Antitachycardia Pacing Research Articles

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 & 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.

Fewer Worsening Heart Failure Events With HeartLogic on top of Standard Care: a Propensity-Matched Cohort Analysis

The implantable cardiac defibrillator-based HeartLogic algorithm aims to detect impending fluid retention in patients with heart failure (HF). Studies show that HeartLogic is safe to integrate into clinical practice. The current study investigates whether HeartLogic provides clinical benefit on top of standard care and device telemonitoring in patients with HF. A multicenter, retrospective, propensity-matched cohort analysis was performed in patients with HF and implantable cardiac defibrillators, and it compared HeartLogic to conventional telemonitoring. The primary endpoint was the number of worsening HF events. Hospitalizations and ambulatory visits due to HF were also evaluated. Propensity score matching yielded 127 pairs (median age 68 years, 80% male). Worsening HF events occurred more frequently in the control group (2; IQR 0-4) compared to the HeartLogic group (1; IQR 0-3; P = 0.004). The number of HF hospitalization days was higher in controls than in the HeartLogic group (8; IQR 5-12 vs 5; IQR 2-7; P = 0.023), and ambulatory visits for diuretic escalation were more frequent in the control group than in the HeartLogic group (2; IQR 0-3 vs 1; IQR 0-2; P = 0.0001). Integrating the HeartLogic algorithm in a well-equipped HF care path on top of standard care is associated with fewer worsening HF events and shorter duration of fluid retention-related hospitalizations.

Right ventricular function is a predictor for sustained ventricular tachycardia requiring anti-tachycardic pacing in arrhythmogenic ventricular cardiomyopathy: insight into transvenous vs. subcutaneous implantable cardioverter defibrillator insertion.

Arrhythmogenic right ventricular cardiomyopathy (ARVC) patients develop ventricular arrhythmias (VAs) responsive to anti-tachycardia pacing (ATP). However, VA episodes have not been characterized in accordance with the device therapy, and with the emergence of the subcutaneous implantable cardioverter defibrillator (S-ICD), the appropriate device prescription in ARVC remains unclear. Study aim was to characterize VA events in ARVC patients during follow-up in accordance with device therapy and elicit if certain parameters are predictive of specific VA events. This was a retrospective single-centre study utilizing prospectively collated registry data of ARVC patients with ICDs. Forty-six patients were included [54.0 ± 12.1 years old and 20 (43.5%) secondary prevention devices]. During a follow-up of 12.1 ± 6.9 years, 31 (67.4%) patients had VA events [n = 2, 6.5% ventricular fibrillation (VF), n = 14], 45.2% VT falling in VF zone resulting in ICD shock(s), n = 10, 32.3% VT resulting in ATP, and n = 5, 16.1% patients had both VT resulting in ATP and ICD shock(s). Lead failure rates were high (11/46, 23.9%). ATP was successful in 34.5% of patients. Severely impaired right ventricular (RV) function was an independent predictor of VT resulting in ATP (hazard ratio 16.80, 95% confidence interval 3.74-75.2; P < 0.001) with a high predictive accuracy (area under the curve 0.88, 95%CI 0.76-1.00; P < 0.001). VA event rates are high in ARVC patients with a majority having VT falling in the VF zone resulting in ICD shock(s). S-ICDs could be of benefit in most patients with ARVC with the absence of severely impaired RV function which has the potential to avoid consequences of the high burden of lead failure.

P454 ARRHYTHMIC RISK AND REPOLARIZATION ALTERATIONS ON THE ECG UNCOVERED BY AN ISOPRENALINE TEST

Abstract A 62–year–old man came to our attention for a syncopal episode that occurred during a competitive race, without prodromes, lasting a few seconds, with total, spontaneous regression and without issues. On ECG sinus bradycardia, HR 46/min and QRS fragmented in V1. During monitoring were documented many polymorphic premature ventricular complex (PVC) and polymorphic nonsustained ventricular tachycardia (NSVT). Coronary angiography showed normal coronary arteries. The Isoprenaline test was performed (intravenous infusion of Isoprenaline 0.2 mg in 100 ml of physiological solution at variable speed until obtaining a HR increase of at least 20% compared to baseline). As HR increased, a clear epsilon wave in V1 became evident. Also documented numerous polymorphic PVC and polymorphic NSVT. Cardiac magnetic resonance (MRI) was performed with documentation of findings suggestive of primary cardiomyopathy with biventricular phenotypic expression with a clear left prevalence. All these elements placed the patient at high arrhythmic risk. An implantable cardiac defibrillator was then performed. The isoprenaline–induced increase in heart rate made the epsilon wave manifest, which is an expression of an extremely delayed depolarization caused by the fibroadipose replacement of portions of the myocardium (as documented by cardiac MRI). It was also possible to exclude a J–wave syndrome in which the alterations are of repolarization and are due to the epi–endocardial electrical gradient which increases and becomes more evident at lower heart rates. The test with isoprenaline has therefore allowed us to distinguish depolarization disorders from repolarization disorders and to direct us towards the former.

C70 WEARABLE CARDIOVERTER DEFIBRILLATOR IN LONG QT SYNDROME DURING PREGNANCY: TIME TO USE THE SHIELD

Abstract Introduction Long QT Syndrome (LQTS) is a rare cardiac channelopathy characterized by a high risk of lethal arrhythmias. Pregnancy and post–partum period may induce an increased vulnerability, so an appropriate prevention is needed. Case presentation A 31–year–old primigravid woman at 36 weeks of pregnancy was referred to our Cardiomyopathy Unit located in a tertiary centre for LQTS screening. The patient had a family history of LQTS (mother and brother) and Brugada syndrome (cousin). The 12–lead ECG (Figure 1) showed a long QT interval (QT corrected: 508 msec), while the transthoracic echocardiogram was unremarkable. The genetic test performed is still ongoing. The patient reported sporadic episodes of palpitations at rest and the following 24–hour ambulatory ECG revealed a very high burden of polymorphic ventricular arrhythmias, with about sixteen thousand premature ventricular complexes and a non–sustained ventricular tachycardia. Therefore, due to the patient’s high–risk for life–threatening arrhythmic events, metoprolol 25 mg o.d. was initiated and a wearable cardioverter defibrillator (WCD) with remote monitoring was provided during pregnancy and labour. After 3 weeks a caesarean delivery in epidural analgesia was performed and managed by a pregnancy heart team including a cardiologist, gynaecologist, obstetrician, and anaesthetist in close cardiac monitoring. No maternal or infant complications occurred, without arrhythmic episodes detected by the device. The WCD will be maintained also in the post–partum period with a narrow follow–up of the patient. Discussion In pregnant high–risk LQTS patients, beta–blockers are the first line therapeutic option, but they do not able to interrupt lethal arrythmias in out–of–hospital setting. The implantable cardiac defibrillator is not the best choice, due to the concerns about radiation exposure and anaesthesia during pregnancy. Moreover, lead–associated thrombosis and infections during pregnancy were reported in literature. The WCD is the ideal option in these cases. It is an external device suited for transient higher arrhythmic risk periods. Moreover, it allows a remote monitoring of arrhythmic burden (figure 2) which may help clinicians in guiding the follow–up and the therapeutic management of the patient. One drawback is the need of continuous patient’s compliance. Finally, a pregnancy heart team is mandatory in presence of these rare cardiac syndromes.

P162 ARRHYTHMIC MITRAL VALVE PROLAPSE OCCURRING AS ABORTED SUDDEN CARDIAC DEATH

Abstract Mitral valve prolapse (MVP) is the common valvular heart disease, with a prevalence about 1–3% in the population. MVP is characterized on echocardiography by an abnormal systolic displacement of mitral valve leaflets into left atrium (LA) ≥ 2 mm above the mitral annulus. We described a clinical case of a 15 years–old boy with a first clinical presentation of out–of–hospital cardiac arrest related to ventricular fibrillation (VF) with a successful resuscitation after 2 DC shocks. Retrospectively, an episode of loss of awareness reported as post–minational. No familiar history of sudden cardiac death (SCD) or MVP was noticed. In the emergency room, the patient was hemodynamically unstable and was sedated and intubated. The surface electrocardiogram (ECG) showed sinus rhythm, QRS with fragmentation, and frequent monomorphic isolated premature ventricular contractions (PVCs) with RBBB/LAFB configuration.Frequent monomorphic PVCs with bigeminy was observed during continuous ECG monitoring, so the patient was treated with magnesium sulphate and metoprolol. The patient was subsequently weaned from ventilation support, presenting good gas exchange and without neurological sequalae. The 24h Holter monitoring showed an average of 53 bpm, extremely rare supraventricular extrasystoles, high incidence of monomorphic PVCs (23% of the total beats) with 4 couplets. Transthoracic echocardiography documented normal size and thickness with systolic function (GLS –21%, mild asynchrony of posterior basal segments), bi–leaflet prolapse associated to mild–moderate mitral regurgitation, and mitral annular disjunction (MAD) of 6.2 mm. The late gadolinium enhancement cardiac magnetic resonance showed bi–leaflet prolapse with mild insufficiency and maximum MAD 9 mm, mild LA dilatation, and slightly dilated both ventricles, without regional wall motion abnormalities; no scar or fibrosis at the late gadolinium enhancement was observed. According to guidelines, the patient received a subcutaneous implantable cardiac defibrillator for the secondary prevention of SCD and maintained under betablockers in order to control the arrhythmic burden. The genetic sampling did not show any pathogenetic mutation potentially related to cardiomyopathies or channelopathies. This case show an arrhythmic MVP complex with probably posterior papillary muscle source. The early PVCs with R/T constituted a possible trigger of VF. The betablocker therapy exhibited a full suppression of extrasystolic burden.

LB-456640-2 MULTICENTER FIRST IN HUMAN CLINICAL FEASIBILITY STUDY TO EVALUATE SAFETY AND EFFICACY OF LOW ENERGY MULTI-PULSE THERAPY FOR VENTRICULAR TACHYCARDIA

Implantable cardioverter defibrillators (ICD) are effective in terminating ventricular tachycardia (VT). High energy shocks are deleterious and anti-tachycardia pacing is limited in suppressing VT. Multi-Pulse Therapy (MPT) is a novel anti-arrhythmic therapy which has a unique waveform sequence including multiple stages of electrical pulses, requires less energy compared to conventional biphasic defibrillation.

Genetic profile and genotype–phenotype correlations in childhood cardiomyopathy

BackgroundGenetic cardiomyopathy is a rare disease in childhood. AimsTo analyse clinical and genetic aspects of a paediatric cardiomyopathy population, and to establish genotype–phenotype correlations. MethodsWe performed a retrospective study of all patients with idiopathic cardiomyopathy aged<18years in Southeast France. Secondary causes of cardiomyopathy were excluded. All data (clinical, echocardiography, genetic testing) were collected retrospectively. Patients were classified into six groups: hypertrophic cardiomyopathy; dilated cardiomyopathy; restrictive cardiomyopathy; left ventricular non-compaction; arrhythmogenic right ventricular dysplasia; and mixed cardiomyopathy. Patients who did not have a complete genetic test according to current scientific developments had another deoxyribonucleic acid blood sample during the study time. Genetic tests were considered positive if the variant found was classified as pathogenic, likely pathogenic or a variant of uncertain significance. ResultsEighty-three patients were included between 2005 and 2019. Most patients had hypertrophic cardiomyopathy (39.8%) or dilated cardiomyopathy (27.7%). The median age at diagnosis was 1.28years (interquartile range: 0.27–10.48years). Heart transplantation was performed in 30.1% of patients, and 10.8% died during follow-up. Among 64 patients with a complete genetic analysis, 64.1% had genetic anomalies, mostly in MYH7 (34.2%) and MYBPC3 (12.2%) genes. There were no differences in the whole cohort between genotype-positive and genotype-negative patients. In the hypertrophic cardiomyopathy group, 63.6% had a positive genetic test. Patients with a positive genetic test more often had extracardiac impact (38.1% vs. 8.3%; P=0.009), and more often required an implantable cardiac defibrillator (23.8% vs. 0%; P=0.025) or a heart transplant (19.1% vs. 0%; P=0.047). ConclusionsIn our population, children with cardiomyopathy had a high positive genetic test rate. Hypertrophic cardiomyopathy with a positive genetic test is associated with a worse outcome.

Outcomes of Ventricular Tachycardia Catheter Ablation in Patients Who Underwent Cardiac Defibrillator Implantation Nationwide Readmission Database Analysis

The timing of when to perform ventricular tachycardia (VT) ablation while receiving an implantable cardioverter defibrillator (ICD) during the same hospitalization has not been explored. This study aimed to investigate the use and outcomes of VT catheter ablation in patients with sustained VT receiving ICD in the same hospital stay. The Nationwide Readmission Database 2016 to 2019 was queried for all hospitalizations with a primary diagnosis of VT with subsequent ICD during the same admission. Hospitalizations were later stratified according to whether a VT ablation was performed. All catheter ablation of VT were performed before ICD implantation. The outcomes of interest were in-hospital mortality and 90-day readmission. A total of 29,385 VT hospitalizations were included. VT ablation was performed with subsequent ICD placement in 2,255 (7.6%), whereas 27,130 (92.3%) received an ICD only. No differences were found regarding in-hospital mortality (adjusted odds ratio [aOR] 0.83, 95% confidence interval [CI] 0.35 to 1.9, p=0.67) and all-cause 90-day readmission rate (aOR 1.1, 95% CI 0.95 to 1.3, p=0.16). An increase in readmission because of recurrent VT was noted in the VT ablation group (aOR 1.53, 8% vs 5% CI 1.2 to 1.9, p <0.01); the VT ablation group encompassed a higher number of patients with heart failure with reduced ejection fraction (p <0.01), cardiogenic shock (p <0.01), and mechanical circulatory support use (p <0.01). In conclusion, the use of VT ablation in patients admitted with sustained VT is low and reserved for higher risk patients with significant co-morbidities. Despite the higher risk profile of VT ablation cohort, no differences were found in the short-term mortality and readmission rate between the groups.

Risk Factors for Infections of Cardiac Implantable Electronic Device in Saudi Arabia

Background and Objectives: Cardiac implantable electronic device (CIED) infections are increasing worldwide due to the increased use of implantable cardiac devices. (CIED) infection is a serious complication that is associated with increased mortality and morbidity as well as increased healthcare costs. However, risk factors for infection of implanted devices are poorly documented in Saudi Arabia. We aimed to determine risk factors for CIED infection in our region. Methods and Results: A retrospective study was carried out in cardiology departments at different centers in Saudi Arabia. Our population consisted of all patients with device-related infections over twenty years from January 2009 to December 2020 with one control case matched to each confirmed infection of the implanted device, resulting in 137 patients with device infection. The mean age was 58±16 years, where males constituted 75.2%. Most infections occurred in patients with the first implant. (63.5%) patients had chronic kidney disease, (59.9%) of patients had diabetes mellitus, (65%) of patients had hypertension, and (43.1%) of patients had coronary artery disease. Most of the patients had a pocket infection. Preop antibiotics were obtained in all patients before implanting. The median time from the last surgical intervention involving the device to infection symptoms was 730 days. The median length of hospitalization was 27±23 days. 130 patients survived at the time of discharge, resulting in an overall mortality rate of 5.1%. Using Multivariate analysis, we identified male gender (P = 0.000), hypertension HTN (P = 0.002), diabetes DM (P = 0.006), and presence of underlying heart disease CHD (P = 0.000) Type of the device (P = 0.000) as significantly associated with a higher risk of CIED infection. Conclusion: Our data show that gender, diabetes, hypertension, and heart disease are independent risk factors for infection after cardiac device implantation. As regards device characteristics, ICD device is associated with a higher infection rate compared to other devices.

Comparing ICD shock ratios between Type 1, Type 2 and non diabetic patients

Objective: The use of permanent pacemakers and implantable cardioverter defibrillators (ICDs) is increasing. With technological advances, the devices' implantation techniques and programmable features are improving, and indications are expanding. Several technical and clinical problems are encountered during implantation and follow-up of these devices. Methods: Our study retrospectively evaluated diabetic and non-diabetic patients who underwent ICD implantation in Mersin University Cardiology Department between January 2010 and December 2013 according to current indications. All clinical characteristics, baseline, 1-month and 6-month follow-up pacemaker data and baseline laboratory values were recorded. Results: A total of 106 ICD patients (57 diabetics and 49 nondiabetics) were enrolled at the 1st and 6th months of follow-up. 47.2% of the patients were male and the mean age was 56±7.3 years. ICDs were implanted for secondary prevention in 83.9% of patients. ICD was implanted for coronary artery disease +/- ventricular tachycardia (VT) or ventricular fibrillation (VF)+/- synchronization disorder. 75.4% of patients had CAD, and 89.6% had heart failure. The mean ejection fraction ratio (EF) was 31.3%. Early complications were observed in 10.3% of patients. 47.1% of patients received any treatment by the ICD, 34.9% had the appropriate shock, and 12.2% had inappropriate shock. The complication rate was 10.3%. While there was no difference in ventricular impedance and threshold values in diabetic patients compared to the control group, ventricular lead R amplitude values were found to be higher. The rate of atrial fibrillation was significantly different in the treated group. Treatment response was obtained in 71.4% of patients who underwent treatment change due to appropriate shock, incorrect shock and ATP. Conclusion: In conclusion, the incidence of appropriate shock and anti-tachycardic pacing was higher in diabetic patients than non-diabetic patients.

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).

Antitachycardia pacing at the His bundle is safer than conventional right ventricular antitachycardia pacing in a canine myocardial ischemic injury model.

Antitachycardia pacing (ATP) is used to terminate ventricular tachycardia (VT) by delivering rapid, low energy pacing to the right ventricle (RV). Unfortunately, ATP is not effective against all VT episodes and can result in adverse outcomes, such as VT acceleration and degeneration into ventricular fibrillation (VF). Improving ATP is therefore desirable. Our objective was to compare the efficacy and safety of ATP delivered at the His bundle to traditional ATP. Six dogs were anesthetized and pacing leads were implanted in the RV and His bundle. The left anterior descending artery was occluded for 2 h to create an ischemic injury. In a study 4-7 days later, a 128-electrode sock was placed snugly around the ventricles and VT was induced using rapid pacing. ATP was delivered from either the His bundle or RV lead, then attempted at the other location if unsuccessful. Success rates and instances of VT acceleration and degeneration into VF were calculated. We induced 83 runs of VT and attempted ATP 128 times. RV ATP was successful in 36% of attempts; His ATP was successful in 38% of attempts. RV ATP resulted in significantly more adverse outcomes. RV and His ATP induced VT acceleration in 9% and 3% of trains, respectively, and induced degeneration into VF in 5% and 1% of trains, respectively. His bundle ATP is safer, but not significantly more effective, than RV ATP.

PO-05-078 SHOCK REDUCTION THROUGH EARLY DELIVERY OF ANTITACHYCARDIA PACING FOR FAST VENTRICULAR TACHYCARDIAS

Antitachycardia pacing (ATP) is a programmable therapy in implantable cardiac defibrillator (ICD) devices that has been demonstrated to effectively reduce the need for shocks. Limited data, however, exists on the potential benefits of early ATP delivery in the ventricular fibrillation (VF) zone. While ATP is programmed to be delivered as a first line of therapy for ventricular tachycardia (VT) events, it does so only once the episode meets detection criteria by the ICD. Newer generations of BIOTRONIK ICDs have the ability for earlier delivery of ATP, called Early ATP OneShot, to be programmed in the VF therapy zone. Early ATP is delivered when 12 out of 16 events, plus stability criteria, are met to target fast VTs detected in the programmed VF therapy zone. This option is available for patients with longer detection times (VF detection counters of 16 out of 20 or higher) and allows the device to deliver ATP before episode detection counter criteria is met, thus providing therapy earlier than traditional ATP. To compare the success rates of Early ATP OneShot (eATP) for episodes in the VF zone against traditional ATP OneShot (tATP) programming. Using BIOTRONIK’s real-world research database, CERTITUDE, 696 patients with eATP capable ICD devices with VF episodes transmitted via remote monitoring were divided into groups based on tATP (n=584) or eATP (n=112) programming for the VF therapy zone. Each device detected episode was evaluated to determine the therapy (ATP and/or shocks) delivered, whether therapy was successful, or if the episode self-terminated. Patients with detection zone counters lower than 16 out of 20 were excluded. eATP was successful in 69.4% of cases in terminating episodes in the VF zone whereas tATP was successful in 49.1% of cases (p<0.0001). Extrapolation of the eATP success rate to the tATP cohort results in 30.0% less shocks (203 avoided shocks out of 676 total shocks). Cohorts did not differ statistically in mean R-R interval at episode detection, nor in device programming for detection limit zone or counters. Episode duration was shorter in the eATP cohort (p<0.0001). As compared to traditional programming, use of Early ATP OneShot provides increased success rates to terminate fast VTs detected in the VF zone, potentially reducing unnecessary shocks.Tabled 1Table: Comparison of ATP Therapy Groups for Device Detected VF Episodes (PO-05-078)OutcomeEarly ATP OneShotTraditional ATP OneShotp value (difference)Patients with VF Event112584-ATP Therapy Success Rate (Successes/Attempts)69.4% (161/232)49.1% (491/1001)<0.0001Median VF Episode Duration (sec)1217<0.0001Mean R-R interval at VF Episode Detection (ms)2572530.17Mean Programmed Rate of VF Detection Limit (ms)2882910.20Median Programmed Detection Counters for Programmed VF Zone (X/Y criteria)18/2418/240.94 Open table in a new tab

PO-05-082 ANTITACHYCARDIA PACING IS MORE EFFECTIVE WHEN DELIVERED TO THE LEFT BUNDLE BRANCH COMPARED TO THE RIGHT VENTRICLE IN A CANINE ISCHEMIC VENTRICULAR TACHYCARDIA MODEL

Implantable cardioverter-defibrillators (ICDs) can terminate ventricular tachycardia (VT) with Antitachycardia pacing (ATP) delivered to a right ventricular (RV) pacing lead, thereby avoiding painful and damaging high-energy shocks. However, ATP efficacy is limited for fast VT, and ATP can accelerate VT or convert VT to ventricular fibrillation (VF). Physiological pacing delivered to the left bundle branch (LBB) has emerged as a clinically relevant target to minimize ventricular dyssynchrony and pacing-induced heart failure. ATP efficacy and safety delivered to the LBB are yet to be investigated. Evaluate the therapeutic efficacy and safety of ATP delivered to an LBB lead compared to ATP delivered to a conventional RV lead. In 6 anesthetized dogs, pacing leads from two ICDs (CobaltTM XT DR, Medtronic, Inc) were implanted at the RV apex (6947 Sprint Quattro SecureTM, Medtronic, Inc) and the LBB (3830 SelectSecureTM, Medtronic, Inc). A lateral thoracotomy procedure was performed, and a two-hour lateral anterior descending artery ischemia-reperfusion injury was caused. The thoracotomy was closed and on post-infarct day 4, dogs were anesthetized, and sustained VT episodes were induced by programmed electrical stimulation. ATP (up to 5 trains of 8 pulses at approximately 88% of the VT cycle length) was delivered to either the LBB or RV pacing site in a randomized fashion. The success rate of ATP in terminating the VT episodes and the rate of VT acceleration and degeneration into VF from both pacing locations were evaluated. In our canine ischemic VT model, VT was induced 80 times, with a mean VT cycle length of 178±35 ms. ATP was delivered and tested for each episode. For ATP delivered to the RV, the success rate for terminating VT was 54%. The success rate for terminating VT for ATP delivered to the LBB was 73% (Fig. A, p < 0.05). ATP resulted in VT acceleration for 10% and 5% of ATP attempts delivered to the RV and LV, respectively (Fig. B, p = Not Significant, NS). Degeneration to VF occurred for 5% of all ATP attempts delivered to the RV, and there was no such incident for ATP delivered to the LBB (Fig. B). Higher efficacy and lower incidence of VT acceleration were observed with ATP delivered to LBB compared to ATP delivered to the RV in this canine ischemic VT model. Improved performance of ATP delivered to LBB compared to RV provides additional incentive for expanded use of LBB leads for pacing and therapy delivery.

CI-452769-3 INAPPROPRIATE ICD SHOCKS IN PATIENTS WITH LVADS: PREVALENCE, ASSOCIATED FACTORS, AND ETIOLOGIES

Left Ventricular Assist Devices (LVADs) are increasingly used to treat advanced heart failure. While most patients with an LVAD have an implantable cardiac defibrillator (ICD) in situ, there are limited data on the frequency and causes of ICD therapies in patients with LVADs. To define the incidence, programming and patient characteristics associated with appropriate and inappropriate shocks in persons with ICDs and LVADs. We performed a retrospective review at Duke University Hospital of all LVAD recipients implanted with a HeartWare, HeartMate II, and HeartMate III (January 1, 2013 to June 30, 2019) and an ICD in situ. ICD shocks were adjudicated by the treating physician and a 2nd review for the purpose of this study. Among 437 patients with an ICD in situ undergoing LVAD implant, 147 (33.6%) patients had at least one shock episode following LVAD implantation. 12 patients were excluded due to incomplete device history. Among 135 patients, there were a total of 332 shock episodes: 257 (77.4%) appropriate and n=75 (22.6%) inappropriate. Etiologies for inappropriate shocks included SVT (n=66, 19.9%), physiologic oversensing (n=1, 0.3%), and non-physiologic oversensing (n=8, 2.4%). Overall, 92 (68.1%) patients had no inappropriate shock episodes, 43 (31.8%) patients had ≥ 1 inappropriate shock episodes, and 14 (10.4%) patients had ≥ 2 inappropriate shock episodes. Moreover, 26 (19.3%) patients had only inappropriate shock episodes. Among persons with inappropriate shocks, 0 of 47 patients had device programming consistent with consensus AHA recommendations (published after end of follow-up). The rate of inappropriate shocks in LVAD recipients is very high and is most often due to supraventricular arrhythmias. Implementation of current consensus AHA recommendations for LVAD programming may help avoid inappropriate shocks.

CE-454029-1 THE IMPACT OF GENDER ON DECISIONAL CONFLICT SURROUNDING IMPLANTABLE CARDIOVERTER DEFIBRILLATOR IMPLANTATION AMONG BLACK PATIENTS AT RISK FOR SUDDEN CARDIAC DEATH

Implantable cardiac defibrillators (ICD) reduce the risk of sudden cardiac death (SCD) in patients with heart failure with reduced ejection fraction (HFrEF). Previous studies have shown that women are less likely to undergo ICD implantation than men. "Videos to Address Racial Disparities in Implantable Cardioverter-Defibrillators Via Innovative Designs (VIVID): A Randomized Clinical Trial" (VIVID) investigated the impact of a video-based decision support tool on the decision for ICD implantation and associated decisional conflict. The overall aim of this study is to analyze the impact of gender on decisional conflict and ICD receipt among Black men and women with HFrEF at risk for SCD. The VIVID trial was conducted from September 2016 to April 2020. Gender and race were self-reported. Black patients were randomized to a video-based decision support tool or usual care. A decisional conflict scale (DCS) adapted from the Ottawa Decision Support Framework was used to assess decisional conflict associated with ICD implantation before and after the intervention. Logistic regression was used to measure differences in ICD implantation within 90 days of study enrollment and the association between decisional conflict and ICD implantation between men and women at 90 days. ANCOVA regression was used to measure differences in DCS between Black men and women and the interaction by intervention group. Among 330 Black patients included in the final analysis, 309 patients (197 men and 112 women) had gender and DCS data available. At 90-day follow-up, 73.9% of women compared with 61.9% of men underwent ICD implantation (adjusted OR (95% CI): 2.07 (1.14, 3.78); p=0.02). There was no significant interaction between gender and intervention for ICD implantation. Among all participants, decisional conflict scores decreased and did not differ by intervention (adjusted mean difference (95% CI): -2.00 (-4.05, 0.05)). Women had a greater mean decrease in DCS scores than men (adjusted mean difference (95% CI): -2.16 (-4.23, -0.09); p=0.04); and there was no significant interaction between gender and intervention in DCS scores (p=0.32). Among Black patients eligible for an ICD, women had less decisional conflict associated with ICD implantation and were more likely to receive an ICD than men. Future research should seek to understand the role of gender on decision-making for an ICD.Tabled 1Table 1. Differences in ICD Implantation within 90 Days.Number of ICD Implants/Total (%)Odds Ratio (95% CI)P-valueIntervention GroupUsual Care71/99 (71.7%)Video-Based Decision Support Tool128/203 (63.1%)1.48 (0.83, 2.63)0.18GenderMen118/192 (61.5%)Women81/110 (73.6%)2.07 (1.14, 3.78)0.02All values are adjusted for patient characteristics including age, educational attainment, income, marital status, work status and pertinent comorbidities including hypertension, hyperlipidemia, diabetes, coronary artery disease and atrial fibrillation. Open table in a new tab

PO-05-069 ASSOCIATION BETWEEN LEFT VENTRICULAR WALL-THICKNESS BY CT AND ENDOCARDIAL VOLTAGE POTENTIALS IN PATIENTS WITH ISCHEMIC CARDIOMYOPATHY UNDERGOING VT ABLATION

Although cardiac magnetic resonance (CMR) is the gold standard for planning ventricular tachycardia (VT) ablation, its accuracy is hindered in patients with implanted cardiac defibrillators (ICD) and resynchronization therapy (CRT). Cardiac computed tomography (CT) has emerged as an alternative for ablation planning in these patients. This pilot study aimed to evaluate the relationship between wall thickness (WT) on CT and voltage of electrical potentials on endocardial electroanatomic mapping (EAM) in patients with ischemic cardiomyopathy. Single centre retrospective study enrolling consecutive patients with ischemic cardiomyopathy referred for endocardial VT ablation that underwent cardiac CT for procedure planning since 2021. Patients were excluded if EAM had < 1000 data points. ADAS 3D® software was used to analyse CT images, automatically segmenting the left ventricle (LV) into the 17 American Heart Association segments and calculating end-diastolic WT for each one. Four standardized views (anterior-posterior, posterior-anterior, superior, and inferior) of the segmented LV on ADAS 3D® were used to aid in manual segmentation of the EAM. The endocardial voltage maps were created using CARTO3® software (Biosense Webster®). For each patient, EAM was interpreted to create 2 different bulls’ eye maps, according to the presence or absence of bipolar potentials < 0.5 (dense scar) or < 1.5mV (low voltage). Only segments with >20% extension of low bipolar voltage were considered as altered. We included a cohort of 8 patients (mean age 67±12 years, 87.5% male, median LVEF of 32% [IQR 25-49]). All but one patient had an implanted cardiac device (6 ICD, 1 CRT-D). Cardiac CT was performed 1 day (IQR 0-2) before the ablation. Overall, 136 segments were analysed, 8 of which did not have voltage information. Of the remaining 128, 51 (39.8%) had dense scar and 57 (41.9%) had low voltage. There was a good correlation between mean WT and the presence or absence of both dense scar (area under de curve (AUC) 0.799, p<0.001) and low voltage (AUC 0.838, p<0.001) in each LV segment. WT measured by CT appears to have a strong correlation with dense scar and low voltage in EAM in patients with ischemic cardiomyopathy undergoing VT ablation. This technique may be useful to plan interventions in patients in whom CMR is not feasible.

PO-02-018 SIGNIFICANCE OF VENTRICULAR ARRHYTHMIA SUBSTRATE AS A PROGNOSTIC MARKER OF CARDIAC RESYNCHRONIZATION THERAPY

Implantable cardioverter-defibrillator (ICD) shock is associated with mortality. There are, however, conflicting data whether ventricular arrhythmia (VA) leading to ICD shock or shock itself increases mortality. In addition, paced electrical delay is related to both VA substrate and cardiac resynchronization therapy (CRT) response. Little is known about the significance of VA substrate as a prognostic marker of CRT. The aim of this study is to assess the relationship between VA substrate and prognosis such as cardiac death and/or heart failure (HF) hospitalization. We investigated consecutive 330 CRT patients with the follow-up data one year after CRT implantation. VA was defined as lasted ≥30s or treated by anti-tachycardia pacing (ATP) or shock. CRT responder was defined as more than 15% reduction of left ventricular end-systolic volume. Primary endpoint was composite endpoint of cardiac death and/or HF hospitalization. Forty-three patients had VA within one year after CRT implantation. During median follow-up of 2.8 years (interquartile range 1.5-5.0 years), the patients with VA within one year had higher risk of primary endpoint (p<0.01). VA >200bpm was associated with increased risk of primary endpoint (VA >200bpm vs VA ≤200bpm, hazard ratio [HR] 2.34; 95% confidence interval [CI] 1.08-5.08, p=0.03), though shock was not associated with primary endpoint (shock vs anti-tachycardia pacing, HR 1.66; 95%CI 0.76-3.61, p=0.20). The patients with VA within one year had lower prevalence of CRT responder (19 [44%] vs 184 [64%], p=0.01) and longer time of left-ventricular pacing to right ventricular sensing (174±23ms vs 143±36ms, p<0.01) than the patients without. VA occurrence within one year was related to paced electrical delay and poor response to CRT. VA substrate could be associated with poor prognosis among the CRT patients.

Admission triglyceride-glucose index is predictor of long-term mortality and appropriate implantable cardiacdefibrillator therapy in patients with heart failure.

Background: In this study, the main aim was to evaluate the relation of the triglyceride-glucose (TyG) index to long-term mortality and proper shock therapy in patients with an implantable cardiacdefibrillator (ICD) implanted for heart failure with reduced ejection fraction. Methods: This retrospective study group consisted of 773 patients treated with ICD for heart failure with reduced ejection fraction. The long-term prognostic effect of the TyG index among tertiles was evaluated regarding mortality and appropriate ICD therapy. Results: In the adjusted model, the mortality rates were 14.0% (hazard ratio: 2.24; 95% CI: 1.42-6.88) in tertile 2 and 23.3% (hazard ratio: 3.88; 95% CI: 1.84-14.38) in tertile 3. Conclusion: The TyG index was found to be an independent predictive marker for both long-term mortality and appropriate ICD therapy.