Hypertrophic cardiomyopathy. The importance of the site and the extent of hypertrophy. A review

2024 AHA/ACC/AMSSM/HRS/PACES/SCMR Guideline for the Management of Hypertrophic Cardiomyopathy: A Report of the American Heart Association/American College of Cardiology Joint Committee on Clinical Practice Guidelines

AIM

The "2024 AHA/ACC/AMSSM/HRS/PACES/SCMR Guideline for the Management of Hypertrophic Cardiomyopathy" provides recommendations to guide clinicians in the management of patients with hypertrophic cardiomyopathy.

METHODS

A comprehensive literature search was conducted from September 14, 2022, to November 22, 2022, encompassing studies, reviews, and other evidence on human subjects that were published in English from PubMed, EMBASE, the Cochrane Library, the Agency for Healthcare Research and Quality, and other selected databases relevant to this guideline. Additional relevant studies, published through May 23, 2023, during the guideline writing process, were also considered by the writing committee and added to the evidence tables, where appropriate.

STRUCTURE

Hypertrophic cardiomyopathy remains a common genetic heart disease reported in populations globally. Recommendations from the "2020 AHA/ACC Guideline for the Diagnosis and Treatment of Patients With Hypertrophic Cardiomyopathy" have been updated with new evidence to guide clinicians.

2024 AHA/ACC/AMSSM/HRS/PACES/SCMR Guideline for the Management of Hypertrophic Cardiomyopathy: A Report of the American Heart Association/American College of Cardiology Joint Committee on Clinical Practice Guidelines

AIM

The "2024 AHA/ACC/AMSSM/HRS/PACES/SCMR Guideline for the Management of Hypertrophic Cardiomyopathy" provides recommendations to guide clinicians in the management of patients with hypertrophic cardiomyopathy.

METHODS

A comprehensive literature search was conducted from September 14, 2022, to November 22, 2022, encompassing studies, reviews, and other evidence on human subjects that were published in English from PubMed, EMBASE, the Cochrane Library, the Agency for Healthcare Research and Quality, and other selected databases relevant to this guideline. Additional relevant studies, published through May 23, 2023, during the guideline writing process, were also considered by the writing committee and added to the evidence tables, where appropriate.

STRUCTURE

Hypertrophic cardiomyopathy remains a common genetic heart disease reported in populations globally. Recommendations from the "2020 AHA/ACC Guideline for the Diagnosis and Treatment of Patients With Hypertrophic Cardiomyopathy" have been updated with new evidence to guide clinicians.

Obstruction in Hypertrophic Cardiomyopathy: Many Faces

Hypertrophic cardiomyopathy (HCM), the most common inherited cardiomyopathy, exhibits left ventricular hypertrophy not secondary to other causes, with varied phenotypic expression. Enhanced actin-myosin interaction underlies excessive myocardial contraction, frequently resulting in dynamic obstruction within the left ventricle. Left ventricular outflow tract obstruction, occurring at rest or with provocation in 75% of HCM patients, portends adverse prognosis, contributes to symptoms, and is frequently a therapeutic target. Transthoracic echocardiography plays a crucial role in the screening, initial diagnosis, management, and risk stratification of HCM. Herein, we explore echocardiographic evaluation of HCM, emphasizing Doppler assessment for obstruction. Echocardiography informs management strategies through noninvasive hemodynamic assessment, which is frequently obtained with various provocative maneuvers. Recognition of obstructive HCM phenotypes and associated anatomical abnormalities guides therapeutic decision-making. Doppler echocardiography allows monitoring of therapeutic responses, whether it be medical therapies (including cardiac myosin inhibitor therapy) or septal reduction therapies, including surgical myectomy and alcohol septal ablation. This article discusses the hemodynamics of obstruction and practical application of Doppler assessment in HCM. In addition, it provides a visual atlas of obstruction in HCM, including high-quality figures and complementary videos that illustrate the many facets of dynamic obstruction.

Concurrent Resistance and Cardiorespiratory Training in Patients with Hypertrophic Cardiomyopathy: A Pilot Study

Background: Exercise training in patients with HCM has evidenced benefits on functional capacity, cardiac function, and a reversion of adverse cardiac remodeling. The objective of this study was to assess the effect of a concurrent resistance and cardiorespiratory training program on functional capacity, biochemical parameters, and echocardiographic variables in a pilot group. Methods: Two HCM patients were evaluated before and after 12 weeks of individualized concurrent training with two sessions/week. Pre- and post-training data were compared for each patient. Evaluations included a cardiopulmonary exercise test (CPET), body composition, echocardiography, electrocardiography, and blood analysis. Results: Training promoted an increase in functional capacity (+4 mL·kg-1·min-1), ventilatory thresholds, and other CPET-derived variables associated with a better prognosis and long-term survival. Muscular mass was augmented (0.8 and 1.2 kg), along with a mean increase of 62% in upper and lower body strength. Echocardiographic features demonstrated the maintenance of cardiac function with signs of positive left ventricular remodeling and an improvement in diastolic function. Blood analyses, including cardiac troponins and NT-proBNP, displayed uneven changes in each patient, but the values fell into normal ranges in both cases. Conclusions: The available data suggest a positive effect of concurrent resistance and cardiorespiratory training on patients' functional capacity and cardiac function that may improve their functional class, quality of life, and long-term prognosis. The replication of this protocol in a larger cohort of patients is warranted to confirm these preliminary results.

Contemporary Surgical Management of Hypertrophic Cardiomyopathy

More than half of symptomatic patients with hypertrophic cardiomyopathy (HCM) have left ventricular outflow tract (LVOT) obstruction. Septal reduction therapy by septal myectomy can dramatically relieve exertional dyspnea, chest pain, and presyncope in properly selected patients and is an important management pathway for many patients. The distribution and degree of hypertrophy in patients with obstructive HCM are variable and, as discussed in this review, can influence clinical manifestations of the disease and surgical management. Subaortic septal hypertrophy is the most common phenotype of obstructive HCM associated with LVOT obstruction, but midventricular obstruction and apical hypertrophy may occur in isolation or in conjunction with subaortic septal hypertrophy. In many comprehensive HCM centers, transaortic septal myectomy is the preferred method of septal reduction therapy for symptomatic patients with obstructive HCM. Early surgical approaches aimed at alleviating left LVOT obstruction were hampered by a lack of understanding of the anatomy and pathophysiology of obstructive HCM. With the advent of Doppler echocardiography and, more recently, cardiac magnetic resonance imaging, surgeons can precisely assess the location and degree of obstruction, left ventricular size and function, and morphology and function of the mitral valve. This review discusses the current understanding of the role of septal myectomy in the management of patients with HCM and details contemporary operative methods.

Hemodynamic Predictors of Outcome Following Alcohol Septal Ablation for Hypertrophic Obstructive Cardiomyopathy

BACKGROUND

Alcohol septal ablation (ASA) is a minimally invasive treatment for drug-refractory obstructive hypertrophic cardiomyopathy. Detailed assessment of pressure changes and predictors of mortality and procedure success are not well defined.

METHODS

This is a single-center study evaluating pressure changes and predictors of mortality and procedure success in transseptal ASA. Survival analysis and predictors of mortality were assessed using the Kaplan-Meier analysis and Cox regression, respectively.

RESULTS

A total of 156 patients were included (mean age, 67.3 years; 46.8% women). Left atrial (LA) pressure and left ventricular outflow tract (LVOT) gradient decreased, whereas aortic pulse pressure (PP) increased post-ASA. Patients with lower baseline mean LA pressure (82% (gradient change median), and PP increase >19% (PP change median) had superior survival. On Cox univariable regression, baseline mean LA pressure >median (19 mm Hg; hazard ratio [HR], 2.09 [95% CI, 1.05-4.18]; P=0.036), residual LVOT gradient (HR, 1.02 [95% CI, 1.01-1.03]; P=0.003), and LVOT gradient percent reduction median (28 mm Hg; HR, 2.36 [95% CI, 1.17-4.76]; P=0.016), baseline mean LA pressure >median (19 mm Hg; HR, 2.70 [95% CI, 1.33-5.50]; P=0.006), percentage reduction in gradient

CONCLUSIONS

ASA is associated with an acute decrease in the LVOT gradient and LA pressures and increase in aortic PP. Mean LA pressure, percentage decrease in LVOT gradient, and increase in PP are strong predictors of survival free of all-cause mortality following ASA and are important variables for procedural guidance.

Collapse

Key Words

• cardiomyopathy, hypertrophic
• heart atria
• hemodynamics

Collapse

MESH Headings

• Humans
• Female
• Aged
• Male
• Treatment Outcome
• Ethanol/adverse effects
• Cardiomyopathy, Hypertrophic/diagnostic imaging
• Cardiomyopathy, Hypertrophic/surgery
• Cardiac Surgical Procedures
• Hemodynamics
• Ablation Techniques/adverse effects

Collapse

Grants Collapse

Affiliation(s)

Mohamad S. Alabdaljabar Departments of Internal Medicine (M.S.A.), Mayo Clinic, Rochester, MN
Emily E. Cendrowski Cardiovascular Medicine (E.E.C., R.A.N., W.R.M., J.B.G., C.S.R., M.F.E.), Mayo Clinic, Rochester, MN
Rick A. Nishimura Cardiovascular Medicine (E.E.C., R.A.N., W.R.M., J.B.G., C.S.R., M.F.E.), Mayo Clinic, Rochester, MN
William R. Miranda Cardiovascular Medicine (E.E.C., R.A.N., W.R.M., J.B.G., C.S.R., M.F.E.), Mayo Clinic, Rochester, MN
Jeffrey B. Geske Cardiovascular Medicine (E.E.C., R.A.N., W.R.M., J.B.G., C.S.R., M.F.E.), Mayo Clinic, Rochester, MN
Charanjit S. Rihal Cardiovascular Medicine (E.E.C., R.A.N., W.R.M., J.B.G., C.S.R., M.F.E.), Mayo Clinic, Rochester, MN
Mackram F. Eleid Cardiovascular Medicine (E.E.C., R.A.N., W.R.M., J.B.G., C.S.R., M.F.E.), Mayo Clinic, Rochester, MN

Collapse

Comparative study of myocardial function in cases of feline hypertrophic cardiomyopathy with and without dynamic left-ventricular outflow-tract obstruction

In recent years, hypertrophic cardiomyopathy (HCM) in cats has become much more common in clinical practice due to improvements in diagnostic techniques and equipment performance. One phenotype is obstructive HCM with left ventricular (LV) outflow tract obstruction (DLVOTO). It has been reported that the presence or absence of DLVOTO does not affect long-term prognosis in cats with HCM. In this study, we evaluated and compared myocardial function in HCM-affected cats with and without DLVOTO using the two-dimensional speckle-tracking echocardiography. LV longitudinal strain of the endocardial, epicardial, and whole layer and LV circumferential strain of the epicardium were significantly decreased in all HCM-affected cats compared to healthy cats. However, these values were not significantly different between those with and without DLVOTO. In contrast, the endocardial and whole layers of LV circumferential strain were only significantly decreased in HCM-affected cats with DLVOTO compared to healthy cats. This could be attributed to the fact that the LV pressure load associated with DLVOTO affected the endocardial myocardium more in the LV endocardial layer, and that lower values of LV endocardial strain lowered the values of LV strain in the whole layer. In conclusion, our results suggest that LV myocardial function may have been more compromised in the HCM-affected cats with DLVOTO.

Concomitant Septal Myectomy with Aortic Valve Replacement for Severe Aortic Stenosis with Left Ventricular Outflow Tract Obstruction

Objectives

Septal myectomy confers survival benefits on patients with hypertrophic cardiomyopathy. However, its role in the treatment of severe aortic stenosis (sAS) with left ventricular outflow tract obstruction (LVOTO) remains under investigation. Another challenging question in the era of transcatheter aortic valve replacement is who would benefit more from traditional surgical aortic valve replacement (SAVR) with myectomy. Therefore, this study aimed to investigate myectomy cases at our hospital in Japan.

Methods

A total of 740 patients who underwent SAVR for sAS between 2012 and 2019 were identified. The demographics and baseline echocardiographic findings were retrospectively compared between patients who underwent concomitant myectomy and those who did not. The myectomy group was further assessed for factors predisposing to LVOTO, operative details, echocardiographic changes, and prognosis. The resected septa were histopathologically analyzed.

Results

The myectomy group mostly comprised elderly females with a small hypercontractile heart. Myectomy with SAVR led to statistically significant improvements in concentric left ventricular hypertrophy and LVOTO parameters. Survival was comparable with that reported in previous reports, even in the elderly subset (≥ 75 years). The septa showed mild fibrosis.

Conclusions

Myectomy can be safely performed with SAVR for sAS with LVOTO, even in the elderly, and it effectively improves LVOTO. Special attention should be paid to elderly females with relatively more severe AS and a small yet extra-hypertrophic and extra-hypercontractile heart. Such patients warrant comprehensive assessment of LVOTO, and despite its invasiveness, SAVR may be potentially more beneficial by allowing direct observation of LVOTO and ancillary myectomy.

Pulmonary congestion during Exercise stress Echocardiography in Hypertrophic Cardiomyopathy

Background

B-lines detected by lung ultrasound (LUS) during exercise stress echocardiography (ESE), indicating pulmonary congestion, have not been systematically evaluated in patients with hypertrophic cardiomyopathy (HCM).

Aim

To assess the clinical, anatomical and functional correlates of pulmonary congestion elicited by exercise in HCM.

Methods

We enrolled 128 HCM patients (age 52 ± 15 years, 72 males) consecutively referred for ESE (treadmill in 46, bicycle in 82 patients) in 10 quality-controlled centers from 7 countries (Belgium, Brazil, Bulgaria, Hungary, Italy, Serbia, Spain). ESE assessment at rest and peak stress included: mitral regurgitation (MR, score from 0 to 3); E/e’; systolic pulmonary arterial pressure (SPAP) and end-diastolic volume (EDV). Change from rest to stress was calculated for each variable. Reduced preload reserve was defined by a decrease in EDV during exercise. B-lines at rest and at peak exercise were assessed by lung ultrasound with the 4-site simplified scan. B-lines positivity was considered if the sum of detected B-lines was ≥ 2.

Results

LUS was feasible in all subjects. B-lines were present in 13 patients at rest and in 38 during stress (10 vs 30%, p < 0.0001). When compared to patients without stress B-lines (n = 90), patients with B-lines (n = 38) had higher resting E/e’ (14 ± 6 vs. 11 ± 4, p = 0.016) and SPAP (33 ± 10 vs. 27 ± 7 mm Hg p = 0.002). At peak exercise, patients with B-lines had higher peak E/e’ (17 ± 6 vs. 13 ± 5 p = 0.003) and stress SPAP (55 ± 18 vs. 40 ± 12 mm Hg p < 0.0001), reduced preload reserve (68 vs. 30%, p = 0.001) and an increase in MR (42 vs. 17%, p = 0.013) compared to patients without congestion. Among baseline parameters, the number of B-lines and SPAP were the only independent predictors of exercise pulmonary congestion.

Conclusions

Two-thirds of HCM patients who develop pulmonary congestion on exercise had no evidence of B-lines at rest. Diastolic impairment and mitral regurgitation were key determinants of pulmonary congestion during ESE. These findings underscore the importance of evaluating hemodynamic stability by physiological stress in HCM, particularly in the presence of unexplained symptoms and functional limitation.

Association of NT-proBNP and hs-cTnT with Imaging Markers of Diastolic Dysfunction and Focal Myocardial Fibrosis in Hypertrophic Cardiomyopathy

Serum biomarkers such as N-terminal prohormone of the brain natriuretic peptide (NT-proBNP) and cardiac troponins are elevated in patients with hypertrophic cardiomyopathy (HCM). At present, it is not clear if these markers are associated with distinct clinical alterations in HCM, such as left ventricular hypertrophy, outflow tract obstruction, myocardial fibrosis and/or diastolic dysfunction (DD), which are associated with adverse cardiovascular outcome. Here we evaluate the association of NT-proBNP and high sensitivity cardiac troponin T (hs-cTnT) to a variety of cardiac imaging parameters in HCM patients in a multivariable regression analysis. This retrospective cross-sectional study included 366 HCM patients who underwent transthoracic echocardiography (TTE), 218 of whom also obtained cardiovascular magnetic resonance (CMR) to assess focal myocardial fibrosis by LGE. Multivariable regression analyses revealed the strongest association of the DD parameters E/E′ mean and E/E′ septal with NT-proBNP (b = 0.06, 95%-CI [0.05−0.07], p < 0.001, R2 = 0.28; b = 0.08, 95%-CI [0.06−0.1], p < 0.001, R2 = 0.25) and LGE size showed the strongest association with hs-cTnT (b = 0.20, 95%-CI [0.15−0.24], p < 0.001, R2 = 0.28). This study indicates that NT-proBNP and hs-cTnT are associated with structural and functional alterations in HCM. NT-proBNP is a stronger predictor for DD, while hs-cTnT is associated with the extent of focal myocardial fibrosis. Both biomarkers might be useful in the diagnostic procedure in addition to imaging parameters.

Endocardial Radiofrequency Ablation vs. Septal Myectomy in Patients With Hypertrophic Obstructive Cardiomyopathy: A Systematic Review and Meta-Analysis

Background

Septal myectomy (SM) has been the gold standard therapy for most patients with hypertrophic obstructive cardiomyopathy (HOCM). Endocardial radiofrequency ablation of septal hypertrophy (ERASH) is a novel treatment for septal reduction. We aimed to assess the efficacy and safety between two treatment strategies.

Methods

We searched PubMed, Web of Science, Cochrane Library, and Embase databases to identify relevant studies published up to March 2021. Random-effect models were used to calculate standardized mean difference (SMD) and 95% confidence intervals (CIs) for resting left ventricular outflow tract gradient (LVOTG) and septal thickness.

Results

Twenty-five studies are included in this review, eighteen studies for SM and seven studies for ERASH. During follow-up, there were significant reductions of the mean resting LVOTG in adults (SM groups: SMD = −3.03, 95% CI [−3.62 to −2.44]; ERASH groups: SMD = −1.95, 95% CI [−2.45 to −1.45]) and children (SM groups: SMD = −2.67, 95% CI [−3.21 to −2.12]; ERASH groups: SMD= −2.37, 95% CI [−3.02 to −1.73]) after the septal reduction therapies. For adults, SM groups contributed to more obvious reduction than ERASH groups in interventricular septal thickness (SM groups: SMD = −1.82, 95% CI [−2.29 to −1.34]; ERASH groups: SMD = −0.43, 95% CI [−1.00 to 0.13]). The improvement of the New York Heart Association class was similar in the two groups (SM groups: 46.4%; ERASH groups: 46.7%). The periprocedural mortality in SM and ERASH were 1.1 and 1.8%, respectively.

Conclusions

This systematic review suggests that SM is superior to ERASH in the treatment of HOCM. But for the patients who are at risk for open cardiac surgeries or prefer a less invasive approach, ERASH might be an optional approach.

The Impact of Mavacamten on the Pathophysiology of Hypertrophic Cardiomyopathy: A Narrative Review

Hypertrophic cardiomyopathy (HCM) is a chronic, progressive disease of the cardiomyocyte with a diverse and heterogeneous clinical presentation and course. This diversity and heterogeneity have added to the complexity of modeling the pathophysiological pathways that contribute to the disease burden. The development of novel therapeutic approaches targeting precise mechanisms within the underlying biology of HCM provides a tool to model and test these pathways. Here, we integrate the results of clinical observations with mavacamten, an allosteric, selective, and reversible inhibitor of cardiac myosin, the motor unit of the sarcomere, to develop an integrated pathophysiological pathway model of HCM, confirming the key role of excess sarcomeric activity. This model may serve as a foundation to understand the role of HCM pathophysiological pathways in the clinical presentation of the disease, and how a targeted therapeutic intervention capable of normalizing sarcomeric activity and repopulating low-energy utilization states may reduce the impact of these pathways in HCM and potentially related disease states.

Transapical Ventricular Remodeling for Hypertrophic Cardiomyopathy With Systolic Cavity Obliteration

BACKGROUND

Some patients with hypertrophic cardiomyopathy (HCM) present with reduced left ventricular (LV) stroke volume and elongated systolic cavity obliteration due to symmetric LV hypertrophy. In this report, we detail our experience with transapical septal myectomy to enlarge the LV volume and to relieve cavity obliteration in this unique subgroup of patients with HCM.

METHODS

We analyzed 38 patients with HCM who had extended symmetric LV hypertrophy and underwent transapical septal myectomy to enlarge the LV cavity from February 2001 to May 2021.

RESULTS

At the time of evaluation for operation, 84.2% (n = 32) of the patients were in New York Heart Association class III/IV. The peak oxygen consumption was 51.5% (44.0%-58.0%) of the normal predicted values on the preoperative exercise stress test (n = 16). Preoperative left atrial sizes in this cohort were enlarged (left atrial volume index, 39.0 [33.5-51.5] mL/m²), despite only 4 patients with moderate or greater mitral valve regurgitation. All patients underwent transapical septal myectomy to enlarge the LV cavity size. There was no postoperative (within 30 days) death. During a median (interquartile range) follow-up of 3.4 (0.7-6.9) years, the estimated survival rates were 100%, 92%, and 87% at 1, 3, and 5 years, respectively. Follow-up surveys suggested that 16 of the 17 contacted patients experienced improvement in their heart function after the procedure.

CONCLUSIONS

Transapical myectomy to enlarge LV cavity volume can be performed safely with good early survival and functional results. This procedure is an important alternative to cardiac transplantation for HCM patients with systolic cavity obliteration and progressive heart failure.

Determinants of Exercise Capacity in Patients With Hypertrophic Cardiomyopathy

BACKGROUND

Reduced exercise capacity reflects symptom severity and clinical outcomes in patients with hypertrophic cardiomyopathy (HCM). The present study aimed to identify factors that may affect exercise capacity in patients with HCM.

METHODS

In 294 patients with HCM and preserved left ventricular (LV) ejection fraction, we compared peak oxygen consumption (peak VO₂) evaluated by cardiopulmonary exercise testing as a representative parameter of exercise tolerance with clinical and laboratory data, including N-terminal pro-hormone of brain natriuretic peptide (NT-proBNP), diastolic parameters on echocardiography, and the grade of myocardial fibrosis on cardiac magnetic resonance imaging (CMR).

RESULTS

Median peak VO₂, was 29.0 mL/kg/min (interquartile range [IQR], 25.0-34.0). Age (estimated β = -0.140, P < 0.001), female sex (β = -5.362, P < 0.001), NT-proBNP (β = -1.256, P < 0.001), and E/e' ratio on echocardiography (β = -0.209, P = 0.019) were significantly associated with exercise capacity. Peak VO₂ was not associated with the amount of myocardial fibrosis on CMR (mean of late gadolinium enhancement 12.25 ± 9.67%LV).

CONCLUSION

Decreased exercise capacity was associated with age, female sex, increased NT-proBNP level, and E/e' ratio on echocardiography. Hemodynamic changes and increased filling pressure on echocardiography should be monitored in this population for improved outcomes.

A complex unit for a complex disease: the HCM-Family Unit

Hypertrophic cardiomyopathy (HCM) is a group of heterogeneous disorders that are most commonly passed on in a heritable manner. It is a relatively rare disease around the globe, but due to increased rates of consanguinity within the Kingdom of Saudi Arabia, we speculate a high incidence of undiagnosed cases. The aim of this paper is to elucidate a systematic approach in dealing with HCM patients and since HCM has variable presentation, we have summarized differentials for diagnosis and how different subtypes and genes can have an impact on the clinical picture, management and prognosis. Moreover, we propose a referral multi-disciplinary team HCM-Family Unit in Saudi Arabia and an integrated role in a network between King Faisal Hospital and Inherited and Rare Cardiovascular Disease Unit-Monaldi Hospital, Italy (among the 24 excellence centers of the European Reference Network (ERN) GUARD-Heart).   Graphical Abstract.

Surgical management of diastolic heart failure after septal myectomy for obstructive hypertrophic cardiomyopathy

Objective

Some patients with obstructive hypertrophic cardiomyopathy may remain limited after surgical relief of the subaortic obstruction. In this report, we describe experience in surgical management of patients with advanced diastolic heart failure symptoms after adequate transaortic septal myectomy for obstructive hypertrophic cardiomyopathy.

Methods

We identified adult patients who presented with heart failure symptoms after previous transaortic septal myectomy for obstructive hypertrophic cardiomyopathy and underwent repeat sternotomy for transapical myectomy to enlarge a small left ventricular cavity. Functional recovery after hospital dismissal was assessed through a questionnaire-based survey.

Results

Six patients with previous septal myectomy presented with New York Heart Association functional class III symptoms. Preoperative transthoracic Doppler echocardiography confirmed adequate relief of subaortic outflow tract obstruction with only trivial or mild mitral valve regurgitation; left atrial volume index was increased at 46 mL/m² (range, 44-47 mL/m²). Following transapical myectomy, the left ventricular diameter was enlarged from 23 mm (range, 21-27 mm) to 29 mm (range, 27-31 mm) at end-systole and from 40 mm (range, 38-42 mm) to 43 mm (range, 42-50 mm) at end-diastole. All the patients were alive after a median follow-up of 0.6 years (range, 0.4-3.5 years), and 5 patients responded to a postoperative survey and indicated improvement in their heart condition compared with functional status before the repeat myectomy.

Conclusions

Patients with diastolic heart failure after septal myectomy for obstructive hypertrophic cardiomyopathy may present with systolic cavity obliteration due to excessive myocardial hypertrophy. Repeat transapical myectomy can enlarge the left ventricular chamber and augment the diastolic volume, which results in improved physical capacity and patient-perceived functional status.

Preintervention imaging and intraoperative management care of the hypertrophic obstructive cardiomyopathy patient

With an estimated overall mortality of less than 1 percent per year, hypertrophic cardiomyopathy, is the most common genetic cardiomyopathy. Intraoperative transesophageal echocardiography is the standard of care for assessing patients with hypertrophic obstructive cardiomyopathy undergoing surgical septal myectomy, allowing surgical planning, intraoperative hemodynamic monitoring, and postprocedural assessment of the repair, including detection of immediate complications. At various phases during surgical septal myectomy, the changing hemodynamic conditions may lead to worsening or improvement in left ventricle outflow tract obstruction by change in preload or afterload, systolic anterior motion of the mitral valve, or sympathetic stimulation. These characteristics represent unique challenges in the management of these patients, requiring a comprehensive understanding of the management of all the conditions required to decrease the left ventricle outflow tract gradient avoiding obstruction, which include the maintenance of sinus rhythm, adequate rate avoiding tachycardia and bradycardia, and avoidance of systemic hypotension preserving preload and afterload, with adequate vasoactive agents. The aim of this review is to summarize the perioperative assessment and management of patients undergoing hypertrophic obstructive myopathy surgery.

Hypertrophic cardiomyopathy with latent obstruction: Clinical characteristics and surgical results

BACKGROUND

The role of mitral subvalvular anomalies in the etiology of latent left ventricular outflow tract (LVOT) obstruction has rarely been reported; and the results of surgical treatment for latent LVOT obstruction have been infrequently reported as a separate group by other medical centers other than Mayo clinic.

METHODS

Among 292 eligible patients, 45 with resting gradients <30 mmHg had provoked obstruction. Their clinical characteristics and surgical results were compared with those of 247 patients with resting LVOT obstruction. The patients were followed up for a median of 13 months.

RESULTS

Comparatively, patients with latent obstruction were younger (51.6±12.1 years vs. 57.2±11.6 years, p=0.003) and had higher prevalence of mitral subvalvular abnormalities (73.3% vs. 16.2%, p<0.001) and basal variant of hypertrophic cardiomyopathy (84.5% vs. 62.0%, p=0.014), less marked septal thickness (16.9±2.8 mm vs. 18.6±3.8 mm, p=0.005), lower resting gradients (22.2±5.7 mmHg vs. 93.0±25.7 mmHg, p < 0.001), and lower mitral regurgitation severity (median, 2.0 vs. 3.0, p<0.001). After surgery, no surgical death occurred in patients with latent LVOT obstruction. Only one (2.2%) patient from the latent group developed complete atrioventricular block. No follow-up death or reoperation was recorded with a significant improvement in New York Heart Association functional status in either group. The provoked LVOT gradients of patients with latent obstruction decreased sharply from the preoperative value (11.8±3.7 mmHg vs. 89.8±16.4 mmHg, p < 0.001), with no occurrence of residual obstruction.

CONCLUSIONS

Symptomatic patients with latent LVOT obstruction may have a higher prevalence of mitral subvalvular abnormalities and have less marked septal hypertrophy; and concomitant mitral management during myectomy for the treatment of this patient group achieved excellent results.

Automatic Electrocardiogram Detection of Suspected Hypertrophic Cardiomyopathy: Application to Wearable Heart Monitors

In this letter, an automatic detection algorithm for hypertrophic cardiomyopathy (HCM) is presented. Of particular interest is the algorithm's ability to differentiate HCM subjects and healthy volunteers from a single lead ECG dataset. Suspected HCM subjects are identified by the primary clinical abnormality associated with HCM: left ventricular hypertrophy (LVH). In total, n = 43 human subjects ECG datasets are investigated: n = 21 healthy volunteers and n = 22 LVH patients. Significant differences of p-value 0.01 and 0.04 were found for the respective ECG parameters, i.e., S-wave amplitude and ST-segment, when differentiating between the LVH patients and healthy human volunteers.

Cardiopulmonary Exercise Test in Patients with Hypertrophic Cardiomyopathy: A Systematic Review and Meta-Analysis

BACKGROUND

Patients with chronic diseases frequently adapt their lifestyles to their functional limitations. Functional capacity in Hypertrophic Cardiomyopathy (HCM) can be assessed by stress testing. We aim to review and analyze the available data from the literature on the value of Cardiopulmonary Exercise Test (CPET) in HCM. Objective measurements from CPET are used for evaluation of patient response to traditional and new developing therapeutic measurements.

METHODS

A systematic review of the literature was conducted in PubMed, Web of Science and Cochrane in Mar-20. The original search yielded 2628 results. One hundred and two full texts were read after the first screening, of which, 69 were included for qualitative synthesis. Relevant variables to be included in the review were set and 17 were selected, including comorbidities, body mass index (BMI), cardiac-related symptoms, echocardiographic variables, medications and outcomes.

RESULTS

Study sample consisted of 69 research articles, including 11,672 patients (48 ± 14 years old, 65.9%/34.1% men/women). Treadmill was the most common instrument employed (n = 37 studies), followed by upright cycle-ergometer (n = 16 studies). Mean maximal oxygen consumption (VO2max) was 22.3 ± 3.8 mL·kg^-1·min^-1. The highest average values were observed in supine and upright cycle-ergometer (25.3 ± 6.5 and 24.8 ± 9.1 mL·kg^-1·min^-1; respectively). Oxygen consumption in the anaerobic threshold (ATVO2) was reported in 18 publications. Left ventricular outflow tract gradient (LVOT) > 30 mmHg was present at baseline in 31.4% of cases. It increased to 49% during exercise. Proportion of abnormal blood pressure response (ABPRE) was higher in severe (>20 mm) vs. mild hypertrophy groups (17.9% vs. 13.6%, p < 0.001). Mean VO2max was not significantly different between severe vs. milder hypertrophy, or for obstructive vs. non-obstructive groups. Occurrence of arrhythmias during functional assessment was higher among younger adults (5.42% vs. 1.69% in older adults, p < 0.001). Twenty-three publications (9145 patients) evaluated the prognostic value of exercise capacity. There were 8.5% total deaths, 6.7% cardiovascular deaths, 3.0% sudden cardiac deaths (SCD), 1.2% heart failure death, 0.6% resuscitated cardiac arrests, 1.1% transplants, 2.6% implantable cardioverter defibrillator (ICD) therapies and 1.2 strokes (mean follow-up: 3.81 ± 2.77 years). VO2max, ATVO2, METs, % of age-gender predicted VO2max, % of age-gender predicted METs, ABPRE and ventricular arrhythmias were significantly associated with major outcomes individually. Mean VO2max was reduced in patients who reached the combined cardiovascular death outcome compared to those who survived (-6.20 mL·kg^-1·min^-1; CI 95%: -7.95, -4.46; p < 0.01).

CONCLUSIONS

CPET is a valuable tool and can safely perform for assessment of physical functional capacity in patients with HCM. VO2max is the most common performance measurement evaluated in functional studies, showing higher values in those based on cycle-ergometer compared to treadmill. Subgroup analysis shows that exercise intolerance seems to be more related to age, medication and comorbidities than HCM phenotype itself. Lower VO2max is consistently seen in HCM patients at major cardiovascular risk.

Uric acid is associated with cardiac death in patients with hypertrophic obstructive cardiomyopathy

BACKGROUND

The role of uric acid (UA) in survival of patients with hypertrophic obstructive cardiomyopathy (HOCM) has not been fully evaluated. This study aimed to determine whether UA could be an independent risk factor of cardiac death in patients with HOCM.

METHODS

A total of 317 patients with HOCM, who were receiving conservative treatment in Fuwai Hospital from October 2009 to December 2014, all of them completed UA evaluations, were analyzed. Patients were divided into three groups according to the UA levels: Tertile 1 (≤ 318 μmol/L, n = 106), Tertile 2 (319 to 397 μmol/L, n = 105), and Tertile 3 (≥ 398 μmol/L, n = 106).

RESULTS

During a median follow-up of 45 months, 29 cardiac deaths (9.1%) occurred, including 6 sudden cardiac deaths and 23 heart failure-related deaths. Cardiac death in Tertile 3 (n = 16, 55.2%) was significantly higher than in Tertile 1 (n = 6, 20.7%) and Tertile 2 (n = 7, 24.1%). In univariate model, UA level (continuous value) showed predictive value of cardiac death [hazard ratio (HR) = 1.006, 95% CI: 1.003−1.009,P = 0.009]. Univariate Cox survival analysis had shown a significant higher property of cardiac death in patients of Tertile 3 when compared with those of Tertile 1, but cardiac death in patients of Tertile 2 did not show significant prognositic value compared with those of Tertile 1 (HR = 3.927, 95% CI: 0.666−23.162,P = 0.131). UA was found to be an independent risk factor (HR = 1.005, 95% CI: 1.001−1.009,P = 0.009) of cardiac death in the multivariate regression analysis after the adjustment for age, body mass index, atrial fibrillation, hemoglobin, creatinine, high-sensitivity C-reactive protein, interventricular septum/left ventricular posterior wall ratio, left ventricular outflow tract and left ventricular ejection fraction.

CONCLUSIONS

UA concentration was found to be independently associated with cardiac death in HOCM patients receiving conservative treatment. Randomized trials of UA-lowering agents for HOCM patients are warranted.

2020 AHA/ACC Guideline for the Diagnosis and Treatment of Patients With Hypertrophic Cardiomyopathy: Executive Summary: A Report of the American College of Cardiology/American Heart Association Joint Committee on Clinical Practice Guidelines

AIM

This executive summary of the hypertrophic cardiomyopathy clinical practice guideline provides recommendations and algorithms for clinicians to diagnose and manage hypertrophic cardiomyopathy in adult and pediatric patients as well as supporting documentation to encourage their use.

METHODS

A comprehensive literature search was conducted from January 1, 2010, to April 30, 2020, encompassing studies, reviews, and other evidence conducted on human subjects that were published in English from PubMed, EMBASE, the Cochrane Collaboration, Agency for Healthcare Research and Quality reports, and other relevant databases.

STRUCTURE

Many recommendations from the earlier hypertrophic cardiomyopathy guidelines have been updated with new evidence or a better understanding of earlier evidence. This summary operationalizes the recommendations from the full guideline and presents a combination of diagnostic work-up, genetic and family screening, risk stratification approaches, lifestyle modifications, surgical and catheter interventions, and medications that constitute components of guideline directed medical therapy. For both guideline-directed medical therapy and other recommended drug treatment regimens, the reader is advised to follow dosing, contraindications and drug-drug interactions based on product insert materials.

2020 AHA/ACC Guideline for the Diagnosis and Treatment of Patients With Hypertrophic Cardiomyopathy: Executive Summary: A Report of the American College of Cardiology/American Heart Association Joint Committee on Clinical Practice Guidelines

Aim This executive summary of the hypertrophic cardiomyopathy clinical practice guideline provides recommendations and algorithms for clinicians to diagnose and manage hypertrophic cardiomyopathy in adult and pediatric patients as well as supporting documentation to encourage their use. Methods A comprehensive literature search was conducted from January 1, 2010, to April 30, 2020, encompassing studies, reviews, and other evidence conducted on human subjects that were published in English from PubMed, EMBASE, the Cochrane Collaboration, Agency for Healthcare Research and Quality reports, and other relevant databases. Structure Many recommendations from the earlier hypertrophic cardiomyopathy guidelines have been updated with new evidence or a better understanding of earlier evidence. This summary operationalizes the recommendations from the full guideline and presents a combination of diagnostic work-up, genetic and family screening, risk stratification approaches, lifestyle modifications, surgical and catheter interventions, and medications that constitute components of guideline directed medical therapy. For both guideline-directed medical therapy and other recommended drug treatment regimens, the reader is advised to follow dosing, contraindications and drug-drug interactions based on product insert materials.

Progression of Myocardial Fibrosis in Hypertrophic Cardiomyopathy: A Cardiac Magnetic Resonance Study

OBJECTIVES

This study examined fibrosis progression in hypertrophic cardiomyopathy (HCM) patients, as well as its relationship to patient characteristics, clinical outcomes, and its effect on clinical decision making.

BACKGROUND

Myocardial fibrosis, as quantified by late gadolinium enhancement (LGE) in cardiac magnetic resonance (CMR), provides valuable prognostic information in patients with HCM.

METHODS

A total of 157 patients with HCM were enrolled in this study, with 2 sequential CMR scans separated by an interval of 4.7 ± 1.9 years.

RESULTS

At the first CMR session (CMR-1), 70% of patients had LGE compared with 85% at CMR-2 (p = 0.001). The extent of LGE extent increased between the 2 CMR procedures, from 4.0 ± 5.6% to 6.3 ± 7.4% (p < 0.0001), with an average LGE progression rate of 0.5 ± 1.0%/year. LGE mass progression was correlated with higher LGE mass and extent on CMR-1 (p = 0.0017 and p = 0.007, respectively), greater indexed left ventricular (LV) mass (p < 0.0001), greater LV maximal wall thickness (p < 0.0001), apical aneurysm at CMR-1 (p < 0.0001), and lower LV ejection fraction (EF) (p = 0.029). Patients who were more likely to have a higher rate of LGE progression presented with more severe disease at baseline, characterized by LGE extent >8% of LV mass, indexed LV mass >100 g/m², maximal wall thickness ≥20 mm, LVEF ≤60%, and apical aneurysm. There was a significant correlation between the magnitude of LGE progression and future implantation of insertable cardioverter-defibrillators (p = 0.004), EF deterioration to ≤50% (p < 0.0001), and admission for heart failure (p = 0.0006).

CONCLUSIONS

Myocardial fibrosis in patients with HCM is a slowly progressive process. Progression of LGE is significantly correlated with a number of clinical outcomes such as progression to EF ≤50% and heart failure admission. Judicious use of serial CMR with LGE can provide valuable information to help patient management.

Neo-LVOT and Transcatheter Mitral Valve Replacement: Expert Recommendations

With the advent of transcatheter mitral valve replacement (TMVR), the concept of the neo-left ventricular outflow tract (LVOT) was introduced and remains an essential component of treatment planning. This paper describes the LVOT anatomy and provides a step-by-step computed tomography methodology to segment and measure the neo-LVOT while discussing the current evidence and outstanding challenges. It also discusses the technical and hemodynamic factors that play a major role in assessing the neo-LVOT. A summary of expert-based recommendations about the overall risk of LVOT obstruction in different scenarios is presented along with the currently available methods to reduce the risk of LVOT obstruction and other post-procedural complications.

Clinical presentation and survival of childhood hypertrophic cardiomyopathy: a retrospective study in United Kingdom

Aims

Understanding the spectrum of disease, symptom burden and natural history are essential for the management of children with hypertrophic cardiomyopathy (HCM). The effect of changing screening practices over time has not previously been studied. This study describes the clinical characteristics and outcomes of childhood HCM over four decades in a well-characterized United Kingdom cohort.

Methods and results

Six hundred and eighty-seven patients with HCM presented at a median age of 5.2 years (range 0–16). Aetiology was: non-syndromic (n = 433, 63%), RASopathy (n = 126, 18.3%), Friedreich’s ataxia (n = 59, 8.6%) or inborn errors of metabolism (IEM) (n = 64, 9%). In infants (n = 159, 23%) underlying aetiology was more commonly a RASopathy (42% vs. 11.2%, P < 0.0001) or IEM (18.9% vs. 6.4% P < 0.0001). In those with familial disease, median age of presentation was higher (11 years vs. 6 years, P < 0.0001), 141 (58%) presented <12 years. Freedom from death or transplantation was 90.6% (87.9–92.7%) at 5 years (1.5 per 100 patient years) with no era effect. Mortality was most frequently sudden cardiac death (SCD) (n = 20, 2.9%). Children diagnosed during infancy or with an IEM had a worse prognosis (5-year survival 80.5% or 66.4%). Arrhythmic events occurred at a rate of 1.2 per 100 patient years and were more likely in non-syndromic patients (n = 51, 88%).

Conclusion

This national study describes a heterogeneous disease whose outcomes depend on the age of presentation and aetiology. Overall mortality and SCD rates have not changed over time, but they remain higher than in adults with HCM, with events occurring in syndromic and non-syndromic patients.

Left ventricular remodeling in elite and sub-elite road cyclists

Marked adaptation of left ventricular (LV) structure in endurance athletes is well established. However, previous investigations of functional and mechanical adaptation have been contradictory. A lack of clarity in subjects' athletic performance level may have contributed to these disparate findings. This study aimed to describe structural, functional, and mechanical characteristics of the cyclists' LV, based on clearly defined performance levels. Male elite cyclists (EC) (n = 69), sub-elite cyclists (SEC) (n = 30), and non-athletes (NA) (n = 46) were comparatively studied using conventional and speckle tracking 2D echocardiography. Dilated eccentric hypertrophy was common in EC (34.7%), but not SEC (3.3%). Chamber concentricity was higher in EC compared to SEC (7.11 ± 1.08 vs 5.85 ± 0.98 g/(mL)^2/3 , P < .001). Ejection fraction (EF) was lower in EC compared to NA (57 ± 5% vs 59 ± 4%, P < .05), and reduced EF was observed in a greater proportion of EC (11.6%) compared to SEC (6.7%). Global circumferential strain (GCε) was greater in EC (-18.4 ± 2.4%) and SEC (-19.8 ± 2.7%) compared to NA (-17.2 ± 2.6%) (P < .05 and P < .001). Early diastolic filling was lower in EC compared with SEC (0.72 ± 0.14 vs 0.88 ± 0.12 cm/s, P < .001), as were septal E' (12 ± 2 vs 15 ± 2 cm/s, P < .001) and lateral E' (18 ± 4 vs 20 ± 4 cm/s, P < .05). The magnitude of LV structural adaptation was far greater in EC compared with SEC. Increased GCε may represent a compensatory mechanism to maintain stroke volume in the presence of increased chamber volume. Decreased E and E' velocities may be indicative of a considerable functional reserve in EC.

Left Ventricular Mass in Hypertrophic Cardiomyopathy Assessed by 2D-Echocardiography: Validation with Magnetic Resonance Imaging

We aim to validate echocardiographic left ventricular (LV) mass (echoLVM) in sixty-one patients with hypertrophic cardiomyopathy (HCM), using cardiac magnetic resonance measures (cmrLVM) as gold standard. cmrLVM was calculated using LV short-axis images, from base to apex, whereas echoLVM by LV epicardial minus LV endocardial volumes in 4 and 2 chamber views, using Simpson disk summation; trabeculae and papillary muscle were excluded in both cmrLVM and echoLVM. cmrLVM and echoLVM were not different by paired t test (145 ± 66 vs 147 ± 61; p = 0.240), and their correlation was good (r = 0.977; p < 0.0001). Intraclass correlation demonstrated reliability of echoLVM with cmrLVM (ρ = 0.987; Cls = 0.978-0.992; p < 0.0001). LV end-diastolic volume was higher by CMR than that by echo (137 ± 33 vs 85 ± 28 mL, p < 0.0001), resulting in a lower mass/volume ratio (1.1 ± 0.4 vs 1.8 ± 0.8, p < 0.0001). EchoLVM may be determined in patients with HCM. However, mass/volume ratio is higher by echocardiography than that by CMR.

Ventricular tachycardia and heart failure in a patient of mid-ventricular obstructive hypertrophic cardiomyopathy with apical aneurysm: A case report

Mid-ventricular obstructive hypertrophic cardiomyopathy (MVOHC) with apical aneurysm is a rare type of cardiomyopathy. It is associated with an elevated risk of ventricular arrhythmias, thromboembolism, heart failure and sudden cardiac death. The present case study reports on a patient with MVOHC and apical aneurysm who developed ventricular arrhythmias and heart failure. The patient received an implantable cardioverter defibrillator for prevention of fatal arrhythmias. Ventricular tachycardia was terminated by increased doses of amiodarone and β-blocker. Transthoracic echocardiography indicated a mid-ventricular gradient of 64 mmHg. The patient refused surgical treatment and opted for alcohol septal ablation (ASA). At the 6-month follow-up, a rebound of the gradient following ASA was observed on echocardiography. In the present study, timely recognition of MVOHC with apical aneurysm led to prompt defibrillator implantation for prophylaxis regarding further malignant arrhythmias. Surgical management should be considered in symptomatic patients with MVOHC and apical aneurysm.

Echocardiographic measurements of left ventricular end-diastolic diameter and interventricular septal diameter in collegiate football athletes at preparticipation evaluation referenced to body surface area

Background

Are borderline echocardiogram structural measurements due to physiological adaptation or pathology in college football players? The normal reference data are very limited in this population. We report left ventricular end-diastolic diameter (LVEDD) and interventricular septal diameter (IVSD) echocardiogram findings in college football athletes.

Methods and results

A retrospective cohort review of preparticipation examination transthoracic echocardiogram measurements of LVEDD and IVSD from 375 American collegiate football athletes cleared for participation from the University of Florida in 2012–2017 and University of Georgia in 2010–2015 was performed.

LVEDD and IVSD were analysed by field position (lineman, n=137; non-lineman, n=238), race (black, n=216; white, n=158) and body surface area (BSA) for associations. Values were compared with non-athlete norms, and collegiate football athlete-specific reference norm tables were created.

Twenty-one (5.6%) athletes had LVEDD and 116 (31%) had IVSD measurements above the reference normal non-athlete values. Univariate analyses indicated that the lineman position and increasing BSA were associated with larger values for LVEDD and IVSD. Black race was associated with larger IVSD values, and white race was associated with larger LVEDD values. Player position correlated strongly with BSA (r>0.7); we created normal reference tables for LVEDD and IVSD, stratified by BSA group classification (low, average and high BSA). Proposed clinical cut-offs for normal and abnormal values are reported for raw echocardiograph metrics and BSA-indexed scores.

Conclusions

A significant number of collegiate football athletes had LVEDD and IVSD values above non-athlete norms. BSA-specific normal values help clinicians interpret results for football athletes.

Left atrial remodeling postseptal myectomy for severe obstructive hypertrophic cardiomyopathy: Analysis by two-dimensional speckle-tracking echocardiography

BACKGROUND

Septal myectomy relieves left ventricular outflow obstruction (LVOTO) and is associated with excellent long-term outcomes. LVOTO is associated with diastolic dysfunction and increased left atrial (LA) size. We sought to investigate the changes in LA volumes and function postmyectomy and the association between these changes with clinical outcomes postmyectomy.

METHODS

Sixty-six hypertrophic cardiomyopathy patients undergoing myectomy were retrospectively studied. Preprocedural and 6- to 18-month postmyectomy follow-up transthoracic echocardiographic images were obtained. LA volumes and strain were assessed by two-dimensional speckle-tracking echocardiography.

RESULTS

Left atrial volumes, that is, indexed maximal, minimal, and pre-A volumes reduced postmyectomy, yet remained increased compared to controls (105.6 ± 34.5 mL vs 84.9 ± 26.7 mL, 45.2 ± 25.7 mL vs 35.4 ± 22.6 mL, 70.1 ± 31.4 mL vs 35.4 ± 22.6 mL, respectively, P < 0.05). The total emptying index did not improve postmyectomy and remained lower than controls (58.6 ± 12.4 vs 59.9 ± 12.8, P = NS) whereas atrial contraction improved, yet did not normalize (active emptying index 36.1 ± 14.9 vs 41.1 ± 16.2, P < 0.05). The conduit volume remained reduced postmyectomy (18.6 ± 13.3 mL vs 16.6 ± 15.1 mL, P = NS). LA strain also did not improve postmyectomy (26.8 ± 7.3 vs 28.5 ± 8.8, P = NS). A multivariable logistic regression identified preprocedural E/e' ratio and indexed maximal LA volume, as independent predictors for LA volume reduction ≥20% postmyectomy. During a mean follow-up of 4.9 ± 2.3 years postmyectomy, 24.2% of the patients developed atrial fibrillation and <5% of patients were severely symptomatic. We found no associations between LA volumes/function and atrial fibrillation or symptoms postmyectomy.

CONCLUSION

Postmyectomy LA volumes decreased, and the contractile function improved. There was no association between LA volumes/function and clinical outcomes postmyectomy. Notably, the LA remained enlarged (though to a lesser degree) with reduced strain and emptying fraction, suggesting possible atrial myopathy.

Outcomes following general anaesthesia in children with hypertrophic cardiomyopathy

BACKGROUND

Children with hypertrophic cardiomyopathy (HCM) have historically been considered to be high-risk candidates for general anaesthesia (GA), but there is currently a paucity of evidence regarding the safety of anaesthesia and perioperative outcomes in this population.

METHODS

Clinical features and outcomes of all paediatric patients (<18 years) with HCM undergoing GA between 2000 and 2016 were reviewed.

RESULTS

86 patients (median 12.4 years (IQR 6.5, 14.9)) underwent 164 separate GA procedures. Aetiology included non-syndromic disease (n=44, 56%), malformation syndromes (n=22, 26%), inborn error of metabolism (n=10, 12%) and neuromuscular disease (n=4, 5%). At the time of GA, mean maximal wall thickness (MWT) on echocardiography was 19 mm (SD±8 mm), 23 (14%) patients had severe left ventricular hypertrophy (MWT>30 mm) and 35 (21%) patients had a haemodynamically significant left ventricular outflow tract (LVOT) gradient (>50 mm Hg). The majority (n=143, 87%) had no perioperative complications. 20 (12%) patients had minor perioperative complications: bradycardia (n=4), hypotension (n=15) or transient ST segment changes (n=1). One (0.6% of GA procedures) patient experienced a cardiac arrest during anaesthetic induction with death occurring 3 days later. Clinical parameters (including age, MWT, LVOT gradient, systolic and diastolic dysfunction) were not associated with an increased risk of complications CONCLUSIONS: This is the largest published series to date of paediatric patients with HCM undergoing GA, which demonstrates that, in an expert centre, patients can be anaesthetised with a relatively low perianaesthetic mortality (0.6%) and prevalence of minor complications (12%). Future studies are required to systematically identify clinical features that may predict anaesthetic risk.

Yield of Clinical Screening for Hypertrophic Cardiomyopathy in Child First-Degree Relatives

BACKGROUND

Hypertrophic cardiomyopathy (HCM) is a heritable myocardial disease with age-related penetrance. Current guidelines recommend clinical screening of relatives beginning at 10 years of age, but the clinical value of this approach has not been systematically evaluated.

METHODS

Anonymized clinical data were collected from children referred for family screening between 1994 and 2017 after diagnosis of HCM in a first-degree relative.

RESULTS

Of 1198 consecutive children (≤18 years of age) from 594 families who underwent serial evaluation (median, 3.5 years; interquartile range, 1.2-7), 32 individuals met diagnostic criteria at baseline (median maximal left ventricular wall thickness, 13 mm; interquartile range, 8-21 mm), and 25 additional patients developed HCM during follow-up. Median age at diagnosis was 10 years (interquartile range, 4-13 years); 44 (72%) were ≤12 years of age. Median age of affected patients at the last follow-up was 14 years (interquartile range, 9.5-18.2 years). A family history of childhood HCM was more common in those patients diagnosed with HCM (n=32 [56%] versus n=257 [23%]; P<0.001). Eighteen patients (32%) were started on medication for symptoms; 2 (4%) underwent a septal myectomy; 14 (25%) received an implantable cardioverter-defibrillator; 1 underwent cardiac transplantation; 2 had a resuscitated cardiac arrest; and 1 died after a cerebrovascular accident.

CONCLUSIONS

Almost 5% of first-degree child relatives undergoing screening meet diagnostic criteria for HCM at first or subsequent evaluations, with the majority presenting as preadolescents; a diagnosis in a child first-degree relative is made in 8% of families screened. The phenotype of familial HCM in childhood is varied and includes severe disease, suggesting that clinical screening should begin at a younger age.

Clinicopathological and Genetic Profiles of Cases with Myocytes Disarray-Investigation for Establishing the Autopsy Diagnostic Criteria for Hypertrophic Cardiomyopathy

Myocyte disarray of >10% in the heart is broadly accepted as a diagnostic pitfall for hypertrophic cardiomyopathy (HCM) at postmortem. The present study aims to propose an additional diagnostic criterion of HCM. Heart specimens from 1387 serial forensic autopsy cases were examined. Cases with myocyte disarray were extracted and applied to morphometric analysis to determine the amount of myocyte disarray. Comprehensive genetic analysis by using next-generation sequencing was subsequently applied for cases with myocyte disarray. Fifteen cases with myocyte disarray were extracted as candidate cases (1.1%, 11 men and 4 women, aged 48–94 years). In terms of the cause of death, only 2 cases were cardiac or possible cardiac death, and the other was non-cardiac death. Six cases showed myocyte disarray of >10% and 3 cases showed myocyte disarray of 5% to 10%. The other 6 cases showed myocyte disarray of <5%. Nine rare variants in 5 HCM-related genes (MYBPC3, MYH7, MYH6, PRKAG2, and CAV3) were found in 8 of 9 cases with myocyte disarray of >5%. The remaining 1 and 6 cases with myocyte disarray of <5% did not have any such variant. Myocyte disarray of >5% with rare variants in related genes might be an appropriate postmortem diagnostic criterion for HCM, in addition to myocyte disarray of 10%.

Myocardial Contraction Fraction Predicts Cardiovascular Events in Patients With Hypertrophic Cardiomyopathy and Normal Ejection Fraction

BACKGROUND

Myocardial contraction fraction (MCF), the ratio of left ventricular stroke volume to myocardial volume, is a novel parameter that can distinguish between pathologic and physiologic hypertrophy. However, its prognostic value in hypertrophic cardiomyopathy (HCM) has never been examined. The objective was to determine if MCF is associated with functional capacity and predicts adverse cardiovascular outcomes in patients with HCM and normal left ventricular ejection fraction (LVEF).

METHODS AND RESULTS

We conducted a prospective cohort study of 137 patients with HCM and LVEF ≥55%. Patients were followed for 2.7 ± 2.5 years. We examined association of MCF with New York Heart Association (NYHA) functional class and a composite outcome of embolic stroke, heart transplantation, and cardiac death. We performed time-to-event analysis with the use of Cox proportional hazards modeling and stepwise elimination. The average age was 52 ± 18 years. The average MCF was 26 ± 11%. MCF was inversely correlated with NYHA functional class (P = .001). A total of 20 subjects experienced an outcome event with an event rate of 5.6% per patient-year. MCF independently predicted the outcome (adjusted hazard ratio 0.50 per 10% increase, 95% confidence interval 0.28-0.90, adjusted P = .02).

CONCLUSIONS

In patients with HCM and normal LVEF, MCF is associated with functional capacity and independently predicts adverse cardiovascular outcomes.

Borisov K, Seggewiß H. Hypertrophic Obstructive Cardiomyopathy

BACKGROUND

Hypertrophic cardiomyopathy (HCM) is caused by mutations in a number of genes. Its prevalence is 0.2% to 0.6%.

METHODS

This review is based on publications retrieved by a selective literature search and on the authors' clinical experi- ence.

RESULTS

70% of patients with HCM suffer from the obstructive type of the condition, clinically characterized by highly dynamic and variable manifestations in the form of dyspnea, angina pectoris, and stress-dependent presyncope and syn- cope. Younger patients are at particular risk of sudden cardiac death; thus, all patients need not only symptomatic treatment, but also risk assessment, which can be difficult in individual cases. Left ventricular obstruction, which usually causes symptoms, is treated medically at first, with either a beta- blocker or verapamil. If medical treatment fails, two invasive treatments are available, surgical myectomy and percu- taneous septum ablation. Both of these require a high level of expertise. If performed successfully, they lead to sustained gradient reduction and clinical improvement. Septum ablation is associated with low perioperative and peri-interventional mortality but necessitates permanent pacemaker implantation in 10-20% of patients.

CONCLUSION

In the absence of evidence from randomized comparison trials, a suitable method of reducing the gradient should be determined by an HCM team in conjunction with each individual patient. Important criteria for decision-making include the anatomical findings and any accompanying illnesses.

Electrocardiogram and Imaging: An Integrated Approach to Arrhythmogenic Cardiomyopathies

Cardiovascular imaging has radically changed the management of patients with arrhythmogenic cardiomyopathies. This article focuses on the role of echocardiography and MRI in the diagnosis of these structural diseases. Cardiomyopathies with hypertrophic pattern (hypertrophic cardiomyopathy, restrictive cardiomyopathies, amyloidosis, Anderson-Fabry disease, and sarcoidosis), cardiomyopathies with dilated pattern, inflammatory cardiac diseases, and right ventricular arrhythmogenic cardiomyopathy are analyzed. Finally, anatomic predictors of arrhythmias and sudden cardiac death are discussed. Each paragraph is attended by clinical cases that are discussed on the electrocardiogram, after integrated with the anatomic, functional, and hemodynamic modifications of cardiovascular imaging.

A 66-Year-Old Female with Apical Hypertrophic Cardiomyopathy Presenting with Hypertensive Crises and Type 2 Myocardial Infarction and a Normal Coronary Angiogram

A 66-year-old female presented to the emergency room with an episode of chest pain that lasted for a few minutes before resolving spontaneously. Electrocardiogram showed a left bundle branch block, left ventricular hypertrophy, and T wave inversions in the lateral leads. Initial cardiac troponin level was 0.15 ng/ml, with levels of 4 ng/ml and 9 ng/ml obtained 6 and 12 hours later, respectively. The peak blood pressure recorded was 195/43 mmHg. Echocardiogram with DEFINITY showed a small left ventricular cavity with apical hypertrophy, and coronary angiogram showed no stenotic or occluding lesions in the coronary arteries. The patient was admitted for a type 2 myocardial infarction with hypertensive crises. She was diagnosed with having apical hypertrophic cardiomyopathy, which is a variant of hypertrophic cardiomyopathy (HCM) in which the hypertrophy predominantly involves the apex of the left ventricle resulting in midventricular obstruction, as opposed to the left ventricular outflow tract obstruction seen in HCM. Patients with apical HCM may present with angina, heart failure, myocardial infarction, syncope, or arrhythmias and are typically managed with medications like verapamil and beta-blockers for those who have symptoms and antiarrhythmic agents like amiodarone and procainamide for treatment of atrial fibrillation and ventricular arrhythmias. An implantable cardioverter defibrillator (ICD) is recommended for high-risk HCM patients with a history of previous cardiac arrest or sustained episodes of ventricular tachycardia, syncope, and a family history of sudden death.

Comparison of Clinical Effects between Percutaneous Transluminal Septal Myocardial Ablation and Modified Morrow Septal Myectomy on Patients with Hypertrophic Cardiomyopathy

Background

Percutaneous transluminal septal myocardial ablation (PTSMA) and modified Morrow septal myectomy (MMSM) are two invasive strategies used to relieve obstruction in patients with hypertrophic cardiomyopathy (HCM). This study aimed to determine the clinical outcome of these two strategies.

Methods

From January 2011 to January 2015, 226 patients with HCM were treated, 68 by PTSMA and 158 by MMSM. Both ultrasonic cardiograms and heart functional class were recorded before, after operations and in the follow-up. Categorical variables were compared using Chi-square or Fisher's exact tests. Quantitative variables were compared using the paired samples t-test.

Results

Interventricular septal thickness was significantly reduced in both groups (21.27 ± 4.43 mm vs. 18.72 ± 4.13 mm for PTSMA, t = 3.469, P < 0.001, and 21.83 ± 5.03 mm vs. 16.57 ± 3.95 mm for MMSM, t = 10.349, P < 0.001, respectively). The left ventricular outflow tract (LVOT) pressure gradient (PG) significantly decreased after the operations in two groups (70.30 ± 44.79 mmHg vs. 39.78 ± 22.07 mmHg for PTSMA, t = 5.041, P < 0.001, and 74.58 ± 45.52 mmHg vs. 13.95 ± 9.94 mmHg for MMSM, t = 16.357, P < 0.001, respectively). Seven patients (10.29%) in the PTSMA group required a repeat operation in the follow-up. Eight (11.76%) patients were evaluated for New York Heart Association (NYHA) III/IV in the PTSMA group, which was significantly more than the five (3.16%) in the same NYHA classes for the MMSM group at follow-up. Less than 15% of patients in the PTSMA group and none of the patients in the MMSM group complained of chest pain during follow-up.

Conclusions

Both strategies can not only relieve LVOT PG but also improve heart function in patients with HCM. However, MMSM might provide a more reliable reduction in gradients compared to PTSMA.

The relationship between left ventricular structure and function in the elite rugby football league athlete as determined by conventional echocardiography and myocardial strain imaging

AIMS

The aims of this study were to establish the left ventricular (LV) phenotype in rugby football league (RFL) athletes and to mathematically model the association between LV size, strain (ɛ) and ejection fraction (EF).

METHODS AND RESULTS

139 male athletes underwent echocardiographic LV evaluation including ɛ imaging. Non-athletic males were used for comparison. All absolute and scaled structural indices were significantly larger (P < 0.05) in athletes with a predominance for normal LV geometry. EF and global ɛ were similar between groups but strain rates (SR) were significantly lower (P < 0.05) in athletes. Lower apical rotation (P < 0.001) and twist (P = 0.010) were exhibited in athletes.

CONCLUSION

Normal EF is explained by divergent effects of LV internal diastolic dimension (LVIDd) and mean wall thickness (MWT) on LV function. Reductions in SR and twist may be part of normal physiological LV adaptation in RFL athletes.