title: Long-term follow-up of arrhythmias in patients with myotonic dystrophy treated by pacing: a multicenter diagnostic pacemaker study.
abstract: OBJECTIVE
  We hypothesized that pacemaker (PM) implantation in patients with myotonic dystrophy (MD) with a prolonged HV interval, even asymptomatic, may protect them against sudden death related to atrioventricular (AV) block. We sought to prospectively document the true incidence of AV block episodes in this high-risk population and accurately trace, in the long term, by the PM, the occurrence of arrhythmias that may remain undetected during conventional follow-up.
  
  
  BACKGROUND
  Myotonic dystrophy is associated with a high risk of sudden death, commonly attributed to AV block or ventricular arrhythmias, but cardiac pacing is only recommended as a secondary prevention.
  
  
  METHODS
  Patients with MD with an HV interval > or =70 ms, even in the absence of related symptoms, prospectively received a cardiac PM, including an algorithm capable of diagnosing episodes of bradycardia and tachyarrhythmias.
  
  
  RESULTS
  The population consisted of 49 patients (45.5 +/- 8.9 years old) followed for 53.5 +/- 27.2 months. Paroxysmal arrhythmias were recorded in 41 patients (83.7%), consisting of complete AV block (n = 21), sino-atrial block (n = 4), or atrial (n = 25) or ventricular (n = 13) tachyarrhythmias. No patient died of AV block during follow-up, but 10 deaths occurred, 4 of them sudden. An arrhythmic cause could be excluded by postmortem PM interrogation in two cases of typical sudden death.
  
  
  CONCLUSIONS
  Arrhythmias are common in patients with MD with infrahisian conduction abnormalities. The prophylactic implantation of a pacing system when the HV interval is > or =70 ms seems appropriate. The PM protects the patient against the clinical consequences of paroxysmal profound bradycardia and facilitates the diagnosis and management of frequent paroxysmal tachyarrhythmias.
authors.affiliation: Service de Cardiologie et de Biostatistique, Hôpital Cochin, Paris, France. lazarus@inparys.com
authors.forename: Arnaud
authors.initials: A
authors.lastname: Lazarus
authors.forename: Jean
authors.initials: J
authors.lastname: Varin
authors.forename: Dominique
authors.initials: D
authors.lastname: Babuty
authors.forename: Frédéric
authors.initials: F
authors.lastname: Anselme
authors.forename: Joel
authors.initials: J
authors.lastname: Coste
authors.forename: Denis
authors.initials: D
authors.lastname: Duboc
mesh_terms: D000328:Adult; D000465:Algorithms; D002304:Cardiac Pacing, Artificial / Q000379:methods*; D002423:Cause of Death; D018572:Disease-Free Survival; D004562:Electrocardiography; D005260:Female; D005500:Follow-Up Studies; D006327:Heart Block / Q000209:etiology / Q000517:prevention & control*; D006801:Humans; D008297:Male; D008875:Middle Aged; D009223:Myotonic Dystrophy / Q000150:complications* / Q000235:genetics / Q000503:physiopathology; D010138:Pacemaker, Artificial