Single-chamber Implantable Cardioverter-defibrillator Research Articles

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.

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

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

Substernal lead removal: experience from the EV ICD pivotal study

Abstract Background The extravascular implantable cardioverter defibrillator (EV ICD) has recently emerged as a new option for guideline indicated ICD patients. Previous study results from the EV ICD Pilot and Pivotal studies have demonstrated that the device can provide safe and effective therapy through chronic follow up. However, less has been reported regarding EV ICD lead removal. Purpose To report on the experience of lead removal in the EV ICD Pivotal Study. Methods The EV ICD Pivotal study was an international, prospective, single-arm, premarket clinical study. Patients with a class I or IIa indication for a single-chamber ICD per ESC or ACC/AHA/HRS guidelines were enrolled. Lead removal summary data was reported. Results Of 316 patients with an implant attempt, (74.7% male, age 53.8±13.1 years, 82% primary prevention, LVEF of 38.9%±15.4%, and NYHA Class I [23.7%] or II/III [65.5%]) 299 were fully implanted; 17 (5.7%) of which had a lead removal procedure (14–752 days post-implant, at 13 sites) with 3 of them having been implanted for more than 1 year. Reasons for lead removal were lead dislodgement (n=7), infection (n=5), high impedance alert due to lead fracture (n=2), pacing indication (n=1), cardiac transplant (n=1), or scheduled sternotomy (n=1). New EV ICD leads were placed in 7/17 (41.2%) patients. No serious adverse events were adjudicated as related to the explant procedures. There was a single observation of incision site haemorrhage, that was resolved with wound care. Additional details on lead removal will be included at the time of presentation. Conclusions The EV ICD lead was successfully removed 14-752 days post implant. Nine patients were re-implanted with either extravascular or transvenous systems. Longer term extraction data collection is ongoing through the EV ICD Pivotal study and through the EV ICD post-approval study and will continue to provide additional insights.Lead removed 24 months post-implant.

Catastrophic implantable cardioverter-defibrillator misclassification of ventricular tachycardia

Inappropriate therapy is a frequent adverse consequence of implantable cardioverter-defibrillator. Inappropriate therapy often occurs due to the misinterpretation of sinus tachycardia or atrial fibrillation/flutter with rapid atrioventricular conduction by the device. Current implantable cardioverter-defibrillator (ICD) mechanisms integrate various discriminators into algorithms to differentiate supraventricular tachycardia (SVT) from ventricular tachycardia (VT), to prevent such occurrences. A 40-year-old man suffered seizures and cardiac arrest abruptly, without prior complaints of chest pain. Without delay, he initiated cardiopulmonary resuscitation (CPR), resulting in the regaining of spontaneous circulation. The patient had previously received a single-chamber ICD due to recurring VT and a prior episode of cardiac arrest. The patient had a medical background of coronary artery disease with complete revascularisation and no previous occurrence of SVT. Interrogating the ICD revealed captured non-sustained ventricular tachycardia (NSVT) and SVT events but no VT episode or shock therapy. During the specified time period, the patient underwent an electrophysiological study, and no SVT was induced with the normal function of the atrioventricular and sinoatrial nodes. Various causes can lead to errors in morphology discrimination criteria in single-chamber ICDs. Extending the detection interval is highly recommended to avoid misclassification of ICDs.

A CATASTROPHIC COMPLICATION OF A CHEST TRAUMA: A CASE REPORT

Abstract A 43 year old patient came to the Emergency Department of our hospital for a cardiology visit. The EKG revealed polymorfic ventricular tachycardia with a heart rate of 160 bpm so that he was admitted to the Intensive Care Unit. In 2005, he had a post traumatic myocardial infarction after a car accident treated with the implantation of one drug eluted stent on the descending artery. Three years later, a single–chamber ICD was placed. On admission in Intensive Care Unit, cardiac auscultation revealed normal heart sounds without murmurs. No lower extremity edema was observed. A transthoracic echocardiogram showed general hypokinesis with reduced global left ventricle systolic function and no pericardial effusion (EF=20%). The patient was haemodynamically stable, the blood pressure was of 130/80 mmHg. The device was also interrogated and it showed six ineffective attempts of antitachycardia pacing. After that, the patient was given an effective intracavitary shock. Moreover, the patient underwent coronary angiography which showed no disease progression and patency of the stent previously implanted on the proximal descending artery. The electrophysiological study was performed and subsequently 3 ventricular ectopic focuses were effectively ablated. Multiple DC shocks were delivered during the procedure and the atrioventricular bundle was damaged. In consideration of the clinical features and the left ventricular reduced ejection fraction, an indication to the implantation of CRT–D was given. Conclusions This case report describes a rare complication of a blunt chest trauma. A young patient with no significant past medical history suffered a dissection of the coronary descending artery resulting in ST–elevation myocardial infarction. The mechanism of coronary occlusion following blunt chest injury may be due to: shear force applied to the coronary arteries leading to intraluminal thrombosis; vascular rupture; embolism to the coronary arteries; fissuring of an atherosclerotic plaque with dislodgment of plaque material; vascular spasm at the site of the injury. Anyway, severe left ventricular dysfunction caused the developing of polymorfic ventricular tachycardia which was unresponsive to medical treatment and was treated with ablation.

Chronic safety and performance of the extravascular ICD: results from the global EV ICD Pivotal study

Abstract Background Implantable cardioverter defibrillators (ICDs) prevent sudden cardiac death in patients at high risk for ventricular arrhythmias, but conventional systems carry a risk of transvenous (TV) lead-related complications. The novel extravascular ICD (EV ICD) may reduce some of these complications, while offering anti-tachycardia pacing (ATP), pause prevention pacing, and a device of similar size and projected battery longevity as a TV ICD, by placing a lead substernally. The EV ICD Pivotal study demonstrated EV ICD safety and performance for termination of ventricular arrythmias at 6 months. Longer-term performance is unknown. Purpose To report the chronic safety and performance of the EV ICD system. Methods The extravascular implantable cardioverter defibrillator (EV ICD) Pivotal study was a prospective, international, single-arm, premarket clinical study. Patients with a class I or IIa indication for a single-chamber ICD per ESC or ACC/AHA/HRS guidelines were enrolled. Freedom from major system- and/or procedure-related complications at 18 mo was evaluated, as well as conversion of arrhythmias by anti-tachycardia pacing (ATP) or shock through all available follow up. Rates of ATP success were evaluated using the generalized estimating equation (GEE) and simple proportions. Results Implantation was attempted in 316 patients: 74.7% male, age 53.8±13.1 years, 82% primary prevention, left ventricular ejection fraction of 38.9%±15.4%, and New York Heart Association Class I (23.4%) or II/III (65.5%). Of 299 implanted patients (average follow up 16.2±7.2 mo), 19 experienced 80 spontaneous, appropriately treated arrhythmic episodes: 37 treated by ATP, 15 by ATP and shock, and 28 by shock alone with a Kaplan-Meier (KM) estimated 6.8% of patients experiencing appropriate therapy by 18 mo (Figure). Of discrete episodes treated with shock, 21/21 (100%) were successfully terminated. ATP was delivered in 12 patients, successfully treating 35/52 episodes (67.3%; GEE adjusted 59.0%). Inappropriate shocks occurred in 35 patients through all follow up, with a rate of 10.2% at 1 year. The KM estimate of freedom from major EV ICD system-or procedure-related complications rate through 18 mo was 91.9% (95% CI: 88.2% to 94.4%). The most common event was lead dislodgment (10 events in 9 patients) identified 0 to 120 days post-implant, predominantly due to anchoring technique. Conclusion The safety and effectiveness of a novel EV ICD system with a substernal lead extends through chronic follow up. Shocks were avoided in nearly half of all spontaneous episodes because of the availability of ATP.Figure

The Pacemaker and Implantable Cardioverter-Defibrillator Registry of the Italian Association of Arrhythmology and Cardiac Pacing - Report 2022

The Pacemaker (PM) and Implantable Cardioverter-Defibrillator (ICD) Registry of the Italian Association of Arrhythmology and Cardiac Pacing (AIAC) collects information about demographics, clinical characteristics, main indications for PM/ICD therapy and device types from the voluntary Italian collaborating centers. For the year 2022 main data about national PM and ICD implantation activity were obtained on the basis of European Cards and subsequently analyzed to create a standard report. PM Registry: data about 17 800 PM implantations were collected (14 191 first implants and 3609 replacements). The number of collaborating centers was 152. Median age of treated patients was 81 years (75 quartile I; 86 quartile III). Main ECG indications included atrioventricular conduction disorders in 46.0% of first PM implants, sick sinus syndrome in 17.7%, atrial fibrillation plus bradycardia in 7.7%, other unspecified ECG and electrophysiological abnormalities in 43.0%. For first PM implants, pacing in DDDR mode was reported in 42.2%, followed by DDD mode (20.6%), VVIR mode (25.1%), VVI mode (11.1%) and finally VDD-VDDR (5.1%). Median value of longevity of explanted PMs was 8.3 years. ICD Registry: data about 5210 ICD implantations were obtained (3656 first implants and 1554 replacements). The number of collaborating centers was 301. Median age of treated patients was 72 years (63 quartile I; 79 quartile III). Primary prevention indication was reported in 72.4% of first implants, secondary prevention in 27.6% (cardiac arrest in 4.6% of records). A single-chamber ICD was used in 30.3% of first implants, dual-chamber ICD in 30.0% and biventricular ICD in 39.7%. Median value of longevity of explanted ICDs was 7.0 years. In the calendar year 2022, the Italian PM Registry showed stable electrocardiographic and symptom indications, with an important prevalence of dual-chamber pacing. The ICD Registry documented a large use of prophylactic and biventricular ICDs, reflecting a favorable adherence in clinical practice to trials and guidelines. The ICD longevity and the number of recalls demonstrated a favorable trend.

Single- Versus Dual-Chamber Implantable Cardioverter-Defibrillator for Primary Prevention of Sudden Cardiac Death in the United States.

Background Routine addition of an atrial lead during an implantable cardioverter-defibrillator (ICD) implantation for primary prevention of sudden cardiac death, in patients without pacing indications, was not shown beneficial in contemporary studies. We aimed to investigate the use and safety of single- versus dual-chamber ICD implantations in these patients. Methods and Results Using the National Inpatient Sample database, we identified patients with no pacing indications who underwent primary-prevention ICD implantation in the United States between 2015 and 2019. Sociodemographic and clinical characteristics, as well as in-hospital complications, were analyzed. Multivariable logistic regression was used to identify predictors of in-hospital complications. An estimated total of 15 940 patients, underwent ICD implantation for primary prevention of sudden cardiac death during the study period, 8860 (55.6%) received a dual-chamber ICD. The mean age was 64 years, and 66% were men. In-hospital complication rates in the dual-chamber ICD and single-chamber ICD group were 12.8% and 10.7%, respectively (P<0.001), driven by increased rates of pneumothorax/hemothorax (4.6% versus 3.4%; P<0.001) and lead dislodgement (3.6% versus 2.3%; P<0.001) in the dual-chamber ICD group. Multivariable analyses confirmed atrial lead addition as an independent predictor for "any complications" (odds ratio [OR], 1.1 [95% CI, 1.0-1.2]), for pneumo/hemothorax (odds ratio, 1.1 [95% CI, 1.0-1.4]), and for lead dislodgement (odds ratio, 1.3 [95% CI, 1.1-1.6]). Conclusions Despite lack of evidence for clinical benefit, dual-chamber ICDs are implanted for primary prevention of sudden cardiac death in a majority of patients who do not have pacing indication. This practice is associated with increased risk of periprocedural complications. Avoidance of routine implantation of atrial leads will likely improve safety outcomes.

Atrial fibrillation diagnosis in patients with single- and dual chamber ICD devices in England: a real-world cohort study

Abstract Funding Acknowledgements Type of funding sources: Private company. Main funding source(s): BIOTRONIK SE &amp; Co. KG Background and Purpose Atrial fibrillation (AF) detection and subsequent treatment is known to be sub-optimal in the general population. It is unclear how implanted devices with atrial sensing contribute to AF diagnosis. This study compares real-world AF diagnosis rates in patients with ICDs without (single chamber ICD, VR ICD) and with atrial sensing (dual chamber ICD, DR ICD) and contrasts them with detection rates in trials which are estimated to be 200 per 1000 person years (Reinhold, 2018). Methods Linked primary care data from the Clinical Practice Research Datalink (CPRD), secondary care data from Hospital Episode Statistics (HES) and mortality statistics from the Office of National Statistics (ONS) were used. All patients who received a VR- or DR ICD between 1 April 2016 and 31 October 2020, with at least 12 months primary care registration and no AF diagnosis prior to ICD implant were included in the analysis. Time to AF detection was calculated; in Cox proportional hazards regression analysis comorbidities, age, gender, and disease aetiology were adjusted for. Stroke rates were estimated for the total cohort. Results 835 patients with a VR ICD and 1034 patients with a DR ICD were identified. Both patient groups had similar comorbidity profiles, with VR ICD patients being on average younger (mean 57.5±13.9 vs 61.5±15.4 years). During 2700 and 3600 person-years follow-up the incidence of new AF diagnoses was 45.6 (CI: 37.6-53.7) per 1000 person years in VR ICD and 54.7 (CI: 47.1-62.4) per 1000 person-years in DR ICD patients. Median time to AF diagnosis was also similar at 36.3 (IQR: 26-49.6) and 36.9 (IQR: 25.2-51.5) months, respectively. In the adjusted analysis, ICD-10 or SNOMED coded diagnosis of AF was not significantly different between groups (HR: 0.88 [95% CI 0.70-1.10]; p-value=0.3). Stroke rates in the total cohort (with or without AF) were 5.7% in the VR ICD and 3.4% in the DR ICD cohort at 36 months. Conclusion The analysis highlights a difference between the rate of clinically relevant AF observed in patients with cardiac implanted electronic devices (CIED) in clinical trials and in real-world practice. The occurrence of stroke appears to also be higher in real world practice than in clinical trial populations and this is particularly marked in patients with VR ICD. These findings could indicate low use of remote monitoring or clinician uncertainty about the clinical relevance of CIED-detected AF in the real world. The latter may be because of a still accumulating body of predictive evidence towards the surveillance of AF. We propose that consistent use of remote monitoring with daily transmission in combination with CIEDs with atrial sensing will enable improvement of care.

Trends in adoption of extravascular devices compared to conventional devices: real-world data from the Netherlands Heart Registration

Abstract Funding Acknowledgements Type of funding sources: None. Introduction Extravascular devices (EVD), such as the subcutaneous ICD (S-ICD) and leadless pacemaker (LP), have been developed to circumvent pocket- and lead-related device complications. Knowledge on trends in adoption of these devices among patient categories and hospital types is mainly derived from industry-initiated studies or selected populations. Purpose To assess the real-world nationwide trends in adoption of EVDs in the Netherlands. Methods Using real-world data registered at the Netherlands Heart Registration from 72 Dutch device-implanting hospitals, all consecutive patients were included with an EVD implantation (de novo or replacement) from 2012-2020. To describe the relative adoption of EVDs, all consecutive patients with a single-chamber conventional ICD or pacemaker were also included (pacemakers from 2014, the first LP registration). Trends in EVD adoption are described for different patient (age, gender, and BMI) and hospital (tertiles of device-implanting volume and implanting center [general , intervention, or thorax]) characteristics. Differences in adoption were tested using Chi-square and Fisher’s exact tests. Results From 2012-2020, 2862 S-ICDs and 15806 single-chamber conventional ICDs were implanted, while from 2014-2020, 785 LPs and 16530 single-chamber conventional pacemakers were implanted. S-ICD use among single-chamber ICD recipients increased from 7% to 22% and LP use among single-chamber pacemaker recipients increased from 1% to 8%, although utilization has levelled off in recent years (Fig. 1). The relative use of S-ICDs was largest in patients aged 10-30 years and declined with higher age (p&amp;lt;0.001); LP use ranged between 0 and 6% among age groups, with no specific preference at older age (p=0.002)(Fig. 2A). S-ICDs were used more in female than male ICD recipients (p=0.005); LPs more in male than female pacemaker recipients (p=0.002)(Fig. 2B). EVD utilization was largest in patients with a BMI &amp;lt;25 kg/m2 (S-ICDs p&amp;lt;0.001; LPs p=0.02)(Fig. 2C). EVDs were mostly implanted in high-volume centers (S-ICDs p=0.03; LPs p&amp;lt;0.001). S-ICDs were implanted mostly in thorax centers (p&amp;lt;0.001); LPs in thorax centers only. Conclusions Although EVDs have been adopted early in the Netherlands, their utilization has levelled off in recent years, possibly driven by higher cost, battery issues, or the COVID-19 pandemic. Utilization of S-ICDs is highest among younger patients while utilization of LPs was not specifically high in certain age groups. The effects of gender and BMI were smaller. EVDs were mainly implanted in high-volume thorax centers.

Implant failures in conduction system pacing: single centre experience

Abstract Funding Acknowledgements Type of funding sources: None. Background Conduction system pacing (CSP) ensures physiological ventricular activation and avoids the dyssynchrony associated with traditional myocardial pacing. New dedicated tools makes it possible to increase procedural success but not yet comparable to myocardial pacing. Objective Retrospective analysis of 3-years CSP implants, focusing on implant failures. Methods From January 2019 to June 2022, 639 CSP implant were performed (91% PMs and 9% ICDs). Single-chamber ICDs implants and devices replacements were excluded from the analysis because the conduction system pacing could not be an option in those cases. Pacing indications were standard with prevalence of AV block (51%); AF with slow ventricular rate 14.5%; sick sinus syndrome 14.5%; ablate&amp;pace 4%; heart failure or cardiomyopathy 14.5%, re-interventions after malfunction of a previous implant 1.5%. Mean age was 78±9 years; 62% were males. Results CSP was successfully achieved in 605 cases (94.6%). In 34 cases lead implant failed. Reasons for failure were "anatomical" in 15 cases (5 due to excessive right atrial enlargement, 5 due to severe pulmonary hypertension; 3 due to scar in the septum and 2 due to stenosis of the venous axis in upgrading procedure) and "technical" in 19 cases (5 due to unacceptable high thresholds, 10 due to uncorrected bundle branch block, 4 due to dislodgment during cutting without reposition). In 52% of the CSP implant failures, an underlying cardiomyopathy or heart failure were documented. Considering CSP failure, the implant was concluded with standard biventricular pacing in 18 cases (in 4 cases the coronary sinus implantation also failed) while 16 implants were concluded with the lead implanted in the septum or apex. Conclusions conduction system pacing is feasible in daily clinical practice; available tools allow to achieve high procedural success rate (94.8% implant success rate in our experience). Procedural failures were 5.2% and were caused by anatomical (44%) or technical reason (56%).

P467 CHALLENGING MANAGEMENT OF ORAL ANTICOAGULANT THERAPY IN A OBESE PATIENT WITH DILATED CARDIOMYOPATHY, ATRIAL FIBRILLATION AND ICD LEAD THROMBUS

Abstract Obesity is a worldwide epidemic condition at high risk for AF development; nevertheless, obese patients are underrepresented in RCTs of anticoagulant agents. Robust evidence assessing efficacy of DOACs in these patients is lacking and, to date, major Associations do not recommend DOACs in patients &amp;gt; 120 Kg (BMI&amp;gt;40 Kg/m2). The use of implantable cardiac devices has substantially increased in recent years; among potential complications are sterile intracardiac clots on the leads, typically discovered as incidental echocardiographic findings. 46 ys old male patient, III degree obesity (160 Kg,BMI 51 Kg/m2), ex–smoker. In 2012, acute heart failure and diagnosis of non–ischemic dilated cardiomyopathy (EF 20%). During the follow–up by a tertiary Center, in 2021 he was implanted with single–chamber ICD in primary prevention. At presentation, HFrEF pharmacological therapy was optimal (ARNI,SLGT2i,MRA,B–blocker). He came to the ED complaining of weakness; ECG showed atrial fibrillation, mean ventricular rate 160 bpm. CHA2DS2–VASc was 1. Anticoagulation with subcutaneous enoxaparin 10000UI twice daily was started. He was admitted to the cardiology ward and remained hemodynamically stable, with persistence of AF. Transesophageal echocardiography excluded thrombus in the left atrial appendage; unexpectedly, a filamentous, floating formation of about 30mm on the atrial side of the ICD lead was observed, compatible with a thrombotic formation, since the patient, afebrile, didn’t show any suggestive sign of endocarditis nor past history of infection; blood cultures, CRP and Procalcitonin were negative. In the absence of any shunt at the level of interatrial septum, it was felt safe to proceed to electrical cardioversion, able to restore sinus rhythm with a single 250J biphasic synchronized shock. Oral anticoagulation with warfarin was started, since no DOAC was considered adequate for effective anticoagulation. The following in hospital course and post–discharge weeks were uneventful, despite unstable INR values. Follow–up is ongoing; the patient has not yet repeated imaging to check for mass resolution. Stroke prevention in severely obese patients with AF is challenging and points toward warfarin use, as the evidence of DOACs efficacy is sparse. In our case, anticoagulant choice was also motivated by concomitant presence of a lead thrombus, a scenario in which optimal management and anticoagulation regimen are not clearly established yet.

P415 THE STRANGE CASE OF A LATE POCKET HEMATOMA

Abstract Case report: male, 85 years old. Hospitalization in 2013 at the Ancona Cardiology Department due to severe left ventricular dysfunction. In the history of pulmonary lobectomy results (2005). ⦁ EKG: PR 220 msec, left bundle block ⦁ coronary angiography: ed ⦁ blood analysis: hemoglobin 15 g/dl, PLT 229/mm3, Creatinine 1.1 mg/dl, Glycemia 84 mg/dl. ⦁ Echocardiogram: severe LV dilatation (LVVT 105 ml/m2) and severe reduction of LVEF due to diffuse hypokinesia. Strain test for possible CRTD implant: no intraventricular asynchrony. A single–chamber ICD was implanted in primary prevention in the left subclavicular site ( antibiotic prophylaxis with ciprofloxacin 1 g). Chest x–ray showed correct lead placement, no pneumothorax. The patient was discharged with antibiotic therapy. Since then he has continued the cardiological follow–up on a regular basis (cardiological visit + six–monthly ICD check). It should be noted that NOAC (Rivaroxaban 20 mg) was introduced in 2020 for the detection of atrial fibrillation. In December 2021, at last ICD check: no arrhythmic events, no alterations of the electrical parameters, good condition of the PM pocket. On 09.01.22, access to the ER due to the appearance of elastic swelling of the pocket. Apiretic. The ER doctor performed ultrasound (non–trabecular subcutaneous effusion) and proceeded to aspirate 15 cc of serum–blood fluid. He discharged the patient with appointment at the PM clinics. Cardiological consultation or blood chemistry tests were not carried out. On 19.01.22 the patient presented to our clinics: voluminous elastic swelling of the soft tissues overlying the pocket, which appeared floating. No local inflammation or cutaneous ischemic suffering. No solutions of continuity in the skin. No pain. He also reported not having taken the prescribed antibiotic. He denied fever or trauma in the previous weeks. As the blood chemistry tests were not performed in the ER, the blood count (Hb? WBC?), renal function (rivaroxaban overdose?), inflammation indices were not known (CRP? PCT?), coagulation function (spontaneous INR?). Urgent hospitalization was scheduled for surgical revision, pocket decompression, swab culture and blood cultures. Conclusions The hypotheses are hematoma during NOAC, pocket infection or cystic hygroma. After surgery evidence of organized hematoma of tissue adjacent to the pocket with negative blood cultures.

P160 WHEN IMPEDANCE TRENDS LIE, REMOTE MONITORING HELPS FOR DIAGNOSIS

Abstract An 82–years old female patient with history of hypertension, diagnosis of dilatative cardiomyopathy with normal coronary arteries and permanent atrial fibrillation (AF) was implanted with a dual chamber implantable cardioverter defibrillator (ICD), Guidant Ventak Prizm DR (Boston Scientific,Marlborough,USA) as a secondary prevention of sudden cardiac death in 2002. The ICD was electively replaced in 2005 and in 2010 with a Guidant, Vitality 2 DR (Boston Scientific,Marlborough,USA). In 2016, despite an optimized medical therapy, the patient experienced an episode of palpitation due to an AF with high ventricular response. Considering the difficulties of the heart rate management with the pharmacological therapy the patient underwent to an ablation of AV node. In 2017 we performed a third replacement of the ICD downgrading the system to a single chamber ICD, Fortify Assura VR (Abbott,Sylmar,USA) and providing the patient with a bedside–transmitter Merlin@home (Abbott,Sylmar,USA) The patient, followed for 4 years remotely, did not experience ventricular arrhythmias and the ventricular lead electrical parameters, including pacing and shock impedances, were stable and in the normal range. In March 2021 an alert of the Merlin system triggered an unscheduled transmission that showed several episodes of ventricular oversensing. The episodes revealed that an electrical interference inhibited the ventricular pacing causing episodes of asystole with a maximum duration of three seconds (Fig.1). Unexpectedly electrical parameters such as the pacing and shock impedances showed a stable and normal measurements (Fig .2), while the chest X–rays showed that the ventricular lead was kinked at 90–degrees below the clavicle evidencing a lead fracture (Fig.3). The patient was therefore implanted with a new ventricular lead avoiding inappropriate shocks and further episodes of asystole. The occurrence of a lead failure represents an insidious and potentially harmful event for the device implanted population, especially for ICD or pacemaker–dependent patients. The diagnosis of a lead failure is not easily predictable, and it is usually driven after a clinical event of inappropriate shock or unexplained syncope. Our case highlighted how Remote Monitoring is extremely helpful even more in this case of apparently correct functioning based on electric measurements.

P332 A CASE OF METABOLIC ACIDOSIS AFTER INITIATION OF SGLT2–I THERAPY IN HEART FAILURE WITH REDUCED EJECTION FRACTION

Abstract In July 2022 C.M., a 58–year–old woman, was admitted to our Heart Failure Outpatient Clinic. Patient with permanent AF undergoing DOAC therapy, previous double mitral and tricuspid valve replacement with bioprosthesis. As comorbidities she had stage IIIb CKD, previous ischemic stroke without outcome, multifactorial anaemia, asthma, ulcerative rectocolitis non–responsive to biological therapy. Since April 2022 progressive reduction in exercise tolerance with dyspnoea for previously well–tolerated exertion, with finding of severe left ventricular systolic dysfunction (FE 25%) due to widespread hypokinesia previously unknown. In September angiographic control confirmed the absence of coronary artery disease. Amiodarone therapy was started for frequent runs of VT. Cardiac MRI confirmed FE 27% with fibrosis of the interventricular septum and lower basal wall of non–ischemic appearance. In view of the clinical–instrumental findings, a single–chamber ICD pacemaker was implanted and the therapy for heart failure with reduced FE was optimised with the introduction of Sacubitril/Valsartan (later discontinued due to hypotension), MRA and SGLT2–I (Empagliflozin). Due to the persistence of labile haemodynamic compensation, an indication was given to perform three cycles of Levosimendan infusion at our Day Hospital. The routine EGA taken during the first infusion cycle showed metabolic acidosis in the absence of significant worsening of renal function (Fig. 1) with mild hypobicarbonatemia and electrolytes in the normal range. On the assumption that the acidosis was secondary to the introduction of SGLT2–I (about two months earlier), Empagliflozin was discontinued. One week after discontinuation, the control EGA (Fig. 1) showed resolution of the acidosis, with a substantially stable glomerular filtrate, so that discontinuation of the drug was confirmed. Conclusions In the literature there are reviews and case reports of euglycaemic diabetic ketoacidosis (euDKA) in DM2 patients on SGLT2–I therapy although there are currently only hypotheses regarding the pathophysiological mechanism. The possibility of inducing acidosis with hypobicarbonatemia in the absence of worsening renal function is unclear. A ‘Fanconi–like‘ mechanism could be hypothesised with induction of type 2 tubular acidosis with bicarbonate loss due to glycosuria.

PO-04-068 STEREOTACTIC ARRHYTHMIA RADIOTHERAPY DOES NOT ALTER TECHNICAL IMPLANTABLE CARDIOVERTER-DEFIBRILLATOR FUNCTION: DETAILED SAFETY RESULTS OF THE PROSPECTIVE STARNL-1 TRIAL

Stereotactic arrhythmia radiotherapy (STAR) is a new potential treatment for patients with therapy-refractory ventricular tachycardia (VT). During STAR, the pro-arrhythmic substrate receives high-dose irradiation in a single fraction. Inherently, part of the implantable cardioverter-defibrillator (ICD) lead tips, leads and the site of lead insertion receive radiotherapy dose as well. This may directly, or indirectly due to induced fibrosis at the site of lead insertion, affect technical ICD functioning. To evaluate the effects of STAR on technical ICD functioning. The STARNL-1 was a prospective, single arm, pre-post intervention study. Patients with recurrent VT despite high doses of anti-arrhythmic drugs and after one or more catheter ablation(s) were considered therapy-refractory. Six patients were treated with a single radiotherapy dose of 25 Gy to the pro-arrhythmic substrate. Per protocol, ICD battery longevity and ICD parameters lead impedance, lead sense, and lead capture of the atrial/ventricular leads were collected from ICD readouts pre-therapy, within the first 24 hours after therapy and at 3 and 12 months after therapy. During targeting, the ICD generator was considered an organ at risk. The ICD leads and lead tips were not taken into account, therefore the ICD lead tips were retrospectively delineated to calculate the received radiotherapy dose. Since this study was not powered for statistical comparison of ICD parameters, ICD parameters were described. All six patients were male (age 54-83 years) and suffered from ischemic cardiomyopathy (left ventricular ejection fraction 24-52%). Four patients completed 12-month follow-up. Five patients had a dual-chamber ICD and one patient had a single-chamber ICD. The ICD generator received a median radiotherapy dose of 0.01 Gy (range 0.00-0.12 Gy), the atrial lead a median radiotherapy dose of 3.9 Gy (range 0.7-7.2 Gy), and the ventricular lead a median radiotherapy dose of 16.8 Gy (range 0.2-24.7 Gy). There was no sudden drop in battery longevity during follow-up. As can be appreciated from Table 1, atrial and ventricular lead impedance, sensing and capture were not altered during 12-month follow-up. Figure 1 shows a line graph of the ventricular lead impedance. STAR for VT does not alter technical ICD functioning within the first 12 months after treatment.Tabled 1ICD parameter results.ICD parameterPre-therapyWithin 24h after therapy3m12mAtrial lead impedance, Ohm419 (330-550)419 (310-550)433 (340-490)404 (390-440)Atrial lead sensing, mV1.8 (0.6-5.0)3.3 (0.9-5.0)2.0 (0.5-5.0)1.6 (0.6-5.0)Atrial lead capture, V0.69 (0.38-1.00)0.56 (0.50-1.00)0.56 (0.38-1.00)0.56 (0.38-0.75)Ventricular lead impedance, Ohm499 (390-766)465 (350-867)455 (360-838)460 (390-737)Ventricular lead sensing, mV12.0 (7.2-19.4)12.0 (11.7-20.1)12.0 (4.4-20.3)11.9 (11.7-19.9)Ventricular lead capture, V1.00 (0.63-3.50)0.88 (0.63-3.50)1.00 (0.63-3.88)0.88 (0.50-2.50)All parameters are provided as median (range). Open table in a new tab

PO-05-080 EFFICACY OF ANTI-TACHYCARDIA PACING IN LVAD PATIENTS WITH AHA SCIENTIFIC STATEMENT-DIRECTED TACHYTHERAPY ICD PROGRAMMING

Ventricular Arrhythmias (VA) and ICD shocks are a common complication in patients with advanced heart failure (AHF) both before and after left ventricular assist device (LVAD) placement. Conservative ICD programming and anti-tachycardia pacing (ATP) may reduce the need for ICD shocks after LVAD. However, the efficacy of ATP and safety of conservative ICD programming remains unclear in this population. We sought to assess the efficacy of ATP and conservative ICD programming in patients undergoing LVAD placement. Consecutive patients who underwent LVAD placement (2015-2019) were included. The majority of patients had AHA Scientific Statement concordant conservative ICD programming with prolonged detection time, high VF zones cutoffs (>240bpm) and aggressive ATP use (>10 episodes before shock). A total of 237 patients who underwent LVAD implant were reviewed. Of these, 198 were discharged after LVAD with an ATP-capable device (age 60.4 ± 14.2, 146 males, 68 ischemic cardiomyopathy, 99 with prior VA). 32 patients were excluded for no ICD and 7 for subcutaneous ICD. 55 had single-chamber ICD (28%), 42 had dual-chamber ICD (22%), and 98 had CRT-D (50%). A total of 78 (39%) patients experienced at least one episode of ATP and 69 (35%) patients received at least one shock. Overall, there were 1131 distinct VT sustained episodes leading to 198 distinctive shock episodes. ATP was successful in terminating VT in 834 episodes (93%) for VT<200bpm, while the remaining 60 (7%) required shock to terminate. ATP was equally effective in patients with and without VT prior to LVAD (84% vs 78% respectively). ATP was less successful but remained effective in conservative VF zones (bpm>200 and <240, 57% success). In patients with fast VT in VF zone (>240bpm), ATP during charge was successful in terminating VT in 20% of cases. Aggressive ATP use (defined at >4 ATP episodes before shock) was also effective with a 54% success rate. ATP episodes causing degeneration and acceleration of VA’s requiring at least one shock occurred in 41 shock episodes (21%). ATP therapy in patients with LVAD can be effective to terminate VT, reducing ICD shocks in patients after LVAD placement. ATP use was more successful in traditional VT zones, but our data supports the use of conservative ICD programming (aggressive ATP use >10 episodes pre-shock and VF zone > 240bpm).

PO-03-075 RISK OF CARDIOVASCULAR IMPLANTABLE ELECTRONIC DEVICE INFECTION IN PATIENTS WITH CARDIAC SARCOIDOSIS

Immunosuppression is an essential aspect of managing cardiac sarcoidosis (CS). The decision to implant a cardiovascular implantable electronic device (CIED) is often made in conjunction with starting immunosuppression. It is unclear if immunosuppression at the time of implantation increases the risk of CIED infections. Since both are potentially life-saving therapies for CS, it is vital to understand if there is a need to adjust immunosuppressive regimen before implanting CIEDs to reduce infection risk. To evaluate the rate of CIED infections in cardiac sarcoidosis patients at a tertiary hospital. We performed a retrospective analysis of patients with biopsy-proven CS and a history of a CIED implant who had received care at the Johns Hopkins Hospital. For each patient, we compiled information on the type of CIED, number of procedures and leads, presence of an antibiotic envelope, and immunosuppressive regimen at the time of each procedure. The primary outcome was a CIED pocket or bloodstream infection (BSI). Of the 175 patients included, average age was 60.1 years (SD=11.4), 111/175 (63.4%) were male, 93/175 (53.1%) were White and 72/175 (41.1%) Black. Most CIEDs were implantable cardioverter-defibrillators (ICD) (162/175, 92.5%). The average follow-up time post-CIED implant was 8.6 years. At the time of CIED implantation, 70/175 were on immunosuppression: 36 on corticosteroid monotherapy, 8 on a steroid-sparing agent alone, and 26 on a combination of both. During the study period, 12/175 patients had documented BSIs, occurring at an average of 5 years post-implant. Five of the 12 patients were on immunosuppression at time of CIED implantation. All 12 patients were treated with antibiotics and 9/12 had device extractions. There was no significant difference in CIED infection rate among those on vs off immunosuppression at the time of CIED implant (5/70 vs 7/105 p=0.90). Two patients with BSIs also had a CIED pocket infection, both occurring in the context of multiple prior CIED procedures. One patient had a dual chamber ICD for 5 years before developing an S. aureus pocket infection, 4 years after a revision performed on immunosuppression. A second patient had a single chamber ICD for 3 years before developing a P. acnes pocket infection, 4 months after a revision performed off immunosuppression. Among patients with CS undergoing a CIED implant, we found no significantly increased risk of CIED infection among patients on immunosuppression at time of implant.

DX single-lead implantable cardioverter-defibrillator system with a floating atrial dipole: when, to whom, and why?

The article reflects information for cardiologists, cardiac surgeons, doctors pro­gramming implanted antiarrhythmic devices, employees and residents of the depart­ments of cardiology and cardiac surgery. Most often, we choose a model of an implantable cardioverter-defibrillator (ICD) strictly individually for each patient, based on the anamnesis characteristics, safety and highest efficiency of ICD systems offered on the market. With each new ICD model, manufacturing companies strive to minimize the number of implantable components and develop better algorithms to discriminate between atrial tachyarrhythmias and true ventricular tachyarrhythmias. However, the risk of inappropriate ICD therapy still remains high. Thus, attending physicians and cardiologists programming implantable antiarrhythmic devices often face difficulties in correcting ICD settings and planning further treatment of a patient with shocks caused by atrial tachyarrhythmias. The authors sought to form an idea about the features of a single-chamber ICD recording atrial potentials using a floating dipole, as well as the advantages of the DX system over classical single-chamber ICD systems, and to define a type of a patient for whom this implantable system would be the best choice preventing sudden cardiac death.