Implantable Cardioverter Defibrillator Recipients Research Articles

Device programming and SMART pass algorithm activation in subcutaneous implantable defibrillator patients: data from a remote monitoring database

Abstract Background In subcutaneous implantable cardioverter-defibrillator (S-ICD) recipients, a previous study demonstrated very low rates of delivered shocks and inappropriate shocks on programming a conditional zone between 200 and 250 bpm and a shock zone for arrhythmias >250 bpm. The extent to which this programming approach is adopted in clinical practice has been little studied, as the activation status of the SMART Pass filter, that was implemented to reduce inappropriate shocks and enhanced over time. Purpose We assessed device programming during follow-up and the rate of detected arrhythmias in a cohort of consecutive S-ICD recipients. Methods We analyzed data from 670 S-ICD patients followed on the remote network at 17 Italian centers for a median of 31 months (25th-75th percentile: 16-51). The enhanced SMART Pass version was available for all patients after October 2022. It makes the deactivation monitor less sensitive to premature ventricular contractions or other transient amplitude changes while maintaining arrhythmia sensitivity and specificity, and it was expected to reduce unintentional deactivation rate. Results At the last remote data transmission, the median programmed conditional zone cut-off was set to 210 bpm (25th-75th percentile: 200-220), the shock zone cut-off was 250 bpm (25th-75th percentile: 240-250), and the SMART Pass was enabled in 586 (87%) patients. During follow-up, 194 automatic deactivation events (0.10/patient-year) were reported in 118 (18%) patients. The SMART Pass-disabled time was 13% of the total observation period. Shocks were delivered in 129 (19%) patients (rate: 0.13/patient-year), and untreated arrhythmias were recorded in 136 (20%) patients (rate: 0.14/patient-year). The rate of shocks was lower when SMART Pass was enabled – 0.12/patient-year (95% CI: 0.10-0.14) versus 0.20 (95%CI: 0.15-0.26) (p=0.002), as it was the rate of untreated arrhythmias – 0.12/patient-year (95% CI: 0.11-0.14) versus 0.23 (95%CI: 0.18-0.30) (p=0.001). The enhanced SMART Pass version was associated with a lower rate of deactivations – 0.04/patient-year (95%CI: 0.02-0.05) versus 0.14 (95% CI: 0.12-0.16) (p<0.001), and with a reduction in treated and untreated arrhythmias (Incidence rate ratios: 0.40 (95%CI: 0.28-0.53) and 0.40 (95%CI: 0.30-0.55), respectively (p<0.001)). Conclusions In current clinical practice, S-ICD implantation centers often program high cut-off rates for arrhythmia detection. Most patients have SMART Pass consistently enabled during follow-up. This is associated with significantly lower rates of detected and treated arrhythmias. The enhanced SMART Pass version seems associated with lower deactivation rate, and with further decrease in treated and untreated detected arrhythmias.

Impact of gender on the utilisation implantable cardioverter defibrillators and outcome: results from the German DEVICE registry

Abstract Background Implantable cardioverter defibrillators (ICD) are an established therapy for the primary and secondary prevention of sudden cardiac death. Real world data regarding the impact of gender on ICD implantation and outcome are scarce. Purpose To determine the impact of gender on the ICD implantation and outcome. Methods The German DEVICE registry is a prospective, nationwide database of ICD and CRT devices implantation and revisions. Between March 2007 and February 2014, 3794 patients undergoing a single or dual chamber ICD implantation and revisions were prospectively included in 44 centres and monitored for a median of 17 months. Herein we conducted the gender-based analysis of the ICD recipients. Results A total of 688 (18,1%) women (mean age 62.5 ± 16.0, median BMI 26.7) and 3106 men (mean age 64.6 ± 12.9, median BMI 26.8) were included in this registry. Significantly less women had coronary artery disease (p<0.001), while more women had hypertrophic cardiomyopathy (p=0.024) and primary electrical heart disease (p<0.001), mainly because of a higher incidence of long QT syndrome and arrhythmogenic right ventricular cardiomyopathy. There was a trend towards a higher rate dual chamber ICD in the female population (31.7% vs. 28.1%; p=0.061). Women were less likely to undergo ambulatory interventions (6.4% vs. 9.0%; p=0.026) and had a trend towards higher rate of ICD implantation for secondary prevention (52.3% vs. 48.7%; p=0.086). Females were more likely to have a history of ventricular fibrillation (51.7% vs. 39.4%; p<0.001) and resuscitation (54.7% vs. 46.3%; p=0.006), but less likely to have a history of ventricular tachycardia (33.1% vs. 45.2%; p<0.001). The overall rate of in-hospital complications (5.3% vs. 2.7%; p=0.005) as well as the rate of major periprocedural complications (3.1% vs. 1.3%; p=0.002) was significantly higher among females, mainly driven by a higher incidence of pneumothorax (1.0% vs. 0.1%; p=0.004) and haemothorax (0.4% vs. 0%; p=0.02). The rate of in-hospital device revision and mortality were similar between genders. The Kaplan-Meier estimated 1-year all-cause mortality was 5.2% for women and 7.1% for men (p=0.073; Fig 1), while the estimated incidence of all-cause mortality or device shocks was significantly lower in the female population (15.1% vs. 19.0%; p=0.02). Women were more likely to undergo resuscitation during follow-up (FU; 1.3% vs. 0.3%; p<0.001) and showed a higher fear of receiving device shocks. There was no difference in terms of ICD-shocks, VT-storm and ablation rates at FU. The all- cause, device-related, and other cardiovascular rehospitalisation rates and the incidence of non-arrhythmic adverse events during FU were similar between genders. Conclusions In this real-life patient cohort only a minority of patients were females. Female patients had a higher risk of major periprocedural complications and in-hospital complications and a trend towards a lower all-cause mortality during FU.Fig 1. Kaplan-Meier estimated survival.

Trends in adoption of extravascular cardiac implantable electronic devices: the Dutch cohort

Abstract Introduction Conventional implantable cardioverter-defibrillators (ICDs) and pacemakers carry a risk of mainly pocket- and lead-related complications. To avoid these complications, extravascular devices (EVDs) have been developed, such as the subcutaneous ICD (S-ICD) and leadless pacemaker (LP). However, data on the actual adoption of EVDs for patient or center characteristics is lacking. Purpose To assess real-world nationwide trends in adoption of EVDs in the Netherlands. Methods Using the Netherlands Heart Registration, all consecutive patients with a de novo S-ICD or conventional single-chamber ICD implantation between 2012-2020, or with a de novo LP or conventional single-chamber pacemaker implantation between 2014-2020 were included. Trends in adoption of EVDs are described for different patient and hospital characteristics (tertiles of device-implanting volume and whether cardiothoracic surgery back-up was available). Differences between patients with EVDs and non-EVDs and differences between implanting centers of EVDs and non-EVDs were tested for by Student’s T-test, Chi-square and Fisher’s exact test. Trends in adoption over time were calculated with linear and logistic regression analysis. Results From 2012-2020, 2190 S-ICDs and 10683 conventional ICDs were implanted; from 2014-2020, 712 LPs and 11103 conventional pacemakers were implanted. The general adoption of both increased (S-ICDs, 8% to 21%; LPs, 1% to 8%), but the increase seems to reach a plateau (Fig. 1). S-ICD recipients were younger than conventional ICD recipients (p<0.001) and more likely to be female (p<0.001); LP recipients were younger than conventional pacemaker recipients (p<0.001) and more likely to be male (p=0.03). Both S-ICDs and LPs were mainly implanted in high-volume centers with thoracic surgery on-site (Fig. 2). Conclusions In this nationwide study we observed a relative quick adoption of innovative EVDs with a plateau after approximately 4 years. The relative adoption of S-ICDs is especially high in younger patients. EVDs are overall mainly implanted in high-volume centers with cardiothoracic surgery available. As LPs can only be implanted in centers with cardiothoracic surgery in the Netherlands, this may have limited its adoption.

Comparative Analysis of Response to Cardiac Resynchronisation Therapy Upgrades in Patients with Implantable Cardioverter-Defibrillators and Pacemakers.

Introduction: The efficacy of de novo cardiac resynchronisation therapy (CRT) in patients with heart failure (HF), left ventricular systolic dysfunction (LVSD), and a broad QRS morphology is well established. However, the optimal stage for upgrading patients with existing pacemakers (PPMs) or implantable cardioverter-defibrillators (ICDs) and HF with high-burden right ventricular (RV) pacing remains uncertain. Thus, this multicentre retrospective analysis compared patients with pre-existing PPMs or ICDs who underwent CRT upgrades to investigate the appropriate stage for CRT implantation in these patients and to assess the validity of treating both PPM and ICD recipients under the same recommendation level in the current guidelines. Materials and Methods: A total of 151 participants underwent analysis in this study, comprising 93 upgrades to cardiac resynchronisation therapy with pacemaker (CRT-P) and 58 upgrades to cardiac resynchronisation therapy with defibrillator (CRT-D) across three centres in the UK. The aim of the study was to investigate the safety and efficacy of upgrading to CRT from an existing conventional pacemaker or an ICD in the context of high-burden RV pacing. The analysis was conducted separately for each group, assessing changes in echocardiographic parameters, functional New York Heart Association (NYHA) class, and procedure-related complications. Results: The PPM group had a higher percentage RVP burden compared to the ICD group. Post-upgrade, NYHA functional class and EF and LV volumes improved in both groups; however, the response to an upgrade from a pacemaker was greater compared to an upgrade from an ICD. Post-procedural complication risks were similar across the two subgroups but significantly higher compared to de novo implantation. Conclusions: Within the CRT-P subgroup, participants exhibited better responses than their CRT-D counterparts, evident both in echocardiographic improvements and clinical outcomes. Furthermore, patients with non-ischemic cardiomyopathy (NICM) were better responders than those with ischaemic cardiomyopathy. These findings suggest that international guidelines should consider approaching each subgroup separately in the future.

Competing Risks for Monomorphic versus Non-Monomorphic Ventricular Arrhythmias in Primary Prevention Implantable Cardioverter Defibrillator Recipients: Global Electrical Heterogeneity and Clinical Outcomes (GEHCO) Study.

Ablation of monomorphic ventricular tachycardia (MMVT) has been shown to reduce shock frequency and improve survival. We aimed to compare cause-specific risk factors of MMVT and polymorphic ventricular tachycardia (PVT)/ventricular fibrillation (VF) and to develop predictive models. The multicenter retrospective cohort study included 2,668 patients (age 63.1±13.0 y; 23% female; 78% white; 43% nonischemic cardiomyopathy, left ventricular ejection fraction 28.2±11.1%). Cox models were adjusted for demographic characteristics, heart failure severity and treatment, device programming, and ECG metrics. Global electrical heterogeneity was measured by spatial QRS-T angle (QRSTa), spatial ventricular gradient elevation (SVGel), azimuth, magnitude (SVGmag), and sum absolute QRST integral (SAIQRST). We compared the out-of-sample performance of the lasso and elastic net for Cox proportional hazards and the Fine-Gray competing risk model. During a median follow-up of 4 years, 359 patients experienced their first sustained MMVT with appropriate ICD therapy, and 129 patients had their first PVT/VF with appropriate ICD shock. The risk of MMVT was associated with wider QRSTa (HR 1.16; 95%CI 1.01-1.34), larger SVGel (HR 1.17; 95%CI 1.05-1.30), and smaller SVGmag (HR 0.74; 95%CI 0.63-0.86) and SAIQRST (HR 0.84; 95%CI 0.71-0.99). The best-performing 3-year competing risk Fine-Gray model for MMVT (ROC(t)AUC 0.728; 95%CI 0.668-0.788) identified high-risk (> 50%) patients with 75% sensitivity, 65% specificity, and PVT/VF prediction model had ROC(t)AUC 0.915 (95%CI 0.868-0.962), both satisfactory calibration. We developed and validated models to predict the competing risks of MMVT or PVT/VF that could inform procedural planning and future RCTs of prophylactic VT ablation.

Sex differences among subcutaneous implantable cardioverter-defibrillator recipients: a propensity-matched, multicentre, international analysis from the i-SUSI project.

Women have been historically underrepresented in implantable cardioverter-defibrillator (ICD) trials. No data on sex differences regarding subcutaneous ICDs (S-ICD) carriers have been described. Aim of our study was to investigate sex-related differences among unselected S-ICD recipients. Consecutive patients enrolled in the multicentre, international i-SUSI registry were analysed. Comparisons between sexes were performed using a 1:1 propensity matching adjusted analysis for age, body mass index (BMI), left ventricular function, and substrate. The primary outcome was the rate of appropriate shocks during follow-up. Inappropriate shocks and other device-related complications were deemed secondary outcomes. A total of 1698 patients were extracted from the i-SUSI registry; 399 (23.5%) were females. After propensity matching, two cohorts of 374 patients presenting similar baseline characteristics were analysed. Despite similar periprocedural characteristics and a matched BMI, women resulted at lower risk of conversion failure as per PRAETORIAN score (73.4% vs. 81.3%, P = 0.049). Over a median follow-up time of 26.5 [12.7-42.5] months, appropriate shocks were more common in the male cohort (rate/year 3.4% vs. 1.7%; log-rank P = 0.049), while no significant differences in device-related complications (rate/year: 6.3% vs. 5.8%; log-rank P = 0.595) and inappropriate shocks (rate/year: 4.3% vs. 3.1%; log-rank P = 0.375) were observed. After controlling for confounders, sex remained significantly associated with the primary outcome (aHR 1.648; CI 0.999-2.655, P = 0.048), while not resulting predictor of inappropriate shocks and device-related complications. In a propensity-matched cohort of S-ICD recipients, women are less likely to experience appropriate ICD therapy, while not showing higher risk of device-related complications. ClinicalTrials.gov Identifier: NCT0473876.

Association of device detected atrial and ventricular tachyarrhythmia with adverse events in patients with an implantable cardioverter-defibrillator.

Heart failure patients with a history of atrial fibrillation (AF) and ventricular tachycardia/ventricular fibrillation (VT/VF) are known to have worse outcomes. However, there are limited data on the temporal relationship between development of these arrhythmias and the risk of subsequent congestive heart failure (CHF) exacerbation and death. The study cohort comprised 5511 patients implanted with an implantable cardioverter-defibrillator (ICD) in landmark clinical trials (MADIT-II, MADIT-RISK, MADIT-CRT, MADIT-RIT, and RAID) who were in sinus rhythm at enrollment. Multivariate cox analysis was performed to evaluate the time-dependent association between development of in-trial device detected AF and VT/VF with subsequent CHF exacerbation and death. Multivariate analysis showed that AF occurrence and VT/VF occurrence were both associated with a similar magnitude of risk for subsequent CHF exacerbation (HR = 1.73 and 1.87 respectively, p < .001 for both). In contrast, only in-trial VT/VF was associated with a significant > two-fold increase in the risk of subsequent mortality (HR = 2.13, p < .001) whereas AF occurrence was not associated with a significant mortality increase after adjustment for in-trial VT/VF (HR = 1.36, p = .096). Our findings from a large cohort of ICD recipients enrolled in landmark clinical trials show that device detected AF and VT/VF can be used to identify patients with increased risk for CHF exacerbation and mortality. These findings suggest a need for early intervention in CHF patients who develop device-detected atrial and ventricular tachyarrhythmias.

Impact of a Chronic Total Coronary Occlusion on the Incidence of Appropriate Implantable Cardioverter-Defibrillator Shocks and Mortality: A Substudy of the Dutch Outcome in ICD Therapy (DO-IT)) Registry.

Chronic total coronary occlusions (CTO) substantially increase the risk for sudden cardiac death. Among patients with chronic ischemic heart disease at risk for sudden cardiac death, an implantable cardioverter defibrillator (ICD) is the favored therapy for primary prevention of sudden cardiac death. This study sought to investigate the impact of CTOs on the risk for appropriate ICD shocks and mortality within a nationwide prospective cohort. This is a subanalysis of the nationwide Dutch-Outcome in ICD Therapy (DO-IT) registry of primary prevention ICD recipients in The Netherlands between September 2014 and June 2016 (n=1442). We identified patients with chronic ischemic heart disease (n=663) and assessed available coronary angiograms for CTO presence (n=415). Patients with revascularized CTOs were excluded (n=79). The primary end point was the composite of all-cause mortality and appropriate ICD shocks. Clinical follow-up was conducted for at least 2 years. A total of 336 patients were included, with an average age of 67±9 years, and 20.5% was female (n=69). An unrevascularized CTO was identified in 110 patients (32.7%). During a median follow-up period of 27 months (interquartile range, 24-32), the primary end point occurred in 21.1% of patients with CTO (n=23) compared with 11.9% in patients without CTO (n=27; P=0.034). Corrected for baseline characteristics including left ventricular ejection fraction, and the presence of a CTO was an independent predictor for the primary end point (hazard ratio, 1.82 [95% CI, 1.03-3.22]; P=0.038). Within this nationwide prospective registry of primary prevention ICD recipients, the presence of an unrevascularized CTO was an independent predictor for the composite outcome of all-cause mortality and appropriate ICD shocks.

Mortality Benefit Among Primary Prevention Implantable Cardioverter-Defibrillator Recipients on Contemporary Heart Failure Treatment

BackgroundPast clinical trials have shown the benefit of implantable cardioverter-defibrillators (ICDs) for reducing sudden cardiac death in at-risk patients. However, heart failure management and ICD technology have changed since these trials were first published. An updated assessment of ICD mortality benefit is needed. ObjectivesThe purpose of this study was to compare mortality rates between patients with a primary prevention (PP) indication for an ICD who did or did not receive an ICD using a contemporary, real-world data set. MethodsData was obtained from a large electronic health record data set covering patients in the United States from 2012 through 2020 who had a PP indication for an ICD and survived at least 1-year postindication. ResultsA total of 25,296 patients were identified as having a PP indication for ICD implantation, of which 2,118 (8.4%) were treated with an ICD within a year. Treated patients were younger than nontreated patients (age 63.4 years vs 66.1 years) with a smaller proportion of women (25.0% vs 36.7%). After 4-to-1 propensity matching, treated patients had similar clinical characteristics to nontreated patients. A Cox proportional hazard model estimated a 24.3% lower risk of all-cause mortality in patients when treated vs not treated with an ICD (HR: 0.757; 95% CI: 0.678-0.835; P <0.001). There was no detectable difference in ICD benefit between patients with ischemic and nonischemic heart disease (P = 0.50). ConclusionsICD treatment of patients with a PP indication is associated with improved mortality even in the context of evolving adjunctive HF treatment, consistent with earlier landmark trials.

Comparison of novel intrinsic versus conventional antitachycardia pacing for ventricular tachycardia among implantable cardioverter-defibrillator recipients.

Intrinsic antitachycardia pacing (iATP) is a novel automated antitachycardia pacing (ATP) that provides individual treatment to terminate ventricular tachycardia (VT). However, the clinical efficacy of iATP in comparison with conventional ATP is unknown. We aim to compare the termination rate of VT between iATP and conventional ATP in patients with implantable cardioverter-defibrillators using a unique setting of different sequential orders of both ATP algorisms. Patients with the iATP algorithm were assigned to iATP-first and conventional ATP-first groups sequentially. In the iATP-first group, a maximum of seven iATP sequences were delivered, followed by conventional burst and ramp pacing. In contrast, in the conventional ATP-first group, two bursts and ramp pacing were initially programmed, followed by iATP sequences. We compared the success rates of VT termination in the first and secondary programmed ATP zones between the two groups. Fifty-eight and 56 patients were enrolled in the iATP-first and conventional ATP-first groups, and 67 and 44 VTs were analyzed in each group, respectively. At the first single ATP therapy, success rates were 64% and 70% in the iATP and conventional groups, respectively. At the end of the first iATP treatment zone, the success rate increased from 64% to 85%. Moreover, secondary iATP therapy following the failure of conventional ATPs increased the success rate from 80% to 93%. There was a significant benefit of alternative iATP for VT termination compared to secondary conventional ATP (100% vs. 33%, p = .028). iATP may be beneficial as a secondary therapy after failure of conventional ATP to terminate VT.

Differences in underlying cardiac substrate among S-ICD recipients and its impact on long-term device-related outcomes: Real-world insights from the iSUSI registry

BackgroundOutcome comparisons among subcutaneous implantable cardioverter-defibrillator (S-ICD) recipients with nonischemic cardiomyopathies are scarce. ObjectiveThe aim of this study was to evaluate differences in device-related outcomes among S-ICD recipients with different structural substrates. MethodsPatients enrolled in the i-SUSI (International SUbcutaneouS Implantable cardioverter defibrillator registry) project were grouped according to the underlying substrate (ischemic vs nonischemic) and subgrouped into dilated cardiomyopathy, hypertrophic cardiomyopathy, Brugada syndrome (BrS), arrhythmogenic right ventricular cardiomyopathy (ARVC). The main outcome of our study was to compare the rates of appropriate and inappropriate shocks and device-related complications. ResultsAmong 1698 patients, the most common underlying substrate was ischemic (31.7%), followed by dilated cardiomyopathy (20.5%), BrS (10.8%), hypertrophic cardiomyopathy (8.5%), and ARVC (4.4%). S-ICD for primary prevention was more common in the nonischemic cohort (70.9% vs 65.4%; P = .037). Over a median (interquartile range) follow-up of 26.5 (12.6–42.8) months, no differences were observed in appropriate shocks between ischemic and nonischemic patients (4.8%/y vs 3.9%/y; log-rank, P = .282). ARVC (9.0%/y; hazard ratio [HR] 2.492; P = .001) and BrS (1.8%/y; HR 0.396; P = .008) constituted the groups with the highest and lowest rates of appropriate shocks, respectively. Device-related complications did not differ between groups (ischemic: 6.4%/y vs nonischemic: 6.1%/y; log-rank, P = .666), nor among underlying substrates (log-rank, P = .089). Nonischemic patients experienced higher rates of inappropriate shocks than did ischemic S-ICD recipients (4.4%/y vs 3.0%/y; log-rank, P = .043), with patients with ARVC (9.9%/y; P = .001) having the highest risk, even after controlling for confounders (adjusted HR 2.243; confidence interval 1.338–4.267; P = .002). ConclusionMost S-ICD recipients were primary prevention nonischemic cardiomyopathy patients. Among those, patients with ARVC tend to receive the most frequent appropriate and inappropriate shocks and patients with BrS the least frequent appropriate shocks.

Association of Device-Detected Atrial High-Rate Episodes With Long-term Cardiovascular and All-Cause Mortality: A Cohort Study

BackgroundDevice-detected atrial high-rate episodes (AHREs) were associated with an increased thromboembolic risk. Although limited data regarding the long-term prognosis of patients with AHRE were controversial, this study aimed to identify the association of device-detected AHRE with mortality. MethodsThis observational study included patients with implantable cardioverter defibrillator (ICD) or cardiac resynchronization therapy defibrillator (CRT-D) placement and no history of atrial fibrillation (AF), atrial flutter (AFL), or atrial tachycardia (AT). During follow-up, patients with at least 1 day of AHRE duration ≥ 15 minutes were identified. The primary endpoint was cardiovascular mortality, and the secondary endpoint was all-cause mortality. ResultsDuring a mean follow-up period of 4.2 years, AHREs were detected in 124 of 343 (36.2%) patients. Of these, 44 deaths (35.5%) occurred in 124 patients with AHREs, which was significantly higher than those without AHREs (43 of 219; 19.6%; P = 0.001). The multivariate analysis revealed that patients with AHRE had a significantly higher risk of cardiovascular (hazard ratio [HR], 2.40; 95% confidence interval [CI], 1.23-4.67; P = 0.010), and all-cause mortality (HR, 2.31; 95% CI, 1.49-3.59; P < 0.001). Further analysis indicated that this association remained significant in patients with higher burden (≥ 6 hours) but not in patients with lower burden (≥ 15 minutes to 6 hours). Notably, even after excluding the patients diagnosed with clinical AF during follow-up, the remaining patients with AHREs still exhibited a higher risk of cardiovascular and all-cause mortality compared with patients without AHREs. ConclusionsAHREs were prevalent in ICD or CRT-D recipients with no history of clinical AF, AFL, or AT and were associated with more than twice the risk of cardiovascular and all-cause mortality. Clinical Trial RegistrationNo. ChiCTR-ONRC-13003695.

Changes in medical therapy after cardiac resynchronization in patients with heart failure: insights from the U.S. Veterans Affairs healthcare system

Abstract Background Patients with heart failure with reduced ejection fraction (HFrEF) are often not treated with comprehensive guideline directed medical therapy (GDMT) due to hemodynamic and renal limitations. Cardiac resynchronization therapy (CRT) improves hemodynamics in patients with HFrEF and ventricular dyssynchrony. Whether CRT facilitates intensification of GDMT in patients with HFrEF has not been well-studied. Purpose To assess pre-procedure GDMT (B-blocker, ACEI [angiotensin converting enzyme inhibitor]/ARB [angiotensin receptor blocker], ARNI [angiotensin receptor neprilysin inhibitor], MRA [mineralocorticoid receptor antagonist], SGLT2i [sodium-glucose cotransporter-2 inhibitor]) utilization in HFrEF patients who received CRT and to compare changes in GDMT in patients who received CRT with patients who received implantable cardioverter-defibrillator (ICD). Methods Veterans with left ventricular ejection fraction (LVEF) 35% who received CRT or ICD from Feb 22, 2000 – Jul 28, 2022 were identified. Patients with end-stage renal disease were excluded. Changes in GDMT 12-months following device implant were characterized and compared between CRT and ICD recipients. Mixed effects logistic regression models were generated to evaluate associations between receipt of CRT and the composite of therapy initiation, dose increase, or target dose achievement compared with ICD. Models were adjusted for clinical characteristics and pre-implant GDMT utilization. Similar models were developed to evaluate the adjusted associations between CRT and changes in estimated glomerular filtration rate (eGFR) and blood pressure (BP) compared with ICD. Results A total of 2,082 CRT recipients and 7,263 ICD recipients were identified. Pre-procedure heart rate, BP, serum potassium, and eGFR were within normal ranges and similar between groups. Prior to device implant, ACEI/ARB/ARNI were most frequently prescribed (91%), followed by -blockers (88%), MRA (46%), and SGLT2i (33% in post-SGLT2i era). Pre-procedure GDMT was similar between CRT and ICD recipients. At 12 months follow-up, CRT was independently associated with increased odds of therapy initiation, dose increase, or target dose achievement for ACEI/ARB/ARNI, ARNI, B-blockers, and MRA (Figure 1). ICD was associated with a decline in eGFR while CRT was associated with an increase in eGFR (mean [standard deviation]: -0.95 [0.17] vs. +0.6 [0.29]; p&amp;lt;0.01), while no differences were observed in BP or LVEF at 12 months. Conclusions In a large, contemporary cohort of patients with HFrEF, most patients were not prescribed MRA or SGLT2i prior to receiving CRT or ICD despite no apparent renal or blood pressure-related contraindications. CRT is associated with increased odds of the composite of initiation, dose increase, or target dose achievement for ACEI/ARB/ARNI, ARNI, B-blockers, and MRA compared with ICD. GDMT intensification may be mediated by beneficial changes in kidney function in CRT recipients.Figure 1

Temporal trends in baseline characteristics of implantable cardioverter defibrillator recipients for primary prevention of sudden cardiac death- The DAIPP program

Abstract Introduction Since expanding the indication for implantable cardioverter defibrillators (ICD) to primary prevention, the patient population of ICD carriers continues to evolve over time. In pursuit of progressively decreasing the burden of sudden cardiac death, improved patient selection and risk-benefit assessment demand, among others, awareness of these temporal changes in clinical baseline characteristics of the ICD population. Purpose The aim was to explore the temporal differences in baseline characteristics of ICD recipients implanted for primary prevention of sudden cardiac death (SCD), and perioperative complications, to improve understanding of ICD population selection over the last two decades in a real-world setting. Methods The Primary Prevention ICD French Registry (DAI-PP program) was initiated in 2002 with an overall aim to assess the risk-benefit ratio of the introduction of ICD for primary prevention over a 20-year period, including a pilot evaluation that finished in 2012. The pilot study laid ground for the ongoing prospective DAIPP Consortium that started in 2018 and is aiming to follow 10000 patients under remote monitoring, using a specific integrational research platform. The two cohorts are in this study compared with regards to baseline characteristics as well as perioperative outcomes, i.e., early mortality and procedural complications. Results This study included 8432 participants, 5521 from the pilot study and 2211 from the prospective trial, with a median follow up of 2.36 (IQR 1.25-3.75) years. Median age was 64 (IQR 56-71) years, 17% female and 61% had ischemic heart disease. Baseline characteristics that remained stable over time were age, cancer burden. Compared to the 2002-2012 period, recent findings found a significant increase in the proportion of females (15 vs 20%, p &amp;lt;0.001), pauci-symptomatic patients (New York Heart Association Functional class-NYHA II, 41 vs. 57%, p &amp;lt;0.001), narrow QRS patients (31 vs. 43%, p&amp;lt;0.001), use of subcutaneous ICD (0 vs. 14%, P&amp;lt;0.001) and more comorbidities including an increase in diabetes, and slight increase in stroke. Regarding pharmacological treatment, there was an increase in use of 2 or 3 medications (2: 6.5% to 16% p&amp;lt;0.001; 3: 20% to 33%, p&amp;lt;0.001) where more received beta blockers and amiodarone in the contemporary study. Perioperative complications decreased over time (13% to 7.9% p&amp;lt;0.001) with a decrease in early reinterventions (1.3% to 0.1% p&amp;lt;0.001) and discrete fall in number of infections (0.7% to 0.1%, p&amp;lt;0.001) and pocket hematoma (4.4% to 3.0% p&amp;lt;0.001). A slight upward trend in number of lead dislodgements was seen over time (1.3% to 1.7% p&amp;lt;0.001). See Table 1 for perioperative complications. Conclusion The primary prevention ICD population has significantly changed over time. An increase in women, comorbidities, and use of 2-3 medications was seen, coupled with more participants receiving a subcutaneous ICD. Perioperative complications decreased over time.

Cardiac magnetic resonance for prophylactic implantable-cardioVerter defibrillator therapy international registry in patients with ischemic cardiomyopathy

Abstract Background Sudden cardiac death (SCD) in patients with ischemic cardiomyopathy (ICM) remains a leading cause of death. Current guidelines provide a class I recommendation for implantable cardioverter–defibrillator (ICD) implantation in ICM patients with transthoracic echocardiographic (TTE) left ventricular ejection fraction (LVEF) ≤35%. and NYHA functional class II or III. The current paradigm is suboptimal in identifying patients who are likely to benefit. In fact, only a relatively small proportion of ICD recipients for SCD primary prevention receive appropriate device therapy and instead there is a not negligible percentage of patients who experienced SCD event despite not fulfilling criteria for implantation. Purpose The DERIVATE-ICM registry sought to evaluate the additional prognostic value for the indication of ICD implantation using cardiac magnetic resonance (CMR) as compared to standard of care based on TTE in a large cohort of ICM patients. Methods We enrolled 861 ICM patients (86% male, mean age 65±11 years) with chronic heart failure and TTE-LVEF&amp;lt;50%. Major adverse arrhythmic cardiac events (MAACE), defined as the combination of SCD, aborted SCD event, and sustained ventricular tachycardia. were the primary endpoint. Independent predictors were used to calculate a CMR risk score for each patient. Risk levels were defined as low (quantile 1 [Q1]), medium (Q2 and Q3) and high (Q4). Results During a median follow-up of 1054 days, MAACE occurred in 88 (10.2%). Left ventricular end-diastolic volume index (HR:1.007, 95%CI:1.000-1.011, p=0.05), CMR-LVEF (HR:0.972, 95%CI: 0.945-0.999, p=0.045) and late gadolinium enhancement (LGE) mass (HR:1.010, 95%CI: 1.002–1.018, p=0.015) were independent predictors of MAACE. Based on the multivariate analysis, CMR weighted risk score was developed according to the following equation [0.005 * EDV/BSA (mL/m2) – 0.029 * LVEF (%) + 0.010 * LGE ischemic mass (g)]. A multiparametric CMR weighted predictive derived score effectively identifies subjects at high risk for MAACE as compared to TTE-LVEF cut-off of 35% with a Continuous NRI: 31.7% (95%CI: 8.6%-54.8%, p=0.007) (Figure 1, Figure 2). Conclusions In this large multicenter registry, a multi-parametric CMR predictive model provides additional prognostic stratification for MAACE predictions in a large cohort of ICM patients as compared to standard of care. This model identifies a large number of patients with TTE-LVEF&amp;lt;35% at low risk of SCD event and on the other side it identifies a subset of patients who are at high risk of MAACE despite TTE-LVEF≥35% (i.e. the population currently not fulfilling the guideline-based criteria for ICD implantation). Further randomized trials to test a CMR guided strategy for ICD implantation versus standard of care are now needed.Kaplan-Meier curvesEvent rate redistribution

Information provision and follow-up of French patients with implantable cardioverter-defibrillators: The APODEC survey

BackgroundImplantable cardioverter-defibrillators reduce mortality, but the electric shocks delivered can impact the patient's quality of life. Patient education is an efficient way to reduce the stress related to both the device and the disease. AimsWe assessed the evolution of knowledge and satisfaction of implantable cardioverter-defibrillator recipients regarding their cardiac disease, implantable cardioverter-defibrillator implantation, follow-up complications, remote monitoring and daily life recommendations. Quality of life, implantable cardioverter-defibrillator-related stress levels and remote monitoring benefits were also evaluated. MethodsA self-administered questionnaire of 43 items was published on the French Association of Cardiac Electrical Device Wearers (APODEC) website and sent to registered patients. ResultsOverall, 330 patients completed the survey. Physicians were the patients’ principal information source regarding their cardiac disease (86.7%) and implantable cardioverter-defibrillator (93.3%), and 90% looked for further information after the procedure, mainly on websites (78.8%). More than half of the patients were not sufficiently informed about implantable cardioverter-defibrillators before implantation (61.2%). In the patients’ opinion, the best sources of further information were their physician (81.8%), patient associations (63.6%) and the Internet (45.8%). Although patient knowledge increased during follow-up, their knowledge could be improved regarding daily life with an implantable cardioverter-defibrillator (52.1%), remote monitoring (34.2%) and their cardiac disease (32.1%). Remote monitoring follow-up was used by 92.1% of patients and mostly improved their peace of mind (67.8%). Implantable cardioverter-defibrillator shocks were associated with major stress for patients receiving them (46.6%). ConclusionThese findings highlight the lack of information provided to implantable cardioverter-defibrillator recipients before implantation, a concerning issue to be addressed in the near future.

Machine learning-derived cycle length variability metrics predict spontaneously terminating ventricular tachycardia in implantable cardioverter defibrillator recipients.

Implantable cardioverter defibrillator (ICD) therapies have been associated with increased mortality and should be minimized when safe to do so. We hypothesized that machine learning-derived ventricular tachycardia (VT) cycle length (CL) variability metrics could be used to discriminate between sustained and spontaneously terminating VT. In this single-centre retrospective study, we analysed data from 69 VT episodes stored on ICDs from 27 patients (36 spontaneously terminating VT, 33 sustained VT). Several VT CL parameters including heart rate variability metrics were calculated. Additionally, a first order auto-regression model was fitted using the first 10 CLs. Using features derived from the first 10 CLs, a random forest classifier was used to predict VT termination. Sustained VT episodes had more stable CLs. Using data from the first 10 CLs only, there was greater CL variability in the spontaneously terminating episodes (mean of standard deviation of first 10 CLs: 20.1 ± 8.9 vs. 11.5 ± 7.8 ms, P < 0.0001). The auto-regression coefficient was significantly greater in spontaneously terminating episodes (mean auto-regression coefficient 0.39 ± 0.32 vs. 0.14 ± 0.39, P < 0.005). A random forest classifier with six features yielded an accuracy of 0.77 (95% confidence interval 0.67 to 0.87) for prediction of VT termination. Ventricular tachycardia CL variability and instability are associated with spontaneously terminating VT and can be used to predict spontaneous VT termination. Given the harmful effects of unnecessary ICD shocks, this machine learning model could be incorporated into ICD algorithms to defer therapies for episodes of VT that are likely to self-terminate.

QRS complex and T wave planarity for the efficacy prediction of automatic implantable defibrillators

ObjectiveTo test the hypothesis that in recipients of primary prophylactic implantable cardioverter-defibrillators (ICDs), the non-planarity of ECG vector loops predicts (a) deaths despite ICD protection and (b) appropriate ICD shocks.MethodsDigital...

Association between nighttime heart rate and cardiovascular mortality in patients with implantable cardioverter-defibrillator: A cohort study

Although studies have shown that an increased resting heart rate measured randomly at a single point of the day has been associated with adverse cardiovascular outcomes, the utility of continuous monitoring of nighttime heart rate (NTHR) has remained largely uninvestigated. This study aimed to explore the association between NTHR and cardiovascular mortality. The Study of Home Monitoring System Safety and Efficacy in Cardiac Implantable Electronic Device-implanted Patients, which is a prospective cohort study, enrolled patients with implantable cardioverter-defibrillator (ICD) or cardiac resynchronization therapy defibrillator between 2010 and 2015. Baseline NTHR was measured during the programmed sleep period from 30 to 60 days after implantation. The primary outcome was cardiovascular mortality, fitted by a restricted cubic spline function. A total of 534 implantable cardioverter-defibrillator recipients with sinus rhythm during the detection window were included in the study. The mean baseline NTHR was 59.6 ± 8.0 beats/min. During the follow-up period of 60.4 ± 21.8 months, 88 (16.5%) patients experienced cardiovascular mortality. After considering potential confounders, a linear association was observed. Each 1 beat/min increase in NTHR was associated with a 7.8%, 10.1%, and 5.7% increase in the risk of cardiovascular mortality in the total population, patients with heart failure, and patients without heart failure, respectively. Continuous monitoring of NTHR may identify patients at high risk of cardiovascular mortality in a timely manner, with the potential for "preemptive" action. No. ChiCTR-ONRC-13003695.

Effect of Carvedilol vs Metoprolol on Atrial and Ventricular Arrhythmias Among Implantable Cardioverter-Defibrillator Recipients

BackgroundBoth selective and nonselective beta-blockers are used to treat patients with heart failure (HF). However, the data on the association of beta-blocker type with risk of atrial arrhythmia and ventricular arrhythmia (VA) in HF patients with a primary prevention implantable cardioverter-defibrillator (ICD) are limited. ObjectivesThis study sought to evaluate the effect of metoprolol vs carvedilol on the risk of atrial tachyarrhythmia (ATA) and VA in HF patients with an ICD. MethodsThis study pooled primary prevention ICD recipients from 5 landmark ICD trials (MADIT-II, MADIT-CRT, MADIT-RIT, MADIT-RISK, and RAID). Fine and Gray multivariate regression models, stratified by study, were used to evaluate the risk of ATA, inappropriate ICD shocks, and fast VA (defined as ventricular tachycardia ≥200 beats/min or ventricular fibrillation) by beta-blocker type. ResultsAmong 4,194 patients, 2,920 (70%) were prescribed carvedilol and 1,274 (30%) metoprolol. The cumulative incidence of ATA at 3.5 years was 11% in patients treated with carvedilol vs 15% in patients taking metoprolol (P = 0.003). Multivariate analysis showed that carvedilol treatment was associated with a 35% reduction in the risk of ATA (HR: 0.65; 95% CI: 0.53-0.81; P < 0.001) when compared to metoprolol, and with a corresponding 35% reduction in the risk of inappropriate ICD shocks (HR: 0.65; 95% CI: 0.47-0.89; P = 0.008). Carvedilol vs metoprolol was also associated with a 16% reduction in the risk of fast VA. However, these findings did not reach statistical significance (HR: 0.84; 95% CI: 0.70-1.02; P = 0.085). ConclusionsThese findings suggests that HF patients with ICDs on carvedilol treatment experience a significantly lower risk of ATA and inappropriate ICD shocks when compared to treatment with metoprolol.