Faculty Bibliography

BACKGROUND:Mitral leaflet elongation is common in hypertrophic cardiomyopathy (HCM), contributes to obstructive physiology, and presents a challenge to dual surgical goals of abolition of outflow gradients and mitral regurgitation. Anterior leaflet shortening, performed as an ancillary surgical procedure during myectomy, is controversial. METHODS:This was a retrospective study of all patients undergoing myectomy from 1/2010 to 3/2020 analyzing survival and echocardiographic results. We compared outcomes of patients treated with myectomy and concomitant mitral leaflet shortening with patients treated with myectomy alone. Over this time technique for mitral shortening evolved from anterior leaflet plication to residual leaflet excision (ReLex). RESULTS:Myectomy was performed on 416 patients age 57.5±13.6 years, 204 (49%) female. Average follow up was 5.4±2.8 years. Survival follow-up was complete in 415. Myectomy without valve replacement was performed in 332 patients, of whom 192 had mitral valve shortening (58%). Mitral leaflet plication was performed in 73, ReLex in 151 and both in 32. Hospital mortality for patients undergoing myectomy was 0.7%. At 8 years, cumulative survival was 95% for both myectomy plus leaflet shortening and myectomy alone groups, with no difference in survival between the two. There was no difference in survival between anterior leaflet plication and ReLex groups. Echocardiography 2.5 years after surgery showed a decrease in resting and provoked gradients, mitral regurgitation and left atrial volume and no difference in key variables between ancillary leaflet shortening and myectomy alone patients. CONCLUSIONS:These results affirm that mitral shortening may be an appropriate surgical judgment for selected patients.

INTRODUCTION/UNASSIGNED:Hypertension affects approximately 50 % of patients with hypertrophic cardiomyopathy (HCM) but clinical course in adults with co-occurring HCM and hypertension is underexplored. Management may be challenging as routine anti-hypertensive medications may worsen obstructive HCM, the most common HCM phenotype. In this scoping review, we sought to synthesize the available literature related to clinical course and outcomes in adults with both conditions and to highlight knowledge gaps to inform future research directions. METHODS/UNASSIGNED:We searched 5 electronic databases (PubMed, CINAHL, Scopus, Embase, Web of Science) to identify peer-reviewed articles, 2011-2023. We followed the Preferred Reporting Items for Systematic Reviews and Meta-Analyses-Scoping Review (PRISMA-ScR) guideline. RESULTS/UNASSIGNED:Eleven articles met eligibility. Adults with both conditions were older and had higher rates of obesity and diabetes than adults with HCM alone. Results related to functional class and arrhythmia were equivocal in cross-sectional studies. Only 1 article investigated changes in medical therapy among adults with both conditions. Hypertension was a predictor of worse functional class, but was not associated with all-cause mortality, heart failure-related mortality, or sudden-death. No data was found that related to common hypertension-related outcomes, including renal disease progression, nor patient-reported outcomes, including quality of life. CONCLUSIONS/UNASSIGNED:Our results highlight areas for future research to improve understanding of co-occurring HCM and hypertension. These include a need for tailored approaches to medical management to optimize outcomes, evaluation of symptom burden and quality of life, and investigation of hypertension-related outcomes, like renal disease and ischemic stroke, to inform cardiovascular risk mitigation strategies.

Currently, there are 2 proposed causes of acute left ventricular ballooning. The first is the most cited hypothesis that ballooning is caused by direct catecholamine toxicity on cardiomyocytes or by microvascular ischemia. We refer to this pathogenesis as Takotsubo syndrome. More recently, a second cause has emerged: that in some patients with underlying hypertrophic cardiomyopathy, left ventricular ballooning is caused by the sudden onset of latent left ventricular outflow tract obstruction. When it becomes severe and unrelenting, severe afterload mismatch and acute supply-demand ischemia appear and result in ballooning. In the context of 2 causes, presentations might overlap and cause confusion. Knowing the pathophysiology of each mechanism and how to determine a correct diagnosis might guide treatment.

INTRODUCTION:Hypertension affects 40%-60% of adults with hypertrophic cardiomyopathy (HCM), the most common inherited cardiac condition. It can be a diagnostic confounder for HCM, contributing to delayed diagnosis. Clinically, treatment of co-occurring hypertension and HCM poses challenges as first-line and second-line antihypertensive medications are often contraindicated in HCM. The clinical course in adults with hypertension and HCM is also not well understood, and studies examining patient outcomes in this population are equivocal. In this paper, we aim to outline the protocol of a scoping review, a type of literature review, to systematically synthesise existing knowledge on adults with co-occurring HCM and hypertension, highlighting knowledge and evidence gaps, and identifying future research directions to optimise outcomes in this population. METHODS AND ANALYSIS:This review is guided by Arksey and O'Malley's conceptual framework on conducting scoping reviews. We will search five electronic databases (PubMed, CINAHL, Scopus, Embase and Web of Science) and reference lists of publications to identify eligible articles focusing on medical therapy, clinical course or outcomes in adults with HCM and hypertension, between 2011 and 2023. Our search strategy and presentation of results will be guided by the Preferred Reporting Items for Systematic Reviews and Meta-Analyses-Scoping Review guideline. First, two independent reviewers will screen articles, by title and abstract, followed by a full-text screen to identify eligible articles. Relevant data will be extracted and synthesised. ETHICS AND DISSEMINATION:Ethical approval is not required for this review as it is a secondary data collection of published articles and does not involve human subject participation. We will present results of this review at relevant professional conferences and patient-centred educational events. Results will be published in a peer-reviewed journal. TRIAL REGISTRATION NUMBER:https://osf.io/cy8qb/?view_only=98197f4850584e51807ff9b62533a706.

Hypertrophic cardiomyopathy (HCM) is a heterogeneous albeit treatable cardiac disease of variable severity, with the potential for heart failure, atrial fibrillation and arrhythmic sudden death, characterized by otherwise unexplained left ventricular (LV) hypertrophy and affecting all ages and races. Over the last 30 years, several studies have estimated the prevalence of HCM in the general population, employing echocardiography and cardiac magnetic resonance imaging (CMR), as well electronic health records and billing databases for clinical diagnosis. The estimated prevalence in the general population based on the disease phenotype of LV hypertrophy by imaging is 1:500 (0.2%). This prevalence was initially proposed in 1995 in the population-based CARDIA study employing echocardiography, and more recently confirmed by automated CMR analysis in the large UK Biobank cohort. The 1:500 prevalence appears most relevant to clinical assessment and management of HCM. These available data suggest that HCM is not a rare condition but likely underdiagnosed clinically and by extrapolation potentially affects about 700,000 Americans and possibly 15 million people worldwide.

Background: Obesity is prevalent among patients with hypertrophic cardiomyopathy (HCM). Obese HCM patients have greater wall thickness, LV mass, worse hemodynamic function and NYHA class. Weight loss may favorably influence the HCM phenotype. Case summary: We describe six patients with hypertrophic cardiomyopathy who lost weight through diet and lifestyle changes (n = 4) or bariatric surgery (n = 2). Radiographic imaging, with cardiac MRI or CT scan, was performed before and after their weight loss. There was a mean decrease in LV mass and indexed LV mass, and a mean numerical decrease in mean wall thickness in up to 14 out of 18 LV segments. There was also NYHA class reduction in symptoms. Discussion: In this case series, we have shown that substantial weight loss in HCM patients can be associated with a decrease in LV mass, wall thickness and improvement in symptoms. These observations indicate the potential for positive remodeling of the heart by weight loss. Prospective studies of the benefits of weight loss in HCM are needed.

BACKGROUND:Apical left ventricular (LV) aneurysms in hypertrophic cardiomyopathy (HCM) are associated with adverse outcomes. The reported frequency of mid-LV obstruction has varied from 36% to 90%. OBJECTIVES/OBJECTIVE:The authors sought to ascertain the frequency of mid-LV obstruction in HCM apical aneurysms. METHODS:The authors analyzed echocardiographic and cardiac magnetic resonance examinations of patients with aneurysms from 3 dedicated programs and compared them with 63 normal controls and 47 controls with apical-mid HCM who did not have aneurysms (22 with increased LV systolic velocities). RESULTS:]; P = 0.004). Complete emptying occurs circumferentially around central PMs that contribute to obstruction. Late gadolinium enhancement was always brightest and the most transmural apical of, or at the level of, complete emptying. CONCLUSIONS:The great majority (95%) of patients in the continuum of apical aneurysms have associated mid-LV obstruction. Further research to investigate obstruction as a contributing cause to apical aneurysms is warranted.