Neuromuscular Disorders and the Role of the Clinical Electrophysiologist

Effects of a neuropsychosocial teleassistance intervention on social cognition and health-related quality of life of pediatric patients with neuromuscular diseases

OBJECTIVE

This study aimed to determine the effects of a neuropsychosocial teleassistance group-based intervention on improving social cognitive functioning and health-related quality of life (HRQoL) in pediatric neuromuscular diseases (NMD).

METHODS

Thirty-five pediatric patients with NMD were assigned to the neuropsychosocial intervention program (n = 20) or waiting list control condition (n = 15). The intervention group received an integrative approach that combines training in social cognition with cognitive behavioral therapy. All participants completed a neuropsychological and clinical assessment at baseline and follow-up, which included tests of social cognition, both for emotion recognition and theory of mind, and HRQoL. Repeated-measures multivariate analysis of covariance was used to determine the effects of the teleassistance program.

RESULTS

Group × Time interactions revealed significant improvements in the intervention group as compared with the control group for different social cognition's indicators (AR NEPSY-II: p = .003, η2p = .24; TM NEPSY: p < .001, η2p = .35; Verbal task: p < .001, η2p = .35; Happé's Strange Stories: p = .049, η2p = .11) and HRQoL (Psychosocial health: p = .012, η2p = .18; Emotional functioning: p = .037, η2p = 0.13; Social functioning: p = .006, η2p = .21; Total: p = .013, η2p = .17), showing medium to large effects.

CONCLUSIONS

Patients receiving the neuropsychosocial intervention showed improvements in their social cognition performance and psychosocial HRQoL, providing evidence about the positive effects of the program in pediatric patients with NMD. This should be considered in further research and interventions in this field.

Clinical Genetic Testing for Atrial Fibrillation: Are We There Yet?

Important progress has been made toward unravelling the complex genetics underlying atrial fibrillation (AF). Initial studies were aimed to identify monogenic causes; however, it has become increasingly clear that the most common predisposing genetic substrate for AF is polygenic. Despite intensive investigations, there is robust evidence for rare variants for only a limited number of genes and cases. Although the current yield for genetic testing in early onset AF might be modest, there is an increasing appreciation that genetic culprits for potentially life-threatening ventricular cardiomyopathies and channelopathies might initially present with AF. The potential clinical significance of this recognition is highlighted by evidence that suggests that identification of a pathogenic or likely pathogenic rare variant in a patient with early onset AF is associated with an increased risk of death. These findings suggest that it might be warranted to screen patients with early onset AF for these potentially more sinister cardiac conditions. Beyond facilitating the early identification of genetic culprits associated with potentially malignant phenotypes, insight into underlying AF genetic substrates might improve the selection of patients for existing therapies and guide the development of novel ones. Herein, we review the evidence that links genetic factors to AF, then discuss an approach to using genetic testing for early onset AF patients in the present context, and finally consider the potential value of genetic testing in the foreseeable future. Although further work might be necessary before recommending uniform integration of genetic testing in cases of early onset AF, ongoing research increasingly highlights its potential contributions to clinical care.

Cardiovascular magnetic resonance in muscular dystrophies: looking ahead

Cardiac magnetic resonance (CMR) is an established tool for risk stratification in several cardiomyopathies, and its role in muscular dystrophies (MuD) looks promising. We sought to assess how CMR performs in predicting cardiac events in a real cohort of MuD patients. A prospective single-center study with the enrollment of consecutive adult MuD patients referred to cardiac screening from 2012 to 2018 with the collection of clinical and CMR data. During follow-up (FUP), major adverse cardiac events were considered a composite of device implantation, ventricular tachycardia (VT), hospitalization due to heart failure, and death. Sixty-five patients were included (mean age of 32±16, 51% female); the majority had myotonic dystrophy (34; 52.3%); most were asymptomatic (60; 92.3%) and at sinus rhythm (64; 98.5%). CMR was abnormal in 23 (43.3%) patients: left ventricle ejection fraction (LVEF) <55% was found in 7 patients, and late gadolinium enhancement (LGE) was present in 23 patients, mainly intra-myocardial or subepicardial (10 and 8 patients, respectively). During a median FUP of 77 months (interquartile range: 33), there were 7 deaths, 8 implanted devices, and one sustained VT. LVEF<55% and the presence of LGE were associated with the occurrence of all events (log rank test, p=0.002 and p=0.045, respectively). LVEF<55% was associated with a 6-fold higher risk of events (crude hazard ratio of 6.15; 95% confidence interval of 1.65-22.93), that remained significant after adjusting for LGE presence (adjusted hazard ratio of 4.81, 95% confidence interval of 1.07-15.9). In our cohort, CMR LVEF<55% and the presence of LGE were significantly associated with adverse events during follow-up, reinforcing the role of this technique on risk stratification of MuD populations.

Epidemiology and Outcomes Associated with PR Prolongation

PR prolongation is defined primarily as delayed conduction through the AV node, but can also signify delayed electrical impulse propagation through any part of the conduction system. The prevalence of PR prolongation ranges from 1% to 5% in patients younger than 50 years, with increasing prevalence, after the sixth decade of life and in patients with organic heart disease. Contemporary studies have documented increased risk of atrial arrhythmias, heart failure, and mortality in patients with PR prolongation. Future studies are needed to more accurately risk stratify elderly patients with PR prolongation who may be at increased risk of adverse outcomes.

Subclinical cardiac involvement present as electrocardiographic abnormalities in various neuromuscular diseases

Background

Cardiac involvement is commonly present in various neuromuscular diseases which may develop life-threatening consequences. The early manifestation is often asymptomatic which however has been insufficiently studied.

Objectives

We aim to characterize electrocardiographic (ECG) changes in neuromuscular diseases without cardiac symptoms.

Methods

Adults having genetically and/or pathologically confirmed type 1 myotonic dystrophy (DM1), Becker muscular dystrophy (BMD), limb girdle muscular dystrophies (LGMDs) and mitochondrial diseases (MtDs) but without history of heart diseases and cardiovascular symptoms were enrolled. The 12-lead ECG characteristics and other test results at diagnosis were retrieved and analyzed.

Results

196 patients with neuromuscular diseases (44 DM1, 25 BMD, 82 LGMDs, 45 MtDs) were consecutively enrolled. ECG abnormalities were identified in 107 (54.6%) patients with a prevalence of 59.1% in DM1, 76.0% in BMD, 40.2% in LGMDs and 64.4% in MtDs. Conduction block was more commonly present in DM1 than the other groups (P < 0.01), which had a longest PR interval and QRS duration of 186.1 ± 38.3 ms and 104.2 [90.0-108.0]ms, respectively. QT prolongation was most frequently seen in DM1 (P < 0.001). Left ventricular hypertrophy features were found in BMD, LGMDs and MtDs (P < 0.05) without intergroup difference, while a significantly higher right ventricular amplitude is observed in BMD than in other groups (P < 0.001).

Conclusions

Subclinical cardiac involvement is commonly present as ECG abnormalities in multiple adult neuromuscular diseases before associated symptoms occur and show diversity in different groups.

Neuromuscular diseases and their cardiac manifestations under the spectrum of cardiovascular imaging

Neuromuscular diseases (NMDs) include a broad spectrum of disorders that affect motor unit in every possible site, extending from the cell body of peripheral nerves to the muscle. The different lesion sites make this group of inherited disorders difficult to diagnose. Many NMDs, especially those involving skeletal muscles, can present significant cardiovascular complications, ranging from rhythm disturbances to the development of dilated or hypertrophic cardiomyopathy. Heart disease represents a major cause of morbidity and mortality among NMD patients, underlining the vital need for further familiarization with the pathogenesis and assessment of cardiac involvement. Cardiovascular imaging is the cornerstone for the evaluation of heart disorders in NMDs, with conventional echocardiography still offering a portable, affordable, and easily accessible solution. Meanwhile, newer echocardiographic techniques such as speckle tracking imaging in combination with cardiac magnetic resonance add new insights into further substrate characterization. The purpose of this review is to offer a brief presentation of the main NMDs and their cardiovascular complications, as well as the presentation of data that highlight the importance of cardiovascular imaging in early diagnosis, monitoring, and prognosis of these patients. Lastly, the authors provide a simple guide about which clinical features, imaging findings, and follow-up plan to adopt in each myopathic disorder.

Cardiac and pulmonary findings in dysferlinopathy: A 3-year, longitudinal study

INTRODUCTION/AIMS

There is debate about whether and to what extent either respiratory or cardiac dysfunction occurs in patients with dysferlinopathy. This study aimed to establish definitively whether dysfunction in either system is part of the dysferlinopathy phenotype.

METHODS

As part of the Jain Foundation's International Clinical Outcome Study (COS) for dysferlinopathy, objective measures of respiratory and cardiac function were collected twice, with a 3-y interval between tests, in 188 genetically confirmed patients aged 11-86 y (53% female). Measures included forced vital capacity (FVC), electrocardiogram (ECG), and echocardiogram (echo).

RESULTS

Mean FVC was 90% predicted at baseline, decreasing to 88% at year 3. FVC was less than 80% predicted in 44 patients (24%) at baseline and 48 patients (30%) by year 3, including ambulant participants. ECGs showed P-wave abnormalities indicative of delayed trans-atrial conduction in 58% of patients at baseline, representing a risk for developing atrial flutter or fibrillation. The prevalence of impaired left ventricular function or hypertrophy was comparable to that in the general population.

DISCUSSION

These results demonstrate clinically significant respiratory impairment and abnormal atrial conduction in some patients with dysferlinopathy. Therefore, we recommend that annual or biannual follow-up should include FVC measurement, enquiry about arrhythmia symptoms and peripheral pulse palpation to assess cardiac rhythm. However, periodic specialist cardiac review is probably not warranted unless prompted by symptoms or abnormal pulse findings.

Epidemiology and Outcomes Associated with PR Prolongation

PR prolongation is defined primarily as delayed conduction through the AV node, but can also signify delayed electrical impulse propagation through any part of the conduction system. The prevalence of PR prolongation ranges from 1% to 5% in patients younger than 50 years, with increasing prevalence, after the sixth decade of life and in patients with organic heart disease. Contemporary studies have documented increased risk of atrial arrhythmias, heart failure, and mortality in patients with PR prolongation. Future studies are needed to more accurately risk stratify elderly patients with PR prolongation who may be at increased risk of adverse outcomes.

Progressive myocardial injury in myotonic dystrophy type II and facioscapulohumeral muscular dystrophy 1: a cardiovascular magnetic resonance follow-up study

AIM

Muscular dystrophy (MD) is a progressive disease with predominantly muscular symptoms. Myotonic dystrophy type II (MD2) and facioscapulohumeral muscular dystrophy type 1 (FSHD1) are gaining an increasing awareness, but data on cardiac involvement are conflicting. The aim of this study was to determine a progression of cardiac remodeling in both entities by applying cardiovascular magnetic resonance (CMR) and evaluate its potential relation to arrhythmias as well as to conduction abnormalities.

METHODS AND RESULTS

83 MD2 and FSHD1 patients were followed. The participation was 87% in MD2 and 80% in FSHD1. 1.5 T CMR was performed to assess functional parameters as well as myocardial tissue characterization applying T1 and T2 mapping, fat/water-separated imaging and late gadolinium enhancement. Focal fibrosis was detected in 23% of MD2) and 33% of FSHD1 subjects and fat infiltration in 32% of MD2 and 28% of FSHD1 subjects, respectively. The incidence of all focal findings was higher at follow-up. T2 decreased, whereas native T1 remained stable. Global extracellular volume fraction (ECV) decreased similarly to the fibrosis volume while the total cell volume remained unchanged. All patients with focal fibrosis showed a significant increase in left ventricular (LV) and right ventricular (RV) volumes. An increase of arrhythmic events was observed. All patients with ventricular arrhythmias had focal myocardial changes and an increased volume of both ventricles (LV end-diastolic volume (EDV) p = 0.003, RVEDV p = 0.031). Patients with supraventricular tachycardias had a significantly higher left atrial volume (p = 0.047).

CONCLUSION

We observed a remarkably fast and progressive decline of cardiac morphology and function as well as a progression of rhythm disturbances, even in asymptomatic patients with a potential association between an increase in arrhythmias and progression of myocardial tissue damage, such as focal fibrosis and fat infiltration, exists. These results suggest that MD2 and FSHD1 patients should be carefully followed-up to identify early development of remodeling and potential risks for the development of further cardiac events even in the absence of symptoms. Trial registration ISRCTN, ID ISRCTN16491505. Registered 29 November 2017 - Retrospectively registered, http://www.isrctn.com/ISRCTN16491505.

[Anesthesia for patients suffering from neuromuscular diseases]

Neuromuscular diseases (NMD) are a heterogeneous group of motor unit disorders. Common to all is the main clinical symptom of muscle weakness. Depending on entity and phenotype, a broad range of disorders of neuronal, junctional or myocytic structures occurs. In addition to a weakness of the skeletal musculature, NMD can also affect throat musculature, respiratory and heart muscles. The possible consequences are immobility, deformities, tendency to aspiration as well as respiratory and cardiac insufficiency. In the context of surgery and anesthesia, complications that can result from the underlying disease and its interaction with anesthesia must be anticipated and averted. This article describes along the treatment pathway how preoperative evaluation, choice of the anesthetic procedure and postoperative care can be effectively and safely tailored to the needs of patients with NMD. Concise and practical recommendations for carrying out anesthesia for the most important NMDs are presented as well as relevant external sources of practice recommendations.

The Optimal Timing of Primary Prevention Implantable Cardioverter-Defibrillator Referral in the Rapidly Changing Medical Landscape

The use of implantable cardioverter-defibrillators (ICDs) significantly reduces the risk of mortality in patients with heart failure with reduced ejection fraction (HFrEF). Current guidelines, which are based on seminal clinical trials published nearly 2 decades ago, recommend that patients be on optimal medical therapy for HF for a minimum of 3 months before referral for prophylactic ICD. This waiting period allows for left ventricular reverse remodelling and improvement in HF symptoms, which may render primary prevention ICD implantation unnecessary. However, medical therapy for HFrEF has significantly evolved since the publication of these landmark trials. Given the plethora of medical therapy options now available for HFrEF, it is appropriate to reassess the duration of this waiting period. In the present review, we examine the landmark randomised trials in primary prevention of sudden cardiac death in patients with HFrEF, summarise the novel medical therapies (sacubitril-valsartan, sodium-glucose cotransporter 2 inhibitors, ivabradine, vericiguat, and omecamtiv mecarbil) that have emerged since the publication of those trials, discuss the optimal timing of ICD referral, and review subtypes of nonischemic cardiomyopathy where timing of ICD insertion is guided by alternative criteria. With the steps now needed to optimise medical therapy for HFrEF, in terms of both classes of drugs and doses of each agent, it can easily take up to 6 months to achieve optimisation. Following that, waiting periods of 3 months for ischemic cardiomyopathy and 6 months for nonischemic cardiomyopathy may be required to allow adequate reverse remodelling before reevaluating for ICD implantation.

The adult multidisciplinary respiratory neuromuscular clinic

Many neuromuscular disorders (NMD) are complicated by respiratory failure. These patients are best managed in a multidisciplinary outpatient clinic to provide timely access to the various disciplines they require. The key mainstay of treatment of respiratory failure in patients with NMD is noninvasive ventilation, supported by secretion clearance, speech and language therapy, optimisation of nutrition and the maintenance of mobility. Patients with specific conditions may also require cardiology, neurology, orthopaedics, urology and psychological services. The respiratory NMD multidisciplinary team should also provide access to palliative care, and caregiver health and wellbeing should also be reviewed at clinical reviews. The future of care for the respiratory NMD patient will increasingly involve home services and telehealth and the clinic should be equipped and resourced to deliver these. Although not all health systems will be able to provide all elements of the multidisciplinary team discussed here, this review provides the “ideal” recipe for the adult multidisciplinary team and the evidence base underpinning this from which a clinic can be developed.

Care for neuromuscular-related respiratory failure is complex and is best delivered in a multidisciplinary context. The future will increasingly involve home services and telehealth, and their burden needs to be considered when establishing this service.https://bit.ly/33fNsMT

Differential diagnosis of arrhythmogenic cardiomyopathy: phenocopies versus disease variants

Arrhythmogenic cardiomyopathy (ACM) is a genetic heart muscle disease caused by mutations of desmosomal genes in about 50% of patients. Affected patients may have defective non-desmosomal genes. The ACM phenotype may occur in other genetic cardiomyopathies, cardio-cutaneous syndromes or neuromuscular disorders. A sizeable proportion of patients have non-genetic diseases with clinical features resembling ACM (phenocopies). The identification of biventricular and left-dominant phenotypic variants has made differential diagnosis more difficult because of the broader spectrum of phenocopies which requires a detailed clinical study with appropriate evaluation of most prominent and discriminatory disease features. Conditions that enter into differential diagnosis of ACM include heart muscle diseases affecting the right ventricle, the left ventricle, or both. To confirm a conclusive diagnosis of ACM, these differential possibilities need to be reasonably excluded by an accurate and targeted clinical evaluation. This article reviews the clinical and imaging features of major phenocopies of ACM and provides indications for differential diagnosis. The recent etiologic classification of Arrhythmogenic Cardiomyopathies, whose common denominator is the distinctive phenotype characterized by a hypokinetic and non-dilated ventricle with a large amount of myocardial fibrosis underlying its propensity to generate ventricular arrhythmias is also addressed.

Proarrhythmic Manifestations of Neuromuscular Dystrophinopathies

Muscular dystrophy has been an elusive term ever since it was first described in the 19th century. Introduced in 1891 by Wilhelm Heinrich Erb, muscular dystrophy has been classified as part of a larger group of genetically determined, progressive degenerative neuromuscular disorders termed "dystrophinopathies." Cardiac arrhythmias may occur during the neurologic course of the disease. Although descriptions of the dystrophinopathies have been reported in the literature, few articles address the use of antiarrhythmic pharmacotherapy in patients with muscular dystrophy. We discuss the pathophysiology of the most common dystrophinopathies, their proarrhythmic sequelae, and the therapeutic use of antiarrhythmic agents in the clinical setting.