Siontis, Konstantinos C.

Introduction: Artificial intelligence applied to electrocardiograms (ECG-AI) enables early and efficient detection of cardiovascular disease. The technical and clinical impact of different approaches to designing ECG-AI remains under-explored. We consider left ventricular hypertrophy (LVH) and examine the impact of disease-specific labeling of minority etiologies of left ventricular wall thickening- hypertrophic cardiomyopathy (HCM) and cardiac amyloidosis (CA) - on ECG-AI performance. Hypothesis: ECG-AI designed to detect HCM or CA outperforms ECG-AI broadly trained to identify LVH due to differences in attention to key ECG features associated with HCM or CA. Methods: Independent neural networks were trained to identify HCM, CA, and LVH. HCM and CA patients were identified using the full depth of EHR data and validated via clinician adjudication (N = 3,025 and 4,251 patients, respectively). Moderate and severe LVH patients (N = 98,144) were identified using echocardiogram results and international LVH criteria. We compared the ability of disease-specific ECG-AI vs. LVH ECG-AI to detect HCM (or CA) by examining model performance within each of the three test sets. Results: 52.6% of HCM patients and 49.5% of CA patients met LVH criteria. Within the HCM test set, the AUROC, sensitivity, specificity, and positive predictive value (PPV) of the HCM ECG-AI were 0.94, 0.88, 0.85, and 60%, respectively, whereas the same for LVH ECG-AI were 0.83, 0.83, 0.64, and 37%. Within the CA test set, CA ECG-AI achieved AUROC, sensitivity, specificity, and PPV of 0.94, 0.81, 0.91, and 69%, respectively, whereas the same for LVH ECG-AI were 0.75, 0.73, 0.68, and 31%. ECGs positive for HCM exhibited higher P wave area, QRS deflection and R wave amplitude compared to LVH-positive ECGs (Cohen's D > 0.75). ECGs positive for CA exhibited lower R wave amplitude/area, QRS deflection and QRS areas (Cohen's D > 0.6). Conclusion: Models trained using carefully labeled HCM or CA identify distinct signals associated with the diseases, resulting in improved disease discrimination compared to a model trained to identify echocardiographic left ventricular thickening. Labeling choices should be communicated transparently to clinicians to ensure safe and effective use of ECG-AI.

Introduction: Disease-causative variants in LMNA -encoded lamin A/C cause a penetrant dilated cardiomyopathy associated with conduction disease (CD) and ventricular arrhythmias (VA). Prior studies show conflicting results regarding the effect of sex, variant type, and CD on severity and sudden death risk in cardiac laminopathy. Methods: In this retrospective study, we utilized a single-center genetic arrhythmogenic cardiomyopathy registry (N=432) to identify patients with ultra-rare LMNA variants and ascertain the effect of sex, mutation type, and clinical presentation on disease severity. Advanced heart failure (AHF) events were defined as ventricular assist device placement or cardiac transplantation whereas VA events were defined as sudden cardiac arrest, sustained ventricular arrhythmia, or appropriate implantable cardioverter-defibrillator shock. Results: The LMNA variant-positive cohort (N=83) had an age of diagnosis of 36 ± 10 years with 80% showing a cardiac phenotype. No difference in the age at diagnosis (37 vs. 34 years; p=0.3) or prevalence of AHF events (14% vs. 18%; p=0.8) and VA events (34% vs. 36%; p=0.9) was observed between females (N=50) and males (N=33). Furthermore, there was no difference in age of diagnosis (37 vs. 33 years; p=0.1) or prevalence of AHF (14% vs. 12%; p=0.9) and VA events (33% vs. 34%; p=0.9) between individuals with missense (N=42) or frameshift (N=32) variants. Interestingly, in comparison to individuals that presented with isolated CD (N=11) those that first presented with left ventricular dysfunction or arrhythmias (atrial or ventricular) (N=41) were more likely to have VA events (9% vs. 53%; p=0.01) and AHF events (0% vs 29%; p=0.05). In addition, those with structural/arrhythmic presentation had earlier time to VA events (15 years vs. 22 years; p=0.04) and AHF events (23 vs undefined; p=0.09) than those with CD. Conclusions: Contrary to prior studies, in this large single-center cardiac laminopathy study, sex and mutation type were not associated with increased risk of AHF or VA events. However, patients presenting with isolated CD had a lower risk of AHF and VA events. Contemporary multi-center studies are needed to better ascertain risk factors associated with AHF and VA events in cardiac laminopathy.

Background: Catheter ablation is an effective tool to reduce ventricular tachycardia (VT) burden. There is a lack of robust data studying the characteristics and outcomes of VT ablation in patients with ischemic (ICM) versus non-ischemic cardiomyopathy (NICM). Aims: The aim of this study was to assess the impact of ICM vs NICM on outcomes of VT ablation. Methods: A single-center, retrospective study of patients undergoing catheter ablation for VT was conducted. Results: A total of 168 patients, undergoing 200 VT ablation procedures, were included in this study. NICM group (112 procedures) was compared to ICM group (88 procedures). Patients in the ICM group were older (66.6 ± 13.4 vs 58.9 ± 14.4 years) and had higher rates of prior myocardial infarction (65.9% vs 3.6) and coronary artery bypass graft surgery (40.9% vs 1.8%). Overall, ICM group had more comorbidities like hypertension (80.7% vs 52.7%), diabetes mellitus (23.9% vs 12.5%), chronic kidney disease (45.5% vs 35.7%), stroke (17% vs 7.1%), and lower left ventricular ejection fraction (36.8 ± 13.2% vs 43.1 ± 14.7%). The ICM group had lower incidence of prior cardiac valvular surgery (9.1% vs 29.5%). The inducibility of VT (93% vs 93.5%; p= 1.0) and the number of different VT morphologies induced during the case (1.9 ± 1.5 vs 2.3 ± 2.5; p=0.19) was similar between the two groups. There was no acute mortality in either group. There was a non-significant trend towards greater VT recurrence in the NICM group (43.2% vs 33.3%, p= 0.19). However, patients with NICM had a lower VT-free survival as determined by Kaplan-Meier analysis (p=0.05) [Figure]. Long term mortality was higher in ICM group when compared to NICM group (18.2% vs 8.9%, p<0.01). Conclusion: Patients undergoing VT ablation in the NICM group when compared to the ICM group were noted to be younger, had fewer comorbidities, and lower long-term mortality. However, they had significantly less VT-free survival, likely owing to more challenging substrate responsible for VT.

Introduction: Advanced imaging with cardiac magnetic resonance (CMR) or computed tomography (CCT) can be helpful for planning of ventricular tachycardia (VT) ablation procedures by defining the arrhythmogenic substrate. The frequency with which these modalities are utilized in the pre-ablation setting and the associated outcomes remain poorly studied. Objectives: (1) Determine the utilization of advanced cardiac imaging prior to structural VT ablation; (2) establish factors associated with improved VT ablation outcomes Methods: We retrospectively evaluated all VT ablations performed in patients with structural heart disease at a tertiary referral institution during a 2.5 year period (1/2020 - 7/2022). We documented pre-ablation use of cardiac imaging modalities and investigated their association with acute and long-term ablation outcomes. The primary outcome was time to VT recurrence, cardiac transplant, or death. Results: Our dataset included n = 129 subjects. Median post-ablation follow-up was 17 months. Recent echocardiogram, CMR, or CCT (<3 months pre-ablation) had been performed in 113 (88%), 48 (37%), and 31 (24%) patients, respectively. CMR was not associated with procedural success, post-ablation VT recurrence (p = 1), or the composite primary outcome (p = 0.72). Similarly, recent CCT was not associated with procedural success (p = 0.5), VT recurrence (p = 0.3), or the composite primary outcome (p = 0.31). When adjusted for other variables, EF (p = 0.048), recent echo (p = 0.02), and procedural success (p = 0.013) were associated with the primary outcome, but recent CCT (p = 0.11) and CMR (p = 0.4) were not. These results did not differ significantly in patients with ischemic and non-ischemic cardiomyopathy. Conclusions: In this large tertiary care ablation center, CMR and CCT were utilized in only a fraction of patients prior to VT ablations. In multivariate analysis, CMR or CCT were not associated with improved acute or long-term ablation outcomes.

Abstract Aims ECG abnormalities are often the first signs of arrhythmogenic right ventricular cardiomyopathy (ARVC) and we hypothesized that an artificial intelligence (AI)-enhanced ECG could help identify patients with ARVC and serve as a valuable disease-detection tool. Methods and results We created a convolutional neural network to detect ARVC using a 12-lead ECG. All patients with ARVC who met the 2010 task force criteria and had disease-causative genetic variants were included. All case ECGs were randomly assigned in an 8:1:1 ratio into training, validation, and testing groups. The case ECGs were age- and sex-matched with control ECGs at our institution in a 1:100 ratio. Seventy-seven patients (51% male; mean age 47.2 ± 19.9), including 56 patients with PKP2, 7 with DSG2, 6 with DSC2, 6 with DSP, and 2 with JUP were included. The model was trained using 61 case ECGs and 5009 control ECGs; validated with 7 case ECGs and 678 control ECGs and tested in 22 case ECGs and 1256 control ECGs. The sensitivity, specificity, positive and negative predictive values of the model were 77.3, 62.9, 3.32, and 99.4%, respectively. The area under the curve for rhythm ECG and median beat ECG was 0.75 and 0.76, respectively. Conclusion Our study found that the model performed well in excluding ARVC and supports the concept that the AI ECG can serve as a biomarker for ARVC if a larger cohort were available for network training. A multicentre study including patients with ARVC from other centres would be the next step in refining, testing, and validating this algorithm.

Abstract Background Cardiac sarcoidosis (CS) is a difficult to diagnose inflammatory heart disease. Certain types of genetic cardiomyopathy have been reported to masquerade as inflammatory cardiomyopathy. The utility of genetic testing in the evaluation of inflammatory cardiomyopathy is not completely explored and data regarding the prevalence of genetic cardiomyopathies in patients with presumed CS is limited. Methods We retrospectively analyzed patients evaluated from May 2020 to October 2022 in our Cardiac Sarcoid Clinic diagnosed with presumed CS as inferred by either fluorodeoxyglucose positron emission tomography (FDG-PET) - computed tomography (CT) or cardiac magnetic resonance (CMR) or both. Pertinent demographic, genetic, electrocardiographic, and imaging data for these patients was extracted from the electronic medical record. Results Genetic testing was obtained in 47 (22%) of the 213 presumed CS patients, among whom 43 (91%) presented with suspected isolated CS, and 4 (9%) with possible cardiac involvement in the setting of systemic sarcoidosis. Among the patients who underwent genetic testing, 10 (21 %) had a pathogenic or likely pathogenic (P/LP) variant(s) in a genetic cardiomyopathy-susceptibility gene, including DSP (n=2), LMNA, FHL1, TPM1, MYBPC3, NRAS, MYH7 (n=2) and TTN (n= 2) genes. All P/LP patients had FDG uptake, and in those with CMR data, 100% had late gadolinium enhancement. The seven patients with P/LP who underwent endomyocardial biopsy had no evidence of granulomatous inflammation. Immunosuppression was initiated in 60% of the P/LP patients before knowledge of genetic results. Conclusion Patients suspected to have CS may have concomitant or primarily genetic cardiomyopathy that may masquerade as an inflammatory phenotype Genetic testing should be considered in these patients, not only to clarify the diagnosis and its prognostic and therapeutic implications, but also to offer cascade screening for the family of patients with P/LP variants who otherwise would not have been considered to have a heritable disease.

Abstract Background Atrial fibrillation (AF) is associated with increased risk of incident tricuspid regurgitation (TR), but types of incident TR in AF versus sinus rhythm (SR) are not well-defined. Purpose We aimed to compare the risk of the different types of incident ≥moderate TR in AF and SR. Methods Adults first diagnosed with AF (2010-2021) who had a transthoracic echocardiogram (TTE) within 30 days after AF and adults with no diagnosis of AF who had a TTE in the same period were identified. Patients with previous cardiac surgeries, congenital heart disease, cardiomyopathy, cardiac devices, primary valve disease, previous or current ejection fraction (EF) &lt;50%, severe diastolic dysfunction (SDD), ≥moderate left-sided valve disease (LVD), right ventricular systolic pressure (RVSP) ≥50 mmHg, ≥moderate TR, any tricuspid stenosis, or with no follow-up TTE ≥6 months from baseline were excluded. Patients were followed for the development of ≥moderate TR, the type of which was identified in a hierarchal order: 1) pacemaker-associated TR, 2) LVD-associated TR in the setting of ≥moderate LVD, 3) low EF or SDD-related TR, 4) pulmonary hypertension (PH)-associated TR if RVSP was ≥50 mmHg, 5) other ventricular functional TR (VFTR) if there was &gt;mild RV enlargement or dysfunction, and 6) atrial functional TR (AFTR) when none of the previous was present. Patients were also followed for the occurrence of risk factors for TR (pacemaker insertion, ≥moderate LVD, low EF or SDD, PH, &gt;mild RV enlargement or dysfunction) in a hierarchal order, and both the prevalence and future risk of the corresponding type of ≥moderate TR was determined at the onset of these conditions in AF and SR. Results Overall, 1,360 patients with new-onset AF (median age 67 years, 34% females) and 20,438 patients in SR (median age 60 years; 54% females) were included. Over median 3.8 (IQR 1.8-6.6) years, incident ≥moderate TR occurred in 110 patients with new-onset AF [2.13 per 100-person years] compared to 378 patients in SR [0.41 per 100-person years, p &lt;.001]. All types of incident ≥moderate TR occurred more frequently in AF (p &lt;.001 for all). The distribution and incidence of each type of TR in AF and SR are shown in Figure 1. The incidence of risk factors associated with the development of TR was higher in the AF group, except for pre-capillary PH, Figure 2A. At time of diagnosis or occurrence of these conditions, the prevalence of the corresponding TR types was higher in AF, except for pacemaker-TR, Figure 2B. The incidence of the corresponding TR type after occurrence of TR risk factors was higher in the AF group for LVD-TR and low EF/SDD-associated TR (p ≤0.03); although numerically higher in AF, the association was only borderline for PH-TR (p =0.05), Figure 2C. Conclusion Incident ≥moderate TR of all types occurred more frequently in patients with AF vs. SR and the distribution of TR types differed by rhythm. Patients with AF may benefit from a closer follow-up.Distribution and incidence rates of TRIncidence of TR risk factors & TR after

Abstract Background/Introduction Arrhythmogenic mitral valve prolapse syndrome (AMVPS) is a female-predominant sudden cardiac death (SCD)-predisposing disorder characterized clinically by myxomatous mitral valve prolapse (MVP), inferolateral T-wave inversions and complex ventricular ectopy. However, insights into the pathogenesis and potential genetic basis of AMVPS are currently lacking. Purpose Considering recent case reports that suggest a potential role for genetic cardiomyopathies in the pathogenesis of AMVPS, we sought to determine the yield of pathogenic/likely pathogenic (P/LP) genetic variants in strong evidence cardiomyopathy-susceptibility genes amongst AMVPS patients who underwent clinical genetic testing. Methods In this retrospective study, the medical records of 4,907 patients referred to our cardiovascular genetics clinic was used to identify those patients with a clinical phenotype consistent with AMVPS. After exclusion of individuals with severe mitral valve regurgitation, pertinent clinical, electrocardiographic, imaging and genetic testing data was extracted from the electronic record. For those AMVPS that underwent a form of genetic testing that encompassed 23 Clinical Genome Resource-defined strong/definitive evidence cardiomyopathy-susceptibility genes, ultra-rare (minor allele frequency ≤ 0.00005 in the Genome Aggregation Database [n=141,456 individuals]) non-synonymous variants identified within these genes were adjudicated independently as P, LP or variant of uncertain significance with the assistance of Varsome. The frequency of P/LP variants was then compared to a previously published cohort of 973 ostensibly healthy control exomes. Results Overall, 56 unrelated patients with suspected AMVPS were identified (82% female; average age at presentation of 31 ± 13 years; 32% with a family history of MVP and/or SCD). Of these, 24/56 (43%) underwent a form of clinical genetic testing that encompassed the pre-defined panel of cardiomyopathy-susceptibility genes. In comparison to control exomes (n=973), P/LP variants in strong/definitive evidence cardiomyopathy-susceptibility genes were over-represented in AMVPS patients [4/24 (16.7%) vs 20/973 (2.1%); p=0.002]. Interestingly, this enrichment was driven in large part by an excess number of A-band-localizing P/LP truncating variants in TTN-encoded titin in AMVPS cases [3/24 (12.5%) versus 4/973 (0.4%); p=0.0004]. Conclusion This study provides further evidence that a subset of AMVPS may arise secondary to a "two-hit" model whereby an underlying cardiomyopathic genetic substrate is exacerbated by the mechanical force generated by genetically unrelated myxomatous MVP resulting in maladaptive and ventricular arrhythmia-predisposing fibrosis within the inferobasal left ventricle and posteromedial papillary muscles. Larger studies are needed to better understand the potential role of genetic testing in the diagnosis, risk-stratification and management of patients with suspected AMVPS.

Background: Multimorbidity is common in atrial fibrillation (AF), particularly among older patients who generally have multiple cardiovascular and non-cardiovascular chronic conditions. However, less is known about the accumulation of chronic conditions in younger patients with AF. Methods: Patients aged <65 with incident AF from 2013-2019 from a 27-county region in the Midwest (N=4907) were matched 1:1 on age (±5 years) and sex to referents from the same community. The index date for the matched pair was the date of first diagnosis of AF. Diagnosis of 20 other chronic conditions was ascertained from 3 years prior to index through 12/31/2022. Mean cumulative function curves were used to visualize the accumulation of conditions; Andersen-Gill models estimated associations between AF/referent status and accumulation of conditions. Results: The mean age was 55 years for both patients with AF and matched referents; 71% were male. In the 3 years leading up to AF diagnosis, only 4% of patients with AF had no additional chronic conditions and 69% had ≥3 chronic conditions. In contrast, 35% of referents had 0 and 32% had ≥3 chronic conditions. The accumulation of chronic conditions was accelerated in patients with AF compared to referents prior to AF diagnosis/index (Figure). After index, patients with AF had increased accumulation of chronic conditions (HR (95% CI): 1.93 (1.71-2.20), 1.82 (1.62-2.05), 1.68 (1.55-1.83), and 1.53 (1.44-1.64) for ages <50, 50-54, 55-59, and 60-64 years, respectively). After 1 year, the differences were attenuated in all age groups with no difference observed between patients with AF and referents in the oldest age group (1.26 (1.08-1.46), 1.28 (1.11-1.47), 1.13 (1.02-1.24), and 1.05 (0.97-1.13) for ages <50, 50-54, 55-59, and 60-64 years). Conclusion: Patients <65 years with AF have an increased accumulation of chronic conditions compared to those without AF, in particular prior to their AF diagnosis and within the first year after AF diagnosis.