Case Reports: Emery-Dreifuss Muscular Dystrophy Presenting as a Heart Rhythm Disorders in Children

Sinus node dysfunction in children: different aetiologies, similar clinical course in two-centre experience

AIM

This study aims to evaluate the clinical characteristics and outcomes of children diagnosed with sinus node dysfunction.

METHODS

This was a retrospective review of patients diagnosed with sinus node dysfunction in two tertiary paediatric cardiology centres in Turkey from January 2011 to June 2022.

RESULTS

In all, 77 patients (50, 64.9% males) were included, with a mean age of 8.2 ± 6.3 years and a mean weight of 28.2 ± 18.8 kg. While age-incompatible bradycardia and pauses were the most common rhythm disturbances, syncope, presyncope, and dizziness (n:33, 43%) were the most frequent initial symptoms. Structural heart disease was present in 58 (75.3%) of the 77 patients, 47 (61%) of whom were congenital. The most commonly associated CHDs were transposition of the great arteries (n:8), atrial septal defect (n:7), and atrioventricular septal defect (n:5). Seven of them also had left atrial isomerism. The remaining 19 patients were isolated. Four patients had SCN5A mutation (two of them were siblings) and two of them had Emery-Dreifuss muscular dystrophy.

CONCLUSION

Although sinus node dysfunction is rare in children, it has been diagnosed with increasing frequency with structural heart disease, especially in patients who have undergone corrective cardiac surgery related to atrial tissue. Since sinus node dysfunction can occur at any time postoperatively, these patients should be kept under constant control. If symptomatic sinus node dysfunction is confirmed, permanent pacing is an effective therapeutic modality.

The cardiac conduction system: History, development, and disease

The heart is the first organ to form during embryonic development, establishing the circulatory infrastructure necessary to sustain life and enable downstream organogenesis. Critical to the heart's function is its ability to initiate and propagate electrical impulses that allow for the coordinated contraction and relaxation of its chambers, and thus, the movement of blood and nutrients. Several specialized structures within the heart, collectively known as the cardiac conduction system (CCS), are responsible for this phenomenon. In this review, we discuss the discovery and scientific history of the mammalian cardiac conduction system as well as the key genes and transcription factors implicated in the formation of its major structures. We also describe known human diseases related to CCS development and explore existing challenges in the clinical context.

Cardiac manifestations and clinical management of X-linked Emery-Dreifuss muscular dystrophy: a case series

Background

Heart disease is an under-recognized cause of morbidity and mortality in patients with Emery-Dreifuss muscular dystrophy (EDMD). Arrhythmias and conduction delays are highly prevalent and given the rarity of this disease the patient care process remains poorly defined.

Case summary

This study closely followed four adult patients from the Neuromuscular Multidisciplinary Clinic (Alberta, Canada) that presented with X-linked recessive EDMD. Patients were assessed and managed on a case-by-case basis. Clinical status and cardiac function were assessed through clinical history, physical examination, and investigations (12-lead electrocardiogram, 24 hour Holter monitor, transthoracic echocardiogram, and plasma biomarkers). Conduction disease, requiring permanent pacemaker, was prevalent in all patients. With appropriate medical therapy over a median follow-up period five years the cardiac status was shown to have stabilized in all these patients.

Discussion

We demonstrate the presentation of arrhythmias, conduction abnormalities, and chamber dilation in adult patients with X-linked EDMD. Cardiac medications and pacemaker therapy are shown to prevent adverse outcomes from these complications. Patients with EDMD are expected to develop heart disease early and prior to the development of an overt neuromuscular phenotype. These patients should be closely monitored in a multidisciplinary setting for effective management to improve their clinical outcomes.