Atrial arrhythmias in the young: early onset atrial arrhythmias preceding a diagnosis of a primary muscular dystrophy

Aims The aetiology of atrial arrhythmias in the otherwise healthy and young is usually unrecognized. We hypothesized that rare cases of atrial arrhythmias in the young may represent the initial manifestation of a muscular dystrophy syndrome. Methods and results We describe the clinical characteristics, disease progression, results of electrophysiological study, and genetic findings in four patients (age,40 years) presenting with idiopathic atrial arrhythmias who subsequently received a diagnosis of a muscular dystrophy syndrome. The mean age at presentation with atrial arrhythmias was 29.5 years (range, 21-37 years), and the mean delay to diagnosis of muscular dystrophy was 3.6 years (range, 0.5-6 years). Two patients received a subsequent diagnosis of myotonic dystrophy type 1 and 2 a diagnosis of Emery-Dreifuss muscular dystrophy. Disease-causing genetic defects were identified in all four patients. One patient underwent catheter ablation of atrial flutter, experiencing improvement in arrhythmia symptoms. Two patients required device therapy, each receiving cardiac resynchronization therapy-defibrillator implantation for progressive left ventricular dysfunction. Conclusion Early onset atrial arrhythmias may be the first clinical manifestation of a muscular dystrophy syndrome. Appropriate clinical assessment and surveillance may uncover this primary cause and provide an opportunity for timely genetic counselling and family screening.