Dual-chamber Implantable Cardioverter-defibrillator Research Articles

Resting heart rate assessed within clinical practice demonstrates no prognostic relevance for defibrillator recipients in the German DEVICE registry

Resting heart rate (RHR) has prognostic implications in heart failure with reduced ejection fraction, where ≤ 70 bpm is targeted. Whether a RHR > 70 bpm assessed within clinical practice goes along with elevated cardiovascular risk in implantable cardioverter-defibrillator (ICD) / cardiac resynchronization therapy-defibrillator (CRT-D) recipients remains incompletely understood. A total of 1589 patients (ICD n = 1172 / CRT-D n = 417, median age 65 years, 22.6% female) undergoing ICD/CRT-D implantation or revision in the prospective German DEVICE multicenter registry were analyzed. RHR was assessed via a 12-channel electrocardiogram at enrollment. 1-year outcomes (all-cause mortality, major cardio- and cerebrovascular events (MACCE), all-cause hospital admission) were compared between patients with a RHR ≤ 70 bpm and > 70 bpm. 733 patients (46.1%) showed a RHR > 70 bpm. Median RHR was 63 (interquartile range 59; 68) bpm (≤ 70 bpm group) and 80 (75; 89) bpm (> 70 bpm group). Heart failure with reduced ejection fraction was present in 76.3%, a prior myocardial infarction in 32.4% and non-ischemic heart disease in 44.9%. One-year all-cause mortality was similar between RHR groups (≤ 70 bpm 5.4% vs. > 70 bpm 5.4%, p = 0.96), and subgroup analysis regarding patient characteristics and comorbidities revealed only a significantly higher rate of patients with dual chamber ICD in the > 70 bpm group (0.8% vs. 9.2%, p = 0.003). MACCE (5.9% vs. 6.1%, p = 0.87) and defibrillator shock rates (9.9% vs. 9.8%, p = 1.0) were similar. Higher all-cause hospital admission rates were observed in patients with > 70 bpm RHR (23.1% vs. 29.0%, p = 0.027) driven by non-cardiovascular events (6.0% vs. 11.7%, p = 0.001). In conclusion, in ICD and CRT-D recipients a RHR at admission > 70 bpm may indicate patients at increased risk of all-cause hospital admission but not of other adverse cardiovascular events or death at 1-year follow-up.

Abstract 4138690: A Case of Hypertrophic Cardimyopathy: Digenic Variants of Uncertain Significance Mutations in MHY7 and RYR2 Genes

Introduction: Hypertrophic Cardiomyopathy (HCM) is primarily a disease caused by mutations in single genes, but around 5% of HCM patients, exhibit 2 (digenic) or more (oligogenic) causal mutations in the same gene or in different genes. We present a case of familial HCM with variants of uncertain significance (VUS) mutations in the MYH7 and RYR2 genes, highlighting the complexity of genetic inheritance and its implications on disease severity. Case presentation: A 40-year-old male presented with a history of hypertension, HCM, and two prior myocardial infarctions. He had syncope, non-sustained ventricular tachycardia, and a family history of sudden cardiac death (SCD) in his maternal grandfather. A dual-chamber ICD was placed for primary prevention of SCD because of his high-risk profile. Echocardiography demonstrated normal LV size and function with moderate asymmetric septal hypertrophy. Cardiac MRI indicated diffuse asymmetric hypertrophy and a 10.9% LV myocardial scar burden. Left heart catheterization revealed normal coronary arteries with LVOT gradient up to 60 mmHg, consistent with HCM. Genetic testing revealed VUS in the MYH7 (c.1305G>A, p.Met435Ile) and RYR2 (c.10528C>A, p.Arg3510Ser) genes (Figure 1). Further family genetic testing confirmed these VUS mutations in multiple relatives (Figure 2). Discussion: The identification of VUS mutations in MYH7 and RYR2 genes in multiple family members highlights the complexity of genetic inheritance in HCM. These findings underscore the challenges in clinical interpretation and risk stratification, as the co-occurrence of mutations in different genes may have synergistic effects on disease severity and phenotype expression. Comprehensive genetic evaluation, including family studies, is crucial for understanding the clinical significance of these mutations and guiding personalized management strategies. Further research is needed to elucidate the impact of VUS mutations on the clinical outcomes of HCM patients.

Atrial rates during treated ventricular tachycardia in patients with implantable cardioverter defibrillators: clinical implications of a vagal sinus node response

Abstract Introduction Autonomic tone plays an important role in the genesis and sustenance of ventricular tachycardia (VT). Whilst sympathetic hyperactivity is an established driver of ventricular arrhythmias, sinus node response during VT varies broadly between patients, and can be paradoxical. Purpose We hypothesized that device-detected changes in sinus node rate could be an important surrogate of the autonomic response to VT, and may exert significant – and potentially modifiable – haemodynamic consequences independent of ventricular activity. Methods Device electrograms were analysed from consecutive patients with dual chamber implantable cardioverter defibrillators (ICDs) requiring anti-tachycardia pacing (ATP) or defibrillation for sustained monomorphic VT. Atrial rates were measured before VT onset (‘baseline’) and again at the point of detection by the device. Sinus node response was characterized as ‘stable’ (atrial rate remained within 10% of baseline), ‘sympathetic’ (atrial rate increased >10%) or ‘vagal’ (atrial rate decreased >10%). Patients who did not maintain ventriculoatrial dissociation or who presented in atrial tachyarrhythmia were excluded. Symptoms and electrical response to ICD therapies were recorded. Results 172 treated episodes of VT were included from 97 patients (median age: 69 years, 65% male, 31% ischaemic cardiomyopathy, median ventricular rate: 205bpm, median ejection fraction: 30%). Sinus node response was stable in 55%, sympathetic in 24% and vagal in 21%. A vagal response was associated with ATP-refractory VT (OR: 2.2 (1.1-4.8) p=0.03) and, when adjusting for ventricular rate, was independently associated with symptoms of presyncope or syncope (adjusted OR: 6 (2.7-13.7), p<0.0001). Conclusions This preliminary analysis suggests that a vagal sinus node response during VT is associated with adverse outcomes in ICD patients. Vagolytic therapy has recently been demonstrated to improve haemodynamic tolerance during VT ablation; whether supportive atrial pacing during VT could mitigate symptoms and potentiate arrhythmia termination in ICD patients warrants further exploration. Figure 1: Change in sinus node rate during sustained monomorphic ventricular tachycardia in patients with dual chamber ICDs, stratified by the occurrence of presyncopal symptoms or syncopeFigure 1

Targeting ventricular tachycardia originating from the anterolateral papillary muscle with stereotactic body radioablation therapy

Abstract Background Ventricular Tachycardia (VT) is prevalent in the setting of non-ischaemic cardiomyopathy (NICM), a heterogeneous group of conditions characterized by myocardial dysfunction in the absence of coronary artery disease. Challenges of catheter ablation to treat VT in NICM patients are well known, and recurrence rates can be as high as 58%. Stereotactic body radioablation therapy (SBRT) involves precise delivery of radiation to arrhythmogenic substrates, and represents a novel treatment to reduce recurrent implantable cardioverter defibrillator (ICD) therapies in patients with refractory VT. Though SBRT has shown preliminary effectiveness in reducing VT episodes, its effectiveness in NICM patients has not been widely evaluated. Purpose To evaluate SBRT effectiveness in NICM patients with scars at the basal anterolateral papillary muscle at a tertiary care center between November-December 2022. Methods Eligible patients had their VT substrate mapped using a single-use ECGI vest and a 4D-CT simulation scan. In addition, MRI scans were used to aid anatomical identification of the anterolateral papillary muscle which could not be seen on the non-contrast diagnostic CTs. SBRT was delivered in a single fraction of 25 Gy under image guidance. Effectiveness of the treatment was evaluated as changes in frequencies of total antitachycardia pacing (ATP) and ICD shock episodes from 6 months pre-, and within to 3, 6, and 12 months follow up post SBRT. Results Participants were 3 males with NICM, aged 56, 60, and 73 with previous dual chamber ICD implantation, 2 of whom had a history of VT ablation/ VT storm and paroxysmal atrial fibrillation. All participants had basal lateral scar, and were receiving beta blockers, mexiletine, and amiodarone with refractory VT before SBRT treatment. Prior to SBRT, ICD device interrogation showed a total of 119 (77, 7, and 35 in patients 1-3 respectively) ATPs, and 27 (10, 1, and 16 in patients 1-3 respectively) ICD shocks delivered. At 12 month follow-up, none of the participants experienced any episodes of ATP or ICD shock. Ejection fraction remained consistent pre-post SBRT. Conclusion SBRT showed remarkable success in reducing ATP and ICD shock episodes, facilitating uncomplicated 1 year follow-up in 3 male patients with NICM and VT from the anterolateral papillary muscle.

Unique Tachycardia Recorded on a Cardiac Implantable Electronic Device: What is the Mechanism?

In a 55-year-old man with nonischemic cardiomyopathy, a unique tachycardia was recorded on a dual-chamber implantable cardioverter defibrillator (St. Jude Medical [Abbott]) as an automatic mode switch episode. This case report discusses the mechanism of tachycardia, how it can be differentiated from similar rhythms, and its clinical implications. The report explores device limitations in managing such tachycardias and presents reprograming strategies to prevent recurrence. This case emphasizes the importance of careful analysis of device-mediated arrhythmias and appropriate programming.

Cardiac sarcoidosis presenting as multiple right intra-atrial masses mimicking cardiac tumor

BackgroundCardiac sarcoidosis though in itself, a rare entity, very rarely presents primarily with conduction abnormalities as the primary manifestation in the spectrum of presentations accounted by this chronic granulomatous systemic disease. Sarcoidosis presenting as intra-atrial masses is virtually unheard of.CaseA middle aged female presented with progressive conduction system disease was found to have right atrial masses of unclear etiologic on relevant imaging. Over the course of 3 months she underwent a dual-chamber ICD implant for her eventual complete heart block and a surgical resection following an inconclusive biopsy of the right atrial free wall mass. She was then diagnosed with cardiac sarcoidosis and started on immunosupressants almost instantaneously as a part of her treatment.ConclusionThis is an entirely new and unreported presentation of cardiac sarcoidosis as an intra-atrial mass. Through this case we bring light to cardiac sarcoidosis as a potential differential for intra-cardiac masses and how with available data do we go about treating it.

Electrogram-guided Bachmann bundle area pacing to correct interatrial block: Initial experience, safety, and feasibility

BackgroundA lack of standard Bachman Bundle(BB) capture criteria has affected the clinical impact of Bachmann Bundle Area Pacing(BBAP) in patients with inter-atrial block(IAB). ObjectiveWe evaluated the feasibility and safety of electrogram guided BBP using sheath assisted, stylet-driven atrial lead implantation. MethodsPatients with a baseline IAB undergoing dual chamber PPI or ICD implantation were enrolled in a single center,prospective study. BBAP was attempted in all patients with the aid of a Selectra 3D S-40 delivery sheath and Solia S-60 pacing lead. BB capture was confirmed using a combination of fluoroscopy,P wave morphology,and electrophysiological criteria. These included the recording of a high frequency BB potential and a transition between non-selective(NS) to selective(S) BB capture during threshold testing. Procedure-related complications,lead parameters,and P wave morphology were assessed at implantation and follow up. ResultsPermanent BBAP was successful in 32 of the 36(88.9%) enrolled patients. Baseline P wave duration was 148.5+16.1ms. Among patients who underwent successful BBP, the final paced P wave duration was 117.8+19.6ms. There was a correction of the partial or complete interatrial block in 22(91.7%) and 6(75.0%) patients, respectively. BB potentials were recorded in 83.3% of all study patients.A transition from NS to S-BB capture could be demonstrated during threshold testing in 22(87.5%) patients. The only major complications were 2 BBAP lead dislodgements within 24 hours and a rise in pacing impedance at 3 weeks in 1 patient. ConclusionBBAP is feasible in a high percentage of patients and is associated with stable capture thresholds during follow up.

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

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

Ventricular arrhythmia events in patients with implantable cardioverter-defibrillator before and after the treatment with sodium-glucose co-transporter 2 inhibitors

Abstract Background The role of sodium-glucose co-transporter 2 inhibitors (SGLT2i) in the treatment of chronic heart failure is expanding. However, the timing of implantable cardioverter-defibrillator (ICD) implantation for primary prevention in relation to the use of SGLT2i remains unclear. A small case series has described appropriate shocks from ICD in two patients following the initiation of SGLT2i, but a comprehensive analysis is lacking in the literature. Methods This study aimed to investigate the rate of ventricular arrhythmic burden and appropriate anti-tachycardia therapy from ICD before and after the initiation of SGLT2i therapy. We conducted a retrospective single-center analysis, comparing ventricular events from home monitoring reports three months before and three months after SGLT2i therapy initiation. Results Seventeen patients were enrolled in the study. At baseline, clinical characteristics were as follows: 13 (76%) were male, 9 (53%) had ischemic, 2 (12%) had valvular, and 6 (35%) had idiopathic cardiomyopathy. The mean end-diastolic volume (EDV) was 203 ± 90 ml, and the mean left ventricular ejection fraction was 0.36 ± 0.09. All patients were treated with beta-blockers, 14 (82%) with sacubitril-valsartan, 13 (76%) with aldosterone antagonists, 16 (94%) with furosemide, and 5 (29%) with amiodarone. SGLT2i started with dapagliflozin for 13 patients (76%), empagliflozin for 3 patients (18%), and canagliflozin for 1 patient (6%). Ten patients (59%) had single-chamber or dual-chamber ICDs, and 7 had implantable cardiac resynchronization therapy (CRT) defibrillators. In the three months before SGLT2i treatment, 4/17 patients had non-sustained ventricular tachycardia (NSVT), compared to 8/17 (23% vs. 47%, p-value 0.23) patients with NSVT after treatment. Seven patients (41%) experienced an increase in the rate of NSVT events, with one patient having 28 NSVT events after treatment versus none before treatment. No patients had anti-tachycardia therapy in the three months before treatment, while in the three months after SGLT2i treatment, 1 patient had ventricular tachycardia treated with anti-tachycardia pacing (110 days after the beginning of the treatment), and 2 patients had ventricular tachycardia treated with appropriate shocks (2 and 25 days after the initiation of SGLT2i treatment). Conclusion This small retrospective analysis revealed an increase in ventricular arrhythmic events in the three months following the initiation of SGLT2i. These findings highlight the need for a more extensive analysis to establish a stronger statistical correlation.

Factors influencing inappropriate device therapy in implantable cardioverter defibrillators: a predictive analysis

Abstract Background Implantable cardioverter defibrillator (ICD) implantation and subsequent ICD therapy have shown to be efficacious in the prevention of sudden cardiac death. However, patients with an ICD are at risk of inappropriate device therapy (IDT), which is associated with worse outcomes, reduced quality of life (QoL), and may influence psychosocial and mental wellbeing. Purpose This study aimed to predict which patients are at risk of IDT by investigating the influence of pre-implant clinical parameters on occurrence of IDT. Methods From January 2010 to December 2019, patients who received an ICD in our medical center, were included in a prospective registry. Only patients with ICD (including ICDs used for cardiac resynchronization therapy, i.e. CRT-D) with an atrial lead were included in the current analysis, to better distinguish between appropriate and inappropriate device therapy. After implant, the device was interrogated at least every 6 months and clinical symptoms related to the device, recorded events, and relevant technical setting changes were recorded. IDT was defined as antitachycardia pacing (ATP) or shock delivered for any reason other than ventricular arrhythmia. Follow-up ended after IDT, death, or loss-to-follow-up. Results 428 patients underwent an implantation of a dual chamber ICD or CRT-D of various manufacturers. 14 patients were lost to follow-up within the first year and one patient was excluded because of a dislocated atrial lead, leaving 413 patients (76% male, mean age 67±9.7 years, 39% CRT-D) with a minimum of 1-year follow-up. During a mean of 5.3 (±3.0) years, 136 (32.9%) patients received appropriate therapy and 36 (8.7%) patients received IDT. Of those 36 patients, 18 patients received only ATP, 12 received ATP followed by a shock, and 6 patients received a shock without prior ATP. The median time from implantation to IDT was 2.8 [0.3-5.8] years. Univariate logistic regression on 40 clinical parameters followed by a forward multivariate logistic regression was performed. The area under the ROC curve of the resulting multivariate model was 0.724 (95%CI 0.622-0.826). Cox regression analysis resulted in device type (CRT-D) (HR=0.533, 95%CI 0.234-1.211, p=0.133), use of mineralocorticoid receptor-antagonists (MRA) (HR=0.280, 95%CI 0.104-0.754, p=0.012), use of diuretics (HR=3.378, 95%CI 1.479-7.714, p=0.004), and eGFR (HR=1.217, 95%CI 0.972-1.523, p=0.087) as predictors of IDT. A history of atrial fibrillation was not a significant predictor of IDT. Conclusion This study identified CRT-D and use of MRAs to be protective against IDT, and use of diuretics and lower eGFR as risk factors of IDT. To inform patients optimally, pre-implant assessment of those factors could help identify patients at higher risk of IDT. Furthermore, it could dictate more cautious device programming and consequently reduce rates of IDT, reducing the negative influence of IDT on QoL and wellbeing in the ICD population.

INTERATRIAL BLOCK AS A FIRST CLINICAL PRESENTATION OF ATRIAL CARDIOMYOPATHY RELATED TO A NOVEL LMNA VARIANT: A CASE REPORT

Abstract Interatrial block (IAB) is a conduction delay in Bachmann’s bundle with a well–described association with structural heart disease, supraventricular arrhythmias, and cardiovascular events. We report the case of an asymptomatic 35–year–old man in whom the presence of IAB at electrocardiogram led to a comprehensive evaluation including speckle–tracking echocardiography, 24 h Holter monitoring, and genetic testing. Speckle–tracking echocardiography demonstrated a decrease in the longitudinal strain of interventricular septum, a typical feature of LMNA–related cardiomyopathy, and decreased indices of left atrial deformation. A diagnosis of cardiac laminopathy related to the frame shift variant c.1367 (p.Asn456Thrfs*24) of the LMNA gene was made. A dual–chamber implantable cardioverter defibrillator implantation was performed for the high risk of life–threatening ventricular tachyarrhythmias. This case demonstrates that IAB could be a rare presentation of a life–threatening laminopathy. Strain echocardiography is an essential tool to evaluate the deposition of fibrosis tissue in subclinical cardiomyopathies. Our report describes a novel variant of LMNA gene associated with a high risk of sudden cardiac death.

A VENTRICULAR TACHYCARDIA CASE NOT TREATABLE WITH TRANSCATHETER ABLATION DUE TO APICAL THROMBOSIS OF THE LEFT VENTRICLE RESOLVED WITH RADIOTHERAPY BASED ON THE NON–INVASIVE MAPPING SYSTE

Abstract The clinical case focuses on a 52–year–old man smoker, heavy alcohol consumer. In 2017 he began with sustained ventricular tachycardia (VT) effectively treated with DC–shock. The following ECG showed signs of anterior necrosis. Severe left ventricular (LV) dilatation, apical thrombosis and severe impairment of LV function were found on echocardiogram. Angiography was performed and LAD occlusion was found. Since of 68% necrosis of the LV at myocardial scintigraphy, no revascularization was performed. He underwent to a dual chamber ICD implantation and started oral anticoagulation therapy. In the following years recurrence of arrhythmic episodes, despite the optimization of antiarrhythmic therapy, led the patient to numerous hospitalizations. Unfortunately the persistence of the apical thrombosis, made transcatheter ablation NOT possible. The only chance for the patient remained stereotactic arrhythmia radioablation. But which area of the LV to highlight as responsible for the arrhythmia and how to program the radiotherapy treatment plan was a challenging problem. We proposed in March 2023 non–invasive mapping of arrhythmia using Cardioinsight. The patient performed heart high–resolution computed tomography (CT) for the anatomical reconstruction with precise spatial resolution of all LV aereas and surrounding structures. A 252–electrode vest is applied to the patient’s torso and connected to the system Cardioinsight. A programmed ventricular stimulation was performed using ICD inducing two VT morphologies. Through electroanatomical mapping we identified the mid LV antero–septal and infero–septal sites as target areas. Thanks to multidisciplinary team a personalized treatment plan was created to deliver an effective lesion in the target area and minimize exposure to nearby organs at risk. The treatment was generated, optimized and delivered by TrueBeam, lasted 3 minutes and no complications arose. The patient was quickly discharged in good clinical condition. After 3 months of clinical well–being he was hospitalized for a single episode of VT. Up to now no hospitalizations occurred. This treatment may represent a "bail–out" choice in patients with advanced heart failure with arrhythmic storm who have exhausted all other therapeutic options.

Internal Mammary Artery Graft Flow Steal by a Large Dialysis Arteriovenous Fistula Characterized by Electrical Storm

Background: Steal syndrome describes a condition in which a dilated vessel distal to a smaller artery attempts to compensate for decreased blood flow by “stealing” from the smaller artery. Steal syndrome is not uncommon and can be seen in certain physiologic and pathologic states. The classic example is an occluded atherosclerotic coronary artery resulting in a misdirection of blood flow into the open channels that have developed over time resulting in downstream ischemia. Case Report: A 66-year-old male fourteen years post 4-vessel coronary artery bypass grafting using his left internal mammary artery to bypass a stenotic segment of the left anterior descending artery, along with three saphenous venous conduits to the right coronary artery. He also had a stent placement by PCI. He was on dual antiplatelet therapy with aspirin and clopidogrel. An electrophysiology study revealed inducible VF and he underwent implantation of a dual chamber ICD 9 months prior to presentation. He experienced an unprovoked fall at home and a workup revealed the flow volume through the patient’s fistula increased to such a degree that the patient developed a steal syndrome from his left internal mammary artery graft. In addition, went into a state of electrical storm caused by ischemic damage to cardiac tissue distal to the graft. By ligating the fistula, the patient’s steal syndrome resolved and he did not suffer further ventricular arrhythmias. Conclusion: Both coronary bypass grafting and fistula formation are common and necessary interventions and providers should take care to monitor for interactions between these proposed interventions to best serve their patients without causing additional harm. Increased vascular flow through any portion of the body can induce a steal syndrome from an upstream region. Patients who undergo arteriovenous (AV) fistula placement may develop a steal syndrome from ipsilateral bypass grafts.

Nutritional Status Predicts the Length of Stay and Mortality in Patients Undergoing Electrotherapy Procedures.

(1) Background: Nutritional status is a factor that impacts the patients' outcomes in various medical conditions including cardiovascular patients or surgical procedures. However, there is limited available information about its impact on the short-term outcomes of cardiac implantable electronic device (CIED) implantations. This study aimed to assess the relationship between nutritional status, complications, mortality risk, and length of stay at the hospital in patients undergoing CIED implantations. (2) Material and Methods: 588 patients who underwent CIED implantation in 2022 and 2023 were included in the retrospective analysis. The nutritional status assessment was performed using NRS 2002 and BMI. The implanted devices were single-chamber pacemakers (n = 82), dual-chamber pacemakers (n = 329), one-chamber ICDs (n = 83), dual-chamber ICDs (n = 19), CRT-P (n = 19), and CRT-D (n = 56). (3) Results: The regression analysis showed that the NRS 2002 score predicted the length of stay (age-adjusted: β = 1.02, p = 0.001) among the CIED-implanted patients. The CRT-D subgroup was particularly responsible for this relationship (β = 4.05, p = 0.003 after age adjustment). The analysis also revealed significant differences between the NRS 2002 score in the in-hospital death subgroups (1.75 ± 1.00 points for deaths vs. 1.00 ± 1.00 points for survivors; p = 0.04). There were no significant differences in nutritional status parameters regarding early complications subgroups. (4) Conclusions: This study showed that nutritional risk assessed with NRS 2002 is a predictor of length of stay (particularly for CRT-D) and mortality among patients undergoing CIED implantations. The results of the analysis point out the impact of patients' nutritional status on short-term outcomes of CIED implantations, particularly in CRT-D implants where 1 NRS 2002 point was a predictor of a mean 4.05 days (77.2%) longer hospitalization.

Appropriateness of implantable cardioverter-defibrillator device implants in the United States

BackgroundThe appropriate use criteria (AUCs) are a diverse group of indications aimed to better evaluate the benefits of implantable cardioverter-defibrillator (ICD) and cardiac resynchronization therapy. ObjectiveThe purpose of this study was to quantify the proportion of ICD and cardiac resynchronization therapy with defibrillator (CRT-D) implants as appropriate, may be appropriate (MA), or rarely appropriate (RA) on the basis of the AUC guidelines. MethodsThis is a multicenter retrospective study of patients within the National Cardiovascular Data Registry undergoing ICD implantation between April 2018 and March 2019 at >1500 US hospitals. The appropriateness of ICD implants was adjudicated using the AUC. ResultsOf 309,318 ICDs, 241,438 were primary prevention implants (78.1%) and 67,880 secondary prevention implants (21.9%); 243,532 (79%) were mappable to the AUC. For primary prevention, 185,431 ICDs (96.4%) were appropriate, 5660 (2.9%) MA, and 1205 (0.6%) RA. For secondary prevention, 47,498 ICDs (92.7%) were appropriate, 2581 (5%) MA, and 1157 (2.3%) RA. A significant number of RA devices were implanted in patients with New York Heart Association class IV heart failure who were ineligible for advanced therapies (53.9%) and those with myocardial infarction within 40 days (18.1%). The appropriateness of the pacing lead was more variable, with 48,470 dual-chamber ICD implants (62%) being classified as appropriate, 29,209 (37.4%) MA, and 448 (0.6%) RA. Among CRT-D implants, 63,848 (82.2%) were appropriate, 9900 (12.7%) MA, and 3940 (5.1%) RA for left ventricular pacing. A total of 99,754 implants were deemed appropriate but excluded from Centers for Medicare & Medicaid Services National Coverage Determination. More than 92% of hospitals had an RA implant rate of <4%. ConclusionIn this large national registry, 95% of mappable ICD and CRT-D implants were considered appropriate, with <2% of RA implants. Nearly 100,000 appropriate implants are excluded by Centers for Medicare & Medicaid Services National Coverage Determination.

PP49 Cost Of Cardiac Implantable Electronic Device (CIED) Infections In Australia: A Private And Public Sector Payer Perspective

IntroductionIn Australia, approximately 200,000 patients have a cardiac implantable electronic device (CIED), and in an aging population that number is rising. CIED-related infections are also increasing, causing considerable morbidity and mortality, and substantial healthcare costs. Internationally, the rate of CIED infection ranges from 1.0 percent to 1.6 percent, while in Australia, the reported range is from less than 1 percent to 7.0 percent. The average hospital cost to treat an infection in the US ranges between USD48,000–USD83,000. To date, few publications have estimated the cost of CIED infections in Australia. Critical appraisal of these studies has highlighted issues in their methodology, making them unreliable sources for use in economic evaluations. The purpose of this study was to utilize Australian routinely collected health data to robustly model costs of CIED infections to reduce uncertainty for future health technology assessment (HTA).MethodsThe cost of treating a CIED infection was modeled for the public and private sector including cost of system removal and re-implantation procedures, hospital and intensive care unit (ICU) stay, and outpatient follow-up. Cost inputs were obtained from the Australian Prostheses List, Medicare Benefits Schedule, Australian Institute of Health and Welfare, and Private Hospital Data Bureau. Other inputs were obtained by surveying Australian clinicians, which were validated with published data. Phone interviews and online surveys were conducted with clinicians to elicit specific Australian practice pathways for patients with a CIED infection.ResultsThe majority of patients with a CIED have their device system removed (95-100%) and re-implanted (83%) once the infection has cleared. In the private sector, cost of infection ranged from AUD80,869 (USD54,384) for a single chamber pacemaker (PM), to AUD140,103 (USD94,248) for a dual chamber Implantable Cardioverter-defibrillator (ICD). Modeled costs of CIED infection were slightly lower in the public sector (AUD73,643-AUD88,446 (USD49,555 – USD59,516) for the same devices).ConclusionsThe cost of a CIED infections to the healthcare system is high and differs by device type. Utilizing local real-world data to estimate costs will improve accuracy of economic evaluations and reduce uncertainty for decision makers.

Choice of cardiac implantable electronic device and age-stratified clinical outcome in patients with known heart failure prior to implant

Abstract Background Patients with heart failure (HF) and bradycardia may be eligible for different types of cardiac implantable devices, depending on presence of AV conduction disease, left ventricular ejection fraction, severity of heart failure symptoms, other comorbidities, and age. Once a pacing device is in place, there is a risk that ensuing heart failure progression or worsening of symptoms do not always prompt a device upgrade to resynchronization or conduction system pacing therapy, even if this should be warranted. We therefore aimed to compare prognosis in a national cohort of patients with prior HF diagnosis, who received a pacemaker or defibrillator with or without resynchronization therapy. Methods All patients with preexisting HF diagnosis who received a pacemaker with a right ventricular lead during the period 2005-2018 in Sweden were identified via the Pacemaker Registry. Data was crossmatched with the population registry and national disease registries. Primary outcome was 5-year mortality, and secondary was mode of death and hospitalization for heart failure. Cox regression and Kaplan Meier curves with log rank test were used for time dependent outcome analyses. Demography variables were compared with Chi2 test or Mann Whitney U test, as appropriate. Adjustment was done for history of atrial fibrillation, diabetes, hypertension, malignancy, age, gender, ischemic heart disease, renal disease, lung disease and cerebrovascular disease. Separate analyses were made for patients with complete AV block, based on the assumption of 100% ventricular pacing in this group, regardless of choice of implanted device. Results 37745 patients were included in the study (see figure 1). Demographic data was similar for the different device groups, except that patients with single chamber pacemaker were older, and all those with single chamber devices (pacemaker, ICD) were more likely to have a history of atrial fibrillation. All listed comorbidities, male sex and higher age were associated with lower 5-year survival in multivariable Cox regression analyses. Unadjusted 5-year mortality was 40% (highest for single chamber pacemakers (61%), and lowest for dual chamber ICDs (17%), p=0.001). When stratified by age group, and adjusted for relevant covariables, patients with single-chamber pacemakers still had higher mortality in all age decile groups (ranging from &amp;lt;60 to &amp;gt;90 years old, all p&amp;lt;0.001). Proportion of device upgrades to CRT was very low; 2.9% for dual- and 0.8% for single-chamber pacemakers. 17% of patients with traditional pacemakers died from HF, and 31% were hospitalized for HF. Conclusions Survival for patients with prior HF diagnosis who receive traditional pacemakers is poor, risk of HF hospitalization is high, whereas upgrades to CRT are scarce. This highlights the need for choosing correct device type at the primary implant, if ventricular pacing is anticipated.Flowchart of included patientsAge stratified survival per device group

Abstract 13000: Twiddler’s Syndrome - A Rare Cause of Pacemaker Malfunction

Description of Case: A 76-year-old female with a past medical history of chronic atrial fibrillation and symptomatic tachycardia and bradycardia status-post dual-chamber pacemaker with right atrial and ventricular leads who presented with dyspnea on exertion. TTE showed normal biventricular function and no significant valvular abnormalities. Upon further evaluation of her pacemaker, she was found to have a very high ventricular capture threshold suggesting RV lead failure. The patient underwent RV lead replacement. The inspection of the pacemaker pocket during the procedure showed manual dislodgement of both tie-down sleeves and the pacemaker leads required untangling. A new RV lead was subsequently placed. Upon further imaging review, displacement of the previous RV lead was evident from initial placement. In addition, the patient had previously had a history of interval diaphragmatic stimulation as well. Overall, the presentation was felt to be consistent with Twiddler’s Syndrome. Discussion: Twiddler’s or Reel Syndrome occurs when conscious or subconscious self-manipulation and spinning of the pulse generator result in lead dislodgement and loss of pacing and pacemaker malfunction. The reeling of the leads around the generator can also cause stimulation of the brachial plexus or phrenic nerve stimulation and subsequent rhythmic arm twitching or diaphragmatic pacing, respectively. It has previously been reported in cases of single- and dual-chamber ICDs, deep brain stimulators, and spinal nerve stimulators with varying presentation. The diagnosis requires clinical suspicion based on history, physical exam, imaging, or surgical inspection suggesting the displacement of leads with evidence of coiling of the wires around the pacemaker. Treatment often requires revision and focus should be maintained on patient education for both primary and secondary prevention of Twiddler’s Syndrome.

Abstract 16616: Automatic Measurement of Short-Term Variability of Repolarization Captures Modulation by Pacing on Human Intracardiac Electrograms

Introduction: Short-term variability of repolarization (STV) increases prior to ventricular arrhythmias (VA) both in humans and in animal models of VA, and is therefore a promising tool for real-time monitoring of arrhythmic risk. To integrate this concept in cardiac devices, a method to automatically determine STV on intracardiac electrograms (EGM) was developed. This STV algorithm demonstrated high efficacy in predicting life-threatening VA in animal studies, but still needs to be evaluated on human signals. Objective: To assess the performance of the novel automatic method of STV measurement on human EGMs during sinus rhythm (SR) and pacing. Methods: ECG and EGM signals with a 1 kHz sampling frequency were recorded in 14 dual chamber implantable cardioverter-defibrillator (ICD) patients during implantation (n=4) or replacement (n=10) procedures. Recordings were obtained in SR, atrial pacing at 80 beats per minute (AAI80) and atrioventricular pacing at the same frequency (DDD80). STV was calculated over 31 consecutive beats as Σ

Abstract 14731: T-wave Oversensing Secondary to an Inappropriate ICD Shock Resulting in Subsequent Unnecessary Shocks

Introduction: Inappropriate ICD shocks commonly result from persistent atrial arrhythmias or oversensing. We report a scenario where an ICD shock for a rapid, sustained atrial tachycardia (AT) resulted in T-wave oversensing (TWO), triggering further inappropriate shocks. Presentation: A 69-year-old woman with secondary prevention dual chamber ICD underwent pulmonary vein isolation for symptomatic paroxysmal atrial fibrillation (AF). The patient remained free of AT/AF off antiarrhythmics for 3 months after the procedure when she was admitted with four consecutive ICD shocks. Electrolytes were within normal limits. Device interrogation showed that the first shock was triggered by a rapid, sustained AT (cycle length: 270 msec) detected in the VF zone (single zone device; 280 msec cut-off) and failed ATP. Following the first shock, an irregular AT ensued, with cycle length ranging from 280-370 msec, but now with high amplitude T-waves in the RV channel, resulting in TWO and three subsequent inappropriate shocks (Figure). She received IV metoprolol and digoxin with subsequent resolution of AT and TWO. Beta-blocker dosing was increased and she has remained free of AT/AF at 6 month follow-up. Conclusions: ICD shocks can trigger marked repolarization changes in near-field intracardiac RV electrograms resulting in TWO and subsequent appropriate shocks. Further studies are warranted to understand the mechanism underlying this phenomenon and potential risk for these events.