ICD Placement Research Articles

Abstract 4119554: Septal Thickness has a Variable Effect on Shock Incidence Rate by ICD Indication in Hypertrophic Cardiomyopathy.

Introduction: Hypertrophic cardiomyopathy (HCM) is the most common cardiomyopathy. People with HCM are at risk of cardiac arrest. ACC/AHA guideline-supported indications for ICD placement include cardiac arrest or VT, family history of sudden cardiac death in a close relative ≤50, massive septal hypertrophy (MSH - septal thickness ≥30mm), apical pouch, and non-sustained ventricular tachycardia (NSVT). Methods: People attending any Mayo Clinic site on > 1 occasion who underwent ICD placement for HCM who had documented cardiac magnetic resonance (CMR) results were included in the study from time of ICD placement to last device interrogation. Outcome was incidence rate of first appropriate shock. Multivariable cox regression was used to examine the association between septal thickness and shock rate, controlling for current age, sex and secondary vs primary prevention device. An interaction term for association between septal thickness and each ICD indication in turn was incorporated into regression, and stratum specific estimates produced using linear computation. Results: 326 people were included in the study, of whom 50 experienced at least one appropriate ICD shock over 1,487.95 person years (incidence rate 3.36 per 100 person years, NNT 29.76 per year). MSH was strongly associated with shock rate (HR 2.29 [1.19 to 4.40], p=0.013). In people without MSH, there was a 50% reduction in shocks where a subjective measure (syncope or family history of sudden cardiac death) was present (table 1). In this cohort, NSVT resulted in a threefold increase in incidence of shock (HR 3.15 [1.446 to 6.47], p=0.003). In the presence of MSH, there was a four-fold increase in shock rate in people who underwent ICD insertion for family history of sudden cardiac death or for syncope (table 2). There was no difference in shock rates in people with NSVT prior to ICD placement based on septal thickness (HR 0.76 [0.21 to 2.74], p=0.679). There was strong evidence of interaction between NSVT and MSH on shock rates (LR χ2 =6.94, p=0.008), such that presence of both risk factors did not increase shock rate. Concurrent presence of late gadolinium enhancement (LGE) >15% on CMR and MSH was associated with a significant increase in shock rate (3.58 [1.43 to 8.98], p=0.006). Conclusion: MSH is a helpful indicator of who will benefit from ICD placement among people with a pre-existing indication for a device, particularly among those with a more subjective indication for a device.

Abstract 4138424: Ring of Power: Unraveling a Rare Diagnosis in a Young Male with Palpitations

Case Description: A 36-year-old male presented for an outpatient treadmill ECG stress test for further evaluation of palpitations exacerbated by exercise. He had no ischemic ECG changes, but developed a sustained episode of polymorphic VT at 13 minutes (Figure 1a). The test was stopped and the VT self-terminated after 43 seconds. The patient was admitted for further workup. Lab workup was unremarkable; baseline ECG demonstrated no ST-T wave changes and displayed normal QT and QRS duration. TTE showed mild biventricular dysfunction. Coronary CT angiogram showed type 3 subtype of Vieussens’ arterial ring (VAR), with an absent left main and super-dominant RCA supplying both LAD and LCx. FFR-CT showed non-hemodynamically significant stenosis in the mid-distal LAD (Figure 1b). Left heart catheterization confirmed presence of VAR and mild diffuse disease in a small-caliber mid-distal LAD (Figures 1c&d). No malignant course or dynamic coronary compression was present. Cardiac MRI revealed normal biventricular function and the absence of late gadolinium enhancement. An exercise stress test, now with myocardial perfusion, was performed and was entirely normal without evidence of myocardial ischemia. Genetic testing for catecholaminergic polymorphic VT was negative. After a multidisciplinary discussion, it was decided not to pursue CABG in the absence of demonstrable ischemia at peak exercise. He underwent an ICD placement for secondary prevention and was discharged on beta blockers. Discussion: Three distinct subtypes of VAR have been described, with type 3 being the rarest. The coronary anomaly was first described by Raymond de Vieussens in 1706, and represents an embryologic remnant of the conotruncal circle. It may be diagnosed incidentally in asymptomatic patients or present with angina especially if underlying CAD, aneurysms or fistulae are present. We report the first case of exercise-induced polymorphic VT in a type 3 VAR patient, theorizing that intermittent myocardial ischemia at peak exercise may induce VT in these patients. Surgical revascularization may be considered if myocardial ischemia is demonstrated on stress testing, although its benefit in patients without such evidence of ischemia is unknown.

Utility of routine follow-up defibrillation safety margin testing in young patients with epicardial implantable cardioverter-defibrillators.

Routine defibrillation threshold testing (DFT) of transvenous implantable defibrillators (ICDs) has largely been in decline. In patients with non-transvenous ICDs that utilize subcutaneous and pleural ICD leads, serial DFT testing can detect a significant number of failures. Data about the utility of follow-up defibrillation safety margin testing (DSM) testing in pediatric patients and young adults with an epicardial ICD are lacking. Patients aged<25 years old who underwent epicardial ICD placement at Mayo Clinic from 2014 to 2023 with at least one follow-up DSM test were included. The patients were divided into a "routine" (R) and "clinically indicated" (CI) group based on the index of clinical concern. Inadequate DSM was defined as unsuccessful defibrillation at an output of less than 10 J below the maximum output of the device. The purpose of this study was to assess the utility of follow-up DSM testing. An epicardial ICD system was placed in 122 patients. A total of 26 patients met inclusion criteria and underwent a total of 47 DSM follow up tests. Inadequate DSM occurred in 1/33 (3%) in the R group and 2/14 (14%) DSM tests in the CI group. The median follow-up period was 54 and 36 months for the R and CI group, respectively. Our data suggest that epicardial ICDs are reliable and routine follow-up DSM testing may not be necessary for all patients. DSM testing should be performed in individuals with epicardial ICD systems when there is clinical concern about lead or coil performance.

Novel scoring system for predicting mortality in patients with ventricular arrhythmias: Analysis from a 24,000 patient cohort

Abstract Background Several scoring systems have been developed to predict mortality in ventricular tachycardias (VT) in selected populations (for example, patients undergoing ablation) with limited follow-up times. We aimed to develop a simple scoring system to predict all-cause mortality in a large cohort of VT patients followed up for &amp;gt;10 years. Methods We mined electronic data from 2008 to 2022 from a large suburban academic and community healthcare system, for the endpoint of all-cause mortality in adults diagnosed with ventricular tachycardia using the ICD 10 code of I47.2. We related the endpoint to covariates including sex, race, socioeconomic factors and comorbidities identified with standard ICD codes (prior to the diagnosis of VT) using cox-proportional hazards model. We then tested a scoring system using coefficients developed in the training cohort (70%) in an independent test cohort. Results We identified 24278 adult patients diagnosed with VT. Of these, 2921 (12%) died within 249 (23,1095) days of diagnosis. Figure 1 shows factors associated with mortality, adjusted for race, gender and ethnicity, which were: congestive heart failure [HR:1.78; (1.62,1.96)] chronic kidney disease [HR:1.75; (1.60,1.91)] ,atrial fibrillation[HR:1.53; (1.40,1.67)], diabetes [HR:1.47; (1.35,1.61)] , coronary artery disease [HR:1.57; (1.43, 1.72)] , peripheral arterial disease [HR:1.29; (1.17,1.42)] , hypertension [HR:1.39; (1.26,1.54) , COPD [HR:1.21,1.50)] , and hyperlipidemia [HR:-.87; (0.80 -0.95)] . The novel 9-point (CKAD(ICV)SHL) score predicts mortality with a C-index of 0.66. Conclusions In a population of over 20 thousand patients with ventricular arrhythmias, a scoring system based on heart failure, CKD, AF and other factors predicts mortality. This may form a basis for revised efforts for screening, risk stratification and trial design for ICD placement and guideline directed medical management.

Abstract 15984: Toxic Twist: A Case of Bupropion Induced Brugada Syndrome

Introduction: Brugada syndrome is an inherited sodium channel pathology typically diagnosed by ECG findings. The condition can also be triggered by electrolye imbalances, fever and medications. It can result in ventricular tachycardia or fibrillation which can lead to sudden cardiac death. Therefore, it is vital to recognize the Brugada pattern on ECG and identify the potential triggers. Case Presentation: 36-year-old woman with past medical history of depression and prior suicidal attempt presented to emergency department with altered mental status secondary to intentional overdose of bupropion. Vitals were HR 118 beats per minute, BP 160/95 mmHg, RR 14 and SpO2 100% on room air. Physical examination was significant for tachycardia and lethargy. Laboratory values were significant for K + :3.3 mEq/L , HCO3 - :20 mEq/L , anion gap: 15, lactic acid: 5.5 mmol/L, ABG pH: 7.3. ECG on admission showed sinus tachycardia with rate of 121 and prolonged QTc 488 ms. Patient was monitored with serial ECGs given concern for Qtc prolongation. Later in the hospital course, ECG showed coved ST segment elevation in V1-V2 followed by a negative T wave. Echocardiogram was without structural abnormalities with EF of 55-60%. ICD placement was not indicated given this condition was drug induced with type 1 Brugada pattern and there was no family or personal history of syncope, arrhythmia or sudden cardiac death. Patient’s medication regimen was optimized with discontinuation of bupropion which was contraindicated in Brugada syndrome and avoidance of medications with sodium channel blocking effects was emphasized. Discussion: Brugada syndrome is a rare but potentially fatal condition. It becomes more challenging diagnosis in the absence of personal or familial cardiac history. It is very important to consider medications as a possible trigger for the condition given the management differs from inherited type and it does not generally require ICD placement.

Abstract 17362: Left Atrial Stiffness is Increased in Pediatric Hypertrophic Cardiomyopathy and May Be of Incremental Value in Predicting Major Adverse Cardiac Events in This Group

Background: Determining risk factors by echocardiography to prevent major adverse cardiac events (MACE) is crucial in pediatric patients with hypertrophic cardiomyopathy (HCM). Recent studies have shown that LA stiffness and strain may serve as surrogate markers in children, to differentiate elevated pulmonary capillary wedge pressure from normal and predict COVID-19 related myocardial injury. Hypothesis: LA stiffness may predict MACE in pediatric patients with HCM. Methods: We retrospectively enrolled 201 pediatric patients with HCM diagnosed by echocardiography. They were divided into two groups: MACE (n=61) and non-MACE (n=140) groups. LV systolic function, and LA strain were evaluated by conventional 2D and speckle tracking echocardiography. Noninvasive LA stiffness was calculated as the ratio of E/e’ to LA strain as depicted in the following equation: LA Stiffness= E/e ' ratio / LA Peak Strain (% -1 ). The primary outcome was a composite endpoint of MACE (including ICD placement, myomectomy, heart transplant or death) during follow-up. Results: The MACE group showed significantly decreased LV global longitudinal strain (GLS) compared to non-MACE group (GLS - 16.76 ± 5.05% vs. - 20.25 ± 3.40%, p &lt; 0.001), even though LV ejection fraction showed no significant difference between the two groups. LA peak strain was significantly reduced (21.96 ± 7.24% vs. 30.80 ± 7.10%, p &lt; 0.001), whereas, noninvasive LA stiffness was significantly increased (0.72 ± 0.48 % -1 vs. 0.34 ± 0.16 % -1 , p &lt; 0.001) in the MACE group. Among the LV diastolic indices, LA stiffness was the superior-most index for predicting MACE (see Table 1, Figure 1) (AUC: 0.814, cut off value: 0.49% -1 ). Also, LA stiffness was independently associated with increased risk of the composite endpoint of MACE (HR: 3.26 [95% CI: 1.77 -5.99]; P &lt; 0.001, see Table 2). Conclusion: LA stiffness is a newly described index in children, that may be of incremental value in predicting risk of MACE in pediatric HCM patients.

Sex and Gender Differences in Ventricular Arrhythmias

Ventricular arrhythmias, including ventricular tachycardia and VF, commonly occur in patients with underlying cardiomyopathy. Sex differences exist in almost every aspect of ventricular arrhythmia from epidemiology, anatomy, and physiology to management and response to therapy. Some of these may be attributed to variations in etiology, types, and rates of cardiomyopathy as well as biological differences between males and females, but the full explanation for these differences remains incomplete. Additionally, women have been underrepresented in many trials studying therapies for ventricular arrhythmias including ICD placement and ablation; thus, there remains a need for continued research in this population. This review will discuss the differences between the sexes as well as outline opportunities for future research in women with ventricular arrhythmias.

Anesthetic Choice for Cardiovascular Implantable Electronic Device Placement and Lead Removal: A National Anesthesia Clinical Outcomes Registry Analysis

The authors evaluated the anesthetic approach for cardiovascular implantable electronic device (CIED) placement and transvenous lead removal, hypothesizing that monitored anesthesia care is used more frequently than general anesthesia. A retrospective study. National Anesthesia Clinical Outcomes Registry data. Adult patients who underwent CIED (permanent cardiac pacemaker or implantable cardioverter-defibrillator [ICD]) placement or transvenous lead removal between 2010 and 2021. None. Covariates were selected a priori within multivariate models to assess predictors of anesthetic type. A total of 87,530 patients underwent pacemaker placement, 76,140 had ICD placement, 2,568 had pacemaker transvenous lead removal, and 4,861 had ICD transvenous lead extraction; 51.2%, 45.64%, 16.82%, and 45.64% received monitored anesthesia care, respectively. A 2%, 1% (both p < 0.0001), and 2% (p=0.0003) increase in monitored anesthesia care occurred for each 1-year increase in age for pacemaker placement, ICD placement, and pacemaker transvenous lead removal, respectively. American Society of Anesthesiologists (ASA) physical status ≤III for pacemaker placement, ASA ≥IV for ICD placement, and ASA ≤III for pacemaker transvenous lead removal were 7% (p=0.0013), 5% (p=0.0144), and 27% (p = 0.0247) more likely to receive monitored anesthesia care, respectively. Patients treated in the Northeast were more likely to receive monitored anesthesia care than in the West for all groups analyzed (p < 0.0024). Male patients were 24% less likely to receive monitored anesthesia care for pacemaker transvenous lead removal (p=0.0378). For every additional 10 pacemaker or ICD lead removals performed in a year, a 2% decrease in monitored anesthesia care was evident (p=0.0271, p < 0.0001, respectively). General anesthesia still has a strong presence in the anesthetic management of both CIED placement and transvenous lead removal. Anesthetic choice, however, varies with patient demographics, hospital characteristics, and geographic region.

High-risk phenotypes of arrhythmic mitral valve prolapse: a systematic review and meta-analysis

Background Mitral valve prolapse (MVP) is associated with aggravated risk of ventricular tachycardia (VT), ventricular fibrillation (VF) and sudden cardiac death (SCD). There is a lack of specific guideline recommendation regarding risk stratification and management, despite multiple proposed high-risk phenotypes. We performed systematic review and meta-analysis to evaluate high-risk phenotypes for malignant arrhythmias in patients with MVP. Methods We comprehensively searched the databases of MEDLINE, SCOPUS, and EMBASE from inception to April 2023. Included studies were cohort and case-control comparing between MVP patients with and without VT, VF, cardiac arrest, ICD placement, or SCD. Data from each study were combined using the random-effects. Pooled odds ratios (OR) and 95% confidence intervals (CI) were calculated. Results Nine studies from 1985 to 2023 were included involving 2,279 patients with MVP. We found that T-wave inversion (OR 2.52; 95% CI: 1.90–3.33; p < 0.001), bileaflet involvement (OR 2.28; 95% CI: 1.69–3.09; p < 0.001), late gadolinium enhancement (OR 17.05; 95% CI: 3.41–85.22; p < 0.001), mitral annular disjunction (OR 3.71; 95% CI: 1.63–8.41; p < 0.002), and history of syncope (OR 6.96; 95% CI: 1.05–46.01; p = 0.044), but not female (OR 0.96; 95% CI: 0.46–2.01; p = 0.911), redundant leaflets (OR 4.30; 95% CI: 0.81–22.84; p = 0.087), or moderate-to-severe mitral regurgitation (OR 1.24; 95% CI: 0.65–2.37; p = 0.505), were associated with those events. Conclusion Bileaflet prolapse, T-wave inversion, mitral annular disjunction, late gadolinium enhancement, and history of syncope are high-risk phenotypes among population with MVP. Further research is needed to validate the risk stratification model and justify the role of primary prophylaxis against malignant arrhythmias.

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.

Abstract 15535: A Case of Suspected Menstruation Induced QTc Prolongation Leading to Torsades De Pointes

Estrogen is known to produce changes in cardiac electrophysiology specifically in premenopausal women, increasing the risk of arrhythmias. We report a case of Torsades de Pointes (TdP) in a young premenopausal female. A 25-year-old female with a history of anxiety presented to the emergency room (ED) with several days of vomiting. While in the ED, she had an unwitnessed syncopal event, and was found to be in pulseless ventricular fibrillation (V-Fib) . She required one defibrillation to obtain return of spontaneous circulation (ROSC). Initial work up showed calcium 7.6 mg/dl, phosphorous 1.1 mg/dl, magnesium 2.4 mg/dl, potassium 4.0 mg/dl. Remainder of electrolytes were normal. Toxicology screen was positive for cannabinoids. Post ROSC EKG showed sinus tachycardia at a rate of 103bpm with a prolonged QTc of 531ms. Patient was not on any medications outpatient. On further discussion, patient reported no prior history of syncopal episodes, palpitations, and denied any family history of sudden cardiac death. She did report she was presently on her menses. Shortly after admission, she had recurrent polymorphic ventricular tachycardia which degenerated to TdP. She was loaded with magnesium. Echocardiogram showed an ejection fraction (EF) of 35-39% and global hypokinesis. Diagnostic left heart catheterization was performed revealing clean coronaries. Cardiac MRI revealed EF of 43% without any late gadolinium enhancement. Her QTc remained prolonged even with electrolyte normalization. She underwent successful ICD placement and remained event free during the remainder of the hospital course. She will undergo genetic work up for long QT syndrome. Female sex hormones, specifically estrogen, have been described in literature as pro-arrhythmic given its effects on QT prolongation and ion gated channels. Prior cases of menstruation dependent arrhythmias have speculated that the abrupt reduction in estradiol prior to menstruation is associated with increased cyclic adenosine monophosphate dependent arrhythmogenicity. This case highlights the multifactorial etiology of sudden V-Fib arrest in a young female, and the importance of understanding the role that sex hormones play in the underlying pathogenesis.

Implantable cardioverter-defibrillator placement among patients with left ventricular ejection fraction ≤35 % at least 40 days after acute myocardial infarction

BackgroundImplantable cardioverter-defibrillators (ICDs) reduce the risk of sudden cardiac death among patients with persistently reduced (≤35 %) left ventricular ejection fraction (LVEF) at least 40 days following acute myocardial infarction (AMI). Few prior studies have used LVEF measured after the 40-day waiting period to examine primary prevention ICD placement. MethodsWe sought to determine factors associated with ICD placement among patients who met LVEF criteria post-MI within a large integrated health care system in the U.S by conducting a retrospective cohort study of Veteran patients hospitalized for AMI from 2004 to 2017 who had documented LVEF ≤35 % from echocardiograms performed between 40 and 455 (90 days +1 year) days post-MI. We used multivariable logistic regression to examine factors associated with ICD placement. ResultsOf 12,893 patients with LVEF ≤35 % at least 40 days post-MI, 2176 (16.9 %) received an ICD between 91- and 455-days post-MI. Younger age, fewer comorbidities, revascularization with PCI, and greater use of GDMT were associated with increased odds of receiving an ICD. However, half of patients treated with a beta-blocker, ACE inhibitor or angiotensin receptor blocker, and mineralocorticoid receptor antagonist prior to LVEF assessment did not receive an ICD. Eligible Black patients were less likely (odds ratio 0.80, 95 % confidence interval 0.69–0.92) to receive an ICD than White patients. ConclusionMany factors affect ICD placement among Veteran patients with a confirmed LVEF ≤35 % at least 40 days post-MI. Greater understanding of factors influencing ICD placement would help clinicians ensure guideline-concordant care.

C48 PROGNOSTIC IMPACT OF ECHOCARDIOGRAPHIC RESTRICTIVE FILLING PATTERN IN PATIENTS AFFECTED BY HYPERTROPHIC CARDIOMYOPATHY AND PRESERVED SYSTOLIC EJECTION FRACTION

Abstract Background “Restrictive phenotype” is an uncommon presentation of Hypertrophic Cardiomyopathy (HCM), associated with severe functional limitation and poor prognosis. For this reason, current therapeutic aims are prevention of complications through periodic follow–ups and diagnostic investigations, up to the ICD placement. Objectives The primary aim of this study was to evaluate the impact of the restrictive filling pattern in HCM on the incidence of complex composite outcome included arrhythmic events, events related to heart failure and general events, correlating it to clinical and imaging data. Methods This study is an experimental, multicentric, retrospective and non–randomized analysis, including all patients over the age of 18 suffering from classical HCM, excluding phenocopies and systolic dysfunction. Patients were followed up and selected by specialized Centers of Trieste and Turin and divided by degree of diastolic dysfunction, particularly on the basis of the presence or absence of the restrictive filling pattern. Results A total of 367 patients with HCM were included. Restrictive filling pattern was present in 23 patients (6.3%). This subgroup of patients was younger than all other patients (P &amp;lt; 0.001); percentage of ICD patients suffering from severe diastolic dysfunction at follow–up is significantly higher than patients without restrictive filling pattern (39.1% vs 4.1%, P &amp;lt; 0.001). On average, left atrial volume has larger sizes in restrictive filling pattern (109.7ml, SD 43.06 vs 82.8ml, SD 35.81, P = 0.003). Patients with restrictive filling pattern, compared to other patients, are more subjected to heart transplantation (8.7% vs 0.3%, P = 0.009) and hospitalized for heart failure (21.7% vs 7.8%, P = 0.028). Restrictive pattern was not an independent predictor of adverse events at the multivariable analysis. In our cohort, the independent predictors were found to be the left atrium diameter and the presence of LGE on CMR. Conclusions In patients with HCM and preserved EF, the evidence of a restrictive diastolic pattern identifies a poor prognosis subgroup. Severe diastolic alteration was not associated with a significant independent role either for events related to heart failure, or for arrhythmic events during a median follow up of 7 years. However, the high rate of ICD implantation in patients with severe diastolic dysfunction suggests a high clinical perception of adverse events in this subgroup.

Abstract 44: Impact Of Social Isolation During Covid-19 Pandemic On Individual Subjective Assessment Of Cardiac Disease Symptoms

Background: Impact of social isolation associated with the COVID-19 pandemic on the severity and frequency of cardiac symptoms has not been well investigated. Material and methods: This was a single tertiary center cohort study of inpatients admitted with a primary diagnosis of either CHF or acute myocardial infarction. Each patient rated the extent of isolation related to the pandemic and severity and frequency of symptoms during an in-person interview. Results: The study cohort included 54 patients, 48.1% females (26 of 54), 70.2+/-13.5 years old, who reported moderate or severe isolation in 57% (31 of 54). Symptom severity worsening was reported in 48% (26 of 54) of patients and was more common in socially isolated patients (74 vs. 29%, p=0.001; 17 of 23 vs. 9 of 31). Symptom frequency increase was reported in 43% (24 of 54) and was also more common in socially isolated patients (61 vs. 33%, p=0.036; 14 of 23 vs. 10 of 31). There was no difference in mortality between the two groups (p=0.6971). There was a trend of increased hospitalizations, on average, among patients who reported drastic isolation than patients who maintained social contacts (0.826+/-1.614 vs. 0.484+/-0.996 admissions, p=0.349). These findings were not affected by the diagnosis (CHF vs. MI), age, gender, race, and co-morbidities including HTN, DM, atril fibrillation, COPD or asthma, and/or chronic renal insufficiency. Likewise, there was no association between symptom worsening and GDT utilization including beta-blockers, RAAS inhibitors, MRA, anticoagulants, ICD or PPM placement. Conclusions: Our findings suggest that independent of age, gender, race, LVEF, recorded comorbidities, and recorded active therapeutics, the COVID-19 pandemic resulted in a significant cardiac symptom increase in patients who reported social isolation. Interventions aimed at reducing social isolation require investigation and implementation.

PO-687-02 THE EXTRAVASCULAR IMPLANTABLE CARDIOVERTER - DEFIBRILLATOR: A CASE FOR CONCERN

The investigational Extravascular Implantable Cardioverter Defibrillator (Medtronic EV-ICD) system with its substernal lead placement may offer an alternative to transvenous ICD while reducing the risks associated with transvenous system such as infection requiring extraction, vascular injury, and venous obstruction. The EV-ICD lead is placed just beneath the sternum in the retrosternal space. Patients with prior or planned sternotomy and prior chest radiotherapy are excluded from the EV-ICD trials due to increased surgical risk. We describe a patient with cardiac sarcoidosis in whom we decided not to implant the EV-ICD due to pericardial adhesions noted on preoperative imaging. N/A A 55-year-old man with history of chronic systolic heart failure due to cardiac sarcoidosis and family history of sudden cardiac death was noted to have non sustained ventricular tachycardia on an event monitor. He underwent an electrophysiologic study which showed inducible monomorphic ventricular tachycardia. ICD implantation was recommended. Due to an active lifestyle and no pacing indication, he opted for an EV-ICD. As part of the pre-operative protocol, a chest X ray is obtained but is not used to determine device eligibility. However, in this case it was noted that the right ventricle was closely approximated to the sternum. Due to history of inflammatory cardiomyopathy, a gated cardiac CT was obtained to evaluate the retrosternal space. Cardiac CT showed adhesion of the right ventricular pericardium to the midline sternum. The right ventricle was tethered but not adherent to the sternum. The EV-ICD procedure was cancelled due to increased surgical risk associated with tunneling with an adherent pericardium. He later underwent a transvenous ICD placement. Pericardial adhesions may be associated with inflammatory cardiomyopathies such as cardiac sarcoidosis. Thorough preoperative evaluation of the retrosternal space is recommended in such patients prior to considering substernal lead tunneling.

Orthotopic Heart Transplant in Toddler with Histiocytoid Cardiomyopathy and Left Ventricular Non-Compaction

<h3>Introduction</h3> Histiocytoid cardiomyopathy (HC) is a rare form of cardiomyopathy associated with ventricular arrhythmias and sudden death in infancy. Most cases are diagnosed at autopsy or, occasionally, after heart explant at heart transplantation (HT). We report the case of a toddler with recalcitrant arrhythmias despite multiple medications for whom HC was not suspected. The patient underwent HT, after which biopsy of the explanted heart revealed HC. This case highlights the potential value of a pre-transplant diagnosis of this rare disease, especially in age groups with anticipated long waitlist times. <h3>Case Report</h3> A 16-month old female patient was admitted to the cardiac intensive care unit for Wolf-Parkinson White syndrome (WPW) and recalcitrant ventricular tachycardia (VT) with left ventricular noncompaction (LVNC). She underwent ICD placement, bilateral sympathectomies, and transitioned to oral antiarrhythmic agents with adequate rhythm control. She required readmission for multiple AICD discharges for VT and VF. Despite maximizing antiarrhythmic therapy, she had increasing episodes of VT and was ultimately listed for HT (status 1A by exception). She remained on the waitlist for 37 days prior undergoing HT. Biopsy of her explanted heart showed subendocardial fibrosis, a diffuse nodular thickening of the subendocardium with a proliferation of clear cuboidal/polygonal cells that have granular cytoplasm and bland round nuclei, and stained positive for MYOD1, findings diagnostic for HC in addition to LVNC (Figure 1). <h3>Summary</h3> HC, particularly alongside LVNC, is a rare condition that requires endomyocardial tissue for diagnosis. Pre-HT diagnosis is not described. In this case, pre-transplant listing likely would have prompted earlier listing for HT. Despite the risks associated with catheterization and biopsy in patients with cardiomyopathy and arrhythmia, the pursuit of a pre-HT diagnosis may be warranted to affect patient management and justify status 1A exception requests.

Sudden Cardiac Death Risk over Time in HCM Patients with Implantable Cardioverter-Defibrillator.

Background: In patients with HCM at high risk of SCD, an ICD should be considered as a standard of care. Current risk approximation algorithms recommended by ESC 2014 criteria indicate that SCD risk is not stable. The aim of the study was to investigate how the calculated SCD risk in HCM patients with an ICD implanted in the past changed over time. Methods: We analyzed 64 HCM patients with ICD for primary prevention, referred for ICD re-implantation, and 32 HCM patients referred for a first-time ICD placement during the same period. The 5-year-SCD risk was assessed for suitable patients using the recommended ESC calculator. Results: The first-time group had a higher 5-year-SCD risk than those referred for ICD re-implantation: 7.50 (IQR 5.98–10.46) vs. 4.88 (IQR 3.42–7.25), p < 0.05. Out of the patients with an initial calculated risk below 4%, the risk increased in 22% of cases, reaching the 4–6% range. In 78% of patients, the risk remained stable and low. In 31% of patients with an initial calculated SCD risk ≥ 6%, the risk decreased over time to below 6%, and in 14% of the cases, below 4%. Conclusions: SCD risk in HCM patients is usually stable or gets lower. Our data suggest it is important to re-evaluate the risk profile for patients with HCM when ICD re-implantation is considered.

Permanent Pacemaker Implantation in a Patient with Ventricular Fibrillation due to Spontaneous Coronary Artery Dissection: A Case Report

We present here the case of a 43-year-old female without any known past medical history who was brought into the emergency department (ED) by the emergency medical services (EMS) after receiving cardiopulmonary resuscitation (CPR) on the field. Per EMS, on arrival patient was found to be on ventricular fibrillation and was shocked 3 times. Patient had no past medical history. In the ED, EKG showed sinus rhythm and troponin was 23 which is slightly high compared to upper limit. Patient was taken to the cath lab immediately which showed small to medium caliber septal 1 branch severe mid segment disease with distal tapering suggestive of spontaneous coronary artery dissection. No stent was placed. Electrophysiology was consulted and an Implantable Cardioverter Defibrillator was placed. Spontaneous coronary artery dissection (SCAD) is a phenomenon where an epicardial coronary artery dissection occurs that is not related to atherosclerosis, trauma or iatrogenia. Patients with SCAD presenting with ventricular arrhythmias are not very common. In a Canadian registry analyzing 1056 patients with SCAD, only 84 of them presented with ventricular fibrillation (VF) or ventricular tachycardia (VT) and only 8 underwent ICD placement. They followed up the patients for 5 years and 8 patients suffered VT/VF. 5 of those 8 patients had VT/VF on initial SCAD presentation, and only 1 of them had undergone ICD insertion. There are no specific guidelines regarding ICD placement on patients with coronary artery dissection, but the AHA/ACC/HRS guidelines can help us make decisions. Our case underscores the importance of more prospective or retrospective studies to identify those patients with SCAD who would benefit from ICD placement for secondary prevention. The current guidelines for ventricular arrhythmias are an excellent tool for the electrophysiologist regarding the management of these arrhythmias in other specific scenarios but guidance on SCAD is still lacking.

Utility of electrophysiologic testing for sudden death risk stratification in cardiac sarcoidosis patients with mildly impaired left ventricular function

BackgroundVentricular arrhythmias (VA) account for at least 25% of deaths caused by cardiac sarcoidosis (CS) and may arise in patients with mildly impaired LVEF (>35%). ObjectiveIn the current study, we examine whether EP study may be used for sudden death risk stratification in CS patients who have mildly impaired LVEF and a diagnosis of highly probable or probable CS according to the World Association of Sarcoidosis and Other Granulomatous Diseases Sarcoidosis Organ Assessment Instrument (WASOGI). MethodsAll patients: (1) exhibited a diagnosis of highly probable or probable CS according to the WASOGI, (2) exhibited cardiac MRI findings consistent with CS, (3) exhibited LVEF >45% and (4) underwent EP study. Device interrogations, transmissions and medical records were reviewed for all patients. ResultsWe identified 46 CS patients with mildly impaired LVEF. VA were induced in 11 patients and 10/11 patients underwent ICD placement. Thirty-five patients had no VA and 24/35 patients underwent placement of an ILR. During the follow-up period, the VA event rate was 6.5%. The negative and positive predictive values of the EP study for the development of VA were 100% and 27.2%, respectively. ConclusionsIn CS patients with mildly impaired LVEF and a diagnosis of highly probable or probable CS, a negative EP study was highly predictive of the absence of VA. The successful execution of future prospective studies is contingent upon enrollment of phenotypically homogenous cardiac sarcoidosis patients.

Abstract 13308: Are Current Unplanned or Recent Hospitalizations Due to Non-Heart Failure Reasons Associated With Worse Outcomes After Implantable Cardioverter-Defibrillator Placement in Medicare Beneficiaries With Heart Failure?

Introduction: Elective ICD placement is efficacious for patients with chronic stable HF. ICD placement during or shortly after HF hospitalizations has been associated with worse outcomes. However, the impact of ICD placement in relation to non-HF hospitalizations is unknown. Methods: We identified all ICDs placed among older (age ≥ 66) HF patients without prior cardiac arrest using 20% random sample Medicare data (2008-2018). Setting of ICD was classified as: during unplanned 1) HF hospitalization or 2) non-HF hospitalization, within ≤ 3 months of 3) HF hospitalization or 4) non-HF hospitalization, or 5) electively during planned hospitalization or as outpatient. Non-HF hospitalization was defined as hospitalization without a primary or secondary HF diagnosis. We described patient characteristics and 3-yr mortality across these 5 settings. We estimated adjusted hazard ratios (HRs) using multivariable Cox regression with elective as reference. Results: Among 97,925 ICD patients (mean age 76, 67% male, 85% white), those getting ICDs during unplanned or after recent HF or non-HF hospitalizations were older and had more comorbidities vs elective patients ( Table ). The 3-year mortality after elective ICD placement was 21% but &gt; 35% in non-elective groups. After adjustment, HR was significantly higher in unplanned HF (HR = 1.7), recent HF (HR= 1.6), unplanned non-HF (HR = 1.4), and recent non-HF (HR = 1.5) groups ( Figure). Conclusions: ICD placement during unplanned or after recent hospitalization is associated with worse outcomes, irrespective of hospitalization reasons. Randomized trials to understand appropriate settings of ICD placement are needed to maximize the benefit.