title: Prevalence of type 1 Brugada ECG pattern after administration of Class 1C drugs in patients with type 1 myotonic dystrophy: Myotonic dystrophy as a part of the Brugada syndrome.
abstract: BACKGROUND
  Both type 1 myotonic dystrophy (MD1) and Brugada syndrome (BrS) may be complicated by conduction disturbances and sudden death. Spontaneous BrS has been observed in MD1 patients, but the prevalence of drug-induced BrS in MD1 is unknown.
  
  
  OBJECTIVE
  The purpose of this study was to prospectively assess the prevalence of type 1 ST elevation as elicited during pharmacologic challenge with Class 1C drugs in a subgroup of MD1 patients and to further establish correlations with ECG and electrophysiologic variables and prognosis.
  
  
  METHODS
  From a group of unselected 270 MD1 patients, ajmaline or flecainide drug challenge was performed in a subgroup of 44 patients (27 men, median age 43 years) with minor depolarization/repolarization abnormalities suggestive of possible BrS. The presence of type 1 ST elevation after drug challenge was correlated to clinical, ECG, and electrophysiologic variables.
  
  
  RESULTS
  Eight of 44 patients (18%) presented with BrS after drug challenge. BrS was seen more often in men (26% vs 6%, P = .09) and was related to younger age (35 vs 48 years, P = .07). BrS was not correlated to symptoms, baseline ECG, HV interval, results of signal-averaged ECG, or abnormalities on ambulatory recordings. MD1 patients with BrS had longer corrected QT intervals, greater increase in PR interval after drug challenge, and higher rate of inducible ventricular arrhythmias (62% vs 21%, P = .03). Twelve patients were implanted with a pacemaker and 5 with an implantable cardioverter-defibrillator. Significant bradycardia did not occur in any patients, and malignant ventricular arrhythmia never occurred during median 7-year follow-up (except 1 hypokalemia-related ventricular fibrillation).
  
  
  CONCLUSIONS
  BrS is elicited by a Class 1 drug in 18% of MD1 patients presenting with minor depolarization/repolarization abnormalities at baseline, but the finding seems to be devoid of a prognostic role.
authors.affiliation: Department of Cardiology, University Hospital Rangueil Toulouse, France. Electronic address: mauryjphil@hotmail.com.
authors.forename: Philippe
authors.initials: P
authors.lastname: Maury
authors.affiliation: Department of Cardiology, University Hospital Rangueil Toulouse, France.
authors.forename: Mathieu
authors.initials: M
authors.lastname: Audoubert
authors.affiliation: Department of Neurology, University Hospital Rangueil Toulouse, France.
authors.forename: Pascal
authors.initials: P
authors.lastname: Cintas
authors.affiliation: Department of Cardiology, University Hospital Rangueil Toulouse, France.
authors.forename: Anne
authors.initials: A
authors.lastname: Rollin
authors.affiliation: Department of Cardiology, University Hospital Rangueil Toulouse, France.
authors.forename: Alexandre
authors.initials: A
authors.lastname: Duparc
authors.affiliation: Department of Cardiology, University Hospital Rangueil Toulouse, France.
authors.forename: Pierre
authors.initials: P
authors.lastname: Mondoly
authors.affiliation: Department of Cardiology, University Hospital Arnaud de Villeneuve, Montpellier, France.
authors.forename: Ana-Maria
authors.initials: AM
authors.lastname: Chiriac
authors.affiliation: Department of Neurology, University Hospital Rangueil Toulouse, France.
authors.forename: Blandine
authors.initials: B
authors.lastname: Acket
authors.affiliation: Department of Cardiology, University Hospital Arnaud de Villeneuve, Montpellier, France.
authors.forename: Xinran
authors.initials: X
authors.lastname: Zhao
authors.affiliation: Department of Cardiology, University Hospital Arnaud de Villeneuve, Montpellier, France.
authors.forename: Jean Luc
authors.initials: JL
authors.lastname: Pasquié
authors.affiliation: Department of Cardiology, University Hospital Rangueil Toulouse, France.
authors.forename: Christelle
authors.initials: C
authors.lastname: Cardin
authors.affiliation: Department of Cardiology, University Hospital Rangueil Toulouse, France.
authors.forename: Marc
authors.initials: M
authors.lastname: Delay
authors.affiliation: Department of Cardiology, University Hospital Rangueil Toulouse, France.
authors.forename: Marie
authors.initials: M
authors.lastname: Sadron
authors.affiliation: Department of Cardiology, University Hospital Rangueil Toulouse, France.
authors.forename: Didier
authors.initials: D
authors.lastname: Carrié
authors.affiliation: Department of Cardiology, University Hospital Rangueil Toulouse, France.
authors.forename: Michel
authors.initials: M
authors.lastname: Galinier
authors.affiliation: Department of Cardiology, University Hospital Arnaud de Villeneuve, Montpellier, France.
authors.forename: Jean-Marc
authors.initials: JM
authors.lastname: Davy
authors.affiliation: Department of Neurology, University Hospital Rangueil Toulouse, France.
authors.forename: Marie-Christine
authors.initials: MC
authors.lastname: Arne-Bès
authors.affiliation: Department of Cardiology, University Hospital Arnaud de Villeneuve, Montpellier, France.
authors.forename: Franck
authors.initials: F
authors.lastname: Raczka
mesh_terms: D000328:Adult; D000404:Ajmaline / Q000009:adverse effects* / Q000627:therapeutic use; D053840:Brugada Syndrome / Q000139:chemically induced* / Q000453:epidemiology / Q000503:physiopathology; D016757:Death, Sudden, Cardiac / Q000453:epidemiology* / Q000209:etiology; D017147:Defibrillators, Implantable; D004562:Electrocardiography / Q000187:drug effects*; D005260:Female; D005424:Flecainide / Q000009:adverse effects* / Q000627:therapeutic use; D005500:Follow-Up Studies; D005602:France / Q000453:epidemiology; D006801:Humans; D015994:Incidence; D008297:Male; D009223:Myotonic Dystrophy / Q000150:complications / Q000188:drug therapy* / Q000503:physiopathology; D015995:Prevalence; D011379:Prognosis; D011446:Prospective Studies; D015996:Survival Rate / Q000639:trends; D061567:Voltage-Gated Sodium Channel Blockers
chemical_list: D061567:Voltage-Gated Sodium Channel Blockers; D000404:Ajmaline; D005424:Flecainide
keywords: Brugada syndrome; Myotonic dystrophy; ST elevation; Sudden death