Giudicessi, John R.

Introduction: Recently, we demonstrated transcriptional down-regulation of hypertrophy pathways in myectomy tissue derived from patients with obstructive hypertrophic cardiomyopathy (HCM) despite translational activation of associated hypertrophy pathways. Previous studies of other forms of cardiac hypertrophy demonstrate hypertrophy pathways are activated via histone acetylation and histone deacetylase (HDAC) inhibitors prevented development of hypertrophy. Whether histone modifications regulate hypertrophy pathways in HCM remains unexplored. Methods: Chromatin immunoprecipitation sequencing (ChIP-seq) was performed on myectomy tissues from 40 patients with HCM and 23 controls to characterize differential histone marks for H3K4me3 (active promoter), H3K9ac (active promoter), H3K9me3 (heterochromatin), H3K27ac (active enhancer), H3K27me3 (repression) across the genome. The differential histone marks were integrated with RNA-sequencing (RNA-seq) data derived from the same patients. Results: Overall, we identified 2,912 (7%) differential H3K4me3 peaks impacting 5 pathways, 23,339 (21%) differential H3K9ac peaks impacting 87 pathways, 33 (0.05%) differential H3K9me3 peaks, and 58,837 (42%) differential H3K27ac peaks impacting 50 pathways. There was increased H3K27ac (q-value = 0.002) and H3K9ac (q-value = 0.009) at RAS-MAPK loci. Univariate analysis of concordance between H3K9ac with RNA-seq data showed activation of cardiac hypertrophy signaling (z-score=4.5; -log [BH p-value] = 3.1), while H3K27me showed down-regulation of cardiac hypertrophy signaling (z-score=-2.4; -log [BH p-value] = 2.4). Multivariate integration of the ChIP-seq data with RNA-seq data identified 3,189 transcripts concordant with all five histone marks impacting 254 pathways, 18 (7%) of which are involved in cardiac hypertrophy. Conclusions: Myectomy tissue from patients with obstructive HCM shows enrichment of histone modifications at cardiac hypertrophy loci with activation via H3K27 and H3K9 acetylation and repression via H3K27 methylation. Further studies are needed to understand the balance and temporal relationship between these competing regulators in HCM pathobiology and the potential for epigenetic therapies.

Introduction: Treatment options for patients with recurrent ventricular arrhythmias (VAs) refractory to pharmacotherapy and/or ablation are minimal. Although left cardiac sympathetic denervation (LCSD) is well established in long QT syndrome (LQTS) and catecholaminergic polymorphic ventricular tachycardia (CPVT), LCSD’s role in idiopathic ventricular fibrillation (IVF) is less clear. Here, we report our single-center experience regarding the early outcomes of LCSD in patients with IVF. Hypothesis: To determine the efficacy of LCSD on reducing VAs in IVF patients refractory to conventional therapy. Methods: A retrospective analysis of the electronic health record of patients with IVF between January 2000 to April 2023 was performed. Cardiac event rates [defined as arrhythmic syncope/seizure, appropriate implantable cardioverter defibrillator (ICD) therapy, sudden cardiac arrest (SCA), or sudden cardiac death (SCD)] before and after LCSD for each patient were calculated and a Wilcoxon signed rank test was performed. Results: In total, 94 patients (41% female) were classified as IVF. Overall, 15/94 patients (16%) had LCSD due to refractory VAs (60% male; mean age at LCSD 36 ± 20 years) despite beta-blocker treatment (100%) or combined drug therapy (67%). In total, 14 patients (15%) had an electrophysiology study performed before LCSD of which 10 (67%) had VAs ablation. All patients had a structurally normal heart and genetic testing performed in 14/15 patients (93%) confirmed absence of genetic cardiomyopathies and channelopathies. SCA was the sentinel event in 10 of 15 patients (67%); 14 patients (93%) had an ICD in place. The average follow-up time after LCSD was 3 ± 4 years. The VA event rate before LCSD was 4 ± 3 events per year and was reduced to 1 ± 3 per year (p<0.04) after LCSD. Patients had a median of 3.2 less events per year after LCSD (p=0.02) with 7 patients (47%) having no post-LCSD recurrences thus far while 3 (20%) patients were deemed LCSD non-responders with no reduction of event rate. Conclusions: LCSD represents a substrate-independent, anti-fibrillatory treatment option for patients with life-threatening, genetic arrhythmias. While not curative, the early outcomes of LCSD for patients with medically refractory IVF are promising.

Introduction: Cardiac sarcoidosis (CS) results in HFrEF, but its natural history and response to GDMT remains uncertain. Methods: We queried a registry of 631 CS patients evaluated at our institution to identify those with LVEF < 35% on TTE within 30 d of diagnosis and a follow-up TTE 12-18 months later (external CS diagnoses were excluded). Demographics, LVEF, NT-proBNP, GDMT, immunosuppression, CIED, and outcomes (hyperkalemia, LVAD/transplant, CV hospitalization, death) were recorded. Results: Overall, 25/631 (4%) of CS patients had an LVEF <35% at initial presentation (36% female, 84% white; median age of 58 y; probable/not biopsy-proven CS in 52%). Mean baseline LVEF was 27% (σ=7%), NT-proBNP 1736 pg/mL (n=11), potassium 4.3 mEq/L (n=18), and median NYHA Class II (54%). Patients were on a mean 1.7 GDMT agents at CS diagnosis (Figure). Most were treated with immunosuppression (88%) for mean 0.75 y, usually prednisone (88%, mean 16 mg daily) and fewer with mycophenolate (32%, mean 1875 mg daily), methotrexate (28%, mean 18mg weekly), or TNF-α inhibitor (4%). 64% were on trimethoprim-sulfamethoxazole prophylaxis. At follow-up (median 317 d), 3 patients (12%) required LVAD and 1 (4%) required heart transplant. Mean LVEF improved to 37% (excluding LVAD/transplant, σ=11%, p=0.001). CIED prevalence increased from 48 to 81% (p=0.03). Overall GDMT did not change (mean 2.0 agents, p=0.2) and only beta-blocker dose changed (64 to 138 mg mean daily metoprolol equivalents). Potassium did not change (p=0.4) and hyperkalemic events were infrequent (16%). No patients died, but unplanned hospitalization occurred in 36% of patients. Conclusions: CS patients with HFrEF are usually on partial GDMT at diagnosis, presumably due to earlier recognition of HFrEF, but intensification of GDMT may be limited. Despite improved LVEF which may be due to GDMT, immunosuppression, and/or CIED, over 1/3 patients were hospitalized within 18 mo, highlighting the high-risk profile of HFrEF in CS.

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/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.

Introduction: Sudden cardiac arrest (SCA) and death (SCD) are the most serious sequelae of many genetic heart diseases (GHDs). Increased awareness of this has led to increased detection in employment screenings. For patients in high-risk jobs, premature and potentially unnecessary termination from their profession, rather than “Return-to-Work (RTW),” has become an undesired consequence of this awareness. The objective of this study is to evaluate the outcomes of patients with GHDs in high-risk professions who were allowed to RTW. Methods: We performed a retrospective review of 3,641 working-age patients referred for evaluation of a potential GHD between 6/2000-12/2021 to identify those either in or being recruited into a high-risk profession. A profession was defined as “high-risk” if it is safety-sensitive or required regular medical evaluations. Charts were reviewed for medical history, RTW decision making, and breakthrough cardiac events (BCEs). Results: Overall, 33 patients [(0.9%); 3 females (9%); mean age at diagnosis 25 ± 15 years] had been either put on hold from their high-risk job (n = 15; 45%) or disqualified as a recruit (18; 55%) prior to our evaluation due to their GHD diagnosis. This included 15 military, 10 pilots, 6 law enforcement and first responders, and 2 commercial driver license professionals and recruits. Most patients were diagnosed with Long QT syndrome (n = 23; 70%). After treatment initiation, 14 (93%) professionals and 16 (89%) recruits received physician RTW approval while 3 (9%) patients did not receive RTW approval due to disease severity and/or unwillingness to initiate treatment. Of the remaining 14 professionals that received physician RTW approval, 4 (29%) were not allowed to return to their jobs, while 14/16 recruits (88%) were not permitted to start their career. None of the RTW-approved patients had a BCE after evaluation (160.7 follow-up years). Conclusions: Patients with GHDs in high-risk professions are often terminated due to perceived SCA/SCD risk. However, within our small cohort, the risk of BCEs in optimally treated patients was low. This data suggests that the certification process of individuals in these high-risk and safety-sensitive occupations should be further examined and potentially modified.

Introduction: Hypertrophic cardiomyopathy (HCM) is a disease characterized by genotypic and phenotypic heterogeneity. Correct classification of genetic variation is critical for clinical interpretation. Herein, variants of uncertain significance (VUS) pose a dilemma in clinical practice, limiting physicians’ decision making and causing anguish to patients and family members. Furthermore, with increasing knowledge and changing guidelines, continuous reassessment is crucial to maintain usefulness in practice. This study sought to assess contemporary variant classification in a large cohort of patients with HCM. Methods: Retrospective analysis of all patients with HCM seen at Mayo Clinic and all patients with a variant in one of 8 genes with strong disease association for HCM were included. Genetic test reports were obtained from electronic health records along with their original variant classification assigned by either a commercial or research laboratory. Reassessment of variant pathogenicity was performed using the 2015 ACMG guideline criteria. Population frequency was obtained using Gnomad. Co-segregation presence or absence was determined by family history and co-segregation studies. Combined Annotation Dependent Depletion (CADD) was used as computational evidence of genetic deleterious effects for single nucleotide variants. Results: Between 2003 to 2019, a total of 1,782 patients underwent laboratory or commercial HCM genetic testing. Of these, 787 (44%) had positive genetic test with a variant at least 1 of the 8 genes. The original pathogenic classification was obtained for 754 patients. Of those, 430 (57%) variants where within the gene MYBPC3, 244 (32%) within MYH7 and 80 (11%) within either ACTC1, MYL2, MYL3, TINNI3, TNNT2 or TPM1. Overall, 222 patients (29%) originally had one or more variants classified as a VUS. Upon reassessment, 120 (54%) were reclassified as either pathogenic (33%), likely pathogenic (58%), benign (5%) or likely benign (3%). Conclusion: Periodic reassessment for HCM genetic variants, especially VUS, is critical for adequate patient care and management. Cascade screening could decrease patients’ uncertainty regarding their prognosis and management.

Background: Long QT syndrome (LQTS) is a genetic heart disease affecting about 1 in 2000 persons. Around 40% of patients with LQTS can have a nondiagnostic, normal QTc at rest. The treadmill exercise stress test (TEST) can help unmask patients with concealed LQTS with a characteristic maladaptive, paradoxical increase in QTc ( 460 ms) during the recovery phase. In fact, the recovery phase QTc value has been added to the latest diagnostic score for LQTS. Objective: To characterize the TEST-derived QTc profile of untreated patients with LQTS and determine its diagnostic and prognostic utility. Methods: Retrospective analysis was performed on TEST data derived from 249 patients with LQTS (129 LQT1, 64 LQT2 and 56 LQT3) untreated at the time of their TEST compared with 236 controls. The Bazett’s corrected QTc was calculated at rest (sitting, supine, and standing), during exercise at 1 min, 3 mins, and peak exercise, and during recovery phase at 1, 3 and 5 mins. Results: The mean resting QTc was significantly higher in LQTS patients (457 ± 30 ms) compared to controls (420 ± 24 ms; p<0.0001) as well as at every stage during the TEST (p<0.001). For LQT1 patients, highest QTc was observed at peak exercise (mean 496 ± 38 ms) and during the third minute of recovery phase (mean 500 ± 40 ms). In contrast, LQT2 patients showed the lowest QTc (mean 452 ± 48 ms) during peak exercise but the greatest QTc latency (QTc at 5 min - QTc at 1 min recovery; mean QTc latency 33 ± 77 ms; p=0.005) compared to controls. For LQT3, the mean QTc was greatest at rest compared to controls (p<0.001), and there was no difference during exercise and recovery phases. Among 162 LQT1 and LQT2 patients that presented with concealed LQTS, 119 (73%) showed a maladaptive QT response. ROC analysis showed that in patients with LQT1, a maladaptive QTc > 523 ms at 3 min of recovery was highly predictive of breakthrough cardiac events (AUC 0.84; sensitivity 100%, specificity 72%); no such association was identified for LQT2 or 3. Conclusions: This comprehensive characterization of the QTc response before, during, and after a TEST in the largest untreated cohort of patients with LQTS provides important genotype-specific characteristics and can be used as a predictor for potential LQT1-triggered cardiac events after diagnosis and treatment.