Benefits of upgrading right ventricular to biventricular pacing in heart failure patients with atrial fibrillation.

AIMS: Recommendations on cardiac resynchronization therapy (CRT) in patients with atrial fibrillation or flutter (AF) are based on less robust evidence than those in sinus rhythm (SR). We aimed to assess the efficacy of CRT upgrade in the BUDAPEST-CRT Upgrade trial population by their baseline rhythm. METHODS AND RESULTS: Heart failure patients with reduced ejection fraction (HFrEF) and previously implanted pacemaker (PM) or implantable cardioverter defibrillator (ICD) and ≥20% right ventricular (RV) pacing burden were randomized to CRT with defibrillator (CRT-D) upgrade (n = 215) or ICD (n = 145). Primary [HF hospitalization (HFH), all-cause mortality, or <15% reduction of left ventricular end-systolic volume] and secondary outcomes were investigated. At enrolment, 131 (36%) patients had AF, who had an increased risk for HFH as compared with those with SR [adjusted hazard ratio (aHR) 2.99; 95% confidence interval (CI) 1.26-7.13; P = 0.013]. The effect of CRT-D upgrade was similar in patients with AF as in those with SR [AF adjusted odds ratio (aOR) 0.06; 95% CI 0.02-0.17; P < 0.001; SR aOR 0.13; 95% CI 0.07-0.27; P < 0.001; interaction P = 0.29] during the mean follow-up time of 12.4 months. Also, it decreased the risk of HFH or all-cause mortality (aHR 0.33; 95% CI 0.16-0.70; P = 0.003; interaction P = 0.17) and improved the echocardiographic response (left ventricular end-diastolic volume difference -49.21 mL; 95% CI -69.10 to -29.32; P < 0.001; interaction P = 0.21). CONCLUSION: In HFrEF patients with AF and PM/ICD with high RV pacing burden, CRT-D upgrade decreased the risk of HFH and improved reverse remodelling when compared with ICD, similar to that seen in patients in SR.

First human safety and effectiveness study of defibrillation with a novel patch wearable cardioverter-defibrillator.

AIMS: Wearable cardioverter-defibrillators (WCDs) are indicated in patients at risk of sudden cardiac arrest who are not immediate candidates for implantable defibrillator therapy. Limitations of existing WCDs include poor compliance and high false alarm rates. The Jewel is a novel patch-WCD (P-WCD) that addresses these limitations with an adhesive-based design for near-continuous wear and a machine learning algorithm designed to minimize inappropriate detections. This was a first-in-human study of the Jewel P-WCD conducted in an electrophysiology (EP) lab to determine the safety and effectiveness of the device in terminating ventricular tachycardia/ventricular fibrillation (VT/VF) with a single shock. The aim was to evaluate the safety and effectiveness of terminating VT/VF with a single shock using the Jewel P-WCD. METHODS AND RESULTS: This was a first-in-human, prospective, single-arm, single-centre study in patients scheduled for an EP procedure in which VT/VF was expected to either spontaneously occur or be induced. The Jewel P-WCD was placed on consented patients; upon confirmation of VT/VF, a single shock (150 J) was delivered via the device. A group sequential design and Pocock alpha spending function was used to measure the observed proportion of successful VT/VF single-shock terminations. The endpoint was achieved if the lower confidence limit exceeded the performance goal of 62%, using a one-sided lower 97.4% exact confidence bound. Of 18 eligible subjects, 16 (88.9%, 97.4% confidence bound: 65.4%) were successfully defibrillated with a single shock, exceeding the primary endpoint performance goal with no adverse events. CONCLUSION: This first-in-human evaluation of the Jewel P-WCD demonstrated the safety and effectiveness of terminating VT/VF. CLINICAL TRIAL REGISTRATION: URL: https://clinicaltrials.gov/; Unique identifier: NCT05490459.

An unusual cause of inappropriate shocks delivered by an implantable cardioverter defibrillator.

INTRODUCTION: Cardiac implantable electronic device (CIED) complications present significant challenges in clinical practice, especially in elderly patients with multiple comorbidities. Common adverse events include infection, lead malfunction, and device migration. Twiddler's Syndrome, a rare but serious CIED complication characterised by patient manipulation causing lead displacement and device malfunction, is often underreported. The literature consists mainly of case reports and small series, providing limited guidance on prevention and management. As CIEDs are critical for managing cardiac arrhythmias and heart failure, understanding and addressing Twiddler's Syndrome is essential. This case report aims to contribute to the literature by detailing a case of Twiddler's Syndrome, emphasising the importance of a multidisciplinary approach for optimal management. CASE PRESENTATION: A 59-year-old male presented with discomfort around his implantable cardioverter defibrillator (ICD) site and the sternal area over the past two days. He denied pain, dyspnoea, or dizziness. Clinical examination revealed a normal heart rhythm and no peripheral pulse deficit. Ultrasound revealed a reduced left ventricular ejection fraction. The atrial lead was not visible, and the shock coil was misplaced. ICD interrogation showed inappropriate shocks due to sensing artifacts and exit block in both leads, with no arrhythmias detected. An X-ray confirmed lead dislodgement and significant entanglement in the pocket. The patient was diagnosed with Twiddler's Syndrome and scheduled for surgical revision. DISCUSSION/CONCLUSIONS: Dilated cardiomyopathy (DCM), characterised by left ventricular dilatation and dysfunction, accounts for a significant proportion of systolic heart failure cases. Despite advancements in heart failure management, DCM patients remain at high risk for sudden cardiac death (SCD), making ICD implantation crucial. However, CIED placement carries risks of complications, including Twiddler's Syndrome. This condition can lead to lead dislodgement and device malfunction, resulting in inappropriate shocks and potential patient harm. In this case, a single-session extraction and re-implantation were successfully performed using a multidisciplinary approach, emphasising the importance of comprehensive management strategies to address such complications effectively. Regular follow-up showed no adverse events, highlighting the procedure's success and the potential benefits of using advanced antimicrobial adjuncts to prevent infections. This case underscores the need for awareness and standardised protocols for managing Twiddler's Syndrome to improve patient outcomes in the growing population of CIED recipients.

Outcomes of Cardiac Resynchronization Therapy by New York Heart Association Class: A Patient-Level Meta-Analysis.

BACKGROUND: Data on the benefits of cardiac resynchronization therapy (CRT) in patients with severe heart failure symptoms are limited. We investigated the relative effects of CRT in patients with ambulatory New York Heart Association (NYHA) IV versus III functional class at the time of device implantation. METHODS AND RESULTS: In this meta-analysis, we pooled patient-level data from the MIRACLE (Multicenter InSync Randomized Clinical Evaluation), MIRACLE-ICD (Multicenter InSync Implantable Cardioversion Defibrillation Randomized Clinical Evaluation), and COMPANION (Comparison of Medical Therapy, Pacing, and Defibrillation in Heart Failure) trials. Outcomes evaluated were time to the composite end point of the first heart failure hospitalization or all-cause mortality, and time to all-cause mortality alone. The association between CRT and outcomes was evaluated using a Bayesian hierarchical Weibull survival regression model. We assessed if this association differed between NYHA III and IV groups by adding an interaction term between CRT and NYHA class as a random effect. A sensitivity analysis was performed by including data from RAFT (Resynchronization-Defibrillation for Ambulatory Heart Failure). Our pooled analysis included 2309 patients. Overall, CRT was associated with a longer time to heart failure hospitalization or all-cause mortality (adjusted hazard ratio [aHR], 0.79 [95% credible interval [CI], 0.64-0.99]; posterior probability or P=0.044), with a similar association with time to all-cause mortality (aHR, 0.78 [95% CI, 0.59-1.03]; P=0.083). Associations of CRT with outcomes were not significantly different for those in NYHA III and IV classes (ratio of aHR, 0.72 [95% CI, 0.30-1.27]; P=0.23 for heart failure hospitalization/mortality; ratio of aHR, 0.70 [95% CI, 0.35-1.34]; P=0.27 for all-cause mortality alone). The sensitivity analysis, including RAFT data, did not show a significant relative CRT benefit between NYHA III and IV classes. CONCLUSIONS: Overall, there was no significant difference in the association of CRT with either outcome for patients in NYHA functional class III compared with functional class IV.

Predictors of Shock-Reduction Programming and Its Impact on Implantable Cardioverter-Defibrillator Therapies and Mortality: The CERTITUDE Registry.

BACKGROUND: Shock-reduction implantable cardioverter-defibrillator programming (SRP) was associated with fewer therapies and improved survival in randomized controlled trials, but real-world studies investigating SRP and associated outcomes are limited. METHODS AND RESULTS: The BIOTRONIK CERTITUDE registry was linked with the Medicare database. We included all patients with an implantable cardioverter-defibrillator implanted between August 22, 2012 and September 30, 2021 in the United States. SRP was defined as programming to either a therapy rate cutoff ≥188 beats per minute or number of intervals to detection ≥30/40 for treatment. Among 6781 patients (mean 74±9 years; 27% women), 3393 (50%) had SRP. Older age, secondary prevention indication, and device implantation in the southern or western United States were associated with lower use of SRP. The cumulative incidence rate of implantable cardioverter-defibrillator shocks was lower in the SRP group (5.1% shocks/patient year) compared with the non-SRP group (7.2% shocks/patient year) (adjusted hazard ratio [HR], 0.83 [95% CI, 0.73-0.96]; P=0.005). Over a median follow-up of 2.9 years, 739 deaths occurred in the SRP group and 822 deaths occurred in the non-SRP group (adjusted HR, 0.97 [95% CI, 0.88-1.07]; P=0.569). SRP was associated with a lower all-cause mortality among patients without ischemic heart disease compared with patients with ischemic heart disease (adjusted HR, 0.64 [95% CI, 0.48-0.87] versus adjusted HR, 1.02 [95% CI, 0.92-1.14]; Pinteraction=0.004). CONCLUSIONS: Adoption of SRP is low in real-world clinical practice. Age, clinical variables, and geographic factors are associated with use of SRP. In this study, SRP-associated decrease in mortality was limited to patients without ischemic heart disease.

Incidence, implications, and management of sense-B-noise failure in subcutaneous cardioverter-defibrillator patients: insights from a large multicentre registry.

AIMS: Subcutaneous implantable cardioverter-defibrillators (S-ICDs) offer potentially distinct advantages over transvenous defibrillator systems. Recent randomized trials showed significantly lower lead failure rates than transvenous ICD. Still, S-ICDs remain associated with the risk of inappropriate shocks (IAS). While previous studies have reported varying causes of IAS, this study explores a rare cause of IAS, referred to as 'sense-B-noise.' It was recently described in case series, but its incidence has not been studied in a large cohort of S-ICD patients. METHODS AND RESULTS: We retrospectively reviewed data from patients implanted with S-ICD models 1010, A209, and A219 between October 2009 and July 2023 across nine centres in Europe and the USA. The analysis concentrated on determining the incidence and understanding the implications of sense-B-noise events. Sense-B-noise represents a rare manifestation of distinct electrogram abnormalities within the primary and alternate sensing vectors. Data were collected from medical records, device telemetry, and manufacturer reports for investigation. This registry is registered on clinicaltrials.gov (NCT05713708). Subcutaneous implantable cardioverter-defibrillator devices of the 1158 patients were analysed. The median follow-up time for all patients was 46 (IQR 23-64) months. In 107 patients (9.2%) ≥1 IAS was observed during follow-up. Sense-B-noise failure was diagnosed in six (0.5 and 5.6% of all IAS) patients, in all patients, the diagnosis was made after an IAS episode. Median lead dwell time in the affected patients was 23 (2-70) months. To resolve the sense-B-noise defect, in three patients reprogramming to the secondary vector was undertaken, and two patients underwent system removal with subsequent S-ICD reimplantation due to low amplitude in the secondary vector. In one patient, the secondary vector was initially programmed, and subsequently, an S-ICD system exchange was performed due to T-wave-oversensing IAS episodes. CONCLUSION: This multicentre analysis' findings shed light on a rare but clinically highly significant adverse event in S-ICD therapy. To our knowledge, we provide the first systematic multicentre analysis investigating the incidence of sense-B-noise. Due to being difficult to diagnose and limited options for resolution, management of sense-B-noise is challenging. Complete system exchange may be the only option for some patients. Educating healthcare providers involved in S-ICD patient care is crucial for ensuring accurate diagnosis and effective management of sense-B-noise issues.

Effect of empagliflozin on ventricular arrhythmias in patients with type 2 diabetes treated with an implantable cardioverter-defibrillator: the EMPA-ICD trial.

BACKGROUND: Sodium-glucose cotransporter 2 (SGLT2) inhibitors reduce the risk of hospitalization for heart failure and cardiovascular death with type 2 diabetes; however, their effect on arrhythmias is unclear. The purpose of this study was to investigate the effects of empagliflozin on ventricular arrhythmias in patients with type 2 diabetes. METHODS: A total of 150 patients with type 2 diabetes who were treated with an implantable cardioverter-defibrillator or cardiac resynchronization therapy defibrillator (ICD/CRT-D) were randomized to once-daily empagliflozin or placebo for 24 weeks. The primary endpoint was the change in the number of ventricular arrhythmias from the 24 weeks before to the 24 weeks during treatment. Secondary endpoints included the change in the number of appropriate device discharges and other values. RESULTS: In the empagliflozin group, the number of ventricular arrhythmias recorded by ICD/CRT-D decreased by 1.69 during treatment compared to before treatment, while in the placebo group, the number increased by 1.79. The coefficient for the between-group difference was - 1.07 (95% confidence interval [CI] - 1.29 to - 0.86; P < 0.001). The change in the number of appropriate device discharges during and before treatment was 0.06 in the empagliflozin group and 0.27 in the placebo group, with no significant difference between the groups (P = 0.204). Empagliflozin was associated with an increase in blood ketones and hematocrit and a decrease in blood brain natriuretic peptide and body weight. CONCLUSIONS: In patients with type 2 diabetes treated with ICD/CRT-D, empagliflozin reduces the number of ventricular arrhythmias compared with placebo. Trial registration jRCTs031180120.

Assisting Black Patients With Decision-Making for Implantable Cardioverter Defibrillator Therapy: Qualitative Findings From the Videos to Reduce Racial Disparities in ICD Therapy via Innovative Designs (VIVID) Trial.

BACKGROUND: The VIVID (Videos for Addressing Racial Disparities in Implantable Cardioverter Defibrillator Therapy via Innovative Designs) study was a multicenter, randomized controlled trial aimed at evaluating the effectiveness of a video-based decision support tool in enhancing informed consent for implantable cardioverter defibrillator (ICD) implantation among Black patients who met guideline criteria for primary prevention ICDs. Within the broader VIVID randomized trial, a qualitative investigation was conducted to elucidate the decisional factors among Black individuals considering ICD implantation for the primary prevention of sudden cardiac arrest. METHODS: Between October 2016 and July 2019, in-depth interviews were conducted at 2 time points from randomization, ≈7 days (time interval for the decision) and at 90 days; the time interval for determining ICD implantation. Interview findings were categorized by randomized groups, those assigned to 1 of the 2 encounter-based video decision support tools or standard care (without video). Interview participants were purposefully selected to ensure diversity across gender, age, educational background, research site, and randomization group; participants were sampled from 14 academic and community-based electrophysiology clinics in the United States. Data analysis employed applied thematic analysis techniques. RESULTS: A diverse sample of Black individuals were interviewed at 1 week (n=59; female, 37.3%) and 90 days (n=48; female, 39.6%). The primary factors influencing the decisions of Black individuals considering a primary prevention ICD implantation were (1) their clinicians' recommendations for ICD implantation; (2) their perception of their cardiac health status; and (3) a desire to prolong their lives for the sake of their families. CONCLUSIONS: These findings offer valuable insights that may guide clinicians in their communication with Black patients during shared decision-making encounters related to ICD implantation.

Occurrence of premature battery depletion in a large multicentre registry of subcutaneous cardioverter-defibrillator patients.

AIMS: Subcutaneous implantable cardioverter-defibrillators (S-ICDs) have become established in preventing sudden cardiac death, with some advantages over transvenous defibrillator systems, including a lower incidence of lead failures. Despite technological advancements, S-ICD carriers may suffer from significant complications, such as premature battery depletion (PBD), that led to an advisory for nearly 40 000 patients. This multicentre study evaluated the incidence of PBD in a large set of S-ICD patients. METHODS AND RESULTS: Data from patients implanted with S-ICD models A209 and A219 between October 2012 and July 2023 across nine centres in Europe and the USA were reviewed. Incidence and implications of PBD, defined as clinically observed sudden drop in battery longevity, were analysed and compared to PBD with the definition of battery depletion within 60 months. Prospectively collected clinical data were obtained retrospectively from medical records, device telemetry, and manufacturer reports. This registry is listed on ClinicalTrials.gov (NCT05713708). Of the 1112 S-ICD devices analysed, 547 (49.2%) were equipped with a potentially affected capacitor linked to PBD occurrence, currently under Food and Drug Administration advisory. The median follow-up time for all patients was 46 [inter-quartile range (IQR) 24-63] months. Clinically suspected PBD was observed in 159 (29.1%) of cases, with a median time to generator removal or replacement of 65 (IQR 55-72) months, indicative of significant deviations from expected battery lifespan. Manufacturer confirmation of PBD was made in 91.7% of devices returned for analysis. No cases of PBD were observed in devices that were not under advisory. CONCLUSION: This manufacturer-independent analysis highlights a notable incidence of PBD in patients equipped with S-ICD models under advisory, and the rate of PBD in this study corresponds to the rate currently estimated by the manufacturer. To the best of our knowledge, this provides the largest contemporary peer-reviewed study cohort investigating the actual incidence of PBD in S-ICD patients. These findings emphasize the importance of post-market registries in collaboration between clinicians and the manufacturer to optimize safety and efficacy in S-ICD treatment.

Thromboembolic and bleeding complications after elective cardioversion of atrial fibrillation: a nationwide cohort study.

AIMS: Elective cardioversion (ECV) is routinely used in atrial fibrillation (AF) to restore sinus rhythm. However, it includes a risk of thromboembolism even during adequate oral anticoagulation treatment. The aim of this study was to evaluate the risk of thromboembolic and bleeding complications after ECV in a real-life setting utilizing data from a large AF population. METHODS AND RESULTS: This nationwide register-based study included all (n = 9625) Finnish AF patients undergoing their first-ever ECV between 2012 and 2018. The thromboembolic and bleeding complications within 30 days after ECV were analysed. The mean age of the patients was 67.7 ± 9.9 years, 61.2% were men, and the mean CHA2DS2-VASc score was 2.6 ± 1.6. Warfarin was used in 6245 (64.9%) and non-vitamin K oral anticoagulants (NOACs) in 3380 (35.1%) cardioversions. Fifty-two (0.5%) thromboembolic complications occurred, of which 62% were ischaemic strokes, 25% transient ischaemic attacks, and 13% other systemic embolisms. Thromboembolic events occurred in 14 (0.4%) NOAC-treated patients and in 38 (0.6%) warfarin-treated patients (odds ratio 0.77; confidence interval: 0.42-1.39). The median time from ECV to the thromboembolic event was 2 days, and 78% of the events occurred within 10 days. Age and alcohol abuse were significant predictors of thromboembolic events. Among warfarin users, thromboembolic complications were more common with international normalized ratio (INR) <2.5 than INR ≥2.5 (0.9% vs. 0.4%, P = 0.026). Overall, 27 (0.3%) bleeding events occurred. CONCLUSION: The rate of thromboembolic and bleeding complications related to ECV was low without significant difference between NOAC- and warfarin-treated patients. With warfarin, INR ≥2.5 at the time of cardioversion reduced the risk of thromboembolic complications.

Prognostic Impact of Heart Rhythm Shockability Trajectory in Out-of-Hospital Cardiac Arrest: A Multicenter Retrospective Study.

BACKGROUND: This study aimed to investigate the association between the temporal transitions in heart rhythms during cardiopulmonary resuscitation (CPR) and outcomes after out-of-hospital cardiac arrest. METHODS: This was an analysis of the prospectively collected databases in 3 academic hospitals in northern and central Taiwan. Adult patients with out-of-hospital cardiac arrest transported by emergency medical service between 2015 and 2022 were included. Favorable neurological recovery and survival to hospital discharge were the primary and secondary outcomes, respectively. Time-specific heart rhythm shockability was defined as the probability of shockable rhythms at a particular time point during CPR. The temporal changes in the time-specific heart rhythm shockability were calculated by group-based trajectory modeling. Multivariable logistic regression analyses were performed to examine the association between the trajectory group and outcomes. Subgroup analyses examined the effects of extracorporeal CPR in different trajectories. RESULTS: The study comprised 2118 patients. The median patient age was 69.1 years, and 1376 (65.0%) patients were male. Three distinct trajectories were identified: high-shockability (52 patients; 2.5%), intermediate-shockability (262 patients; 12.4%), and low-shockability (1804 patients; 85.2%) trajectories. The median proportion of shockable rhythms over the course of CPR for the 3 trajectories was 81.7% (interquartile range, 73.2%-100.0%), 26.7% (interquartile range, 16.7%-37.5%), and 0% (interquartile range, 0%-0%), respectively. The multivariable analysis indicated both intermediate- and high-shockability trajectories were associated with favorable neurological recovery (intermediate-shockability: adjusted odds ratio [aOR], 4.98 [95% CI, 2.34-10.59]; high-shockability: aOR, 5.40 [95% CI, 2.03-14.32]) and survival (intermediate-shockability: aOR, 2.46 [95% CI, 1.44-4.18]; high-shockability: aOR, 2.76 [95% CI, 1.20-6.38]). The subgroup analysis further indicated extracorporeal CPR was significantly associated with favorable neurological outcomes (aOR, 4.06 [95% CI, 1.11-14.81]) only in the intermediate-shockability trajectory. CONCLUSIONS: Heart rhythm shockability trajectories were associated with out-of-hospital cardiac arrest outcomes, which may be a supplementary factor in guiding the allocation of medical resources, such as extracorporeal CPR.

Prognostic relevance of global work index and global constructive work in patients with non-ischemic dilated cardiomyopathy.

Myocardial work (MW) derived from pressure-strain loops is a novel non-invasive tool to assess left ventricular (LV) function, incorporating global longitudinal strain (GLS) by speckle tracking echocardiography and non-invasively assessed blood pressure. Studies on the role of MW in dilated cardiomyopathy (DCM) are still limited. Therefore, the aim of this study was to evaluate the potential value of MW for predicting adverse outcomes in patients with DCM. 116 consecutive patients with DCM who underwent heart catheterization were retrospectively recruited from June 2009 to July 2014. 34 patients (30%) met the composite endpoints for major adverse cardiac events (MACE) of cardiac transplantation, need for implantable cardioverter-defibrillator (ICD) therapy, heart failure hospitalization and all-cause mortality. Patients with DCM were followed up for a mean of 5.1 years (IQR: 2.2-9.1 years). Global work index (GWI) and global constructive work (GCW) were not only independent predictors but also provided incremental predictive values (Integrated discrimination improvement [IDI] > 0) of MACE in multivariate Cox models. Furthermore, Patients with GWI < 788 mm Hg% (HR 5.46, 95%CI 1.66-17.92, p = 0.005) and GCW < 1,238 mm Hg% (HR 4.46, 95%CI 1.53-12.98, p = 0.006) had higher risks of MACE. GWI and GCW assessed by strain imaging echocardiography may have an additional value beyond LV-EF and GLS for predicting adverse outcomes in DCM.

Lack of Prognostic Value of T-Wave Alternans for Implantable Cardioverter-Defibrillator Benefit in Primary Prevention.

BACKGROUND: New methods to identify patients who benefit from a primary prophylactic implantable cardioverter-defibrillator (ICD) are needed. T-wave alternans (TWA) has been shown to associate with arrhythmogenesis of the heart and sudden cardiac death. We hypothesized that TWA might be associated with benefit from ICD implantation in primary prevention. METHODS AND RESULTS: In the EU-CERT-ICD (European Comparative Effectiveness Research to Assess the Use of Primary Prophylactic Implantable Cardioverter-Defibrillators) study, we prospectively enrolled 2327 candidates for primary prophylactic ICD. A 24-hour Holter monitor reading was taken from all recruited patients at enrollment. TWA was assessed from Holter monitoring using the modified moving average method. Study outcomes were all-cause death, appropriate shock, and survival benefit. TWA was assessed both as a contiguous variable and as a dichotomized variable with cutoff points <47 µV and <60 µV. The final cohort included 1734 valid T-wave alternans samples, 1211 patients with ICD, and 523 control patients with conservative treatment, with a mean follow-up time of 2.3 years. TWA ≥60 µV was a predicter for a higher all-cause death in patients with an ICD on the basis of a univariate Cox regression model (hazard ratio, 1.484 [95% CI, 1.024-2.151]; P=0.0374; concordance statistic, 0.51). In multivariable models, TWA was not prognostic of death or appropriate shocks in patients with an ICD. In addition, TWA was not prognostic of death in control patients. In a propensity score-adjusted Cox regression model, TWA was not a predictor of ICD benefit. CONCLUSIONS: T-wave alternans is poorly prognostic in patients with a primary prophylactic ICD. Although it may be prognostic of life-threatening arrhythmias and sudden cardiac death in several patient populations, it does not seem to be useful in assessing benefit from ICD therapy in primary prevention among patients with an ejection fraction of ≤35%.

Active Arrhythmia Pattern: A Novel Predictor of ICD Shocks-A Subanalysis From the PARTITA Study.

BACKGROUND: In the PARTITA trial (Does Timing of Ventricular Tachycardia Ablation Affect Prognosis in Patients With an Implantable Cardioverter Defibrillator?), antitachycardia pacing (ATP) predicted the occurrence of implantable cardioverter defibrillator (ICD) shocks. Catheter ablation of ventricular tachycardia after the first shock reduced the risk of death or worsening heart failure. A threshold of ATPs that might warrant an ablation procedure before ICD shocks is unknown. Our aim was to identify a threshold of ATPs and clinical features that predict the occurrence of shocks and cardiovascular events. METHODS: We analyzed data from 517 patients in phase A of the PARTITA study. We used classification and regression tree analysis to develop and test a risk stratification model based on arrhythmia patterns and clinical data to predict ICD shocks. Secondary end points were worsening heart failure and cardiovascular hospitalization. RESULTS: Classification and regression tree classified patients into 6 leaves by increasing shock probability. Patients treated with ≥5 ATPs in 6 months (active arrhythmia pattern) had the highest risk of ICD shocks (93% and 86%, training and testing samples, respectively). Patients without ATPs had the lowest (1% and 2%). Other predictors included left ventricle ejection fraction<35%, age of <60 years, and obesity. Survival analysis revealed a higher risk of worsening heart failure (hazard ratio, 5.45 [95% CI, 1.62-18.4]; P=0.006) and cardiovascular hospitalization (hazard ratio, 7.29 [95% CI, 3.66-14.5]; P<0.001) for patients with an active arrhythmia pattern compared with those without ATPs. CONCLUSIONS: Patients with an active arrhythmia pattern (≥5 ATPs in 6 months) are associated with an increased risk of ICD shocks, as well as heart failure hospitalization and cardiovascular hospitalization. These data suggest that additional treatments may be helpful to this high-risk group as a preventive strategy to reduce the incidence of major events. Further prospective randomized trials are needed to confirm the benefits of early ventricular tachycardia ablation in this setting.

Comparison of outcomes and required tools between transvenous extraction of pacemaker and implantable cardioverter defibrillator leads: Insight from single high-volume center experience.

INTRODUCTION: Reports of comparison with procedural outcomes for implantable cardioverter defibrillator (ICD) and pacemaker (PM) transvenous lead extraction (TLE) are old and limited. We sought to compare the safety, efficacy, and procedural properties of ICD and PM TLE and assess the impact of lead age. METHODS: The study cohort included all consecutive patients with ICD and PM TLE in the Cleveland Clinic Prospective TLE Registry between 2013 and 2022. Extraction success, complications, and failure employed the definitions described in the HRS 2017 TLE guidelines. RESULTS: A total of 885 ICD leads, a median implant duration of 8 (5-11) years in 810 patients, and 1352 PM leads of 7 (3-13) years in 807 patients were included. Procedural success rates in ICD patients were superior to those of PM in >20 years leads but similar in ≤20 years leads. In the PM group, the complete success rate of TLE decreased significantly according to the increase of lead age, but not in the ICD group. ICD TLE required more extraction tools compared with PM TLE but cases with older leads required non-laser sheath extraction tools in both groups. The most common injury site in major complication cases differed between ICD and PM TLE, although major complication rates showed no difference in both groups (2.7% vs. 1.6%, p = .12). CONCLUSION: The procedural success rate by TLE is greater for ICD patients than PM patients with leads >20 years old but requires more extraction tools. Common vascular complication sites and the impact of lead age on procedural outcomes and required tools differed between ICD and PM TLE.