Ommen, Steve R.

Introduction: Obesity is an independent risk factor for heart failure in patients with hypertrophic cardiomyopathy (HCM). Bariatric surgery is associated with improved cardiac function in obese patients with heart failure, but the safety of this procedure has not been evaluated in HCM patients. In this study, we examined national trends and early outcomes in bariatric surgery for patients with HCM. Methods: Using the weighted discharge data from the National Inpatient Sample, we identified adult patients with HCM who underwent elective bariatric surgery for obesity between 2011 and 2017. Patients with a history of bariatric surgery or having malignant neoplasms in the esophagus, stomach, small intestine, or pancreas were excluded. Results: A total of 443 obese patients with HCM were identified, and 41.8% (n=185) had obstructive HCM. The annual number of patients increased from 18 in 2011 to 130 in 2017, and nearly half of the patients (48%) had bariatric surgery in 2016 and 2017. Overall, the median (IQR) age was 50 (43-57) years, and 85 (19%) patients were 60 years or older. Approximately 20% (n=90) of the patients had heart failure at the time of operation. Atrial fibrillation was present in 83 (19%) patients, and 22% (n=95) of the cohort had a pacemaker or automatic cardiac defibrillator implanted prior to the operation. Laparoscopic sleeve gastrectomy (72%, n=318) and laparoscopic Roux-en-Y gastric bypass (25%, n=110) were the most commonly performed bariatric procedures. Overall, patients stayed in hospital for a median (IQR) of 2 (1-2) days. During the hospital stay, 1% (n=5) of the patients had acute worsening of chronic heart failure, but there were no deaths, cardiac arrests, or cerebrovascular accidents post procedure. Conclusions: Bariatric surgery in patients with HCM is performed more frequently in recent years and is safe and associated with few perioperative complications. Given the impact of obesity on long-term survival, clinicians should strongly consider bariatric surgery for HCM patients who do not respond to conservative weight loss measures.

Introduction: Hypertrophic cardiomyopathy (HCM) is a major cause of sudden cardiac death in the young and especially in young athletes. The treadmill exercise test (TEST) has an important role in the functional assessment of patients with HCM. Herein, TEST-derived peak oxygen uptake (VO2 max) is a proxy for cardiopulmonary fitness. However, the correlation between symptoms and VO2 - especially in active young patients with HCM - is unclear. Objective: To explore the relationship between TEST-derived VO2 and symptomology in athletes and non-athletes with HCM. Methods: Overall, 91 patients (40% female) with HCM and a TEST with VO 2 data were included in this case-control study. Data were abstracted from the electronic health record using the first TEST performed at Mayo Clinic. Patients were defined as an athlete if they participated in an organized, competitive sport. Results: Overall, 60 HCM patients (33% female) were categorized as an athlete. HCM athletes were younger (17 vs. 27 years; p<0.0001) and less likely to be symptomatic at the time of their TEST (OR=0.24; p=0.01). Additionally, athletes had a higher VO2 max (86% vs. 68% of predicted; p<0.0001) and reached higher exercise times (93% vs 76% of predicted; p<0.0001) compared to the non-athletes with HCM. When comparing symptomatic (n = 18) to asymptomatic patients (n = 73), symptomatic patients had i) a reduced exercise time (68% vs. 92% of predicted; p=0.002) and ii) lower VO2 max (62% vs 84% of predicted; p<0.001). Finally, among the 27 patients (30%) with a VO 2 max < 70% predicted (n=27), they i) more likely had a history of cardiac arrest (4 vs 0; p=0.006) and ii) were more likely to be symptomatic (OR=7.7; p< 0.0001) than those with VO2 ≥ 70% of predicted (n=64). Importantly, however, 15/27 (56%) patients (8 athletes/7 non-athletes) with a VO2 max < 70% were asymptomatic. Conclusions: Reduced exercise capacity is common in athletes with HCM and does not correlate with symptom status. However, if the TEST-derived VO2 max is < 70%, treatment intensification may be necessary as it may portend an adverse outcome both arrhythmically and mechanically.

Background: Treatment of progressive heart failure, due to left ventricular (LV) outflow tract obstruction has been a major component of hypertrophic cardiomyopathy (HCM) disease management for 50 years. Septal myectomy has been the primary treatment option to abolish gradients and relieve heart failure symptoms. The role of myectomy in HCM management has depended on effectiveness in relieving heart failure symptoms, but also an acceptable operative risk. Methods: Over the most recent 15-year period, we reviewed 3,700 consecutive isolated myectomy operations performed at major North American HCM institutions. Composite operative mortality (first 30 days) was only 0.4%. Seventeen operative deaths were at ages 24 to 82 (≥70 years), and only 6 occurred after 2010. Notably, 2 of the 4 Mayo Clinic deaths were in patients with prior alcohol septal ablation. Septal myectomy, when performed in experienced HCM centers, was much safer when compared to operative mortality with coronary artery bypass grafting (2.3%); valve replacement (3.5%); mitral valve replacement specifically (5.7%) (STS Database), similar to atrial or ventricular septal defect closure and 15-fold less than myectomy in community hospital or low volume surgical settings. Conclusions: Surgical myectomy performed in dedicated HCM centers with experienced surgeons and staff is one of the safest open-heart procedures currently practiced, with a mortality rate as low as 0.4%. The large mortality discrepancy for myectomy between community hospitals and dedicated HCM centers underscores that this operation should be considered a specialized procedure best performed in high volume HCM institutions.

Tomas Konecny, 2012 Finalist and Presenting Author

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.

Background: An electrocardiogram (ECG)-based artificial intelligence (AI) algorithm has shown good performance in detecting hypertrophic cardiomyopathy (HCM AI-score). However, its clinical application may be challenging due to the low disease prevalence and potentially high false-positive rate when screening unenriched cohorts. Aims: To identify clinical characteristics associated with false-positive HCM AI-score results to improve screening tool application. Methods: From a cohort of 20,677 patients with a digital 12-lead ECG in routine clinical practice in 2021, we performed a detailed chart review of the 200 patients with highest HCM AI-score to determine their HCM status and collect clinical data. Stepwise forward logistic regression was used to create a clinical variable-based “candidacy for HCM screening” score (CHS score), differentiating true- and likely true-positive from likely false-positive HCM AI-score results. We then validated the CHS score in 200 patients with the highest HCM AI-scores from an independent cohort of 15,147 patients with an ECG in 2022. Results: Among the 200 patients in 2021 (median age 71 years, 48% female), 96 (48%) were likely false-positive HCM AI-score results, 71 (36%) definite or likely true-positive results, and 33 (16%) indeterminate. The CHS score included a history of surgical septal myectomy, coronary artery bypass graft surgery, cardiac valve replacement, and pacemaker, and had an AUC of 0.88 (95% CI 0.83-0.92) for the differentiation of true- versus false-positive AI results. In the 2022 cohort, the CHS score had an AUC of 0.82 (95% CI 0.76 - 0.88). After limiting the cohort to HCM candidates identified by the CHS score, the false-positive results rate was reduced to 27/114 (24%). Conclusions: By applying the CHS score to patients with positive HCM AI-screening results, the false-positive rate decreased from 49% to 24%. Utilizing a clinical model used in tandem with an AI model improved diagnostic yield.

Introduction: Hypertrophic cardiomyopathy (HCM) is characterized by left ventricular hypertrophy. Approximately 40-50% of HCM is caused by pathogenic variants in genes encoding proteins of the cardiac sarcomere. Patients with sarcomeric HCM have earlier expression and more severe disease progression. Herein, we evaluated the proteomic differences between patients with sarcomeric HCM and genotype negative HCM. Methods: Mass-spectrometry was performed on cardiac tissue from genotyped patients with HCM obtained after surgical myectomy, followed by differential proteomics (log2fc ≥

Abstract Aims Data on the clinical course of hypertrophic cardiomyopathy (HCM) are mainly derived from tertiary HCM centre studies, and knowledge of clinical outcomes of patients leaving specialty care and returning to local physicians is limited due to gaps between clinical encounters or complete loss of follow-up. This survey aims to describe the clinical course of HCM in patients following their evaluation at a tertiary referral centre. Methods and results A comprehensive outcomes survey was developed and sent to 4495 eligible patients with HCM previously evaluated at Mayo Clinic. Questions assessed general well-being, New York Heart Association class, procedures performed, and probable HCM-triggered ventricular arrhythmic events (VAEs) since last visit. In total, 2058 patients (mean age 63 ± 15 years; 42% female) responded to the survey covering a total of 10 510 patient-years with an average of 5.4 ± 6.4 years of follow-up since their last on-campus/virtual visit to Mayo Clinic. During their time away from specialty care, 20% of patients reported having cardiac-related hospitalizations and 25% reported having cardiac-related procedures. Similar to high-risk referral cohorts, 5% of patients reported VAEs with an event rate of 0.98 events/100 patient-years. The prevalence of atrial fibrillation, syncope, pre-syncope, cardiac-related hospitalizations, and VAEs during time away from specialty care increased significantly with increasing New York Heart Association class (P &lt; 0.001). Conclusions Acknowledging ascertainment bias, the clinical course of patients away from tertiary care may be more severe than previously anticipated. Among those with exertional symptoms, HCM-related morbidity increased substantially. Higher risk HCM patients should remain in contact with HCM specialty care.

Background: Hypertrophic cardiomyopathy (HCM) is characterized by asymmetric left ventricular hypertrophy. Currently, hypertrophy pathways responsible for HCM have not been fully elucidated. Their identification could serve as a nidus for the generation of novel therapeutics aimed at halting disease development or progression. Herein, we performed a comprehensive multi-omic characterization of hypertrophy pathways in HCM. Methods: Flash-frozen cardiac tissues were collected from genotyped HCM patients (n=97) undergoing surgical myectomy and tissue from 23 controls. RNA sequencing and mass spectrometry–enabled deep proteome and phosphoproteomic assessment were performed. Rigorous differential expression, gene set enrichment, and pathway analyses were performed to characterize HCM-mediated alterations with emphasis on hypertrophy pathways. Results: We identified transcriptional dysregulation with 1246 (8%) differentially expressed genes and elucidated downregulation of 10 hypertrophy pathways. Deep proteomic analysis identified 411 proteins (9%) that differed between HCM and controls with strong dysregulation of metabolic pathways. Seven hypertrophy pathways were upregulated with antagonistic upregulation of 5 of 10 hypertrophy pathways shown to be downregulated in the transcriptome. Most upregulated hypertrophy pathways encompassed the rat sarcoma-mitogen-activated protein kinase signaling cascade. Phosphoproteomic analysis demonstrated hyperphosphorylation of the rat sarcoma-mitogen-activated protein kinase system suggesting activation of this signaling cascade. There was a common transcriptomic and proteomic profile regardless of genotype. Conclusions: At time of surgical myectomy, the ventricular proteome, independent of genotype, reveals widespread upregulation and activation of hypertrophy pathways, mainly involving the rat sarcoma-mitogen-activated protein kinase signaling cascade. In addition, there is a counterregulatory transcriptional downregulation of the same pathways. Rat sarcoma-mitogen-activated protein kinase activation may serve a crucial role in hypertrophy observed in HCM.

Background Information on impact of race and ethnicity on use and early outcomes of septal reduction therapies (SRTs) for obstructive hypertrophic obstructive cardiomyopathy are limited. Methods and Results Using the National Inpatient Sample from January 2012 through December 2019, we identified all adult admissions with a primary diagnosis of obstructive hypertrophic cardiomyopathy and those undergoing SRT. Predictors of receiving SRT and outcomes including in‐hospital mortality, complications, and resource use were evaluated in racial and ethnic groups. Among a total of 18 895 adult admissions with obstructive hypertrophic cardiomyopathy, SRT was performed in 7255 (38.4%) admissions. Septal myectomy was performed in 4930 (26.1%), while alcohol septal ablation was performed in 2325 (12.3%). In adjusted analysis, Black patient (versus White patient adjusted odds ratio, 0.65 [95% CI, 0.57–0.73]; P <0.001) and Hispanic patient admissions (versus White adjusted odds ratio, 0.78 [95% CI, 0.66–0.92]; P =0.003) were less likely to receive SRT. Among admissions undergoing SRT, in‐hospital mortality was significantly higher for Hispanic (adjusted odds ratio, 3.38 [95% CI, 1.81–6.30], P <0.001) and other racial and ethnic groups (adjusted odds ratio 2.02 [95% CI, 1.00–4.11]; P =0.05) compared with White patient admissions, whereas Black patient admissions had comparable mortality. Black, Hispanic, and other ethnic group patients had higher rates of SRT complications and more frequent dismissals to acute care facilities. Conclusions Among obstructive hypertrophic cardiomyopathy hospitalizations, minoritized racial groups were less likely to receive SRT. Importantly, hospitalizations of Hispanic and other ethnic patients undergoing SRT had significantly higher in‐hospital mortality and complication rates. Further studies with granular echocardiographic information to assess indications for SRT are needed to better understand these differences.