title: Cardiovascular profile in myotonic dystrophy type 1: Analysis of a case series in a specialized center.
abstract: BACKGROUND
  Myotonic dystrophy is a multisystem disease associated with cardiac abnormalities that are responsible for high morbidity and mortality. It commonly affects conduction tissue, resulting in changes in heart rate that tend to progress with age.
  
  
  OBJECTIVE
  The aim of the study was to assess overall cardiovascular risk and the risk of arrhythmias in patients with myotonic dystrophy type 1 (DM-1) and to correlate them with genetic study (CTG expansion size).
  
  
  METHODS
  This retrospective study included 31 DM-1 patients referred to the cardiology department of Centro Hospitalar Entre Douro e Vouga by the neurology department for screening for heart disease. Patients' medical records were consulted for the diagnostic tests performed in the diagnostic cardiology consultation: electrocardiogram (ECG), high-resolution ECG, heart rate variability (HRV), Holter 24-hour ambulatory ECG and transthoracic echocardiogram (TTE); results of genetic testing were also consulted.
  
  
  RESULTS
  Of 31 patients studied, 38% had first-degree atrioventricular block (AVB) and 51% had intraventricular conduction disturbances (62% had late potentials). TTE revealed no structural heart disease. Rare supraventricular and ventricular ectopic beats were the most common arrhythmias on 24-hour Holter monitoring. The sample showed lower HRV, reflecting vagal dysfunction. Patients with larger CTG expansions had more cardiac abnormalities.
  
  
  CONCLUSIONS
  Patients with DM-1 had arrhythmic events, with AVB and more significantly intraventricular block, although none had malignant arrhythmias or structural heart disease. No patient died. Patients with larger CTG expansions had greater involvement of cardiac conduction tissue.
authors.affiliation: Hospital de São Sebastião, Santa Maria da Feira, Portugal. Electronic address: liliangomes@sapo.pt.
authors.forename: Lilian
authors.initials: L
authors.lastname: Gomes
authors.affiliation: Departamento de Cardiopneumologia, Escola Superior de Tecnologia da Saúde de Coimbra, Coimbra, Portugal.
authors.forename: Telmo
authors.initials: T
authors.lastname: Pereira
authors.affiliation: Hospital de São Sebastião, Santa Maria da Feira, Portugal.
authors.forename: Luís
authors.initials: L
authors.lastname: Martins
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D001145:Arrhythmias, Cardiac / Q000453:epidemiology / Q000209:etiology*; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D009223:Myotonic Dystrophy / Q000150:complications* / Q000235:genetics; D012189:Retrospective Studies; D018570:Risk Assessment; D055815:Young Adult
keywords: Arrhythmia; Cardiomyopathy; Disritmias; Distrofia muscular miotónica; Miocardiopatia; Myotonic dystrophy