title: Atrial flutter or fibrillation is the most frequent and life-threatening arrhythmia in myotonic dystrophy.
abstract: BACKGROUND
  Several arrhythmias were reported in myotonic dystrophy (MD).
  
  
  OBJECTIVE
  To evaluate the prevalence of atrial fibrillation (AF) and atrial flutter (AFL) in MD and the clinical consequences.
  
  
  METHODS
  One hundred sixty-one patients, mean age 41 ± 14 years, were referred for a type 1 MD. All patients were asymptomatic except four patients and followed during 5 ± 4 years. Electrocardiogram (ECG), echocardiography assessing left ventricular ejection fraction, and Holter monitoring were obtained and repeated.
  
  
  RESULTS
  Twenty-seven patients (17%) presented sustained (>1 hour) AF (n = 15) or AFL (n = 12); two of them presented syncope-related 1/1 AFL. In one of them, 16 years of age, cardiac defibrillator was implanted for a diagnosis of ventricular tachycardia, but the true diagnosis was established after inappropriate shocks. AFL ablation was performed in five patients, but four developed AF. The other seven patients with AFL developed AF. During the follow-up, 22 patients died (14%) from cardiac and respiratory failure; eight patients with AF/AFL died (30%) while only 14 without AF/AFL died (10%; P < 0.01). Univariate analysis indicated that age >40 years (death: 48 ± 14 vs 40 ± 8 in alive patients), abnormal ECG, and occurrence of AF/AFL were significant factors of death. At multivariate analysis, AF at ECG (odds ratio: 3.12) and age >40 (odds ratio: 3.14) were the sole independent variables predicting death.
  
  
  CONCLUSIONS
  AF and AFL were frequent in MD and increased mortality. AFL could present as 1/1 AFL with a poor tolerance and a risk of misdiagnosis despite frequent conduction disturbances. This arrhythmia could explain wide QRS tachycardia occurring in MD and interpreted as VT.
authors.affiliation: Department of Cardiology.
authors.forename: Béatrice
authors.initials: B
authors.lastname: Brembilla-Perrot
authors.forename: Jérôme
authors.initials: J
authors.lastname: Schwartz
authors.forename: Olivier
authors.initials: O
authors.lastname: Huttin
authors.forename: Zied
authors.initials: Z
authors.lastname: Frikha
authors.forename: Jean Marc
authors.initials: JM
authors.lastname: Sellal
authors.forename: Nicholas
authors.initials: N
authors.lastname: Sadoul
authors.forename: Hugues
authors.initials: H
authors.lastname: Blangy
authors.forename: Arnaud
authors.initials: A
authors.lastname: Olivier
authors.forename: Sarah
authors.initials: S
authors.lastname: Louis
authors.forename: Pierre
authors.initials: P
authors.lastname: Kaminsky
mesh_terms: D000293:Adolescent; D000328:Adult; D017677:Age Distribution; D000368:Aged; D001281:Atrial Fibrillation / Q000175:diagnosis* / Q000401:mortality* / Q000628:therapy; D001282:Atrial Flutter / Q000175:diagnosis* / Q000378:metabolism* / Q000628:therapy; D015897:Comorbidity; D004562:Electrocardiography / Q000706:statistics & numerical data; D005260:Female; D005602:France; D006801:Humans; D008297:Male; D008875:Middle Aged; D009223:Myotonic Dystrophy / Q000175:diagnosis* / Q000401:mortality* / Q000628:therapy; D016016:Proportional Hazards Models; D015203:Reproducibility of Results; D018570:Risk Assessment; D012680:Sensitivity and Specificity; D017678:Sex Distribution; D015996:Survival Rate; D055815:Young Adult
keywords: atrial fibrillation; atrial flutter; myotonic dystrophy; prognosis