New Developments in Hypertrophic Cardiomyopathy

Perinatal and cardiac outcomes of women with hypertrophic cardiomyopathy

RATIONALE

Pregnancy causes important physiologic stress for women with hypertrophic cardiomyopathy. Data regarding the impact of this condition on obstetrical outcomes is missing.

OBJECTIVES

Our objective was to report obstetrical and cardiac outcomes in pregnant women with hypertrophic cardiomyopathy and to assess the possible adverse effects of left ventricular outflow tract obstruction in pregnancy.

STUDY DESIGN

This was a retrospective cohort study of pregnant women diagnosed with HCM and followed at single tertiary center between 1995 and 2019. Demographic, medical and surgical data, echocardiographic parameters, and pregnancy outcomes were abstracted through extensive chart review. Patients were divided into 2 groups: obstructive (maximal left ventricular outflow tract gradient over 30 mmHg) versus non-obstructive hypertrophic cardiomyopathy. Outcomes between groups were compared with t-test, Mann-Whitney and Fisher's exact tests when appropriate.

RESULTS

Eighteen women with 27 pregnancies were included. The study population was formed of 18 women with a total of 27 pregnancies that reached at least 20 weeks of gestation: 12 pregnancies in women with obstructive hypertrophic cardiomyopathy and 15 pregnancies in women with non-obstructive hypertrophic cardiomyopathy. Among the non-obstructive hypertrophic cardiomyopathy, 5 of them had been treated for their obstruction. One patient with obstructive hypertrophic cardiomyopathy had a medical termination of pregnancy for uncontrolled arrhythmia at 21 weeks. There were no maternal deaths. Left ventricular outflow tract obstruction was associated with increased cardiac events including arrhythmias and heart failure (5/12 versus 0/15; p = .006). Preterm birth occurred in more than 50% of cases, resulting from induced delivery for a maternal (40%) or fetal reason (60%). Most deliveries were late preterm between 34 and 36 6/7 weeks. In both groups, birthweight was mainly distributed below the 50th percentile (89%) and 35% of neonates were born small for gestational age defined as a birthweight below the 10th percentile. Most severe cases of small for gestational age (birthweight under the 5th percentile) were found in patients with treated obstructive hypertrophic cardiomyopathy.

CONCLUSION

Hypertrophic cardiomyopathy is associated with prematurity and small for gestational age. Left ventricular outflow tract obstruction is associated with adverse cardiac events including arrythmias or heart failure. Treated obstructive cardiomyopathy constitutes a sub-group of patients at high risk of severe small for gestational age and deserves a close surveillance. Therefore, fetal growth surveillance with ultrasound, early in the third trimester and doppler studies to assess the utero-placental perfusion in the second and third trimesters are warranted in all patients with hypertrophic cardiomyopathy regardless of the severity of their condition.

Fibrosis in hypertrophic cardiomyopathy: role of novel echo techniques and multi-modality imaging assessment

Hypertrophic cardiomyopathy (HCM) represents one of the primary cardiomyopathies and may lead to heart failure and sudden cardiac death. Among various histologic features of the disease examined, assessment of myocardial fibrosis may offer valuable information, since it may be considered the common nominator for all HCM connected complications. Late gadolinium-enhanced cardiac magnetic resonance (LGE-CMR) has emerged as the reference noninvasive method for visualizing and quantifying myocardial fibrosis in patients with HCM. T1 mapping, a promising new CMR technique, may provide an advantage over conventional LGE-CMR, by permitting a more valid quantification of diffuse fibrosis. On the other hand, echocardiography offers a significantly more portable, affordable, and easily accessible solution for the study of fibrosis. Various echocardiographic techniques ranging from integrated backscatter and contrast-enhanced ultrasound to two- (2D) or three-dimensional (3D) deformation and shear wave imaging may offer new insights into substrate characterization in HCM. The aim of this review is to describe thoroughly all different modalities that may be used in everyday clinical practice for HCM fibrosis evaluation (with special focus on echocardiographic techniques), to concisely present available evidence and to argue in favor of multi-modality imaging application. It is essential to understand that the role of various imaging modalities is not competitive but complementary, since the information provided by each one is necessary to illuminate the complex pathophysiologic pathways of HCM, offering a personalized approach and treatment in every patient.

Gender- and age-related differences in distinct phenotypes of hypertrophic cardiomyopathy-associated mutation MYBPC3-E334K

The mutation MYBPC3-E334K is a culprit mutation of hypertrophic cardiomyopathy (HCM). The pathogenicity of MYBPC3-E334K is conflicting in ClinVar because of the limited segregation data and the relatively high frequency in gnomAD (0.03% overall, with 0.3% in East Asians and 0.8% in Japanese). The main aim is to clarify the clinical importance and phenotype-genotype correlations in subjects with or without MYBPC3-E334K alone. The prevalence of MYBPC3-E334K was sequenced in 1017 HCM unrelated probands. The clinical features, morphology phenotypes, and electrical phenotypes were further analyzed according to the phenotype and genotype status in families with single-mutation MYBPC3-E334K. Nine of 1017 (0.88%) unrelated HCM probands were detected harboring MYBPC3-E334K, and three of them harbored a second variant in sarcomere protein gene. Family study and co-segregation analyses indicated that patients with single-mutation MYBPC3-E334K showed autosomal dominant mode of inheritance with incomplete penetrance. The overall disease penetrance was 52.6%, and the disease penetrance was higher in males than in females (100% in men vs 25% in women, p = 0.003). The mean age at diagnosis of males was approximately 25 years younger than females (36.57 ± 18.65 vs 62.33 ± 12.10, p = 0.062). The variant MYBPC3-E334K was classified as a likely pathogenic variant, and a second sarcomere variant did not reveal obvious cumulative effects. The patients harboring single-mutation MYBPC3-E334K had incomplete penetrance, and males demonstrated higher penetrance and early onset HCM than females. A second sarcomere variant did not reveal obvious cumulative effects.

Effectiveness of alcohol septal ablation for hypertrophic obstructive cardiomyopathy in patients with late gadolinium enhancement on cardiac magnetic resonance

BACKGROUND

According to European guidelines, alcohol septal ablation (ASA) for hypertrophic obstructive cardiomyopathy (HOCM) may be less effective in patients with extensive septal scarring on cardiac magnetic resonance (CMR). This study aimed to analyze the impact of late gadolinium enhancement (LGE) on CMR on the effectiveness of ASA.

METHOD

We conducted an observational retrospective study involving adult patients with symptomatic drug-refractory HOCM who underwent CMR before ASA at two European centres from May 2010 through June 2019. Patients were compared in binary format based on LGE presence. Moreover, a subanalysis focused on patients with septal fibrosis was performed. The effectiveness of ASA was evaluated by echocardiographic, ECG and clinical findings.

RESULTS

Of the 113 study patients, 54 (48%) had LGE on CMR. The LGE quantification performed in 29 patients revealed septal fibrosis in 17. The mean follow-up was 4.4 ± 2.6 years. Baseline parameters were similar between groups except for basal septal thickness that was greater in LGE+ group (21.1 ± 3.9 mm for LGE+ vs. 19.2 ± 3.2 mm for LGE-: p = .005). ASA improved symptoms in all groups and reduced left ventricular outflow tract obstruction (LVOTO) (delta gradient reduction: LGE+: 62 ± 37.3%; septal LGE+: 75.6 ± 20.8%; LGE-: 72.5 ± 21.0%). However, 13% of the LGE+ and 2% of the LGE- group had residual LVOTO above 30 mmHg (p = .027).

CONCLUSION

ASA was effective in all patients with HOCM, whether they had LGE on CMR or not and whether they had septal fibrosis or not.

Young patients with heart failure: clinical characteristics and outcomes. Data from the Swedish Heart Failure, National Patient, Population and Cause of Death Registers

AIMS

The prevalence and hospitalizations of patients with heart failure (HF) aged <55 years have increased in Sweden during the last decades. We aimed to compare characteristics of younger and older patients with HF, and examine survival in patients <55 years compared with matched controls.

METHODS AND RESULTS

All patients ≥18 years in the Swedish Heart Failure Register from 2003 to 2014 were included. Data were merged with National Patient and Cause of Death Registers. Among 60 962 patients, 3752 (6.2%) were <55 years, and were compared with 7425 controls from the Population Register. Compared with patients ≥55 years, patients <55 years more frequently had registered diagnoses of obesity, dilated cardiomyopathy, congenital heart disease, and an ejection fraction <40% (9.8% vs. 4.7%, 27.2% vs. 5.5%, 3.7% vs. 0.8%, 67.9% vs. 45.1%, respectively; all P < 0.001). One-year all-cause mortality was 21.2%, 4.2%, and 0.3% in patients ≥55 years, patients <55 years, and controls <55 years, respectively (all P < 0.001). Patients <55 years had a five times higher mortality risk compared with controls [hazard ratio (HR) 5.48, 95% confidence interval (CI) 4.45-6.74]; the highest HR was in patients 18-34 years (HR 38.3, 95% CI 8.70-169; both P < 0.001). At the age of 20, the estimated life-years lost was up to 36 years for 50% of patients, with declining estimates with increasing age.

CONCLUSION

Patients with HF <55 years had different comorbidities than patients ≥55 years. The highest mortality risk relative to that of controls was among the youngest patients.

Hemodynamic Instability in Heart Failure Intensifies Age-Dependent Cognitive Decline

This review attempts to examine two key elements in the evolution of cognitive impairment in the elderly who develop heart failure. First, major left side heart parts can structurally and functionally deteriorate from aging wear and tear to provoke hemodynamic instability where heart failure worsens or is initiated; second, heart failure is a major inducer of cognitive impairment and Alzheimer's disease in the elderly. In heart failure, when the left ventricular myocardium of an elderly person does not properly contract, it cannot pump out adequate blood to the brain, raising the risk of cognitive impairment due to the intensification of chronic brain hypoperfusion. Chronic brain hypoperfusion originates from chronically reduced cardiac output which progresses as heart failure worsens. Other left ventricular heart parts, including atrium, valves, myocardium, and aorta can contribute to the physiological shortfall of cardiac output. It follows that hemodynamic instability and perfusion changes occurring from the aging heart's blood pumping deficiency will, in time, damage vulnerable brain cells linked to specific cognitive regulatory sites, diminishing neuronal energy metabolism to a level where progressive cognitive impairment is the outcome. Could cognitive impairment progress be reversed with a heart transplant? Evidence is presented detailing the errant hemodynamic pathways leading to cognitive impairment during aging as an offshoot of inefficient structural and functional heart parts and their contribution to heart failure.

Treatment of coronary microvascular dysfunction

Contemporary data indicate that patients with signs and symptoms of ischaemia and non-obstructive coronary artery disease (INOCA) often have coronary microvascular dysfunction (CMD) with elevated risk for adverse outcomes. Coronary endothelial (constriction with acetylcholine) and/or microvascular (limited coronary flow reserve with adenosine) dysfunction are well-documented, and extensive non-obstructive atherosclerosis is often present. Despite these data, patients with INOCA currently remain under-treated, in part, because existing management guidelines do not address this large, mostly female population due to the absence of evidence-based data. Relatively small sample-sized, short-term pilot studies of symptomatic mostly women, with INOCA, using intense medical therapies targeting endothelial, microvascular, and/or atherosclerosis mechanisms suggest symptom, ischaemia, and coronary vascular functional improvement, however, randomized, controlled outcome trials testing treatment strategies have not been completed. We review evidence regarding CMD pharmacotherapy. Potent statins in combination with angiotensin-converting enzyme inhibitor (ACE-I) or receptor blockers if intolerant, at maximally tolerated doses appear to improve angina, stress testing, myocardial perfusion, coronary endothelial function, and microvascular function. The Coronary Microvascular Angina trial supports invasive diagnostic testing with stratified therapy as an approach to improve symptoms and quality of life. The WARRIOR trial is testing intense medical therapy of high-intensity statin, maximally tolerated ACE-I plus aspirin on longer-term outcomes to provide evidence for guidelines. Novel treatments and those under development appear promising as the basis for future trial planning.

Efficacy and safety of radiofrequency ablation for hypertrophic obstructive cardiomyopathy: A systematic review and meta-analysis

Background

Although radiofrequency ablation is widely used in the treatment of arrhythmias, its role in septal reduction therapy of hypertrophic obstructive cardiomyopathy (HOCM) is unclear. This meta‐analysis aimed to assess the efficacy and safety of radiofrequency septal ablation for HOCM.

Hypothesis

Radiofrequency septal ablation is effective and safe for relieving obstruction and improving exercise capacity in patients with HOCM.

Methods

A systematic review of eligible studies that reported outcomes of patients with HOCM who underwent radiofrequency septal ablation was performed using PubMed, Embase, Cochrane, ProQuest, Scopus, ScienceDirect, and Web of Science database. Pooled estimates were calculated using random‐effects meta‐analysis. Methodological quality was assessed using the Newcastle‐Ottawa scale. Publication bias and sensitivity analyses were also performed.

Results

Eight studies with 91 patients (mean follow‐up 11.6 months) were included. The left ventricular outflow tract (LVOT) gradient at rest decreased significantly after radiofrequency septal ablation (pooled reduction: −58.8 mmHg; 95% confidence interval [CI] −64.3 to −53.5). A reduction was also found in the provoked LVOT gradient with a pooled reduction of −97.6 mmHg (95% CI: −124.4 to −87.1). An improvement of the New York Heart Association classification (mean: −1.4; 95% CI: −1.6 to −1.2) was found during follow‐up. The change in septal thickness was minimal and not statistically significant. Two procedure‐related deaths were documented, and complete heart block occurred in eight patients.

Conclusions

Radiofrequency septal ablation is effective and safe for relieving LVOT obstruction and improving exercise capacity in patients with HOCM.

Head-Up Tilt Test in Risk Stratification of Patients with Hypertrophic Cardiomyopathy

Conflicting results have been published considering the role of head-up tilt test (HUTT) positivity as a prognostic factor in patients with hypertrophic cardiomyopathy (HCM). The relationship between HCM patients' genotype and their HUTT results has not been previously reported. The aim of this study was to evaluate patients with HCM and their HUTT results in regard to its value for outcome prediction and to investigate the relation of patients' genotype and their HUTT results. Seventy-four (51 ± 15 years; 42% women; median follow-up 72 months) HCM patients were divided into two groups based on their HUTT results and were retrospectively analyzed. In 67 (90.5%) subjects included in the analysis, next-generation sequencing-based genomic testing was performed. A composite end point of unexplained syncope, heart failure hospitalization, and death was defined. A total of 14 patients (18.9%) had positive HUTT (HUTT+), whereas 60 (81.1%) had negative HUTT (HUTT-). Except for the New York Heart Association functional class ( p  = 0.01), both groups had similar characteristics. Positive genotype was evenly distributed between the two groups. Composite end point occurred in 5 patients (35.7%) in HUTT+ group versus 14 (23.3%) patients in HUTT- group ( p  = 0.33). We did not find a relationship between HUTT results and long-term outcome. We found no association between HUTT results and genotype.

[Hypertrophic cardiomyopathy: modern aspects of pharmacologic treatment]

This article discusses recent advances in understanding genetic basis and classification of hypertrophic cardiomyopathy. Here, we review pharmacologic treatment strategies and new developments in disease - specific management of HCM.

Hypertrophic cardiomyopathy: New hope for an old disease

Hypertrophic cardiomyopathy (HCM), a common congenital heart disease, is the leading cause of sudden cardiac death in adolescents, young adults, and athletes. Older adults with HCM are less likely to experience sudden cardiac death, but their quality of life can be impaired. This article discusses diagnostic criteria, treatments, and nursing interventions, including patient teaching, for adults with HCM.

The utility of the Mayo Score for predicting the yield of genetic testing in patients with hypertrophic cardiomyopathy

INTRODUCTION

The yield of genetic testing in hypertrophic cardiomyopathy (HCM) is variable. The Mayo HCM Genotype Predictor score (Mayo Score) provides the pre-test probability of a positive HCM genetic test. In the original cohort of Mayo Score patients, only 9 HCM-associated myofilament genes were evaluated. The aim of this study was to validate the Mayo Score in the national HCM cohort and assess the yield of genetic testing using next generation sequencing (NGS) evaluating up to 229 genes.

MATERIAL AND METHODS

We included 336 consecutive unrelated HCM patients (41% women, mean age: 53 ±15 years). We performed NGS-based genomic testing with classification of identified variants according to American College of Medical Genetics and Genomics guidelines. NGS findings were compared with the Mayo Score (ranging from -1 to 5) based on clinical and echocardiographic variables.

RESULTS

We identified 72 variants classified as pathogenic or likely pathogenic in 70 (21%) HCM patients. One patient with the highest Mayo Score of 5 had a pathogenic mutation (100% yield). Patients with a Mayo Score of 4 had a pathogenic mutation in 71% of cases. Patients with a Mayo Score of 3 or 2 had a pathogenic mutation in 50 and 35% of cases, respectively. The yield of genetic testing in patients with a Mayo Score of -1 to 1 was low (6-21%).

CONCLUSIONS

The overall yield of genetic testing using NGS evaluating up to 229 genes was low. The yield of genetic testing was consistently predicted with Mayo Score values.

Advanced Evolution of Pathogenesis Concepts in Cardiomyopathies

Cardiomyopathy is a group of heterogeneous cardiac diseases that impair systolic and diastolic function, and can induce chronic heart failure and sudden cardiac death. Cardiomyopathy is prevalent in the general population, with high morbidity and mortality rates, and contributes to nearly 20% of sudden cardiac deaths in younger individuals. Genetic mutations associated with cardiomyopathy play a key role in disease formation, especially the mutation of sarcomere encoding genes and ATP kinase genes, such as titin, lamin A/C, myosin heavy chain 7, and troponin T1. Pathogenesis of cardiomyopathy occurs by multiple complex steps involving several pathways, including the Ras-Raf-mitogen-activated protein kinase-extracellular signal-activated kinase pathway, G-protein signaling, mechanotransduction pathway, and protein kinase B/phosphoinositide 3-kinase signaling. Excess biomechanical stress induces apoptosis signaling in cardiomyocytes, leading to cell loss, which can induce myocardial fibrosis and remodeling. The clinical features and pathophysiology of cardiomyopathy are discussed. Although several basic and clinical studies have investigated the mechanism of cardiomyopathy, the detailed pathophysiology remains unclear. This review summarizes current concepts and focuses on the molecular mechanisms of cardiomyopathy, especially in the signaling from mutation to clinical phenotype, with the aim of informing the development of therapeutic interventions.

Effect of Institutional Experience on Outcomes of Alcohol Septal Ablation for Hypertrophic Obstructive Cardiomyopathy

BACKGROUND

The current American College of Cardiology Foundation/American Heart Association guidelines on hypertrophic cardiomyopathy state that institutional experience is a key determinant of successful outcomes and lower complication rates of alcohol septal ablation (ASA). The aim of this study was to evaluate the safety and efficacy of ASA according to institutional experience with the procedure.

METHODS

We retrospectively evaluated 1310 patients with symptomatic obstructive hypertrophic cardiomyopathy who underwent ASA and were divided into 2 groups. The first-50 group consisted of the first consecutive 50 patients treated at each centre, and the over-50 group consisted of patients treated thereafter (patients 51 and above).

RESULTS

In the 30-day follow-up, there was a significant difference in the occurrence of major cardiovascular adverse events (21% in the first-50 group vs 12% in the over-50 group; P < 0.01), which was driven by the occurrence of cardiovascular deaths (2.1% vs 0.4%; P = 0.01) and implanted pacemakers (15% vs 9%; P < 0.01). In the long-term follow-up (5.5 ± 4.1 years), the first-50 group was associated with a significantly higher occurrence of major adverse events (P < 0.01) and higher cardiovascular mortality (P < 0.01). Also, patients in the first-50 group were more likely to self-report dyspnea of New York Heart Association class III/IV (16% vs 10%), to have a left ventricular outflow gradient > 30 mm Hg (16% vs 10%) at the last clinical check-up (P < 0.01 for both), and a probability of repeated septal reduction therapy (P = 0.03).

CONCLUSIONS

An institutional experience of > 50 ASA procedures was associated with a lower occurrence of ASA complications, better cardiovascular survival, better hemodynamic and clinical effect, and less need for repeated septal reduction therapy.