2022 HRS expert consensus statement on evaluation and management of arrhythmic risk in neuromuscular disorders.

This international multidisciplinary document is intended to guide electrophysiologists, cardiologists, other clinicians, and health care professionals in caring for patients with arrhythmic complications of neuromuscular disorders (NMDs). The document presents an overview of arrhythmias in NMDs followed by detailed sections on specific disorders: Duchenne muscular dystrophy, Becker muscular dystrophy, and limb-girdle muscular dystrophy type 2; myotonic dystrophy type 1 and type 2; Emery-Dreifuss muscular dystrophy and limb-girdle muscular dystrophy type 1B; facioscapulohumeral muscular dystrophy; and mitochondrial myopathies, including Friedreich ataxia and Kearns-Sayre syndrome, with an emphasis on managing arrhythmic cardiac manifestations. End-of-life management of arrhythmias in patients with NMDs is also covered. The document sections were drafted by the writing committee members according to their area of expertise. The recommendations represent the consensus opinion of the expert writing group, graded by class of recommendation and level of evidence utilizing defined criteria. The recommendations were made available for public comment; the document underwent review by the Heart Rhythm Society Scientific and Clinical Documents Committee and external review and endorsement by the partner and collaborating societies. Changes were incorporated based on these reviews. By using a breadth of accumulated available evidence, the document is designed to provide practical and actionable clinical information and recommendations for the diagnosis and management of arrhythmias and thus improve the care of patients with NMDs.

Association between Physical Activity and Adiposity in Adolescents with Down Syndrome.

PURPOSE: Obesity is highly prevalent among adolescents with Down syndrome (DS); however, reported associations between body composition and moderate-to-vigorous physical activity (MVPA) have been small and nonsignificant. The purpose of this study was to compare group differences between adolescents with and without DS, including dual-energy x-ray absorptiometry (DXA) measured body composition and accelerometer-measured physical activity, and then examine associations within adolescents with DS. METHODS: Thirty-nine adolescents (22 with DS and 17 typically developing controls) 12-18 yr of age participated in the study. Groups had similar distributions of age, sex, and Tanner pubertal stage. Body composition was assessed by DXA, body mass index (BMI), and BMI percentile. MVPA was measured with ActiGraph GT3X+ accelerometers. RESULTS: Adolescents with DS had significantly higher BMI, BMI percentile, and DXA-derived percent body fat (%BF) as well as lower MVPA compared with controls (P < 0.05). Associations between MVPA and %BF in adolescents with DS were moderate (r = -0.39, P = 0.07) but substantially stronger than BMI (r = -0.19, P = 0.40). However, linear regression analyses identified Tanner stage (ß = -0.77, P < 0.001) and MVPA (ß = -0.34, P = 0.047) as significant predictors of %BF. No relevant associations between body composition and MVPA were observed in adolescents with typical development (P > 0.05). CONCLUSIONS: Our findings suggest that MVPA is associated with adiposity when measured with DXA among adolescents with DS.

Rehabilitation of the muscular dystrophies.

The muscular dystrophies (MD) are a heterogeneous group of inherited disorders characterized by findings on muscle biopsy. In general, they feature progressive muscle wasting and weakness. In addition to the musculoskeletal system, direct and indirect effects can be seen in a variety of organ systems. These issues create challenges in patients with MD for ambulation and mobility, self-care, pain, fatigue, and community involvement. Because of its progressive nature and wide variety of pathophysiological mechanisms, patients with MD require individualized rehabilitation care. This chapter reviews specific rehabilitation needs and treatment of patients with MD.

Physical activity patterns of youth with Down syndrome.

The purpose of this study was to examine the physical activity patterns of children with Down syndrome. A cross-sectional approach and accelerometry were used to measure the time children with Down syndrome (N = 104) spent in sedentary, light, and moderate-to-vigorous physical activity. Results indicated that adolescents from ages 14 to 15 years were the most sedentary and spent the least amount of time in light and moderate-to-vigorous physical activity. A general trend of decreasing physical activity as children increase in age was found. This trend is similar to that found among typically developing youth. Participants in this study were found to spend a majority of their day engaged in sedentary activities. Results indicate that most participants were not accumulating the recommended 60 minutes of moderate or vigorous physical activity.

Physical activity benefits of learning to ride a two-wheel bicycle for children with Down syndrome: a randomized trial.

BACKGROUND: People with Down syndrome (DS) display consistent patterns of physical inactivity. If these sedentary behaviors continue over extended periods of time, there will be negative health consequences. OBJECTIVE: The objective of this study was to investigate the physical activity and health-related outcomes of teaching children with DS to ride a 2-wheel bicycle. DESIGN: This study was a randomized intervention in which the control group waited 1 year to receive the intervention. SETTING: This intervention study was conducted in a community setting. PARTICIPANTS: The participants were children who were 8 to 15 years of age and who had been diagnosed with DS. Intervention The participants were randomly assigned to an experimental group (bicycle intervention) or a control group (no intervention). MEASUREMENTS: Measurements were obtained in the month before the intervention (preintervention), at 7 weeks after the intervention, and at 12 months after the preintervention measurement for all participants. RESULTS: The results indicated no group differences at the preintervention session. Fifty-six percent of the participants in the experimental group successfully learned to ride a 2-wheel bicycle during the 5-day intervention. Analysis showed that participants who learned to ride spent significantly less time in sedentary activity at 12 months after the preintervention measurement and more time in moderate to vigorous physical activity than participants in the control group. Body fat appeared to be positively influenced over time in participants who learned to ride. LIMITATIONS: It is unknown how frequently the children in the experimental group rode their bicycles after the intervention. CONCLUSIONS: Most children who are 8 to 15 years of age and who have been diagnosed with DS can learn to ride a 2-wheel bicycle. Learning to ride can reduce time spent in sedentary activity and increase time spent in moderate to vigorous physical activity, which may influence the health and functioning of these children.

Relationship of spasticity to soft tissue body composition and the metabolic profile in persons with chronic motor complete spinal cord injury.

BACKGROUND/OBJECTIVE: To determine the effects of spasticity on anthropometrics, body composition (fat mass [FM] and fat-free mass [FFM]), and metabolic profile (energy expenditure, plasma glucose, insulin concentration, and lipid panel) in individuals with motor complete spinal cord injury (SCI). METHODS: Ten individuals with chronic motor complete SCI (age, 33 +/- 7 years; BMI, 24 +/- 4 kg/m2; level of injury, C6-T11; American Spinal Injury Association A and B) underwent waist and abdominal circumferences to measure trunk adiposity. After the first visit, the participants were admitted to the general clinical research center for body composition (FFM and FM) assessment using dual energy x-ray absorptiometry. After overnight fasting, resting metabolic rate (RMR) and metabolic profile (plasma glucose, insulin, and lipid profile) were measured. Spasticity of the hip, knee, and ankle flexors and extensors was measured at 6 time points over 24 hours using the Modified Ashworth Scale. RESULTS: Knee extensor spasticity was negatively correlated to abdominal circumferences (r = -0.66, P = 0.038). After accounting for leg or total FFM, spasticity was negatively related to abdominal circumference (r = -0.67, P = 0.03). Knee extensor spasticity was associated with greater total %FFM (r = 0.64; P = 0.048), lower % FM (r = -0.66; P = 0.03), and lower FM to FFM ratio. Increased FFM (kg) was associated with higher RMR (r = 0.89; P = 0.0001). Finally, spasticity may indirectly influence glucose homeostasis and lipid profile by maintaining FFM (r = -0.5 to -0.8, P < 0.001). CONCLUSION: Significant relationships were noted between spasticity and variables of body composition and metabolic profile in persons with chronic motor complete SCI, suggesting that spasticity may play a role in the defense against deterioration in these variables years after injury. The exact mechanism is yet to be determined.

Body mass index measures in children with cerebral palsy related to gross motor function classification: a clinic-based study.

OBJECTIVE: To investigate the prevalence of overweight in a clinic-based population of children with cerebral palsy (CP) and its association with gross motor function status. DESIGN: Retrospective chart review. We calculated body mass index (BMI; kg/m2) from charted height and weight and recorded Gross Motor Function Classification Scale (GMFCS levels I-V) on the basis of clinical descriptions in clinic notes for 137 children (2-18 yrs old) with CP seen in a pediatric rehabilitation clinic at an academic medical center. BMI percentiles were reported according to sex-specific age group standards for growth set by the U.S. Centers for Disease Control and Prevention (CDC). Associations were modeled by Pearson's chi2 distribution. RESULTS: Out of the total CP subject group, 29.1% were considered overweight (>95th percentile) or at risk for overweight (85th to 95th percentile). Ambulatory children (GMFCS levels I and II) showed a trend (Pearson's chi2, P = 0.06) toward higher prevalence of overweight (22.7%) compared with nonambulatory children (levels IV and V, 9.6%). Underweight was more prevalent in nonambulatory children (P < 0.01). Logistic regression analysis did not identify any significant predictors for overweight. CONCLUSIONS: In our patient population, analysis of BMI suggests that children with CP have a high rate of overweight and are at risk of overweight, particularly among ambulatory children. More study is needed, using measures more accurate than BMI, to clarify risk.

Rehabilitation of children and adults who have neuromuscular diseases.

Neuromuscular diseases are a broad group of disorders that affect the motor unit. Recent advances in genetics and molecular biology have greatly furthered understanding of these diseases. Unfortunately, this has not greatly modified treatment strategies. This article addresses some common features of these diseases, and some less commonly addressed issues.

Controversial topic: return to competitive sport after severe traumatic brain injury.

Various guidelines have been proposed for returning to sport after concussion or mild TBI. However, no such guidelines exist for severe TBI. This study presents three cases of athletes who sustained severe TBIs and returned to competition. The rational for their clearance will be discussed.

Cardiac rehabilitation after heart transplantation in a patient with Becker's muscular dystrophy: a case report.

Becker's muscular dystrophy (BMD) is associated with abnormal cardiac findings in 75% of cases; up to one third will develop ventricular dilatation leading to congestive heart failure, at times necessitating cardiac transplant. Candidates are selected from a base of heart failure patients who are usually New York Heart Association (NYHA) class III or IV. Treatment in a phase II cardiac rehabilitation program after transplantation is associated with functional improvement in patients without BMD, but there are no reports of patients with this disorder. We present the case of a 38-year-old man diagnosed with BMD with associated dilated cardiomyopathy. The patient was a NYHA class IIIa and underwent orthotopic cardiac transplantation for intractable heart failure followed by treatment in a phase II cardiac rehabilitation program. At the end of cardiac rehabilitation, his 12-minute walking distance had improved from 716.28 to 929.64 m (30% improvement), he had increased his conditioning metabolic equivalent level from 3.5 to 5.5 (55% improvement), he had a weight loss from 81.65 to 78.93 kg, and his body mass index changed from 23 to 22 kg/m2. The patient now has returned to work, is using a stationary bicycle once a day for 30 minutes, and is walking 1 hour a day. This suggests that treatment in a cardiac rehabilitation program is effective in patients with BMD after cardiac transplant.

Test of the principle of initial value in rat genetic models of exercise capacity.

An inverse relationship between initial level of physical capacity and the magnitude of response to training is termed the principle of initial value. We tested the operation of this principle under experimental conditions of minimal genetic and environmental variation. Inbred rat strains previously identified as genetic models of low [Copenhagen (COP)] and high [Dark Agouti (DA)] intrinsic (untrained) exercise capacity were trained for 8 wk on a treadmill using two disparate protocols: 1) a relative mode where each rat exercised daily according to its initial capacity, and 2) an absolute mode where both strains received the same amount of training independent of initial capacity. Response to exercise was the change in running capacity as estimated by meters run to exhaustion before and after training. When trained with the relative mode, COP rats gained 88 m (+21%; NS) whereas DA rats increased distance run by 228 m (+36%; P < 0.001). When each strain trained with the same absolute amount of training, the COP strain showed essentially no change (-6 m, -2%) and the DA strain gained 325 m (+49%; P < 0.009). Differences in response to exercise between the COP and DA could not be explained by body mass differences, oxidative enzyme activity (citrate synthase or ATP), or spontaneous behavioral activity. Our data demonstrate that genetic factors causative of high response to exercise are not uniquely associated with genetic factors for low intrinsic capacity and thus are not in accord with the principle of initial value.

Amantadine in pediatric patients with traumatic brain injury: a retrospective, case-controlled study.

OBJECTIVE: To determine if amantadine use in pediatric patients with traumatic brain injury is well tolerated and to attempt to assess its effectiveness. DESIGN: This was a retrospective, case-controlled study. RESULTS: Of the 54 patients, aged 3-18 yrs, who were administered amantadine, five (9%) had side effects that might have been related to the drug. These included hallucinations, delusions, increased aggression, and nausea/vomiting. The side effects were reversed when the medication was stopped or the dosage decreased. Patients in the amantadine group had a greater increase in Ranchos Los Amigos level during their admission than those in the control group (median, 3 vs. 2; P < 0.01). This difference may be, at least in part, explained by the fact that the amantadine group started at a lower Ranchos Los Amigos level (median, 3 vs. 4; P < 0.01). There were subjective improvements noted in 29 of the 46 patients (63%) in the amantadine group whose full charts were available for review. CONCLUSION: Amantadine is a well tolerated medication when it is used in pediatric patients with traumatic brain injury. Subjective improvements were noted in the majority of the patients administered amantadine, and the amantadine group showed a greater improvement in Ranchos Los Amigos level during admission, suggesting that it may be effective.