Cardioverter-defibrillator Implantation Research Articles

Abstract 4119472: Predictors of Sudden Cardiac Death in Patients with Atrial Fibrillation and No Apparent Risk Factor of Sudden Cardiac Death

Background: Atrial fibrillation (AF) is associated with sudden cardiac death (SCD). It is known that AF is associated with multiple traditional risk factors of SCD, such as coronary artery disease (CAD), history of myocardial infarction (MI), left ventricular hypertrophy (LVH) and low left ventricular ejection fraction (LVEF). However, AF per se could predispose SCD not mediated by these cardiovascular risk factors, and predictors of SCD in AF patients without these apparent SCD risk factors are unknown. Methods: Using the NTUH iMED database, AF patients without apparent SCD risk factors were longitudinal followed up from Jan. 2010 to Dec. 2021. The primary outcome was implantation of implantable cardioverter defibrillator (ICD) due to SCD. Cox regression was used to identify the predictors of SCD. Results: A total of 11250 AF patients without cardiovascular SCD risk factors and LVEF ≥55 % were longitudinally followed up. We first found CHA2DS2-VASc score did not predict SCD event. We found male gender (hazard ratio [HR ] 1.71 [1.05-2.78 ], p =0.032), hyperthyroidism (HR 3.50 [1.40-8.77 ], p=0.007）and paroxysmal AF (PAF)(HR 2.86 [1.63-5.04 ], p<0.001）were associated with higher SCD risks. We created a AFSCD score using these parameters. We found SCD risk incrementally increased with increasing AFSCD score (p <0.001 for trend). Patients with highest score (5 points) had more than 3-fold SCD risk compared with those with 0-point score (1.18 % person-year vs 0.36 %, p<0.001). The C statistic of AFSCD score was significantly higher than CHA2DS2-VASc score (0.64 [0.57-0.70] vs 0.40 [0.33-0.48], p <0.01). Conclusions: Male gender, hyperthyroid AF and PAF were predictors of incident SCD in AF patients and AFSCD scoring scheme based on these risk factors could possibly be implemented in clinical practice.

Abstract 4120434: A Rare Case Of Localized Ventricular Tachycardia Due To Mitral Annular Disjunction And a Subvalvular Aneurysm

Introduction: Mitral annular disjunction (MAD) is an abnormality of the mitral valve where a portion of the mitral annulus and valve leaflets insert into the left atrium away from the fibrous annulus. Since its identification in 1981 its diagnosis has increased due to the advancements in cardiac imaging. It’s association with ventricular arrythmia (VA) and sudden cardiac death (SCD) underscores the importance of its identification. We present a case of ventricular tachycardia (VT) that is attributed to MAD with associated sub-mitral valve left ventricular aneurysm (SMA) formation. Case: A 51-year-old African American male with history of posterior papillary muscle premature ventricular contractions (PVC), PVC induced cardiomyopathy, and family history of sudden cardiac death in his mother who presented to the emergency department due to palpitations. Electrocardiogram (ECG) showed sustained monomorphic VT at a rate of 160 bpm. This converted to normal sinus rhythm with intravenous amiodarone and metoprolol. Further work up included cardiac magnetic resonance which identified a 4 x 1.8 x 1.4 cm SMA on the basal inferior and inferolateral walls. There was near transmural late gadolinium enhancement (LGE) of the aneurysm and an associated 7 mm of MAD with posterior mitral valve prolapse (MVP). He underwent left heart catheterization which was normal. ECG showed a superior right axis with associated right bundle branch block which correlated to a basal inferolateral exit and to the location of the SMA. Ultimately the patient underwent implantation of secondary prevention implantable cardioverter-defibrillator and initiation of sotalol. Discussion: The prevalence of MAD is approximately 30% in those with MVP and 8% in the general population. Those patients with MAD and MVP appear to be at higher risk for VA and SCD. The most likely mechanism for this association is the fibrotic changes that occur in the basal inferolateral left ventricle because of mechanical stretch on the papillary muscles by the prolapsing leaflets. The scar and aneurysm that develop can serve as substrate for reentrant VA. Treatment for this involves surgical repair of the mitral valve annulus and correction of the MAD distance which has been shown to improve arrythmia. Conclusion: This case illustrates an important but poorly understood arrhythmogenic entity that will increase in incidence as cardiac imaging advances. Its implications in VA and SCD warrant further research.

Abstract 4120249: What Happens to Automated External Defibrillator Rhythm Strips after a Cardiac Arrest?

Background: Following an out of hospital cardiac arrest (OHCA), rhythm strips stored on an automated external defibrillator (AED) help guide important medical decisions, including possible implantable cardioverter defibrillator (ICD) implantation. However, this information is often difficult to obtain. Objective: To evaluate how frequently AED rhythm strips are reviewed following an OHCA prior to placing an ICD. Methods: Using the Cardiac Arrest Registry to Enhance Survival (CARES), we identified patients from 1/2015-12/2023 who were transferred to our institution following an OHCA. Patients were excluded if resuscitation was not attempted, death occurred during the hospitalization or patient identifying information was not available. Results: Of 907 OHCAs identified, 119 patients ( Table 1 ) met the inclusion criteria. The AED rhythm strip was in the electronic medical record on hospital arrival in 22% of cases and only after provider initiation in 6% of cases. None of the rhythm strips from a bystander-only delivered AED shock (n=17) were available on arrival, with only 24% retrieved during the hospitalization, taking 4.5±2.1 days from the date of arrest. Patients with an AED rhythm strip available (n=34) were more likely than those without a rhythm strip (n=85) to have a cardiac MRI (38% v. 13%, p=0.02) and genetic testing (15% v. 1%, p=0.02) done and have an ICD placed (53% v. 27%, p=0.04) or be discharged on a new anti-arrhythmic drug (15% v. 4%, p=0.04). Figure 1 Of the 42 patients who had an ICD placed during the index hospitalization, 54% were implanted without knowing the type of shockable rhythm or confirmation that an appropriate AED shock had been delivered. Conclusion: Rhythm strips help guide clinical decisions when assessing the need for ICD implantation. There is a systems gap in the process of transferring rhythm strips from AEDs to hospital providers following an OHCA.

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.

Incidence of ventricular arrhythmias after implantable cardioverter-defibrillator implantation or replacement, and driving restriction consequences

BackgroundFollowing implantation/replacement of an implantable cardioverter-defibrillator, patients are legally subjected to variable lengths of driving restrictions based on the indication (1 and 3 months after primary and secondary prevention, respectively; 1 week after device replacement). AimTo assess the incidence of ventricular arrhythmia during the theoretical driving restriction period in a large cohort of patients. MethodsPatients who underwent implantable cardioverter-defibrillator implantation for primary or secondary prevention or device replacement between 2015 and 2021 were included retrospectively. The primary endpoint was the occurrence of ventricular arrhythmia during the theoretical driving restriction period, as defined by guidelines. ResultsA total of 914 patients were analysed, including 654 first implantations (438 and 216 for primary and secondary prevention, respectively) and 260 device replacements. The primary outcome occurred in 2/438 patients (0.004%) during the 1-month period following device implantation for primary prevention and in 25/216 patients (11.5%) during the 3-month period following device implantation for secondary prevention; it did not occur in the 1-week period following device replacement. The monthly calculated risk of harm remained below the accepted threshold of 0.005% for each group. ConclusionsPrimary prevention patients, such as those who have undergone device replacement, have a low risk of ventricular arrhythmia, which could lead to a reduction in their driving restriction period. Secondary prevention patients experienced a higher risk of recurrent ventricular arrhythmia, supporting the 3-month driving restriction period.

Association of BMI with adherence and outcome in heart failure patients treated with wearable cardioverter defibrillator.

Obesity is a known risk factor for cardiovascular disease (CVD), yet an 'obesity paradox' has been observed in various CVD contexts. The impact of obesity on heart failure (HF) patients treated with a wearable cardioverter-defibrillator (WCD) remains underexplored. In a multicentre international registry, we retrospectively collected data from a consecutive series of 1003 patients. These patients were divided into three body mass index (BMI) groups: <25kg/m2 (n=348), 25-30kg/m2 (n=383), and >30kg/m2 (n=272), with BMI>30kg/m2 defined as the reference category. Demographics, indications, adherence, WCD shocks, arrhythmic events, rehospitalization due to cardiovascular causes, and mortality were analysed. At 3month follow-up, patients with a BMI>30 showed the greatest improvement in left ventricular ejection fraction (LVEF) at 51.4%, significantly higher than the 41.4% in those with a BMI<25 (P=0.017) and comparable with the 49.4% in the BMI 25-30 group (P=0.635). WCD wearing time and adherence were similar across all BMI groups. The incidence of WCD shock was similar across BMI groups. Rates of ventricular tachycardia (VT), ventricular fibrillation and non-sustained VT (ns-VT) were comparable across BMI groups. The rate of implantable cardioverter-defibrillator (ICD) implantation was 40.3% across all patients, with a slightly lower rate in the BMI>30 group (36.8%) compared with others, although not significantly. Rehospitalization due to cardiovascular causes was significantly lower in the BMI>30 group (55.4%) compared with the BMI 25-30 group (70.9%; P=0.048), but similar to the BMI<25 group (54.9%; P=0.957). At 2year follow-up, mortality was lower in the BMI>30 group (5.9%) compared with the BMI<25 (7.5%; P=0.029) and BMI 25-30 groups (7%; P=0.681). In multivariable analysis, LVEF at long term was significantly associated with a reduction in mortality. Obese patients exhibited significantly greater improvement in LVEF, which was associated with reduced mortality. Adherence to WCD therapy was excellent across all BMI groups. ICD implantation occurred in 40.3% of patients, with similar WCD shock rates and arrhythmic events across BMI groups. An obesity paradox was observed, with obese patients demonstrating significantly lower rehospitalization rates due to cardiovascular causes and reduced mortality at follow-up.

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.

Prognostic yield of echocardiographic measures of cardiac structure and function in HFrEF patients with vs without an ICD or CRT-D

Abstract Background Selected echocardiographic measures of cardiac structure and function are known to be associated with mortality in patients with Heart Failure with reduced Left Ventricular (LV) Ejection Fraction (HFrEF). Whether the predictive ability of measures of cardiac structure and function remain after implantation of an Implantable Cardioverter Defibrillator (ICD) or Cardiac Resynchronization Therapy-Defibrillator (CRT-D) is unknown among patients with HFrEF. Purpose To compare the predictive ability of echocardiographic measures of cardiac structure and function in HFrEF patients with or without an ICD/CRT-D. Methods Echocardiographic examinations were performed between 2003 and 2013 and retrieved from 2168 patients with HFrEF. Patients that had an ICD or CRT-D implanted during follow-up were identified through registries. The endpoint was all-cause mortality and follow-up was 100% to date. Images were analyzed offline in accordance with current guidelines. Associations were assessed by Cox multivariable regression and Cox univariable interaction models. Results After a median of 169 days, 677 patients had an ICD or CRT-D implanted. In total, 68% vs 80% of patients with and without an ICD, respectively, were men (p&amp;lt;0.001) and the median age were 70 vs 71 years (p=0.192). There was a significant difference in resting heart rate (median 74 vs 69, p&amp;lt;0.001) and frequency of ischemic heart disease (64% vs 81%, p&amp;lt;0.001) between the groups. Patients with an ICD had a higher mortality rate (69 per 1000 people/year vs 92 per 1000 people/year, p&amp;lt;0.001) and died significantly faster (median 9.3 vs 8.2 years, p&amp;lt;0.001). Patients with an ICD had higher Left Atrial (LA) End Systolic Volume (59.2 vs 67.3, p&amp;lt;0.001), LA Volume Index (28.5 vs 33.9, p&amp;lt;0.001), LV End Diastolic Volume (137.7 vs 153.7, p&amp;lt;0.001), and LV Mass Index (114.5 vs 124.5, p&amp;lt;0.001), as well as lower LA strain (9.8 vs 6.3, p&amp;lt;0.001) and TAPSE (2.0 vs 1.7, p&amp;lt;0.001). In patients without an ICD, Right Ventricular strain was associated with mortality (HR = 1.05 per 1% decrease mm/m2 [1.005, 1.11] when adjusting for covariates whereas in patients with an ICD, LA Volume Index (HR 1.14 per 1 increase [1.03, 1.25], and LV Ejection Fraction (HR 0.96 per 1% increase [0.92, 0.99]) were associated with mortality when adjusting for covariates. ICD/CRT-D implantation significantly modified the prognostic yield of LV End Diastolic Volume (HR per 1 ml increase: 0.99 without vs 1.01 with an ICD/CRT-D, p=0.005) and LV Mass Index (HR per 1 g/m2 increase: 1.00 without and 1.01 with an ICD/CRT-D, p=0.031). Conclusion Different echocardiographic measures were stronger prognosticators in HFrEF patients with and without an ICD or CRT-D, respectively, and ICD implantation modified the prognostic yield of LV End Diastolic Volume and LV Mass Index in HFrEF patients.Table 1Forest plot

Epicardial ablation in patients with Brugada syndrome: a single centre experience

Abstract Introduction Brugada syndrome (BrS) is a rare disease associated with an increased risk of ventricular fibrillation (VF), ventricular tachycardia (VT), and sudden cardiac death (SCD). The standard prevention of SCD in patients with BrS is the implantation of an implantable cardioverter-defibrillator (ICD), especially in patients who have previously suffered cardiac arrest or arrhythmogenic syncope. Catheter ablation is an effective method to prevent recurrences of VF/VT in these patients. Purpose Retrospective analysis of the results of catheter ablation by epicardial approach and genetic testing in patients with a diagnosis of BrS and repeated adequate ICD interventions. Methods In 2013-2024, catheter ablation by epicardial approach was performed in our centre in 9 patients diagnosed with Brugada syndrome (mean age 41±6 years, nine males, left ventricular ejection fraction 57±4%). All patients had an ICD implanted for secondary prevention of SCD and presented with adequate ICD therapies (mean 9±11 shocks/patient in the last six months before catheter ablation). Before catheter ablation, two patients were treated with quinidine. Patients underwent cardiogenetic testing by next-generation sequencing of 228 genes. Results Type 1 electrocardiogram (ECG) pattern was present at baseline ECG in four (44%) patients; in five (56%) patients, type 1 was induced after ajmaline administration. Genetic testing was performed in seven patients, and only one patient (14%) was found to have a relevant pathogenic mutation in the SCN5A gene. Prior to ablation, sustained VT/VF could be induced by programmed electrical stimulation in three patients (33%). Epicardial ablation was targeted at areas of abnormal electrograms located over the right ventricular outflow tract. No complications were noted. The mean follow-up period was 25±30 months. In one patient (11%), reablation was required to suppress ventricular arrhythmias successfully. After the last ablation, no recurrence of VT/VF was observed in any patient. Conclusions Epicardial ablation is an effective method that leads to the suppression of ventricular arrhythmias in patients with a diagnosis of BrS and repeated ICD interventions. Despite the malignant arrhythmic phenotype, patients in our cohort had a rather low prevalence of signs associated with a high risk of VT/VF, such as spontaneous ECG pattern of BrS, inducibility of VT/VF during electrical programmed stimulation, or the presence of a causative genetic mutation.

Risk stratification for a primary prevention ICD: Performance of the MADIT-ICD Benefit Score in contemporary real world patients

Abstract Background We have recently developed the MADIT-ICD Benefit Score to improve risk stratification for primary implantable cardioverter defibrillator (ICD) implantation by assessing the competing risk of life-threatening ventricular tachyarrhythmia (VTA) vs. non-arrhythmic mortality based using simple clinical variables. Patients with a MADIT-ICD Benefit Score of &amp;lt; 50 are more likely to experience non-arrhythmic mortality than life-threatening VTA, and therefore derive limited benefit from a prophylactic ICD. Purpose We aimed to provide data on the performance of the MADIT-ICD Benefit Score in a real world population, comprising patients with HFrEF and either ischemic or nonischemic cardiomyopathy (ICM/NICM) who are treated with contemporary guideline-directed medical therapy (GDMT). Methods The study population comprised 2875 patients who were implanted with a primary prevention ICD and prospectively followed in a large tertiary healthcare system (the University of Rochester Medical Center, including 3 affiliated hospitals in Upstate New York) between 2017 through 2023. Arrhythmic events were captured from device interrogation data, which were blindly adjudicated by 2 electrophysiologists. Results Among the 2875 study patients, mean age was 62 ± 15 years, 1265 (44%) were women, and 1667 (58%) had ICM. Guideline-directed medical therapies, including angiotensin-converting enzyme inhibitors or angiotensin receptor blockers, angiotensin receptor/neprilysin inhibitors, beta-blockers, mineralocorticoid receptor antagonists, and sodium-glucose transport protein 2 (SGLT2) inhibitors, were prescribed to 43%, 36%, 96%, 67% and 32% of study patients, respectively. The 2-year cumulative incidence of VTA, after accounting for the competing risk of death, was 19% vs. 11% in patients with a Score of ≥50 vs. &amp;lt;50, respectively (p&amp;lt;0.001; Figure 1A). Findings regarding ICD shocks were consistent (8% vs. 4%, respectively, p&amp;lt;0.001; Figure 1B) The rate of VTA events at 4 years was directly correlated with increasing quartiles of the MADIT-ICD Benefit Score, while the corresponding rates of non-arrhythmic mortality were inversely correlated with score quartiles (Figure 1C). A similar direct correlation with increasing Benefit Score quartiles was observed when the endpoint of ICD shocks was assessed (Figure 1D). Accordingly, the benefit of the ICD (calculated as the difference between predicted rates of VTA/shock events and corresponding rates of non-arrhythmic mortality) was attenuated with decreasing quartiles of the MADIT-ICD Benefit Score (Figures 1C and 1D; right column). Conclusions We show good performance of the MADIT-ICD Benefit Score in a large cohort of real world ICD recipients who are treated with contemporary GDMT. These data support the use of the MADIT-ICD Benefit Score for improved risk stratification and for shared decision-making in contemporary candidates for a primary prevention ICD.

Novel electric predictors of lethal arrhythmic event in patients with hypertrophic cardiomyopathy

Abstract Background Little is known regarding the association between electrical markers and lethal arrhythmic events (LAE) in patients with hypertrophic cardiomyopathy (HCM). This study aimed to identify the electrical predictors of LAE in adult patients with HCM. Methods This study was a retrospective analysis of patients with HCM at a single center from 1998 to 2021. LAE was defined as a composite outcome of (1) sustained ventricular arrhythmia, (2) aborted sudden cardiac death (SCD), (3) implantable cardioverter defibrillator (ICD) implantation, and (4) appropriate ICD shock. A 12-lead electrocardiography was performed at the time of diagnosis. Results A total of 611 patients with HCM were analyzed, and 48 (7.8%) experienced LAE. Patients who experienced LAE were diagnosed at a younger age and more frequently had history of ventricular arrhythmia, new-onset atrial fibrillation (AF) or non-sustained ventricular tachycardia. New-onset AF, an increase in the QTc interval, and the absence of massive LVH were associated with LAE risk. In addition to conventional markers of HCM Risk-SCD, consideration of the QTc interval and massive LVH on electrocardiography improved the prediction of LAE (area under curve 0.682 to 0.740). Further inclusion of new-onset AF, history of ventricular arrhythmia, HCM type, and left ventricular mass index improved the predictability to 0.867. Conclusion An increase in the QTc interval, the absence of a massive LVH pattern on electrocardiography (ECG), and new-onset AF were independently associated with an increased risk of LAE. Comprehensive stratification using electrical markers improves the prediction of LAE when combined with conventional markers.

Comparison of ICD implantation approach in children. The IChilDren study

Abstract Background Without dedicated device, implantable cardioverter defibrillators (ICD) implantation in children is a real challenge for physicians. Types of implantation include transvenous, surgical and subcutaneous-ICD approach, but with a lack of reliable data comparing their respective efficacy and safety. Objective We here aim to compare the results of these 3 ICD implantation approaches in children. Methods Consecutive children (&amp;lt;16yo) implanted with an ICD from 2005 to 2021 in 19 french tertiary centers of the French Pediatric and Congenital heart disease network, were retrospectively enrolled in the study. The primary endpoints were the occurrence of lead failure, device infection or inappropriate shock. Results Among 306 patients (mean age 12,6 yo), 34% received a transvenous ICD, 28% a S-ICD and 38% a surgical ICD. During a median follow-up of 4.7 years, endpoints occurred in 24.2% of the total population, more often in the surgical group (p&amp;lt;0.05). After adjustment for age, ICD type and stratification by heart disease, there was an excess risk of lead failure or infection with the surgical ICD compared with the S-ICD (HR 7.54, 95% CI 1.73;32.91, p&amp;lt;0.05). However, when inappropriate shocks were included, the difference was reduced (HR 2.28, 95% CI 1.03;5.04, p&amp;gt;0.05). In addition, no significant difference between transvenous and surgical ICDs was observed in the multivariate analysis. Conclusions We demonstrate a high rate of complication in children implanted with an ICD. The transvenous and surgical approaches are quite similar. S-ICD appears as a promising approach with the lowest serious adverse event rate. Limitation of inappropriate shock remain the main challenge of this technique.Late complications

The triglyceride-glucose index, ventricular arrhythmias and major cardiovascular events in patients at high risk of sudden cardiac death

BackgroundThe association between the triglyceride-glucose (TyG) index and ventricular arrhythmias (VAs) is unclear. This study aimed to investigate the relationship between the TyG index, VAs, and major cardiovascular events in patients at high risk of sudden cardiac death (SCD).MethodsWe enrolled 1046 patients at high risk of SCD with an indication for implantable cardioverter-defibrillator (ICD) implantation at the Chinese National Center for Cardiovascular Diseases. The primary outcome was VAs, defined as sustained ventricular tachycardia and ventricular fibrillation documented by the ICD. The secondary outcomes were cardiac mortality, heart transplantation, and rehospitalization for heart failure.ResultsThe mean (± SD) age was 59.6 ± 14.0 years old, and 25.7% were female. During the mean follow-up of 36.1 months, 342 (32.7%) patients had VAs, and 185 (17.7%) patients had major cardiovascular events. The mean fasting glucose and triglyceride levels were 111.9 ± 42.7 mg/dL and 140.0 ± 95.4 mg/L, respectively, with a TyG index range of 6.96–11.8. In the Fine-Gray subdistribution hazard model analysis, an increase in the TyG index was associated with a significant increase in the VAs (per 1 TyG index, hazard ratio [HR] 2.95; 95% confidence interval [CI], 2.29–3.80) and secondary outcome (HR 2.84; 95% CI 1.86–4.34). When stratified into tertiles, the risk of VAs was significantly higher in the highest tertile (HR 4.08; 95% CI, 2.81–5.92) than in the lowest tertile. Analysis of the secondary outcome revealed similar findings (HR 3.18; 95% CI, 1.73–5.85).ConclusionsIn our cohort, the pre-operational TyG index is significantly associated with VAs and major cardiovascular events for patients with high risk of SCD.

Ventricular tachycardia burden in heart failure with reduced ejection fraction - can we rely on optimized medical therapy

Abstract Introduction Implantation of cardioverter-defibrillator and/or resynchronization (ICD and CRT-D) devices is aimed to prevent sudden cardiac death, fatal complication of heart failure with reduced ejection fraction (HFrEF). Guidelines propose a period of 3 months receiving maximally titrated guideline-directed medical therapy (GDMT) prior to implantation. Ventricular tachycardia (VT) burden in HFrEF has been related to worse outcomes. The effect of GDMT up-titration on VT incidence after device implantation has not yet been fully clarified. Purpose The main goal of this study is to examine the effects of GDMT evidence-based target doses on VT and appropriate device therapy (ADT) incidence in patients with HFrEF implanted with ICD or CRT-D. Methods This registry-based study included patients with HFrEF who were implanted with ICD or CRT-D from January 2021 to November 2023, with at least one follow-up. Titration of GDMT and incidence of VT/ADT were evaluated. We compared VT/ADT incidence in target dose group to incomplete titration group of each drug class. We also compared GDMT titration and VT/ADT incidence in CRT-D to ICD group. The Fisher exact test was used to evaluate the differences between groups. Results Data on 132 patients were collected (mean age 63±26 years, 16% female). Median follow-up time from device implantation was 201 (30-748) days. Target doses were reached for 24.4% beta blockers (BB), 37.8% angiotensin receptor neprilysin inhibitors (ARNI), 73.5% mineralocorticoid receptor antagonists (MRA), 89.5% sodium-glucose contransporter-2 inhibitors (SGLT2I), and 18.8% of complete GDMT. Total VT and ADT incidence was 32.6% and 12.9%, respectively. In target doses vs. incomplete doses groups, VT incidence was 34.4% vs. 32.0% (p=.83) for BB, 28.0% vs. 35.4% (p=.45) for ARNI, 32.0% vs. 34.3% (p=.84) for MRA, 30.1% vs. 50.0% (p=.23) for SGLT2I and 33.3% vs. 32.4% (p=1) for complete GDMT. ADT incidence was 18.8% vs. 11.0% (p=.36) for BB, 12.0% vs. 13.4% (p=1) for ARNI, 12.4% vs. 14.3% (p=.77) for MRA, 11.0% vs. 21.4% (p=.39) for SGLT2i, and 16.7% vs. 12.0% (p=.51) for complete GDMT. In CRT-D vs. ICD group, 31.5% vs. 19,2% (p=.15) BB, 44.4% vs. 33.3% (p=.21) ARNI, 79.6% vs. 69.2% (p=.16) MRA, 98.1% vs. 83.3% (p&amp;lt;0.05) SGLT2I; and 20.4% vs. 16.7% (p=.65) of complete GDMT were maximally titrated. VT incidence was significantly lower in CRT-D group (18.5% vs. 42.3%, p&amp;lt;0.05). ADT was also lower, but without statistical significance (9.3% vs. 15.4%, p=.43). Conclusions Up-titration of any individual drug or complete GDMT to the evidence-based target dose did not directly correlate with a decrease in VT or ADT incidence. Cardiac resynchronization therapy provides more room for target GDMT doses, particularly of BB. We notice only a modest trend in up-titration of GDMT in patients with CRT-D, who had significantly lower incidence of VT.

Sex differences in paediatric onset hypertrophic cardiomyopathy

Abstract Background Hypertrophic Cardiomyopathy (HCM) is a heterogeneous disease characterised by age related incomplete penetrance and variable long term outcomes. Sex differences have been described in both the clinical phenotype and natural history of adults with the disease, which have been attributed to both biological (eg sex hormone effect) and non-biological (eg societal and cultural effects) factors. It is unknown if similar sex differences exist in childhood-onset HCM. Purpose This study aimed to investigate the influence of biological sex on the clinical characteristics and outcomes of children with HCM. Methods Retrospective cohort study from an international registry of patients diagnosed under the age of 18 years with HCM. Patients with syndromic disease (RASopathy syndromes, inborn errors of metabolism, neuromuscular disease) were excluded. Sex differences in baseline characteristics and clinical outcomes were described. Primary outcomes were all-cause mortality or cardiac transplantation, Major Arrhythmic Cardiac Event (MACE) and heart failure event (defined as heart failure death or cardiac transplantation) Results Of 1262 patients, 851 (67.4%) were male (median age 11 yrs (IQR 7.4, 14.4) vs 11.1 (IQR 6.9, 14.0) in females, p=0.0312). Female patients were more likely to have a sarcomeric variant identified (n=208, 85.6% vs 388 (79.4%), p=0.041) despite equivalent genetic testing utilisation between sexes. Female patients were more likely to have severe heart failure symptoms (NYHA 3 or 4) (n=19, 6.1% vs n=20, 2.5% p value 0.030) but there was no difference in the proportion on medical therapy (male n=328, 39.7%, female n=167, 41.8, p value 0.476). The clinical phenotype in terms of degree of hypertrophy, left atrial size and left ventricular outflow tract gradient did not differ by sex. Over a median follow up of 5.2 years (IQR 2.4, 9.9) all-cause mortality or cardiac transplantation did not vary by sex but females were more likely to experience a heart failure event (females 0.6/100,000 pt years (95% CI 0.39-0.92) vs males 0.32/100,000 pt years (95% CI 0.21 – 0.50), hazard ratio 1.89, p value 0.0467). The incidence of MACE did not differ by sex but there was a trend towards higher implantable cardioverter defibrillator implantation in females (n=123, 30.7% vs n=210, 25.4%, p value 0.051). Conclusions For the first time, this study has shown sex differences in paediatric-onset hypertrophic cardiomyopathy. Despite no difference in baseline clinical phenotype, young female patients are more likely to experience heart failure symptoms and heart failure events over follow up. Further studies are required to explore the underlying mechanisms for these observed differences.Table summarising outcomes by sexSurvival free from heart failure

Antithrombotic therapy and the risk of pocket hematoma after subcutaneous implantable cardioverter-defibrillator implantation

Abstract Introduction The PRAETORIAN trial, which randomized S-ICD versus TV-ICD in patients with a class I or IIa indication for ICD therapy, showed that clinically significant pocket hematomas were more frequent following S-ICD implantation. Many ICD recipients have comorbidities requiring anticoagulant (AC) and/or antiplatelet (AP) therapy, which increase the risk for hematoma formation post implantation. In contrast to TV-ICD implantation, little data exists regarding the optimal AC and AP strategy during S-ICD implantation to prevent pocket hematomas. Methods All patients who underwent de novo S-ICD implantations between February 2009 and January 2023 at our tertiary center were included. Data was collected retrospectively from electronic patient records. Clinically significant pocket hematomas were defined as an accumulation of blood at the pocket site within 30 days after S-ICD implantation, necessitating actions including applying a pressure bandage, surgical evacuation, drain insertion, a change in medication or an extended hospital stay or blood transfusion. Results A total of 348 patients were included of which 224 (64.4%) patients used antithrombotic therapy pre-implantation. Median age at implantation was 50 years (IQR: 36-61 years), 33.4% of the patients were female and the vast majority of implants were intermuscular (90.2%). Eighteen (5.2%) patients developed a clinically significant pocket hematoma. A total of 94 (27%) patients used AC therapy prior to the implantation of which 73 (21%) patients used a vitamin K antagonist (VKA). A total of 130 (37.4%) patients used AP therapy at baseline of which 49 (14.1%) patients were on dual AP therapy (DAPT). Continuation of VKA and continuation of DAPT with ticagrelor were independent predictors for pocket hematoma formation (p&amp;lt;0.001, and p&amp;lt;0.001 respectively). There were significantly more pocket hematomas in patients with continued VKA compared to patients with interrupted VKA (27.3 % (6/22) vs. 4.3% (2/47), respectively, p=0.011). Moreover, continuation of DAPT with ticagrelor was associated with significantly more pocket hematomas post implantation compared to continuation of DAPT with clopidogrel (4/12 vs 1/28, respectively, p=0.022). Conclusion This study showed that continuation of VKA during S-ICD implantation was associated with an increased risk of pocket hematoma formation compared to interruption of VKA. The continuation of DAPT with ticagrelor was an independent predictor of pocket hematoma formation and showed significantly more pocket hematomas compared to continuation of DAPT with clopidogrel. These findings support the need for specific peri-operative thrombotic therapy guidelines for S-ICD implantations to reduce the risk of pocket hematomas.

Relationship between erectile dysfunction and alexithymia in male patients with implantable cardioverter defibrillators: a cross-sectional study.

Implantable Cardioverter-Defibrillator (ICD) implantation is a life-saving intervention for individuals at risk of life-threatening arrhythmias. However, the psychosocial impact of ICD implantation extends beyond its cardiovascular benefits, potentially influencing emotional well-being and sexual health. This can lead to erectile dysfunction, which, is often associated with alexithymia. Both erectile dysfunction and alexithymia can significantly affect the psychological well-being of both patients and their partners. This study examines the association of erectile dysfunction with alexithymia in patients after ICD implantation. Additionally, we investigate potential moderators of this association. Patients (N=165) completed self-rating questionnaires: Toronto Alexithymia scale (TAS-20), International Index of Erectile Function (IIEF-5), Adjustment disorder - new module (ADNM-20). Descriptive statistics, correlations, multivariate linear regressions, and moderation analysis were conducted. The determinants of erectile dysfunction in ICD patients were explored in a regression model explaining 22% of the total variance. The ADNM-20 subscale preoccupation was found to significantly moderate the relationship between the alexithymia subscale externally oriented thinking and erectile dysfunction (R2 = 0.02, p=0.03). We did not find evidence for a relationship between externally oriented thinking and erectile dysfunction at low to average levels of preoccupation. However, evidence for such a relationship was found at high levels of preoccupation, where more externally oriented thinking was related to more erectile dysfunction. The intersection of alexithymia and erectile dysfunction represents a promising avenue for future research, offering opportunities to unravel the intricate connections between emotional processing and sexual health. Enhancing insights into this relationship could lead to innovative interventions that address the needs of individuals struggling with both conditions, fostering improved emotional expression, intimate relationships, and sexual satisfaction.

AI-enabled detection of QRS fragmentation from 12-lead electrocardiogram and its clinical relevance for predicting malignant arrhythmia onset.

Electrocardiographic markers differentiating between death caused by ventricular arrhythmias and non-arrhythmic death could improve the selection of patients for implantable cardioverter-defibrillator (ICD) implantation. QRS fragmentation (fQRS) is a parameter of interest, but subject to debate. We investigated the association of an automatically quantified probability of fragmentation with the outcome in ICD patients. From a single-center retrospective registry, all patients implanted with an ICD between January 1996 and December 2018 were eligible for inclusion. Patients with active pacing were excluded. From the electronical medical record, clinical characteristics at implantation were collected and a 12-lead ECG was exported and analyzed by a previously validated machine-learning algorithm to quantify the probability of fQRS. To compare fQRS(+) and fQRS(-) patients, dichotomization was performed using the Youden index. Patients with a high probability of fragmentation in any region (anterior, inferior or lateral), were labeled fQRS(+). The impact of this fQRS probability on outcomes was investigated using Cox regression. A total of 1,242 patients with a mean age of 62.6 ± 11.5 years and a reduced left ventricular ejection fraction of 31 ± 12% were included of which 227 (18.3%) were female. The vast majority suffered from ischemic heart disease (64.3%) and were implanted in primary prevention (63.8%). 538 (43.3%) had a high probability of fragmentation in any region. Patients with a high probability of fragmentation had more frequently dilated cardiomyopathy (39.4% vs. 33.0%, p = 0.019), left bundle branch block (40.8% vs. 32.5%, p = 0.006) and a higher use of cardiac resynchronization therapy with defibrillator (CRT-D) devices (33.9% vs. 26.3%, p = 0.004). After adjustment in a multivariable Cox model, there was no significant association between the probability of global or regional fQRS and appropriate ICD therapy, inappropriate shock and short- or long-term mortality. There was no association between the automatically quantified probability of the presence of fQRS and outcome. This lack of predictive value might be due to the algorithm used, which identifies only the presence but not the severity of fragmentation.

Motor vehicle crash risk after cardioverter-defibrillator implantation: a population-based cohort study

BackgroundLimited empirical evidence informs driving restrictions after implantable cardioverter-defibrillator (ICD) implantation. We sought to evaluate real-world motor vehicle crash risks after ICD implantation.MethodsWe performed a retrospective cohort study using 22...

Thrombosis of the superior vena cava in a patient with an implanted cardioverter–defibrillator: A case report

BACKGROUND: Superior vena cava syndrome results from the occlusion of blood flow in the superior vena cava due to external compression, internal obstruction, or infiltration of the vessel wall by a tumor. Although thrombotic complications caused by electrodes of cardiac implantable devices are uncommon in clinical practice, their incidence has been increasing due to the increasing need for such devices, which effectively correct the compromised electrical or mechanical functions of the heart chambers. CLINICAL CASE DESCRIPTION: Herein, we have presented a case of superior vena cava thrombosis syndrome in a patient who had undergone cardioverter–defibrillator implantation for dilated cardiomyopathy. We have discussed the classification of superior vena cava syndromes, its pathogenesis, and the types of collateral circulation. CONCLUSION: As observed in our patient, the concurrent presence of chronic heart failure syndrome can make it challenging to recognize superior vena cava syndrome in the early stages of diagnosis.