High-grade AV Block Research Articles

Abstract 4123956: Upgrade to Implantable Cardioverter-Defibrillator in Patients Diagnosed with Cardiac Sarcoidosis after Permanent Pacemaker Implantation for High-Grade Atrioventricular Block

Introduction: Unexplained high-grade AV block (AVB) in patients age <65 years is among the salient features of cardiac sarcoidosis (CS). Guidelines recommend that CS patients with high-grade AVB should receive an implantable cardioverter-defibrillator (ICD) or cardiac resynchronization therapy-defibrillator (CRT-D) rather than a permanent pacemaker (PPM). However, in clinical practice, CS may be recognized after PPM implantation for high-grade AVB. Aims: To evaluate the characteristics and outcomes of patients diagnosed with CS after PPM implantation for high-grade AVB and assess the decision-making and rationale for upgrade to ICD/CRT-D. Methods: Retrospective review of the Mayo Clinic Sarcoid Registry (n=848) was performed to identify all patients for which a PPM was implanted for high-grade AVB prior to the diagnosis of CS. Baseline clinical and imaging characteristics were collected during index evaluation at our institution. Decision-making for ICD upgrade, lead management strategy, immunosuppression initiation, and outcomes were assessed. Results: Overall, 29 of 848 (3.4%) of CS patients (62% probable/definite CS; 77% male; median (IQR) age 56 (48-61) years; and median (IQR) LVEF 58% (50-62) received a PPM for high-grade AVB prior to a CS diagnosis. Median (IQR) interval between PPM implant and index evaluation was 10 (3-23) months. Eight of 29 patients underwent upgrade to ICD (n=4) or CRT-D (n=4). Among them, the pacing lead was extracted in 4. All patients were upgraded for primary prevention of sudden cardiac death (SCD), with 3 of them also having LVEF<50% requiring upgrade to CRT-D. Twenty-two (79%) patients in the total cohort were treated with immunosuppression. During median (IQR) follow-up 37 months (11-74), 1 patient in the upgrade group had sustained VT appropriately treated with anti-tachycardia pacing. No events were documented among patients in the non-upgrade group. At last follow-up, 6 (75%) patients in the upgrade group and 12 (57%) in the non-upgrade group were pacemaker dependent. Median LVEF change was 0% in patients who underwent upgrade to CRT-D and –0.2% in those who underwent upgrade to ICD or no upgrade. Conclusions: In this cohort of patients diagnosed with CS several months after a PPM had been implanted for high-grade AVB, incident VT/VF was infrequent with contemporary CS management. In the absence of other SCD risk factors, CS patients who received a PPM for high-grade AVB prior to their CS diagnosis may not require ICD upgrade.

Acute myocarditis presentation and intra-hospital prognosis: results of the multicenter prospective MYOCARDITIRM study

Abstract Background Acute myocarditis (AM) usually presents as chest pain with rising troponin and normal coronary arteries. Despite frequent favorable evolution at the acute phase, it is associated with heart failure and ventricular rhythm disorders and is considered the leading cause of sudden cardiac death in young apparently healthy adults. There is no recommendation for AM, only expert consensus, given the lack of important databases for a strong level of confidence. Methods We performed a multicenter prospective observational study of patients admitted for AM acknowledged by cardiac MRI to describe baseline characteristics, management, in-hospital and long-term outcomes of AM patients in France. Secondary objectives were to investigate determinants of prognosis, modalities of treatment and follow-up, and to identify gaps between expert consensus and real-life management. Results We enrolled 805 consecutive patients hospitalized for AM in 49 participating centers between May 2016 and February 2019. Median age was 31 (IQR 23-41) with 19% of female. Chest pain was the most frequent symptom (93%) and 112 (14%) had severity criteria upon admission (LVEF<50% or severe ventricular arrythmia or high-grade AV block or cardiogenic shock). ST elevation was observed in 49% of patients. One 26-years old patient died during initial hospital stay. Overall, 62 patients (8%) experienced intra-hospital complication of their AM, defined as a combined endpoint of death, LVEF<40% (MRI), sustained ventricular or supraventricular arrythmia, acute renal failure, cardiogenic shock, need for ventricular assistance device, need for inotropic drugs, temporary cardiac pacing, pace-maker or cardiac defibrillator implantation. Patients with initial severity criteria were 10 times more likely to present intra-hospital complication (33% vs 3.6%, p<0.001). Conclusion This prospective cohort represents the largest database on AM worldwide. Here we report baseline characteristics and in hospital events. Most patients had typical presentation with favorable outcomes but as much as 8% of patients did exhibit intra-hospital complication. The prospective follow up will provide valuable data to better identify subset of patients with poor prognosis that may be of interest to develop new therapeutic strategies.Acute myocarditis on cardiac MRI

Endomyocardial biopsy in patients with myocarditis - still justified in the CMR era? A single-centre experience

Abstract Background Endomyocardial biopsy (EMB) is still considered the diagnostic gold standard for myocarditis. However, in the past decades, cardiac magnetic resonance (CMR) was established as a non-invasive tool supporting the diagnosis of myocarditis. Furthermore, there is often reluctance in performing EMB due to rare but potentially severe complications. We therefore sought to identify patient subgroups that could potentially derive benefits from EMB. This involved a comprehensive analysis of the diagnostic and therapeutic outcomes resulting from the procedure at our centre. Methods In this retrospective single-centre study, data of all patients presenting with (peri-) myocarditis between 01/2016 and 06/2023 at our tertiary care centre were included. Frequency of histological confirmation of acute myocarditis and histology leading to immunosuppressive therapy were analysed according to patient risks. Prespecified risk factors were (i) LV-EF ≤30%, (ii) presence of severe arrhythmias (VF, VT, high grade AV-block) or (iii) pre-existing autoimmune disease. Furthermore, the subgroup of recurrent myocarditis cases was analysed separately. Results A total of 150 consecutive patients (36.7 ± 15.5 years, 77.3% male) were included in this study. 26/150 patients had a documented EF ≤30%, 13/150 an EF >30% with another risk factor and 111/150 an EF>30% without another risk factor. EMB was performed in 21/26 patients with EF ≤30% (80.7%), in 7/13 patients with EF >30% and another risk factors (53.8%) and in 16/111 (14%) patients without risk factors. EMB led to the initiation of immunosuppressive therapy in 11/28 patients with risk factors (39.3%) and in none of the patients without risk factors (0/16, 0%, p=0.003)(figure 1). With respect to the subgroup of patients presenting with recurrent myocarditis (n=10), no specific therapy was performed. Conclusion Due to a high therapeutic yield for initiation of immunosuppressive therapy in non-infectious myocarditis, performing EMB should be considered in all high-risk patients. In patients without clinical risk factors including cases of recurrent or relapsing myocarditis no specific therapy was initiated.

TCT-127 Thirty-Day High-Grade AV Block Post Transcatheter Aortic Valve Replacement in Patients Discharged on Heart Rhythm Monitor

TCT-127 Thirty-Day High-Grade AV Block Post Transcatheter Aortic Valve Replacement in Patients Discharged on Heart Rhythm Monitor

Successful prediction of left bundle branch block-induced cardiomyopathy and treatment effect by artificial intelligence-enabled electrocardiogram.

Left bundle branch block (LBBB) induced cardiomyopathy is an increasingly recognized disease entity. However, no clinical testing has been shown to be able to predict such an occurrence. A 70-year-old male with a prior history of LBBB with preserved ejection fraction (EF) and no other known cardiovascular conditions presented with presyncope, high-grade AV block, and heart failure with reduced EF (36%). His coronary angiogram was negative for any obstructive disease. No other known etiologies for cardiomyopathy were identified. Artificial intelligence-enabled ECGs performed 6 years prior to clinical presentation consistently predicted a high probability (up to 91%) of low EF. The patient successfully underwent left bundle branch area (LBBA) pacing with correction of the underlying LBBB. Subsequent AI ECGs showed a large drop in the probability of low EF immediately after LBBA pacing to 47% and then to 3% 2 months post procedure. His heart failure symptoms markedly improved and EF normalized to 54% at the same time. Artificial intelligence-enabled ECGS may help identify patients who are at risk of developing LBBB-induced cardiomyopathy and predict the response to LBBA pacing.

А rare case of Тakoтsubo cardiomyopathy complicated with high-grade AV block and ventricular tachycardia

Takotsubo cardiomyopathy or broken heart syndrome is a stress-induced cardiomyopathy with clinical, laboratory and ECG resemblance to acute coronary syndrome. Major differences stem from transient segmental wall motion abnormalities beyond the territory of a single coronary artery and the lack of obstructive coronary disease during angiography. Overall the condition is considered as a benign one with a favourable outcome, however there are reports of complicated clinical course by cardiogenic shock, apical thrombus, death and arrhythmias. The latter are reported to occur in 13% of the cases with ventricular arrhythmias (ventricular tachycardia, ventricular fi brillation, torsades de pointes) as a leading fi nding and in minor percentage – high-grade AV block. Despite advances in our knowledge and experience there are still no strict guidelines for the management of conduction disorders. We present the case of a 78-year old lady with an apical variant of Takotsubo, complicated by syncope, complete AV block, new left bundle branch block, paroxysmal atrial fi brillation, ventricular tachycardia and implantation of a permanent pacemaker. During the hospitalization she developed acute cardiac failure with echocardiographic evidence of left ventricular systolic dysfunction and an apical thrombus. The presented case demonstrates the complexity of the condition and the necessity of strict follow-up and timely therapy. 

Abstract 15756: To Close or Not to Close: A Case of Multisystem Immune Checkpoint Inhibitor Toxicity and PFO

Introduction: Recent emergence of immune checkpoint inhibitors (ICIs) in oncologic treatments has led to increasing research on their side effect profile. Myocarditis occurs in roughly 0.04-1.14% of patients treated with ICIs and is associated with up to 50% mortality. We present a case of multisystem ICI toxicity requiring comprehensive evaluation to ultimately reveal a PFO shunt as the cause of persistent hypoxemia. Case: A 67-year-old male with Stage IIIC cutaneous melanoma presented with non-radiating pleuritic chest pain, diplopia, dyspnea and syncope. ECG showed high grade AV block and right bundle branch block. Labs showed elevated troponin, creatinine kinase and inflammatory markers. An echocardiogram showed edematous myocardium, a small pericardial effusion, and akinetic apical/inferior septal segments. Despite diuresis, 5g of methylprednisolone, IV immunoglobulin plus mycophenolate and resolution of AV block, the patient had hypoxemia on 100% FiO2. He underwent a CTA (which ruled out PE and ICI-induced pneumonitis) and fluoroscopic sniff test (revealing bilateral moderate diaphragm paresis). A recent cardiac catheterization on prior admission showed no obstructive coronary disease. Arterial blood gas showed pO2 120 mmHg without hypercapnia on 100% FiO2. We suspected a shunt as the underlying cause and obtained a bubble study disclosing a large (> 25 bubble) PFO with right-to-left shunt. Results: Given the timing of symptoms, it was determined that pembrolizumab administration caused myocarditis and myositis with diaphragmatic paresis. In patients with pulmonary disease or diaphragmatic paresis, elevated intrathoracic and pulmonary artery pressures have been a proposed mechanism of acute worsening of right-to-left shunt resulting in hypoxemia. The patient underwent right heart catheterization and PFO closure using Gore Cardioform septal occluder with resolution of hypoxemia. A repeat echocardiogram obtained 1 month later was normal. Conclusion: All concerning clinical symptoms in the setting of ICI use require a thorough evaluation. In this case, persistent hypoxemia despite treatment for ICI toxicity unmasked a large PFO requiring closure. A multisystem approach should be used to assess suspected ICI myocarditis.

A Rare Case of Ventricular Standstill and High-Grade AV Block in Patient with Thyrotoxicosis

Background Stokes-Adams Syndrome can be caused by high-grade AV Block, ventricular tachycardia, and one of the uncommon cause, ventricular standstill. Although thyrotoxicosis is commonly presented as tachycardia, it’s unusual for AV blocks to occur, especially a high-grade one.Case Illustration A 45-year-old female was admitted with fatigue, dizziness, and recurrent episodes of unconsciousness. She had a history of hyperthyroid, routinely managed with Propylthiouracil and Propranolol. Physical examination showed HR: 30 x/min, and other unremarkable systemic examinations. Initial ECG showed 3:1 AV Block. Patient was managed with Dopamin and moved to ICU for further observation. In the ICU, suddenly she had a Stokes-Adam episode presented as a seizure, her monitor showing P waves with an absence of ventricular activity lasting for few seconds. Due to the condition of ventricular standstill, a Temporary Pacemaker (TPM) was installed urgently, and so patient’s vital sign was stable with pacing rhythm. We found Free Thyroxine (T4) level of 46.85 pmol/l, TSH of 0.005 ulU/ml, and unremarkable echocardiographic findings. Considering these results, we suspect that the cause of the ventricular standstill was due to thyrotoxicosis. Propylthiouracil and dexamethasone were given to manage the disease. After 7 days of treatment, she was discharged with sinus rhythm on her ECG. Conclusion Ventricular standstill is frequently associated with conduction blockages, but it can sometimes occur without them. Ventricular standstill treatment often necessitates the use of temporary pacing wires or a pacemaker. In thyroid crises, high-degree AV-block is uncommon, but when the euthyroid condition is restored, clinical status and conduction problems can be reversible.

Mortality Outcomes in Patients With Cardiac Implantable Electronic Devices Before and After Transcatheter Aortic Valve Replacement

Transcatheter aortic valve replacement (TAVR) carries a risk of high-grade AV block requiring cardiac implantable electronic device (CIED) implantation, which has been associated with a higher mortality rate. However, the outcomes of TAVR in patients with preexisting CIEDs are not well understood. We conducted a retrospective analysis of consecutive patients who underwent TAVR from December 2014 to December 2019 at our institution. Patients were categorized into 3 groups: preexisting CIED pre-TAVR (group 1), CIED implanted within 30days after TAVR (group 2), and no CIED implanted (group 3). Cox proportional hazard was conducted to determine the primary end point of all-cause mortality. A total of 366 patients were included, of whom 93 (25.4%), 51 (13.9%), and 222 (60.7%) comprised group 1, 2, and 3, respectively. The median follow-up time was 2.3years. The all-cause mortality rate was higher in group 1 than group 2 (hazard ratio [HR] 2.60, 95% confidence interval [CI] 1.09 to 6.18, p=0.03) and group 3 (HR 1.96, 95% CI 1.24 to 3.08, p=0.004). On the multivariate analysis, there was no statistically significant difference in mortality among the groups (group 1 vs group 2: HR 1.95, 95% CI 0.70 to 5.44, p=0.20 and group 1 vs group 3: HR 1.27, 95% CI 0.66 to 2.43, p=0.47). Preoperative hemoglobin ≤12g/100ml was an independent predictor of all-cause mortality (HR 1.75, 95% CI 1.10 to 2.80, p=0.02). Group 1 had a higher 1year congestive heart failure readmission rate (29%) than group 2 (17.6%) and group 3 (8.1%; p <0.0001). In conclusion, there was no difference in the adjusted long-term survival based on the CIED grouping. However, patients with preexisting CIEDs had higher all-cause mortality and 1-year congestive heart failure readmission rates owing to their higher co-morbidity burden, irrespective of their Society of Thoracic Surgeons score. This can be taken into account for preoperative risk stratification.

Incidence and predictors of hemodynamic compromise due to high-grade AV block after TAVI.

High-grade AV block (HAVB) is the most frequent adverse event after transcatheter aortic valve implantation (TAVI). In rare cases, HAVB is associated with hemodynamic compromise (HC) followed by syncope or application of cardiopulmonary resuscitation (CPR), but data on this severe complication are scarce. The aim of the present study was to investigate the incidence and predictors of HC due to HAVB in patients undergoing TAVI. In this retrospective analysis of 4,602 TAVI cases between 2010 and 2022, 466 developed HAVB. Baseline characteristics and procedural and postprocedural findings were compared for patients with HC versus those without. Univariate and multivariable regression analyses were used to investigate independent predictors of HC. Forty-nine of 466 patients (10.5%) had HC due to HAVB after TAVI. Patients with HC had a longer hospital stay [10 (8-13) vs. 13 (9-18) days; p < 0.001], more frequent peripheral artery disease (PAD) (28.6% vs. 15.1%; p = 0.016), and lower hemoglobin levels [11.8 (±) vs. 12.5 (±) g/dl; p = 0.006]. In the HC group, HAVB onset post-TAVI was delayed compared with the non-HC group [2 (1-4) vs. 1 (0-3) days; p < 0.001]. Before HAVB onset, patients in the HC group more frequently developed post-TAVI delirium [18 (4.6%) vs. 11 (25.0%); p < 0.001]. In univariate regression analysis, PAD, hemoglobin, procedural time, contrast agent volume, and post-TAVI delirium were significant predictors of HC. After adjustment, only post-TAVI delirium and contrast agent volume remained independent predictors [OR 3.22 (95% CI: 1.05-9.89); p = 0.042 and OR: 1.01 (95% CI: 1.0-1.01); p = 0.04, respectively]. HC due to HAVB after TAVI occurred in over 10% of cases. Development of post-TAVI delirium and contrast agent volume are independent predictors of this severe complication.

Incidence and predictors of new-onset sustained ventricular tachycardia in patients with cardiac sarcoidosis and high-grade AV block as first cardiac symptom

Abstract Funding Acknowledgements Type of funding sources: None. Background Cardiac sarcoidosis (CS) is infrequently affecting the heart and may cause heart failure and dangerous arrhythmias. If left untreated, it usually progresses to end-stage heart failure or can cause sudden cardiac death. A frequent initial presentation is AV block, but malignant ventricular arrhythmias can occur in the course of the disease, as well. Ventricular tachycardia or fibrillation (VT/VF) can occur even in patients with normal or nearly normal ejection fraction. Therefore, the current guidelines recommend implantation of ICD devices whenever a pacemaker implantation is needed, such as in case of AV block, although there are little data supporting this opinion. Purpose The purpose of this study was to establish the risk for occurrence of VT/VF in patients with CS, initially presenting with AV block. Furthermore, we sought to establish possible predictors for occurrence of VT/VF. Methods We analyzed 128 patients diagnosed with CS according to the latest JCS criteria. Patients with AV block as initial cardiac presentation were selected and were followed for occurrence of VT/VF or death. We analyzed the differences between the baseline characteristics and the cardiac imaging between those with and without VT/VF. Results Out of 128 patients with CS, 30 (23%) patients (13 female, age 50 ± 10 y; EF 48 ± 12%) with high-grade AV Block as initial cardiac symptom were identified. In 7 of them, a permanent pacemaker had already been implanted. In 15 (50%) patients the diagnosis was confirmed histologically. Cardiac MRI showed presence of LGE in 10 patients with mean LGE volume of 14±8%, and RV involvement in 5 cases. 18FDG-PET showed abnormal tracer enhancement in 12 (40%) patients with SUVmax 9 ± 5. A new sustained VT/VF occurred during the follow up in 10 (30%) patients; and non-sustained VT in other 4. Death occurred suddenly in 2 patients, both without an ICD device. In the univariate analysis, the following baseline characteristics were not associated with occurrence of VT: age, LVEF, amount of LGE, SUVmax, ACE and sIL2-R. Patients with new VT/VF during FU had more frequently RV involvement ( 50% vs. 0 %); LGE in CMR (100% vs 50%) and positive PET ( 100% vs. 57%). Conclusions Patients with cardiac sarcoidosis and AV block as initial presentation have a very high risk of developing sustained VT/VF. Death occurred only in patients without an ICD. ICD implantation, instead of pacemaker, should be considered in all patients with AV block, especially in presence of LGE in CMR, abnormal 18FDG PET and RV involvement.

Invasive risk stratification and implantable loop recorders in brugada syndrome: a single centre experience

Abstract Funding Acknowledgements Type of funding sources: None. Introduction Risk stratification in Brugada syndrome (BrS) is challenging. Cardiogenic syncope, family history of sudden cardiac death and ECG markers are useful variables in determining patient risk. Invasive risk stratification is sometimes needed in those with an intermediate risk phenotype. Implantable loop recorders (ILR) may be considered in those patients with no inducible ventricular arrythmias during programmed ventricular stimulation (PVS). Objective The aim of this study was to retrospectively evaluate the outcome of BrS patients referred for PVS and ILR implantation. Methodology Demographic, clinical and follow-up data of BrS patients seen in clinic were retrospectively analysed from hospital databases. A p vale of &amp;lt;0.05 was considered significant. Results 129 patients have been diagnosed with BrS since launching the inherited arrhythmia clinic service (53.5% males). 15 (high risk patients) had an ICD (n=13, 10.1%) or PM (n=2, 1.6%) implanted because of a hospital cardiac arrest, ventricular arrhythmias, high grade AV Block or cardiogenic syncope. 26 (20.2%) were placed in the intermediate risk category, (65.4% males). Patients were offered an electrophysiology study (EPS/PVS) or an ILR depending on the clinical indication (Figure 1). Most were male (65.4%), with a mean age of 41.8±17.7 years at the time of risk stratification. 6 had a likely or definite pathogenic mutation (n=5 19.2% SCN5A, n=1 3.8% MYBPC3). This group had a median Shanghai score of 4.0±0.9. Gender (p=0.429), age (p=0.246), genotype (p=0.273) and shanghai score (p=0.746) did not differ between strategies. Most (n=12, 9.3%) were offered an EPS/PVS from the offset. Ventricular arrhythmias were induced in 1 (8.3%), an ICD was then implanted. The rest were implanted with an ILR on the day. Patients not offered an EPS (n=14, 10.9%) were initially implanted with an ILR because of insufficient grounds to proceed with an EP study. Patients with an ILR (n=25, 19.4%) were followed up for a median 39 ± 21 months. ILR monitoring identified actionable events in 3 (12.0%) patients. One (4.0%) needed a pacemaker for sick sinus syndrome. Two (8.0%) recorded non-sustained ventricular arrhythmias. Both were subjected to an EPS/PVS, one needed an ICD. None of the patients who had an EPS initially had any significant events during follow up. Conclusion ILR implantation has a role in risk stratifying intermediate risk patients who do not fulfil criteria for EPS referral. This may also be considered in intermediate risk patients who are not keen on an invasive risk assessment with EPS.

Safety of epinephrine-containing local anaesthesia in CIED implantations

Abstract Funding Acknowledgements Type of funding sources: None. Background Cardiac implantable electronic devices (CIED) are common. Permanent pacemaker implantations can improve quality of life of patients with sick-sinus syndrome and prolong survival in those with infranodal high-grade AV block. Nonetheless, pocket haemathoma can be problematic post CIED implantation, especially with the increasing use of oral anticoagulants and antiplatelet agents (especially P2Y12 inhibitors) in the at-risk population. The use of epinephrine in local anaesthetic is common in UK but remains controvesial with 2021 EHRA consensus statement recommending its avoidance(1). Aim To compare the rate of pocket haemathoma and subsequent haemathoma drainage and pocket revisions in CIED patients who have received epinephrine-containing local anaesthetia versus local anesthesia without epinephrine. Methods Retrospective, observational studies across a disctrict general hospital and tertiary cardiology hospital, involving a total of 377 consecutive CIED patients over the course of 2021 - 2022. Patients' demographics, comorbidities, peri-procedural medication use and complication events were retrived from electronic data base. Types of local anaesthesia were recorded. Results and Outcomes Out of 377 patients, 184 patients received 1% epinephrine-containing local anaesthesia (Group 1) and 193 patients received plain local anesthesia only (Group 2). In terms of baseline demographics (age and gender distribution), associated comorbidities (treated hypertension, diabetes type 2, ischaemic heart disease, hypercholesterolemia, smoker) were not statistically different between both groups. Number of leads implanted (DDD vs VVI vs ILR) were not statistically different (26.6% DDD pacemaker and 65.8% VVI pacemaker in Group 1 versus 34.8% DDD and 57.0% VVI in Group 2, p=0.143). Periprocedural usage of oral anticoagulations (38.6% vs 30.5%,p=0.102) and single or dual antiplatelet agents (31.5% vs 29.0%, p=0.796) were not different between both groups. Overall complication rates were low and not statistically different between both groups: 4.35% in Group 1 versus 6.74% in Group2. Only 1 patient received epinephine-containing local anesthesia experienced pocket haemathoma against 6 patients who received plain local anaesthsia (0.543% vs 3.11%,p=0.122). No patients require evacuation of haemathoma, drainage or subsequent pocket revision (p= 1.0). Summary: The results of this retrospective observational study demonstrated that 1% epinephrine-containing local anesthesia for CIED implantation is not associated with increased risk of pocket haemathoma, no increased risk of haemathoma evacuation, drainage or pocket revision. This is despite peri-procedural anticoagulation or antiplatelet use exceeding 70%. This "real-life" result is incongruent with the published MAITRE study which formed the basis for the 2021 EHRA expert consensus statement. Recommendation surrounding epinephrine-containing local anaesthesia in CIED implantation may need to be reviewed.

Intermittent High Grade AV-Block and Atrial Flutter Associated with Lyme Carditis:

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PO-03-111 PACEMAKER DEPENDENCY AND IMPACT ON MORTALITY FOLLOWING TRANSCATHETER AORTIC VALVE REPLACEMENT

Conduction abnormalities requiring permanent pacemaker (PPM) are a frequent complication following TAVR. Few studies have evaluated chronic pacemaker dependency after TAVR. To evaluate post-TAVR pacemaker dependency and impact on mortality at one year. 626 patients with severe aortic stenosis who underwent TAVR between 01/01/2012 and 12/31/2019 were identified. Those with pre-TAVR pacemaker were excluded. Patients underwent post TAVR PPM if found to have high grade AV block,> 5seconds pause or symptomatic bradycardia < 50 bpm. Patients who underwent TAVR without PPM implant represented the control arm. PPM dependency was defined as > 50% pacing during 1 and 30 days post implantation. All-cause mortality was reported at one year. Of 357 patients, 16% required PPM with no difference in either balloon expandable or self-expandable valve types (14.6% vs 17.6%; P=0.471). The mean age was 80 + 8.2 years, and 52.7% were male. The median time to PPM implantation was 2 days. The main indications were complete AV block (67%) and symptomatic bradycardia (8.8%). 56.1% received a dual chamber, 24.6% a single chamber and 8.8% received a biventricular PPM. At day 1 and 30 days following implant 73.7% and 78.9% of patient fulfilled criteria for PPM dependency. There were no difference in mortality between the cohorts at one year (Fig. 1). 78% of patients requiring PPM post TAVR were pace dependent at 30 days. PPM implantation did not have an impact on mortality at 1 year. Indications for acute pacing predicted PPM dependency at 30 days and support the selection criteria used for PPM implantation in this cohort.

PO-05-022 OUTCOMES FOR POST-TRANSCATHETER AORTIC VALVE REPLACEMENT CONDUCTION ABNORMALITIES WITHOUT CLEAR INDICATION FOR PERMANENT PACING

Patients undergoing transcatheter aortic valve replacement (TAVR) often develop conduction abnormalities in the postprocedural period. While high-grade AV block (HAVB), which includes 3rd degree & 2nd degree type 2 Mobitz AV block, is a clear indication for permanent pacemaker (PPM) implantation, other conduction abnormalities do not have a clear indication for PPM. Outcomes and predictors for subsequent PPM in this population is lacking. To investigate outcomes of non-HAVB conduction abnormalities in the immediate post-TAVR setting. We conducted a single-center retrospective study on patient characteristics and outcomes of patients without PPM who underwent TAVR between June 2020 and March 2022 that developed non-HAVB conduction abnormalities without a clear indication for pacing (Table 1A). All these patients received thirty-day ambulatory event monitoring (AEM) at discharge. A total of a hundred and sixty patients underwent TAVR; thirteen patients outright received a new PPM for HAVB while thirty-six patients developed non-HAVB and were discharged with AEM. Mean age was 79.8 ± 6.1 years, mean ejection fraction (EF) was 62.1 ± 9.1%, mean maximum aortic valve velocity was 3.9 ± 0.5 m/sec, average mean gradient across the valve was 36.8 ± 10.0 mmHg, and mean aortic valve area was 0.76 ± 0.18 cm2 for these patients. Among the patients who developed non-HAVB conduction abnormalities after TAVR, four subsequently required PPM implantation. Pre-existing right bundle branch block (RBBB) was more frequent in the group requiring eventual PPM vs. the group not requiring PPM (Table 1B). There were no statistically significant differences between several electrocardiogram metrics, demographics, and valve measurements, outlined in Table 1B. Details of those who received subsequent PPM can be found in Table 1C. Of patients who developed persistent non-HAVB conduction abnormalities in the immediate post-TAVR setting the incidence of pre-existing RBBB was higher in patients who required eventual permanent pacing versus those who did not require eventual permanent pacing.

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-05-236 ATRIAL NON-CAPTURE AT GANGLION PLEXI SITE DURING CARDIONEUROABLATION

Cardioneuroablation (CNA), identification and radiofrequency ablation of ganglionated plexi (GP), has emerged as a viable treatment modality for hypervagal mediated disorders such as cardioinhibitory syncope. CNA is under active investigation and much remains to be learned. We present the observation of atrial non-capture at a GP site with vagal stimulation during a CNA procedure N/A The patient is a 12-year-old female with a history of focal seizures admitted for worsening seizure burden despite escalation of her medical therapies. During hospitalization, bedside monitoring recorded multiple episodes of heart block (ventricular rates in the 20's) and two episodes of ictal high-grade AV block, resulting in 7-10 seconds of asystole. To expand therapy options, including the potential for a vagal nerve stimulator, she was recommended for CNA. The patient was placed under general anesthesia and access obtained via the right femoral vein. Baseline electrophysiology findings were as follows: RR 649 ms, PR 135 ms, AH 58 ms, HV 58 ms, and QT 353 ms. The IVC, SVC, right atrial and left atrial geometry shell was drawn using the EnSite NavX precision cardiac mapping system. The mapping catheter was then advanced into the internal jugular vein to the level of the carotid bifurcation and the vagus nerve stimulated at 50 Hz, easily inducing AV block resulting in more than 8 seconds of asystole. Utilizing complex, fractionated atrial bipolar electrograms (CFAE), the GP sites were identified. While pacing at the left inferior GP site, vagal stimulation resulted in expected transient asystole. Interestingly, there was corresponding, transient atrial noncapture during vagal stimulation (Figure 1). Thereafter, the aortic-SVC and left inferior GP sites were successfully ablated. Post ablation, vagal stimulation resulted in only mild sinus slowing and the longest induceable pause was one second. The patient tolerated the procedure well with no complications. The entire procedure was performed without fluoroscopy. Cardioneuroablation is an emerging treatment modality for hypervagal cardioinhibitory syndromes. Identification of GP sites is critical for success. We speculate that vagal stimulation raises the capture threshold of atrial tissue at GP sites. This may be useful in fine tuning ablation sites during CNA. It is curious if this phenomenon is specific to GP sites. Beyond CNA, this finding may have implications for lead placement during pacemaker implantation.

Cardiac Involvement In Neurosarcoidosis: A Single Center Investigation (P9-5.004)

<h3>Objective:</h3> Describe the frequency of coexistent cardiac disease in a cohort of Neurosarcoidosis (NS) patients. <h3>Background:</h3> Sarcoidosis is a multisystem granulomatous inflammatory disease. We report the incidence of cardiac sarcoidosis in our NS cohort and examined the frequency of other cardiac diseases in the cohort. <h3>Design/Methods:</h3> Of 64 probable/definite NS patients in the University of Utah cohort, 52 patients had at least one electrocardiogram (ECG) and were included in analysis. <h3>Results:</h3> Of 52 NS patients with ECG, 65% were female with average age 60.9 (38–84). 58% had a BMI&gt;30. Symptoms suggestive of cardiac dysfunction included: leg swelling (50%), palpitations (46%), chest pain (44%) and dyspnea (44%). Ten patients (19%) had at least one myocardial infarction confirmed by cardiology. ECG abnormalities included non-specific T wave change (40%), right bundle branch block (RBBB) (19%), AV block (16%), and QT prolongation (12%). 10 patients had sinus tachycardia, 5 had sinus bradycardia, and 1 each had ventricular tachycardia (VT) and non-sustained VT. Six patients required implantable cardioverter-defibrillator placement and one required a pacemaker. Cardiac MRI on 17 patients (33%) revealed 3 (17%) with diffuse myocardial enhancement possibly suggesting cardiac sarcoidosis (CS). All had leg swelling, plus one each with orthopnea, syncope, or dyspnea. Myocardial PET scan was performed on 9 NS patients, confirming 3 known CS, and revealing one newly diagnosed CS, who had leg swelling and dyspnea. 2 additional patients had ICD placement after detection of high-grade AV block and persistent atrial fibrillation, respectively, but no evidence of CS on cardiac MRI. Of 6 confirmed CS patients, 3 patients manifested initially as NS. <h3>Conclusions:</h3> Of 52 NS patients, 12% had cardiologist-confirmed CS. Non-sarcoid cardiac illness was also common, emphasizing the need for comprehensive cardiac evaluation in NS. Research is needed to determine if sarcoid-related morbidity may contribute to increased all-cause cardiac disease. <b>Disclosure:</b> Dr. Noroozi Gilandehi has nothing to disclose. Mr. Wong has nothing to disclose. Dr. Wright has nothing to disclose. Dr. Lord has nothing to disclose. Mr. Stehlik has nothing to disclose. Dr. Kemeyou has nothing to disclose. Dr. Clardy has received personal compensation for serving as an employee of Veterans Health Administration (VHA). Dr. Clardy has received personal compensation for serving as an employee of University of Utah Health. Dr. Clardy has received personal compensation in the range of $10,000-$49,999 for serving as an Editor, Associate Editor, or Editorial Advisory Board Member for Neurology/AAN Publications. The institution of Dr. Clardy has received research support from Sumaira Foundation for NMO. The institution of Dr. Clardy has received research support from Western Institute for Veteran Research. The institution of Dr. Clardy has received research support from NIH/NINDS. Dr. Clardy has received personal compensation in the range of $500-$4,999 for serving as a AAN Summer Meeting CoDirector Travel and Lodging with AAN. Dr. Clardy has received personal compensation in the range of $500-$4,999 for serving as a Grand Rounds Travel and Lodging with U of Iowa. Dr. Clardy has received personal compensation in the range of $500-$4,999 for serving as a Speaker Honoraria for Grand Rounds with Barrow Neurological Institute. Dr. Clardy has received personal compensation in the range of $500-$4,999 for serving as a Speaker Honoraria for Grand Rounds with Beaumont Health.

Predictors of cardiovascular implantable electronic device dependence at long-term follow-up after alcohol septal ablation in hypertrophic cardiomyopathy patients.

The most common complication of alcohol septal ablation (ASA) is transient periprocedural high-grade AV block (HGAVB). To date, no long-term follow-up of cardiovascular implantable electronic device (CIED) utilization after ASA has been reported. We hypothesized that CIED dependence on long-term follow-up can be predicted by ECG or procedural characteristics. We analyzed all patients with HCM who underwent ASA from December 1998 to December 2019 and received their first CIED within 30days after ASA for HGAVB. All follow-up interrogations were reviewed. CIED dependence was defined as ventricular pacing of ≥ 5%. A total of 138 patients with HCM underwent ASA. Of these, 35 had a prior device and were excluded. Of the remaining 103 patients, 25 patients received a CIED for HGAVB within 30days after ASA. Average follow-up duration was 10.1years. On long-term follow-up, 16 patients (64%) were found to be CIED-dependent. Baseline characteristics, including pre- and post-ASA ECG, were not significantly different between dependent and non-dependent patients. The only predictor for CIED dependence was > 1ml of alcohol injected (OR 6.0, p = 0.031). CIED implantation after ASA is common. Almost two thirds of patients who received a CIED for post-procedural HGAVB were CIED-dependent on long-term follow-up. CIED dependence can be predicted by the amount of injected alcohol > 1ml.