Distribution and cardiac outcomes of neuromuscular disorders referred to an inherited cardiac disease unit

Abstract Backgroud Neuromuscular disorders may present with varied cardiac involvement, including myocardial and conduction tissue disease. Sudden death is a common adverse event of cardiomyopathy Purpose The objective was to present clinical characteristics of neuromuscular disorders referred to a dedicated inherited cardiac disease unit with special interest in the mode of presentation, clinical course and cardiac complications. Methods Cardiological anamnesis, 12-lead electrocardiogram and bidimensional echocardiogram were performed to every individual. Gadolinium cardiac MRI/24 hour-Holter/coronariography were performed in particular cases where results of previous tests made it mandatory. Results 199 patients (aged 43.1±18.1 years, 45.2% females, 54.8% males) with neurological disorders evaluated in an inherited cardiac disease clinic from 2003–2021 were included. There were 20 (10.1%) dystrophynopathies, 20 (10.1%) limb girdle muscular dystrophy, 14 (7.0%) other muscular dystrophies (Emery-Dreifuss, facio-scapulo-humeral, oculopharyngeal), 70 (35.2%) myotonic myopathies (Steinert myotonic dystrophy, Becker myotonia congenita, Thomsen myotonia congenita), 7 (3.5%) myofibrillar myopathies, 14 (7.0%) congenital myopathies, 18 (9.0%) metabolic myopathies, 12 (6.0%) unknown origin inherited myopathies, 24 (12.1%) non-myopathic neurological diseases. There were 44 (22.11%) patients affected with a cardiomyopathy. 51/199 (25.6%) had conduction disturbances. 33/51 had pathological cardiac findings without clinical cardiomyopathy. Age of diagnosis of neurological and cardiomyopathy conditions were 28.4±20.4 and 40.6±18.4 years old respectively. Reasons for diagnosis were symptoms (164, 82.4%), family screening (27, 13.6%), incidental finding (7, 3.5%), sudden death (1, 0.5%). 31 (15.6%) had atrial fibrillation, 17 (8.5%) required pacemaker and 15 (7.5%) ICD implantation. 32 (16.1%) patients died or had severe cardiac outcome. 7 (3.5%) had sudden death or equivalent, 3 (1.5%) heart-failure-death, 1 (0.5%) received cardiac transplantation, 18 (9.1%) had other-disease-related-death and 3 (1.5%) other disease non-cadiac-related-death). Conclusion Neuromuscular diseases require periodic cardiac evaluation. Despite onset of neurological symptoms usually precede cardiac involvement, the burden of cardiac involvement and complications is highly significant. Cause of death in neurological conditions with cardiac involvement is mostly driven by the severity of the cardiomyopathy. Funding Acknowledgement Type of funding sources: None.