ICD therapy between the two groups (p=0.90). Conclusion Patients receiving primary prevention ICD for niDCM after publication of the DANISH study were younger with higher LVEF, indicating a change in clinical practice after the publication. Despite this, there was no significant reduction in all-cause mortality or difference in appropriate ICD therapies. Unchanged mortality and event-rates may indicate the correct identification of high-risk patients.

Smaller intrinsic QRS area and smaller reduction of QRS area during cardiac resynchronisation therapy are associated with higher risk of ventricular arrhythmias and appropriate ICD therapy

Abstract Background Cardiac resynchronisation therapy (CRT) patients are at high risk for ventricular arrhythmias (VAs), and little is known about which characteristics are associated with an increased risk for arrhythmic events. Purpose To investigate the association between QRS area parameters and the risk for VAs in patients with heart failure undergoing primary preventive CRT with defibrillator (CRT-D) implantation. Methods All patients receiving CRT-D between 2015 and 2020 at a large-volume tertiary care center were retrospectively evaluated. Digital 12-lead electrocardiograms (ECGs) were collected before and after CRT implantation. Patients were included if they had native LBBB and were implanted with a primary preventive CRT-D. Kors’ regression transformation was used to derive vectorcardiographic QRS area from the 12-lead ECGs. QRS area parameters were analysed in relation to a primary endpoint of first appropriate ICD therapy, i.e., ATP or shock therapy. Results 177 patients with LBBB (68.9 years [60.7–73.8]; 21.5% female; 52.9% New York Heart Association (NYHA) class III-IV; LVEF 25.9±6.3%) were followed over a median follow-up time of 2.5 years [1.6–3.0] after CRT-D implantation. 27 patients reached the primary endpoint. The median pre-CRT QRS area was 134.5 μVs [102.3–163.8]. Multivariable Cox regression identified a small pre-CRT QRS area (HR, per 10 μVs decrease, 1.30; [1.12–1.51]; p=&amp;lt;.001) and a small post-CRT reduction in QRS area (HR, per 10 μVs decrease, 1.30; [1.13–1.49]; p=&amp;lt;.001) as independent predictors of an increased risk of appropriate ICD therapy. In analyses with a scoring variable combining pre-CRT QRS area and QRS area reduction both above or below median, the combination of a small pre-CRT QRS area and a small QRS area reduction was strongly associated with an increased risk of reaching the endpoint (HR, per point increase, 2.47; [1.2–4.9]; p=0.01). Conclusion A small intrinsic QRS area, by itself or in combination with a small reduction of post-CRT QRS area, was strongly associated with a higher risk of ventricular arrhythmias in this cohort of CRT-D treated patients. In conjunction with other parameters, further risk stratification for arrhythmic events could be achieved by assessing QRS area data pre- and post-CRT.Figure 1.K-M pre-CRT QRS area quartilesFigure 2.K-M QRS area score

Ablation of right ventricular endocavitary arrhythmias

Abstract Background The right ventricular moderator band-papillary muscle (RV MB-PM) complex has a rich subendocardial network of purkinje fibers which can lead to ventricular arrhythmias (VA)1. Catheter ablation of such arrhythmias is procedurally challenging and there remains limited studies on long-term procedural success. Purpose We aimed to systematically study RV MB-PM complex VA. Methods A single center retrospective study from January 2013 to December 2023 identified 3249 patients who underwent VA ablation. The RV MB-PM complex was targeted in 47 patients. Acute success was defined as suppression of the targeted VA &amp;gt;=30 minutes post ablation. Long-term success was defined as the absence of symptoms, total PVC burden &amp;lt;5% or improvement in EF in patients presenting with isolated PVCs and as freedom from appropriate ICD therapy in patients presenting with malignant PVCs inducing VF, sustained VT or VT storm. Results Mean age was 51.9 ± 16.7 years and 64% were male. 40 (85%) patients had VA targeted from the MB and 7 (15%) from the PM complex (2 anterior, 2 inferior and 3 septal PM). 34 (72%) had no underlying structural heart disease, 3 (6%) ischemic cardiomyopathy and 10 (21%) non-ischemic cardiomyopathy. No patient had delayed gadolinium enhancement in the RV MB-PM complex. VA were inducible in 42 (89%) of patients and activation mapping was used in 9 (19%), pace mapping in 5 (11%) and a combination of activation and pace mapping used in 33 (70%) patients. Intracardiac echocardiography was used in all cases. Pre-QRS duration was 34.0 ± 10.4 ms. Radiofrequency ablation was used in 37 (78.7%) cases, cryotherapy in 4 (8.51%) cases and a combination of the 2 energy sources in 6 (12.8%) cases. In all cases, acute peri-procedural success was achieved. 24 (51.1%) patients presented with isolated PVCs and were followed up for 4.72 ± 3.55 years after their index procedure. 3 patients underwent repeat catheter ablation targeting the same PVC focus but all patients had long term success with a PVC burden of 16.1 ± 12.5% prior to ablation and 2.40 ± 2.44% at last follow-up. 16 patients underwent ablation for recurrent ICD shocks after initially presenting with PVC induced VF. Patients were followed up for 3.22 ± 2.09 years and 14 (88%) patients remained free from ICD therapy. 7 patients had MB ablation for sustained VT and were followed up for 4.06 ± 3.77 years. 5 (71%) patients remained free from ICD therapy. A purkinje potential was seen in 8% (2/24) cases of isolated PVCs and in 39% (9/23) cases of PVC induced VF or VT (p=0.13). Conclusions RV MB-PM VA commonly present with malignant VF and a purkinje potential is more likely to be seen in these cases suggesting different VA mechanisms to isolated PVCs and catheter ablation is an effective long-term strategy.

Long-term prognostic value of multiple circulating biomarkers for ventricular arrhythmias in patients with left ventricular hypertrabeculation

Abstract Background Left ventricular hypertrabeculation (LVHT) is a rare morphologic phenotype of the heart with heterogeneous manifestations and variable prognosis [1,2]. Ventricular arrhythmia (VA) has been recognized as an independent risk factor that significantly impacts the mortality of LVHT patients [1,3]. However, knowledge regarding the prognosis and risk stratification of VAs in LVHT is currently limited. Purpose To explore the long-term predictive value of multiple circulating biomarkers reflecting cardiac function, endothelial function, inflammation, and oxidative stress for the development of VAs in LVHT patients. Methods This longitudinal cohort study consecutively enrolled morphologically diagnosed LVHT patients between January 2012 and December 2020 at a national-level medical center. All participants possessed thorough profiles of multiple biomarkers [N-terminal pro-brain natriuretic peptide, big endothelin-1 (big ET-1), high-sensitivity C-reactive protein, uric acid and free fatty acid] and had no previously documented ventricular arrhythmic events. The cohort were followed annually until October 2022. VA was defined as a composite of non-sustained ventricular tachycardia, sustained ventricular tachycardia, ventricular fibrillation, and appropriate therapy of implantable cardioverter defibrillator. Potential predictors for VAs in the LVHT cohort were evaluated by multivariable Cox regression. Restricted cubic spline (RCS) analysis was employed to explore the nonlinear association between plasma big ET-1 and clinical outcomes. Differences in the cumulative incidence of VAs according to big ET-1 levels and/or the extent of hypertrabeculation were analyzed by Kaplan-Meier curves. Results A total of 265 morphologically diagnosed LVHT patients (44.2 ± 17.0 years, 65.7% male) were included in this study. Over a median follow-up of 4.34 years, 82 (30.9%) patients experienced ventricular arrhythmic events. Multivariable Cox regression analysis identified that baseline levels of big ET-1 (hazard ratio 1.513, 95% confidence interval 1.136-2.013) and isolated hypertrabeculation in left ventricular lateral wall (LVLW) (hazard ratio 1.810, 95% confidence interval 1.023-3.202) were independently associated with the occurrence of VAs. RCS analysis illustrated that the susceptibility to VAs was remarkably raised with the increase of big ET-1 levels. LVHT patients with higher plasma big ET-1 suffered from more severe cardiac dysfunction and remodeling. Individuals who displayed elevated concentrations of big ET-1 and isolated LVLW hypertrabeculation were at a significantly greater risk of developing VAs. Conclusions Introducing routine assessments for plasma big ET-1 and the extent of hypertrabeculation at baseline can offer valuable support in the risk stratification and clinical management of ventricular arrhythmic events in patients with LVHT.Prognositc value of big ET-1 for VAsbig ET-1/LVLW hypertrabeculation &amp; VAs

Outcomes and complications of transvenous implantable cardioverter defibrillator systems in the pediatric population: a systematic review and meta-analysis

Abstract Background Implantable cardioverter defibrillators (ICDs) are an important therapy for prevention of sudden cardiac death (SCD). Data on transvenous (TV) ICD therapy rates, complications, and system survival in children ≤ 21 years is limited by absolute numbers and inclusion of adults with congenital heart disease. Purpose To determine ICD therapy rates and complications in pediatric patients ≤ 21 years of age. Methods A systematic review and meta-analysis were conducted following the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) statement. Medline, Embase, PubMed Ahead-of-Print and in-process records, and Cochrane Database of Systematic Reviews were searched for full-text articles on pediatric ICD. Articles were assessed for inclusion by two authors via a consensus process; the exclusion criteria included: case reports, review articles, abstracts, editorials, articles not in English, articles solely on epicardial or subcutaneous leads, articles on unrelated topics, articles with &amp;lt;50% ICD leads, and articles with any patients &amp;gt;21 years old. Data were extracted by 1 author and verified by a 2nd author. Meta-analysis of aggregate data was performed, where possible. Random effects models were used for pooled inferences. All reported rates are annualized rates based on reported follow-up times in each study. Results Of 1325 articles, 23 met all inclusion and no exclusion criteria (Figure) representing 1700 patients implanted from 1987-2020. The average age of patients was 12.8 years (95% confidence interval [CI]: 11.9 – 13.7) with weight of 51.1 kg (95% CI: 42.2 – 60.0) (Table). Primary prevention was the indication in 56.4 % (95% CI: 45.0% – 67.7%). Only 14.8% (95% CI: 10.6% – 19.0%) of the patients had congenital heart disease while 22.6% (95% CI: 15.8% – 29.3%) had long QT syndrome. The annualized rate of appropriate shock was 7.0% (95% CI: 5.6% – 8.8%) and the rate of inappropriate shock was 4.8% (95% CI: 3.8% – 6.0%). Annualized rates of reported adverse events included lead failure: 2.3% (95% CI: 1.6% – 3.3%) and infection: 0.8% (95% CI: 0.4% – 1.6%), which could have led to system revision: 4.4% (95% CI: 2.1% – 9.4%). The all-cause mortality rate was 0.8% (95% CI: 0.6% – 1.2%) across 17 studies. In 9 studies with 719 patients, the heart transplant rate was 1.6% (95% CI: 0.6% – 3.9%). Conclusion In this first systematic review and meta-analysis of ICDs in pediatric patients, ICD therapy was effective for prevention of SCD with a 7.0% annualized rate of appropriate ICD shocks. This is comparable to the annualized rate of appropriate ICD shock for secondary prevention of SCD in adult randomized controlled trials. Most common adverse events in the pediatric population were lead failure and system revision. Further refinements in patient selection criteria for implantation and improvements in lead and device technology are needed for pediatric patients.FigureTable

The MADIT-ICD benefit risk score for Japanese patients -from Nippon Storm study-

Abstract Background Implantable cardioverter-defibrillators (ICDs) play a crucial role in preventing sudden death due to lethal arrhythmias such as ventricular tachycardia and ventricular fibrillation. However, like any medical intervention, ICD implantation is not without its complications. It is essential to carefully consider the risks and benefits, and appropriately stratify the risk of sudden death in order to make informed decisions. In 2020, the MADIT-ICD benefit risk score was proposed to utilize personalized integrated assessment of the competing risk of lethal arrhythmias vs. non-arrhythmic mortality in implantable cardioverter-defibrillator (ICD) candidates. Purpose To evaluate the risk stratification of using the MADIT-ICD benefit risk score in Japanese patients. Methods We analyzed the data of 451 patients, enrolled in the Nippon Storm Study, with left ventricular ejection fraction (LVEF) ≤35% who underwent ICD implantation for primary prophylaxis of sudden cardiac death (men, 78%; age, 65±12 years; LVEF, 25±6.4%; cardiac resynchronization therapy, 73%; ischemic cardiomyopathy (ICM), 33%). Results A total of 336 patients were enrolled iln this study. The MADIT-ICD benefit risk scores, except systolic blood pressure, was calculated (Figure 1). These patients were classified into 3 groups (Lowest, Intermediate, Highest). There were no significant differences between the three groups in all-cause mortality, cardiovascular death, non-arrhythmic death, and appropriate ICD therapy (Figure 2). The multivariate analysis demonstrated that LVEF ≤25% was significantly associated with all-cause mortality, cardiovascular death, non-arrhythmic death (p=0.0487, 0.0150, 0.0387). Conclusion The MADIT-ICD benefit risk score may not be appropriate to risk stratification in Japanese patients using ICD for primary prophylaxis.Figure 1Figure 2

High incidence of malignant arrhythmias and heart failure in patients with RBM20-associated cardiomyopathy: a multicenter cohort study and review of the literature

Abstract Background Patients with RBM20 cardiomyopathy commonly experience malignant arrhythmias, sudden cardiac death (SCD), and progressive heart failure (HF). Objective The aim of this study is to investigate genotype-phenotype correlations, clinical outcomes and causes of death in patients with RBM20-associated cardiomyopathy in a multicenter cohort, combined with an overview of the current literature. Methods This international, multicenter cohort included all patients with cardiomyopathy who had a pathogenic (P) or likely pathogenic (LP) RBM20 variant. For survival and regression analysis, we matched a control group based on sex, age, and presence of left ventricular dysfunction. Additionally, we conducted a literature search on studies investigating RBM20-associated cardiomyopathy. Results Sixty-two patients (45% male) were included in the study, with a mean age of 42 ± 15 years at presentation. Of the LP/P RBM20 variants identified, 9 were novel. Eleven variants were truncating, while the remaining variants consisted of missense and splice-site variants. Patients with a truncating variant who developed HF were on average older at the time of diagnosis compared to patients with missense variants (mean age 62 ± 9 vs. 45 ± 14; p=0.01). After a median follow-up duration of 5.0 [1.0 – 10.5] years, 21 (34%) patients reached the composite endpoint of ventricular arrhythmias (VA), implantable cardioverter-defibrillator therapy, heart transplantation (HTx), left ventricular assist device (LVAD) implantation, or cardiovascular death. Of these, 19 (31%) patients experienced malignant VA (mean age 45 ± 15 years, 63% males). Males were at higher risk for the composite endpoint (log-rank p= 0.02), particularly for VA (log-rank p=0.007). The literature review analyzed 34 studies with a total of 678 patients, of whom 53% were male. In these studies, 123 (24%) patients experienced a VA, 58 (12%) underwent HTx or were treated with LVAD, and 52 (11%) died. Conclusion In this multicenter study the patients carrying a LP/P variant in RBM20 variants had a severe phenotype, with a high incidence of VA, particularly in males. Additionally, this study presents 9 novel DNA variants, of which 8 were truncating, and were mainly observed in older individuals. Finally, we report a lower mortality rate compared to the literature, possibly due to a higher number of heart transplantations performed in our patient cohort.Survival composite endpoint for sex

Ringlike late gadolinium enhancement: prevalence, association with cardiac phenotype, and patient outcome in an unselected cohort referred for cardiovascular magnetic resonance imaging

Abstract Background The identification of a non-ischemic ringlike enhancement in the left ventricular (LV) myocardium by cardiac magnetic resonance imaging (CMR) has emerged as a significant biomarker associated with arrhythmogenic cardiomyopathy (CMP) and adverse patient outcomes. Recently, the term "scarring CMP" has been also proposed to encompass various conditions characterized by a high burden of non-ischemic, often ring-like, myocardial scarring, including both genetic and acquired etiologies. Purpose To systematically evaluate CMR phenotypic traits and etiologic backgrounds in patients with ringlike enhancement and to assess the burden of adverse outcomes during follow-up (FU). Methods This is a single-center, retrospective analysis of prospectively enrolled patients undergoing CMR (from 2002 to 2024). Ringlike late gadolinium enhancement (LGE) was defined as continuous enhancement in three or more adjacent segments based on the AHA 17 segment model. Patients records were reviewed for etiologic classification and FU assessment. Results Among 23.472 patients, 19.696 (84%) underwent LGE assessment. In 152 patients (0.77%; 73% male; mean age 48.5 ± 17 years) a ringlike LGE was identified. The mean number of LV segments with LGE was 10 ± 3. Right ventricular (RV) LGE was present in 23% of subjects. LV fatty metaplasia was detected in 22%. Infero-lateral segments were most frequently affected. CMR showed the following morpho-functional features: LV dilatation (53%), LV hypokinesia (69%), LV hypertrophy (10.5%), LV non-compaction (11%), RV dilation (26%), and RV ejection fraction &amp;lt; 40% (21%). Phenotypic classification according to 2023 ESC guidelines identified dilated CMP phenotype (43%), non-dilated LV CMP phenotype (39%), predominant arrhythmogenic right ventricular phenotype (6%), hypertrophic phenotype (7%). 5% of cases remained unclassified, all of them showing LV dilated non-hypokinetic phenotype. Genetic analysis was performed in 101 patients (66%). Etiologic classification revealed non-desmosomal gene related CMP (24%), desmosomal gene related CMP (8%), inflammatory CMP (16%), genetic neuromuscular diseases (5%), congenital metabolic errors (3%), familiar gene elusive CMP (2%) and unknown etiology (45%). Notably, only 17% of patients classified as having inflammatory CMP and 66% of those with unknown etiology underwent genetic testing, with negative results. The median follow-up duration was 3 (IQR: 1-7) years. All-cause mortality occurred in 10.5% of patients, while 17% experienced sustained ventricular tachycardia, appropriate implantable cardioverter-defibrillator therapies, or sudden cardiac death. Heart transplantation or left ventricular assist device implantation was required in 8% of cases. Conclusion Ringlike LGE is a rare, non-disease-specific feature that can be found in different morpho-functional CMP phenotypes. It is associated with frequent genetic-determined etiology and high burden of arrhythmic and non-arrhythmic outcomes.

The impact of QRS complex fragmentation status before and after cardiac resynchronization therapy with defibrillator implantation: Is it a predictor of arrhythmic events?

Abstract Introduction Cardiac resynchronization therapy with an implantable cardioverter defibrillator (CRT-D) has demonstrated efficacy in reducing mortality, hospitalization for heart failure (HF), and sudden cardiac death among subgroups of patients with HF with reduced ejection fraction (HFrEF). However, this population is highly heterogeneous, necessitating risk stratification. Several clinical findings, including QRS complex fragmentation (QRSf), have been identified as potential prognostic factors for arrhythmic risk. Nonetheless, evidence supporting the prognostic significance of QRSf in patients undergoing CRT-D remains limited. Purpose The aim of this study is to assess whether alterations in QRSf status, before and after CRT-D implantation, can predict arrhythmic events (AE) in patients with HFrEF. Methods This study included consecutive patients underwent CRT-D implantation at our center from October 2009 to December 2022. Demographic, clinical, electrocardiographic and echocardiographic data were obtained from electronic medical records and telephone interviews. QRSf was defined by the presence of various RSR′ patterns, including additional R waves (R′) or notching of the R and S wave in two contiguous leads corresponding to a primary coronary artery territory on a 12-lead electrocardiogram conducted before and after CRT-D implantation. An AE was characterized by appropriate ICD therapy (antitachycardia pacing or shock) for a ventricular arrhythmia or sustained ventricular arrhythmia without the need for ICD therapy. Results A total of 176 patients were included (mean age 69.9 ± 9.6 years with 80.6% male). Ischemic etiology accounted for 54.6% of cases of LV systolic dysfunction, with a mean baseline LVEF of 23.6%. CRT-D was indicated as secondary prevention in 18 patients. At baseline, 114 patients (64.8%) presented QRSf. Following CRT implantation, 17 patients (9.8%) without previous QRSf developed QRSf, while 26 patients (14.9%) resolved QRSf. The median follow-up was 43.6 months (interquartile range 19.5-81.1). During follow-up, 90 patients died and 29 AE occurred (16.5%). Among these, 23 patients had QRSf before and after CRT, whereas 6 AE occurred in patients without QRSf. Multivariate survival analysis using Cox regression demonstrated that the presence of QRSf before and after CRT-D was an independent predictor of AE (HR 3.56; 95% CI 1.00-12.70). Univariate and multivariate Cox regression analyses are presented in Table 1. Kaplan-Meier curves for AE in relation to QRSf status before and after CRT-D are illustrated in Figure 1. Conclusions Our findings suggest that the presence of QRSf and its persistence following CRT-D implantation appears to be an independent predictor of AE after CRT-D implantation in patients with HFrEF. Therefore, these patients would benefit from closer monitoring as they exhibit a heightened risk of arrhythmic events. Nevertheless, further research is warranted to validate these results.Table 1.Cox Regression Analysis.