Machine Learning-Based Clustering Using a 12-Lead Electrocardiogram in Patients With a Implantable Cardioverter Defibrillator to Identify Future Ventricular Arrhythmia.

BACKGROUND: Implantable cardioverter defibrillators (ICDs) reduce mortality associated with ventricular arrhythmia in high-risk patients with cardiovascular disease. Machine learning (ML) approaches are promising tools in arrhythmia research; however, their application in predicting ventricular arrhythmias in patients with ICDs remains unexplored. We aimed to predict and stratify ventricular arrhythmias requiring ICD therapy using 12-lead electrocardiograms (ECGs) in patients with an ICD. METHODS AND RESULTS: This retrospective analysis included 200 adult patients who underwent ICD implantation at a single center. Patient demographics, clinical features, and 12-lead ECG data were collected. Unsupervised learning techniques, including K-means and hierarchical clustering, were used to stratify patients based on 12-lead ECG features. Dimensionality reduction methods were also used to optimize clustering accuracy. The silhouette coefficient was used to determine the optimal method and number of clusters. Of the 200 patients, 59 (29.5%) received appropriate therapy. The mean age of patients was 62.3 years, and 81.0% were male. The mean follow-up period was 2,953 days, with no significant intergroup differences. Hierarchical clustering into 3 clusters proved to be the most accurate (silhouette coefficient=0.585). Kaplan-Meier curves for these 3 clusters revealed significant differences (P=0.026). CONCLUSIONS: We highlight the potential of ML-based clustering using 12-lead ECGs to help in the risk stratification of ventricular arrhythmia. Future research in a larger multicenter setting may provide further insights and refine ICD indications.

Synthesized V7 QRS Amplitude and Oversensing Episodes in Patients With Subcutaneous Implantable Cardioverter-Defibrillators.

BACKGROUND: Patients with subcutaneous implantable cardioverter-defibrillators (S-ICDs) experience an oversensing episode (OS) more frequently than those with transvenous ICDs. However, no established electrocardiography (ECG) parameters can accurately detect an OS. This study aimed to evaluate the incidence of an OS in real-world clinical practice and the association of synthesized 18-lead ECG (syn18-ECG) parameters with an OS. METHODS: We retrospectively included 21 consecutive patients who underwent S-ICD implantation and collected syn18-ECG parameters. We placed the generator in a deep posterior position and defined an OS as an inappropriate charging episode caused by cardiac or noncardiac signals. A SMART pass filter and two tachyarrhythmia zones were programed. RESULTS: The most frequent underlying heart disease was Brugada/J wave syndrome (n = 7). During a median follow-up period of 1188 days, an OS was observed in six patients (28.6%). The QRS amplitude in synthesized V7 lead (synV7) was significantly lower in the OS group than in the non-OS group (0.59 ± 0.17 vs. 0.91 ± 0.35 mV, p = 0.019). The optimal cutoff value of synV7 QRS amplitude was 0.61 mV, with a sensitivity of 80.0% and a specificity of 83.7% for predicting an OS. Univariate logistic analysis showed that a synV7 QRS amplitude of <0.61 mV was only associated with an OS (odd ratio, 20.0; 95% confidence interval, 1.66-241.72; p = 0.018). CONCLUSIONS: In patients with S-ICDs, an OS was not a rare complication during long-term follow-up. A low synV7 QRS amplitude was associated with a high OS incidence.

Rapid Return to Play After Extravascular Implantable Cardioverter-Defibrillator Implantation in a Competitive Runner.

We present a case of long QT syndrome type 2 in a competitive runner who underwent implantation of a primary prevention extravascular implantable cardioverter defibrillator with a rapid return to partial activity within 2 weeks and a return to full activity within 4 weeks of implantation without affecting wound healing or device function.

Taurolidine-containing solution for reducing cardiac implantable electronic device infection-early report from the European TauroPace™ registry.

INTRODUCTION: Infection is a significant complication of cardiac implantable electronic device (CIED) therapy. The European TauroPace™ Registry investigates the safety and efficacy of TauroPace™ (TP), an antimicrobial solution containing taurolidine, designed to prevent CIED infections. METHODS: This multicenter study included patients undergoing CIED procedures at participating centers where TP was used as a disinfectant for external hardware surfaces and an antiseptic for irrigating surgical sites. All patients eligible for CIED placement with adjunctive TP as the standard of care were included. Other aspects of CIED procedures adhered to current guidelines. Data on CIED-related infective endocarditis, CIED pocket infection, device and procedure-related complications, adverse events, and all-cause mortality were prospectively collected for 12 months. In cases of revision, the previous procedure was censored, and a new procedure was created. Binomial and Kaplan-Meier statistics were employed to analyze event rates. RESULTS: From January 2020 to November 2022, TP was used in 822 out of 1170 CIED procedures. Among patients who completed the 3-month follow-up, no CIED pocket infections were observed, and one case of CIED-related infective endocarditis was reported. In the 12-month follow-up cohort, two additional local pocket CIED infections were observed, resulting in a total of three major CIED infections within 1 year after the CIED placement procedure. The 3-month and 12-month major CIED infection rates were 0.125% and 0.51%, respectively. During the observation a complication rate of 4.4% was reported. No adverse events related to TP were observed. CONCLUSIONS: TP appears to be effective and safe in preventing CIED infections. CLINICALTRIALS: gov Identifier: NCT04735666.

Pacing-facilitated Short-long-short Sequences Leading to Ventricular Tachyarrhythmias: A Brief Report.

Pacing-induced recurrent short-long-short sequences constitute an important yet overlooked mechanism for triggering ventricular tachyarrhythmias in patients with cardiovascular implantable electric devices. A careful and thorough retrospective analysis of patients' electrograms allows for a timely diagnosis with appropriate management.

Inappropriate Therapies in Modern Implantable Cardioverter Defibrillators: A Propensity Score-matched Comparison between Single- and Dual-Chamber Discriminators in Single-Chamber devices THe sINGle lead Study (THINGS Study).

BACKGROUND: In patients with implantable cardioverter-defibrillators (ICDs), inappropriate therapies (ITs) are often caused by supraventricular tachyarrhythmias (SVTs). OBJECTIVE: To estimate the incidence of IT in modern single-lead ICDs. METHODS: The THINGS study enrolled patients with single-lead ICDs with two SVT discrimination modalities: dual-chamber (DC) via an atrial floating dipole or single-chamber (SC) with morphology criterion. All devices were programmed with two-zone therapy: (i) VT zone from 170 beats-per-minute with ≥15 seconds (≥36 beats) detection time and SVT discriminators, (ii) VF zone from 214 beats-per-minute with ≥7 seconds (≥24 beats) detection time. The primary endpoint was the first occurrence of IT, adjudicated by an independent board. RESULTS: A total of 526 patients (median age 66 years, 83% males), 183 (34.8%) with DC and 343 (65.2%) with SC discrimination, were followed for a median of 2.2 years. The incidence rate of IT was 4.2% (95% CI, 2.7%-6.4%) at 1 year and 7.1% (95% CI, 5.0%-9.9%) at 2 years. Younger age (adjusted HR 0.97, 95% CI 0.95-0.99, P=0.013) and history of atrial fibrillation (adjusted HR 2.67, 95% CI 1.30-5.46, P=0.007) were significantly associated with increased IT risk. In a propensity-score matched comparison, DC discrimination showed a trend towards reduced IT rates compared to SC discrimination in the VT zone (1-year incidence 1.8% vs. 3.5%, P=0.105). CONCLUSION: High-rate VF cutoff and prolonged detection times programming resulted in a low IT rate in single-lead ICD patients with modern SVT discriminators. A trend favoring the DC system was observed in the VT zone.

Long-term outcomes in ICD: all-causes mortality and first appropriate intervention in ischemic and nonischemic etiologies.

BACKGROUND: Real life data comparing the long-term outcome in patients with different heart diseases carrying an Implantable Cardioverter Defibrillator (ICD) are scarce. OBJECTIVE: To compare the long-term risk of first appropriate ICD intervention and overall survival in patients with ICD and heart disease of different etiologies. METHODS: Patients with an ICD implanted between January 1st, 2010 and December 31st 2022 followed in our Center were included. Study outcomes were all-cause mortality and first appropriate ICD intervention. A comparison between ischemic heart disease (IHD) and nonischemic heart disease (NIHD) was performed. In NIHD different etiologies of dilated cardiomyopathy (DCM) were analyzed. RESULTS: 1184 patients (592 IDH - 592 NIHD) were included. During a median follow-up of 53 months all-cause death occurred in 399 (34%) patients while first-appropriate ICD intervention occurred in 320 (27%). All-cause mortality was significantly higher in IHD vs NIHD patients (60% vs 43%; p<0.0001) but no differences in appropriate ICD intervention rate at 10-years (34% vs 40%; p=0.125) were observed. Among NIHD higher 10-year mortality rate were found in valvular heart disease, rctDCM and hypertensive DCM. Hypertrophic cardiomyopathy, alcoholic DCM (alcDCM) and post-radio/chemotherapy DCM (rctDCM) were the least arrhythmic phenotypes among NIHD. Of note, inappropriate interventions in alcDCM and rctDCM were higher than appropriate ones. CONCLUSIONS: Rate of ICD appropriate interventions and mortality is different according to the etiology of heart disease and cardiovascular risk profile; this should be taken into consideration in the prognostic stratification of these patients at the time of implantation.

Sudden cardiac death after myocardial infarction: individual participant data from pooled cohorts.

BACKGROUND AND AIMS: Risk stratification of sudden cardiac death after myocardial infarction and prevention by defibrillator rely on left ventricular ejection fraction (LVEF). Improved risk stratification across the whole LVEF range is required for decision-making on defibrillator implantation. METHODS: The analysis pooled 20 data sets with 140 204 post-myocardial infarction patients containing information on demographics, medical history, clinical characteristics, biomarkers, electrocardiography, echocardiography, and cardiac magnetic resonance imaging. Separate analyses were performed in patients (i) carrying a primary prevention cardioverter-defibrillator with LVEF ≤ 35% [implantable cardioverter-defibrillator (ICD) patients], (ii) without cardioverter-defibrillator with LVEF ≤ 35% (non-ICD patients ≤ 35%), and (iii) without cardioverter-defibrillator with LVEF > 35% (non-ICD patients >35%). Primary outcome was sudden cardiac death or, in defibrillator carriers, appropriate defibrillator therapy. Using a competing risk framework and systematic internal-external cross-validation, a model using LVEF only, a multivariable flexible parametric survival model, and a multivariable random forest survival model were developed and externally validated. Predictive performance was assessed by random effect meta-analysis. RESULTS: There were 1326 primary outcomes in 7543 ICD patients, 1193 in 25 058 non-ICD patients ≤35%, and 1567 in 107 603 non-ICD patients >35% during mean follow-up of 30.0, 46.5, and 57.6 months, respectively. In these three subgroups, LVEF poorly predicted sudden cardiac death (c-statistics between 0.50 and 0.56). Considering additional parameters did not improve calibration and discrimination, and model generalizability was poor. CONCLUSIONS: More accurate risk stratification for sudden cardiac death and identification of low-risk individuals with severely reduced LVEF or of high-risk individuals with preserved LVEF was not feasible, neither using LVEF nor using other predictors.

Circadian (Diurnal/Nocturnal) Pattern of Cardiac Arrhythmias.

Circadian rhythms follow 24-hour biological-cycle patterns controlled by internal biological or circadian clocks that optimize organismal homeostasis according to predictable environmental changes. These clocks are found in virtually all cells in the body, including cardiomyocytes. Triggers for and/or the occurrence of sudden cardiac death (SCD), and cardiac arrhythmias seem to follow such daily patterns. This review highlights data from studies exploring the role of day/night rhythms in the timing of arrhythmic events, studies describing the enviromental, behavioral and circadian mechanisms regulating cardiac electrophysiology focusing on the circadian pattern of arrhythmias and SCD. Mechanisms involved relate to circadian control of electrophysiological properties, vagal tone, and sleep disorders, as well as the potential interaction and synergism among these factors. By studying the diurnal variations of arrhythmias, therapy can be improved by optimally timing it to their circadian pattern and a person's internal body clock-time. Potential treatment targets for arrhythmias with nocturnal onset may include upstream therapy for underlying comorbidities, type and timing of drug intake, pulmonary vein isolation, ablation of the ganglionated plexus, and autonomic nervous system control. Thus, specific history taking, screening and diagnostic workup are recommended to identify and characterize comorbidities and potential contributors to nocturnal arrhythmias, such as obesity, advanced age, diabetes, hypertension and heart failure. In this direction, symptoms of sleep apnea may comprise snoring and excessive daytime sleepiness. Risk factors include obesity, decreased upper airway dimensions, and heart failure. Thus, one should have a low threshold for sleep testing to assess for sleep apnea. Sleep apnea treatment decreases ventricular arrhythmias and ameliorates some severe bradycardic episodes often obviating the need for pacemaker implantation. Importantly, comorbidity treatment and lifestyle optimization remain crucial.

Peripartum management of cardiac arrhythmias: a narrative review.

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

Standard Defibrillator Leads for Left Bundle Branch Area Pacing: First-in-Man Experience and Short-Term Follow-Up.

The authors report for the first time to their knowledge, implantation of a standard implantable cardioverter-defibrillator lead for permanent delivery of left bundle branch area pacing. Implantation was successful and safe in 11 of 12 patients, with adequate defibrillation testing, good electrical and electrocardiographic parameters, and uneventful device-related short-term follow-up.

Body Image Concerns in patients with an Implantable Cardioverter Defibrillator: Association with other PRO measures.

AIM: To investigate associations between Body Image concerns (BICs) measured by the ICD Body Image Concerns Questionnaire (ICD-BICQ) and other Patient-Reported-Outcomes (PROs), in a cohort of patients with an Implantable Cardioverter Defibrillator (ICD). METHODS AND RESULTS: In a cross-sectional survey, we included patients >18 years implanted with a first-time ICD (VVI, DDD and CRT-D) who had lived with their ICD from 3-24 months. They completed the 39-item ICD-BICQ together with the Generalized Anxiety Disorder-scale, Patient Health-Questionnaire, Type D-Scale, Health Status-Questionnaire and the Florida Patient Acceptance-Survey. Data were analyzed using linear regression to compare personality constructs between patients with and without BICs. Logistic repression and receiver operating characteristic curves were used to predict patients with BICs based on other PROs.A total of 330 patients completed the survey. Five patients were excluded due to re-operations leaving 325 patients in the analyses. A total of 20% reported BICs at the recommended cut-off at 36-points. Patients with BICs reported higher anxiety and depression levels, lower device acceptance and health status, had a Type D personality as compared to patients without BICs. FPAS was moderately able to predict BICs, while other PROs only had limited ability to predict BICs. CONCLUSION: Patients with BICs reported poorer PROs. The PRO instruments were not able to predict patients with BICs, indicating that the ICD-BICQ provides independent relevant clinical information. In clinical practice, healthcare professionals can use the ICD-BICQ to identify and obtain information on possible BICs. The ICD-BICQ can also be used to evaluate new operation techniques.

A case report of a combined implantation technique of a cardioverter-defibrillator in an infant with long QT syndrome type 8 (Timothy's syndrome).

We present a case of successful implantation of a cardioverter-defibrillator (ICD) using combined technique in a child with Timothy's syndrome. Due to high risk of sudden cardiac death (SCD) such patients often need ICD for primary or secondary prevention but implantation technique in young children remains controversial. The subcutaneous cardioverter-defibrillators could be an option in some cases, however, reliable cardiac pacing should be implemented for patients with bradyarrhythmias. An ICD implantation technique with the epicardial pacing lead placement and subcutaneous tunnel formation for endocardial defibrillation lead seems to be promising in SCD prevention also providing the opportunity for permanent pacing.

[(LV)EF is a poor predictor of sudden cardiac death : Pro/Contra]. / Die (LV)EF ist ein schlechter Prädiktor für den plötzlichen Herztod : Pro/Contra.

For more than two decades the left ventricular ejection fraction (LVEF) has been utilized with practically uncritical absolutism for the risk stratification of patients with ischemic and, historically, also nonischemic cardiomyopathy, in order to identify patients who could be threatened by sudden cardiac death. Based on historical data and in the absence of other better predictive parameters, the LVEF continues to appear in the guidelines unchanged, with cut-off values that lie in the region of the measurement accuracy of LVEF as determined by echocardiography. The basic identification of high-risk patients who then really benefit from an implantable cardioverter defibrillator (ICD) must be re-evaluated under the aspect of a meaningfully altered interventional and pharmaceutical treatment of heart failure.

Motor Vehicle Driving-Related Anxiety in Patients Undergoing Cardioverter Defibrillator Implantation and Cardiac Resynchronization Therapy With Defibrillators.

BACKGROUND: Reducing anxiety about motor vehicle driving in patients receiving implantable cardioverter defibrillators and cardiac resynchronization therapy with defibrillators is important not only for improving quality of life but also for preventing vehicle collisions owing to driver distraction. This study aimed to clarify the driving-related anxiety of patients with these defibrillators and the factors that predict such anxiety. METHODS: We conducted a cross-sectional survey using a self-administered questionnaire of patients who had been driving a vehicle after device implantation at a general hospital between August 2018 and November 2019. RESULTS: The mean age was 60.8 ± 12.6 years. The reasons for implantation were primary prevention in 47 patients and secondary prevention in 30 patients. A total of 16 patients experienced anxiety about driving and 61 did not. Significantly more younger patients (mean age of 50.4 vs. 63.6 years, p < 0.001) and those with implantable cardioverter defibrillators had anxiety (100% vs. 73.8%, p = 0.02). Multivariable analysis indicated that age was the only independent factor that predicted driving-related anxiety (odds ratio, 0.937; 95% confidence interval, 0.883-0.993). CONCLUSIONS: Identifying and addressing driving-related anxiety in patients (particularly young patients) with defibrillators is important in preventing motor vehicle collisions and improving quality of life.

Extraction and Reimplantation of a Subcutaneous Implantable Cardioverter Defibrillator: Two Cases and a Review of the Literature.

For several years, implantable cardioverter defibrillators (ICDs) have been the cornerstone for the prevention of sudden cardiac death. However, the weakness of traditional transvenous ICD systems lies in the intravascular lead, which is prone to issues such as conductor fracture, insulation abrasion, risk of dislodgement, and infection. With the new generation of subcutaneous defibrillators, these risks are far less common. To date, the frequency of lead fracture is very low, and infection is much rarer. The management of these complications requires complete lead extraction. Traction is the reference procedure, sometimes necessitating the use of a dilating sheath. These techniques remain straightforward to perform without significant risk of procedural complications. Nevertheless, they must be carried out by an expert in cardiac pacing. We report here two cases with indications for lead extraction: one for lead dysfunction and the other for an infection related to a replacement procedure. The management approaches will be described, followed by a review of the literature.

Cardiovascular Implantable Electronic Device Infections: A Contemporary Review.

Infections associated with cardiac implantable electronic devices (CIEDs) are increasing and are a cause of significant morbidity and mortality. This article summarizes the latest updates with respect to the epidemiology, microbiology, and risk factors for CIED-related infections. It also covers important considerations regarding the diagnosis, management, and prevention of these infections. Newer technologies such as leadless pacemakers and subcutaneous implantable cardioverters and defibrillators are discussed.