Dual-chamber Implantable Cardioverter-defibrillator Research Articles

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.

Cardiac Magnetic Resonance Imaging-Derived Left Atrial Characteristics in Relation to Atrial Fibrillation Detection in Patients With an Implantable Cardioverter-Defibrillator.

Background Among patients with an implantable cardioverter-defibrillator, a high prevalence of atrial fibrillation (AF) is present. Identification of AF predictors in this patient group is of clinical importance to initiate appropriate preventive therapeutic measures to reduce the risk of AF-related complications. This study assesses whether cardiac magnetic resonance imaging-derived atrial characteristics are associated with AF development in patients with a dual-chamber implantable cardioverter-defibrillator or cardiac resynchronization therapy defibrillator, as detected by the cardiac implantable electronic device. Methods and Results This single-center retrospective study included 233 patients without documented AF history at the moment of device implantation (dual-chamber implantable cardioverter-defibrillator [63.5%] or cardiac resynchronization therapy defibrillator [36.5%]). All patients underwent cardiac magnetic resonance imaging before device implantation. Cardiac magnetic resonance-derived features of left atrial (LA) remodeling were evaluated in all patients. Detection of AF episodes was based on cardiac implantable electronic device interrogation. During a median follow-up of 6.1 years, a newly diagnosed AF episode was detected in 88 of the 233 (37.8%) patients with an ICD. In these patients, increased LA volumes and impaired LA function (LA emptying fraction and LA strain) were found as compared with patients without AF during follow-up. However, a significant association was only found in patients with dilated cardiomyopathy and not in patients with ischemic cardiomyopathy. Conclusions LA remodeling characteristics were associated with development of AF in patients with dilated cardiomyopathy but not patients with ischemic cardiomyopathy, suggesting different mechanisms of AF development in ischemic cardiomyopathy and dilated cardiomyopathy. Assessment of LA remodeling before device implantation might identify high-risk patients for AF.

Cardiac resynchronization therapy: potential for arrhythmic risk modification

Aim. To evaluate the impact of cardiac resynchronization therapy (CRT) on the risk of sustained ventricular tachyarrhythmias (VT) in patients with heart failure (HF) with a implantable cardioverter-defibrillator (ICD) for the primary prevention of sudden cardiac death.Material and methods. This single-center prospective clinical study included 470 patients (men, 84%) with HF at the age of 57 (51-62) years with a left ventricular ejection fraction (LVEF) of 29 (25-33)%. There were following exclusion criteria: indications for cardiac surgery, known channelopathies, previously registered VT. Depending on intraventricular conduction disorders, dual-chamber ICDs (42%) or CRT-D (58%) were implanted. After ICD implantation, patients were followed up for 24 months to register the end point — a first-time sustained paroxysm of VT detected by the ICD. A positive response to CRT was established in the case of an increase in LVEF by ≥5% of the initial level.Results. A total of 388 patients underwent full postoperative follow-up. The studied arrhythmic endpoint occurred on average 21 (0,6) months after implantation in 104 patients (27%) with higher frequency in the ICD group. However, the differences in the VT rate in the study groups were statistically unreliable (30% in the ICD group versus 24% in the CRT-D group, p=0,142). It was found that the VT rate was reliably lower in CRT-responders (118 patients, 53%): 15% compared to 32% in the group of inefficient CRT. A 5% increase in the LFEF reduced the probability of VT occurrence by 3 times (odds ratio [OR]=0,34; 95% of CI: 0,13-0,86; p=002). Significant modification of arrhythmic risk was verified by increasing LFEF to 36-40% (OR=0,72; 95% CI: 0,63-0,82; p=0,04).Conclusion. The results obtained indicate that effective CRT has the potential to modify arrhythmic risk in patients with HF, especially with an increase in LVEF to the level of 36-40%.

Non-elective heart failure hospitalization in patients with cardiac resynchronisation therapy or dual chamber implantable cardioverter defibrillators in England: a retrospective cohort study

Abstract Funding Acknowledgements Type of funding sources: Private company. Main funding source(s): BIOTRONIK SE &amp; Co. KG Background Limited real-world data are available on the risk of non-elective heart failure-related hospitalization (HFH) in patients with de-novo cardiac implantable electronic devices. Purpose The aim of this study was to quantify and compare the risk of HFH in two distinct HF cohorts: those with cardiac resynchronisation therapy devices including a defibrillator (CRT-D) and those with dual chamber implantable cardioverter defibrillators (DR-ICD). 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, reflecting a representative sample of patients treated within NHS England. Patients with a diagnosis or treatment for HF who received a de-novo CRT-D or DR-ICD between 1 April 2016 and 31 October 2019 were included. The study follow-up period extended to 31 October 2020. We calculated the median time to first post-implantation HFH and for those affected, the time from first-to-second and second-to-third admission. Univariable and multivariable Cox proportional hazards regression models were used to derive hazard ratios (HRs) and quantify the association between device type and admission. Results were adjusted for age, sex, and comorbidities. Results Data were analysed from 2,883 CRT-D (mean age 68.8 years, 79% male, median follow-up 39 months) and 1,643 DR-ICD (mean age 66.6 years, 80% male, median follow-up 41 months) patients. The CRT-D cohort had more baseline comorbidities. At 12 and 36-months post-implantation, the percentage of patients with at least one all-cause or CV-related hospital admission was similar between cohorts, but the percentage with a HFH differed. The risk of first HFH was greater in the CRT-D cohort than the DR-ICD cohort (HR=1.18; CI: 1.07–1.29; p&amp;lt;0.001). Median time to event was 19.8 months (IQR 4.9-38) for the CRT-D cohort and 26.6 months (IQR 6.5-44.6) for the DR-ICD cohort. However, there was no difference in the risk of subsequent HFH between the two cohorts (second admission: HR=0.99; CI: 0.88–1.17; p&amp;gt;0.9; third admission HR=1.05; CI: 0.86–1.27; p=0.6). The incident HFH risk for the CRT-D cohort increased from 17.3 per 100 person years for a first event to 46.6 per 100 person years for a second event and further increased to 76.3 per 100 patient years for the third event. Conclusions Patients implanted with a CRT-D are at greater risk of first post-implant HFH, likely due to these patients having more severe HF. However, when the population is restricted to patients with a previous post-implant HFH, the risk is similar in patients with CRT-D and DR-ICD devices. For both devices, any HFH is associated with an increased risk of subsequent HFH. Future research should seek to identify strategies to reduce repeated HFH in these patient groups.

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.

Gender-specific differences in young patients receiving implantable cardioverter-defibrillator therapy - a subgroup analysis of the german device registry

Abstract Funding Acknowledgements Type of funding sources: None. Background Implantable cardioverter-defibrillator (ICD) and cardiac resynchronization therapy defibrillators (CRT-D) are well established therapies in heart failure. Therapeutic and technological advancements led to increasing numbers of younger patients receiving these devices. Distinguishing patient characteristics among this younger patient cohort, especially gender-specific differences, are important to optimize patient care. Methods Between 2007-2014 the German DEVICE registry enrolled patients from 50 German centers undergoing ICD/CRT-D implantation. Patient characteristics, data on procedural outcome and adverse events during index hospitalization and 1-year follow-up were recorded. All patients under the age of 45 years were identified, separated into two groups according to their gender and analyzed. Results Out of 4181 patients enrolled, 236 patients (5.6%) were under the age of 45 years, of which 162 patients (68.6%) were male and 72 patients were female (31.4%). Male patients were older (39.5 [35.0; 42.0] vs. 34.0 [28.0; 40.0] years, p&amp;lt;0.001) and were more likely to suffer from cardiac disease (77.2 vs. 59.5%, p=0.005) and non-cardiac comorbidities (24.1 vs. 12.2%, p=0.035). The prevalence of Long-QT syndrome was markedly increased in female patients (1.9 vs. 10.8%, p=0.002). Male patients had lower mean left-ventricular ejection fraction (39.8±18.5 vs. 49.5±16.7%, p=0.003), were less likely to be in NYHA functional class I (44.0 vs. 61.4%, p=0.047) and received more betablockers (80,2% vs. 64,9%; p=0,011), ACE-inhibitors (56,2% vs. 46,5%; p=0,005) and statins (27,5% vs. 10,8%, p=0,005). Dual-chamber ICD were more common in female patients (13.0 vs. 27.8%, p=0.006) with a trend towards higher prevalence of pathological AV-conduction in female patients (6.2% vs. 13.5%, p=0.06). There were no differences in the number of implanted CRT-D devices between groups (9.3 vs. 6.9%, p=0.56). There was no detectable difference in overall post-operative complications (1.9 vs. 5.4%, p=0.21) with no cases of in-hospital mortality in both groups. However, there were more pneumothoraces requiring a chest tube insertion in female patients (0.0% vs. 4,1%, p=0.03). Median follow-up time was 514 [398; 669] days. There were no differences in neither device-associated complications requiring revision (15.0 vs. 19.1%, p=0.52), nor in all-cause mortality (3.7 vs. 1.9%, p=0.52; HR 0.5, 95%CI: 0.06-4.27) after 1-year of follow-up, but female patients had a higher mean number of rehospitalizations (1.6±1.5 vs. 2.1±1.3; p=0.026). Conclusion In young patients under 45 years, there were no differences in overall device complications and overall mortality between male and female patients after implantation and after 1-year follow-up. Even though female patients had less cardiac and non-cardiac (co-)morbidities, the number of rehospitalizations after 1-year follow up were higher.

Remote support during cardiac implantable electrical device follow-up: preliminary experience in clinical practice

Abstract Funding Acknowledgements Type of funding sources: None. Background Industry employed allied professionals (IEAPs) traditionally provide technical assistance to physicians during cardiac implantable electrical device (CIED) implantation, programming, troubleshooting, and follow-up, by operating the programmers under the supervision of the physician. The Heart Connect™ application is a data-sharing system intended to provide physicians with the means to establish an online meeting and share the display of the LATITUDE™ Programmer (Boston Scientific) with IEAPs in a remote location. Purpose We describe the preliminary experience of remote IEAP support during CIED follow-up in clinical practice. Methods The Heart Connect™ software was downloaded on the programmer and network connection was established and tested using both Wi-Fi and a 4G cellular adapter at 3 Italian medical centers. External headset and webcam have been connected to the programmer. After system setup, the staff was trained on how to use the application, and online meetings were established with IEAPs of the Remote Clinical Support team during consecutive CIED follow-up visits. Data and users’ feedback were collected on the training provided, the quality of the remote connection, the support at each meeting. Results All the professionals trained in the use of the system judged the information received to be clear and adequate, and felt confident in using the system. Online meetings were established during 34 follow-up visits (12 pacemakers and CRT-P, 13 single- or dual-chamber ICD, 9 CRT-D). The remote connection was successfully established in all cases. In all cases the communication remained stable for the entire duration of the visit, except for 2 cases (connected via 4G) in which a loss of connection occurred (not restored in 1 case). The sound and video quality during two-way communication were rated good or excellent in 31 (91%) cases. The mean duration of the online meeting was 7±3 minutes. Routine CIED checks were performed during the visits: battery status, pacing and sensing thresholds, impedances, current rhythm diagnosis, arrhythmias detected and therapies delivered, device counters and review of programmed parameters, alerts and clinical diagnostics. Programming changes were done during 7 (21%) visits: pacing and sensing parameters, tachycardia detection and therapies. The remote support allowed to successfully complete the visit in 33 (97%) cases, without requiring additional medical or technical support. In all these cases, the support was judged to be equally effective compared to the on-site support, without causing delays or organizational difficulties. Conclusions Remote support during CIED follow-up using Heart Connect™ seems feasible, effective and well accepted. Additional tests are ongoing to demonstrate the potential usefulness of this solution in standard clinical practice, and in the context of restrictions on access to healthcare facilities due to COVID-19 pandemic.

Cardiac resynchronization therapy via left bundle branch area pacing and a dual-chamber ICD; a CROSS-LEFT substudy

Abstract Funding Acknowledgements Type of funding sources: None. Background Left bundle branch area pacing (LBBAP) has emerged as a promising technique to deliver cardiac resynchronization therapy (CRT). Purpose We sought to evaluate the feasibility of a single LBBAP lead connected to a dual-chamber ICD in patients indicated with a CRT-D implantation. Methods The CROSS-LEFT study prospectively included consecutive sinus rhythm patients with a reduced ejection fraction and a complete left bundle branch block. A DF-1 lead was implanted at the right ventricular apex, and an LBBAP lead through the interventricular septum. Patients were implanted with a dual-chamber DF-1 defibrillator (ICD) connected to the atrial lead (RA port), the LBBAP lead (RV IS-1 port), and the defibrillation lead (RV DF-1 port), the IS-1 pin being capped. Atrioventricular delay was optimized to ensure fusion between LBBAP and native conduction from the right bundle. Patients were followed during 6 months. Results A total of 22 patients were included (median age 68 years, 77% male, 41% ischemic). LBBAP resulted in a significant reduction of median QRS width from 161 to 128ms (p&amp;lt;0.0001). At 6 months, median ventricular sensing was 18mV (range 5–31, IQR 9), and LBBAP threshold 0.5V (range 0.25–0.75, IQR 0). Median LVEF significantly improved from 27 to 45% at 6 months (p&amp;lt;0.0001), with a median reduction of LV end-systolic volume of 32% (p=0.0002), 67% of patients being considered as super-responders. Conclusion In patients with a left bundle branch block indicated with a biventricular defibrillator, CRT can be safely and efficiently performed via a single LBBAP lead connected to a dual-chamber ICD, and is associated with significant electromechanical reverse remodeling.

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.

P259 S–ICD OFFERS A POTENTIAL SYNERGISTIC THERAPY FOR HEART FAILURE PATIENTS WITH AN INDICATION FOR ICD IMPLANTATION AND CANDIDATES FOR CCM IMPLANTATION

Abstract CCM (cardiac contractility modulation) is a very promising therapy in heart failure patients as it allows, by increasing intracellular calcium handling, an improvement in cardiac contractility, ejection fraction, and patient quality of life. It delivers high–energy (7.5 V) and long–duration (about 20 milliseconds) pulses in absolute refractory period through the use of two leads on the right ventricular septum. It is indicated in patients with narrow QRS (&amp;lt; 130 msec) and ejection fraction between 25 and 45%. Therefore, a large proportion of patients suitable for CCM therapy also have an indication for ICD implantation. The coexistence of an ICD (single–chamber or dual–chamber) and CCM presupposes the presence of 3 leads in the right ventricle and possibly a catheter in the right atrium if a dual–chamber ICD is used. The presence of numerous leads increases the risk of infection, mechanical complications, and damage on the leads. In view of the above, the strategy we propose in patients with concomitant indication for ICD and CCM is the use of the subcutaneous defibrillator (S–ICD) in patients with potential indication for CCM, narrow QRS, no pacing indication, and ejection fraction &amp;lt;35%, thus limiting the number of leads and the risk of complications. In our center, we have started using this strategy with excellent clinical results and in the absence of complications. One of the cases treated with this strategy is a 60–year–old patient with nonischemic dilated myocardiopathy, ejection fraction 34%, QRS &amp;lt; 130 msec, NYHA class III, despite therapy with beta blockers, ARNI, SGLT2–i, MRA at the maximum dose. The patient, also considering the potential future need for CCM implantation, underwent S–ICD implantation. After 3 months, NYHA class III with reduced quality of life persisted (MLHFQ 82). Therefore, the patient successfully underwent CCM implantation, with marked improvement in symptoms (MLHFQ 71) and ejection fraction (43%) 3 months later. This strategy avoided the placement of additional leads in the right ventricle while ensuring protection from potentially fatal arrhythmias and improvement in contractile function and symptoms. We suggest the use of the subcutaneous defibrillator (S–ICD) in all patients in whom there might be an indication for the use of CCM and no need for pacing, ensuring maximum efficacy and reducing the risk of infection and leads related complications.

P353 A CASE OF FABRY DISEASE WITH ISOLATED CARDIAC INVOLVEMENT

Abstract A 64–year–old patient,hypertensive,ex–smoker,no family history of CAD or MCI,with electrocardiographic abnormalities during checkups for sports activity at age 40,came to our observation for reported brief episodes of heart palpitation.On ecg sinus rhythm,PR 200 msec,elevated QRS voltages,negative T waves from V3–V6 and infero–laterally,isolated BEV. Echocardiogram showed asymmetric left ventricular hypertrophy with involvement of septum and mid–apical segments,absence of obstruction,grade II diastolic dysfunction,enlarged left atrium,ectasia of aortic bulb,ascending aorta and arch with mild valvular insufficiency. Cardiac MRI showed asymmetric hypertrophy with prevalent involvement of the SIV and apex,normal systolic function.Right ventricle within limits.LAM elongated,biatrial dilatation.Areas of enhancement with intramural extension to the inferior SIV and extensive subendocardial area to the infero–lateral wall,picture suggestive of Fabry disease. Holter ecg was performed:RS at mean fc 61 bpm,numerous isolated BEVs and pairs,1 run of TVNS of 11 beats,for which dual–chamber ICD implantation was performed in primary prevention.Genetic examination showed absence of alpha galactosidase enzyme activity and mutation in exon 5 of GLA gene(p.N215S). The patient had no other systemic symptoms typical of Fabry‘s disease such as CRI,acroparesthesias,angiokeratomas,cornea verticillata,gastrointestinal disturbances nor central neurological involvement.In addition,he was starting enzyme replacement therapy with alpha galactosidase on a home regimen.Hypertrophic cardiomyopathy is a frequent finding in clinical practice.In MF, the age of cardiac involvement is usually later than in other forms of cardiomyopathy. Cardiac MRI is the most appropriate technique to place a correct differential diagnosis;numerous studies have demonstrated preferential localization of areas of "delayed enhancement" at the infero–lateral and posterolateral basal wall,present even in the absence of frank ventricular hypertrophy. Systemic involvement, may help in the differential diagnosis because of the presence of characteristic symptoms.In the reported clinical case,however,the diagnosis is even more insidious since in late forms or cardiac variants of MF,as with the p.N215S gene variant,cardiomyopathy may be the only significant clinical manifestation.

P305 MULTIVESSEL SUBACUTE STENT THROMBOSIS

Abstract The presence of comorbidities such as psychiatric pathologies negatively influences the prognosis of patients with acute cardiovascular events. A 62–year–old male patient suffering from arterial hypertension, dyslipidemia, ischemic heart disease, treated 3 years earlier with PCI of LAD, Cx e RCA (EF 45%), and schizophrenia, is hospitalized with a diagnosis of NSTEMI. Coronary angiography shows: eccentric stenosis 70% proximal to the pre–existing stent in the middle LAD; Intrastent occlusion of the middle circumflex branch with omocoronary rehabilitation and ulcerated critical plaque in the proximal segment of the right coronary artery with mild intrastent restenosis in the middle. The patient refuses cardiac surgery, so angioplasty with ultra–thin drug–eluting stents is performed. The patient starts DAPT with clopidogrel, choosing a combination formulation to promote compliance, with discharge on the fourth day. Three days after discharge, the patient returns with anterior STEMI, with multivessel intrastent thrombotic closure (LAD, Cx, RCA), so angioplasty with paclitaxel–releasing balloon is performed on LAD and with NC balloons on the right coronary artery; impossibility to obtain total recanalization of the circumflex branch due to the non–transit of guides, even hydrophilic and of different weights. During angioplasty and for the following 12 hours, bolus and infusion of tirofiban is administered due to the high thrombotic burden. The choice of the second antiplatelet agent in this second procedure fell on prasugrel. The patient is discharged on the sixth day and a long conversation is held with his wife regarding the correct management of the home therapy. One year later, the patient a dual–chamber ICD was implanted at another centre, with correct and regular assumption of home therapy. Our case demonstrates an infrequent form of multivessel thrombosis during STEMI. The presence of schizophrenia influences negatively the evolution of the natural history of ischemic cardiopaty. The psychiatric substrate exposes to a greater number of cardiovascular events, given the reduced therapeutic compliance, also as regards the choice of appropriate therapeutic strategies. A joint path between the hospital, local medicine and the family environment would be desirable in order to correctly manage this type of patient.

PO-05-145 A CASE OF SUSPECTED CARDIAC SARCOIDOSIS MIMICKING ISCHEMIC CARDIOMYOPATHY

Cardiac sarcoidosis (CS) is challenging due to varied clinical presentation and limited accuracy of diagnostic criteria. We describe a case of suspected CS in a patient with ischemic cardiomyopathy (ICM) presenting in ventricular tachycardia (VT) storm. To describe the presentation of suspected CS in a patient with ICM and VT. N/A A 73 year old male with ICM and ejection fraction of 35% initially presented with myocardial infarct requiring 3-vessel coronary artery bypass surgery. Months later he developed sustained monomorphic VT which was detected on his pacemaker and underwent upgrade to a dual chamber implantable cardioverter defibrillator. He continued to have frequent VT ultimately presenting in VT storm. He was loaded on amiodarone and referred for radiofrequency catheter ablation. During index ablation, the left ventricular (LV) endocardial bipolar voltage was normal, which was inconsistent with the inferobasal and basal septal scar identified on pre procedural cardiac computed topography (CT) (Figure 1). The clinical VT was mapped to the anterior interventricular vein and targeted from the LV summit since proximity of AIV to the left anterior descending artery precluded ablation from the AIV. His arrhythmic presentation and LV dysfunction was disproportionate to degree of coronary disease. In addition, discordance between clinical VT origin site, bipolar endocardial voltage, and scar on cardiac CT prompted suspicion of an alternate underlying diagnosis, such as an arrhythmogenic inflammatory cardiomyopathy. A positron emission tomography/computed tomography (PET/CT) later obtained showed evidence of patchy 18F-fluorodeoxyglucose uptake along the inferolateral LV, suggestive of CS. He was started on immunosuppressants but developed recurrent VT despite anti arrhythmic therapy and required 2 subsequent ablations. He has since remained quiescent from a VT standpoint on amiodarone with plans for alcohol septal ablation or stereotactic body radiation therapy if VT recurs. Symptoms have improved with steroids and immunosuppressants with no inflammation detected on most recent PET/CT High suspicion of CS should remain in patients presenting with significant arrhythmic burden. Normal endocardial voltage during VT ablation can be suggestive of an acute inflammatory process and should prompt consideration of CS, especially in cases with discordant areas of scar and wall thinning on imaging.

CE-454610-2 STEREOTACTIC ARRHYTHMIA RADIOABLATION IN VENTRICULAR FIBRILLATION WITH LEFT VENTRICULAR THROMBUS

Stereotactic arrhythmia radioablation (STAR) has been studied for management of refractory ventricular tachycardia (VT) that is not amenable to traditional catheter ablation. We present the case of a patient with recurrent ventricular tachycardia (VT) and left ventricular (LV) thrombus successfully treated with STAR therapy. A 48-year-old man with morbid obesity, paroxysmal atrial fibrillation and infarct related cardiomyopathy was admitted with late presentation of new anterolateral ST elevation myocardial infarction complicated by cardiogenic shock, managed with mechanical circulatory support. He was found to have a 3 x 2.7 cm thrombus in the LV apex (Panel A). He underwent successful percutaneous intervention to an acute left anterior descendinig coronary artery occlusion. During hospitalization, despite aggressive measures, he was noted to have polymorphic ventricular tachycardia (VT), triggered by premature ventricular contractions (PVCs) arising from his LV apical infarct (Panel B). He was treated with multiple antiarrhythmic medications (amiodarone, lidocaine) in addition to electrolyte repletion but unfortunately required repeated external defibrillation for PVC induced VF (Panel C). A dual chamber implantable cardioverter-defibrillator was placed and despite overdrive pacing, he suffered from recurrent life-threatening VT and ventricular fibrillation (VF) requiring additional defibrillation (Panel D). Because he was not a candidate for endocardial ablation, orthotopic heart transplantation, and was deemed too unstable for epicardial ablation, the decision was made to pursue STAR. Surface ECG and 4D computed tomography (Panel E) were used to localize the focus of the VT trigger. A single dose of 25 Gray of radiation was delivered to the LV apex. Our patient has been free of ventricular arrhythmias for 14 months. There has been no clinical evidence of early or late toxicity related to radiotherapy thus far. In challenging cases of PVC induced VT and VF not amenable to traditional therapies, such as our patient, STAR may offer a therapeutic option. Further studies are required.

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-04-090 2 HIT WONDER: AUTOSOMAL RECESSIVE-CPVT WITH CONDUCTION DISEASE

Catecholaminergic Polymorphic Ventricular Tachycardia (CPVT) is a primary arrhythmogenic syndrome with clinical manifestations of syncope and sudden death following exercise or agitation. Present familial cases of autosomal recessive CPVT due to homozygous variants in RYR2 with associated conduction disease. The case was reviewed in detail as below. A 14 year-old girl presented following out of hospital cardiac arrest at a trampoline park. AED strip demonstrated ventricular fibrillation that terminated to sinus rhythm with electrical cardioversion. Workup was notable for a resting ECG with a rate of 52 bpm, a PR of 238 and a right bundle branch block with a QRS duration of 145ms . Exercise stress test resulted in frequent premature ventricular beats and bidirectional couplets. Genetic testing demonstrated homozygosity of a novel VUS in RYR2 (c.9392A>C (p.Tyr3131Ser)). Analysis by REVEL demonstrated a score of (0.763), predicting pathogenicity. Parents were found to be heterozygous asymptomatic carriers of the same variant and one sibling was homozygous for the variant. This sibling had a prolonged PR interval and intraventricular conduction delay and was phenotypically positive during exercise stress test. Two siblings who were heterozygous for the variant had normal ECG and exercise stress tests. The proband was started on nadalol and flecainide and a dual chamber ICD was placed for secondary prevention and significant sinus bradycardia prior to initiation of antiarrhythmics. On follow up EST the patient was noted to have acute onset high grade AV block during exercise resulting in initiation of ventricular pacing as well as runs of atrial tachycardia. Baseline ECG did not demonstrate QRS widening and flecainide level was within limits. The affected sibling was started on nadolol. We report two cases of patients homozygous for a VUS in RYR2 manifesting phenotypically as CPVT with associated conduction disease. Further study of this distinct phenotype of CPVT is warranted.

PO-04-058 AN UNUSUAL CASE OF ATRIAL SENSING BY A DEFIBRILLATOR LEAD CAUSING ASYSTOLE

Integrated bipolar transvenous defibrillator leads (IL) offer advantages over dedicated bipolar defibrillator leads (BL): IL have a simplified construction and are less prone to anodal stimulation. A potential problem for the IL is oversensing due to a large sensing area. We present a case of an IL with intermittent asystole treated by exchange of the IL for a BL. N/A N/A A 51-year-old female with hypertrophic cardiomyopathy received a Boston Scientific (BS) dual chamber ICD in 2011 with a IL (BS 0185) for VT and intermittent heart block. In May 2022, she underwent an uncomplicated generator change. Six months later she presented with presyncopal events. Hospital telemetry showed DDD pacing with intermittent lack of ventricular output and no escape rhythm. There was no evidence of lead dislodgement and manipulation of the pocket did not reproduce an event. Device interrogation showed normal and stable lead thresholds and impedances. She was now pacemaker dependent. Spontaneous asystole was captured by the intracardiac electrogram (IEGM) demonstrating atrial far-field sensing with inhibition of RV pacing. Decreasing the RV sensitivity did not resolve the issue. We urgently turned on “Electrocautery Protection Mode” (DOO 60 and V Tachy Mode-OFF) restoring 100% dual chamber pacing and capture. We suspected that atrial far field sensing was due to the IL design. The size and position of the sensing anode can allow for far-field atrial sensing and inhibition of RV output. Intraoperative manipulation and testing of the generator and leads showed normal parameters. The patient underwent extraction of the IL, and a BL (Medtronic 6935m) was implanted. A BL was selected due to its distal, and closely spaced, pace/sense electrode design. The device was reprogrammed to her prior settings with no further episodes or symptoms occurring. This case shows an unusual problem with the IL design. Capturing this event by IEGM was diagnostic. Reducing the IL sensitivity is not optimal, making the patient vulnerable to undersensing of ventricular fibrillation. Discussion with BS Technical Services confirms that this phenomenon is rarely seen and more likely to occur in patients with a small RV. We suspect that changes in body habitus, a small RV cavity, and progression of heart block exposed the problem years after implant. Exchange of a IL with a BL provided a lasting solution.

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-04-053 OUT-OF-HOSPITAL CARDIAC ARREST ASSOCIATED WITH EARLY REPOLARIZATION

Early repolarization syndrome (ERS) is characterized by J-point elevation presenting as slurring or notching of the terminal part of the QRS complex. Of the several congenital and acquired disorders that encompass J-wave syndromes, ERS has been linked to increased risk of developing polymorphic VT and idiopathic VF that can lead to sudden cardiac death. To describe a patient who presented after a cardiac arrest with initial ECG criteria consistent with Type III ERS who recieved a dual-chamber ICD. n/a We present a case of a 42-year-old man without any prior history that presented to the emergency room after successful resuscitation from out-of-hospital cardiac arrest due to VF. After noticing agonal respiration during early morning hours, his wife called emergency medical services (EMS) and promptly performed cardiopulmonary resuscitation. Upon arrival, EMS found the patient to be in VF. He was shocked once by an automatic external defibrillation leading to ROSC with restoration of sinus rhythm. In the ED, his initial vitals were 122/93 mmHg, 104 bpm, 95% oxygen saturation on room air, and temperature of 36.4 °C. He denied any family history of sudden cardiac death. Wife reported prior history of nocturnal agonal respirations. Initial diagnostic work-up was significant for a leukocytosis of 19,000 and serial high-sensitivity cardiac troponins of 130, 305, and 364 with a 0/3-hour delta change of 234. A12-lead ECG upon presentation is shown in Figure 1 without previous ECGs available for comparison. An emergent coronary angiography was performed which revealed no significant coronary obstruction or anomaly. With both his ECG findings and a Shanghai Score of 7, a diagnosis of Type III ERS was highly suspected. Further diagnostic testing included a TTE showing left ventricular dysfunction with an ejection fraction of 40-45%. CMR showed no delayed gadolinium enhancement. Ultimately, a dual-chamber ICD was implanted during the admission. Follow-up ECGs revealed resolution of slurred terminal QRS complexes. He was discharged on beta blocker and low-dose losartan with close outpatient follow-up with electrophysiology. ECG changes of ERS can be dynamic and may sometimes be concealed, particularly in the setting of an out-of-hospital cardiac arrest. It is important to identify early repolarization patterns due to the adverse prognostic significance especially of Type III ERS which is associated with the highest level of risk for development of malignant arrhythmia.