title: Malignant cardiac involvement in a family with myotonic dystrophy.
abstract: BACKGROUND
  In patients with myotonic dystrophy, histopathological and electrophysiologic abnormalities of cardiac conduction system may lead to sudden cardiac death due to atrioventricular block or to ventricular electrical instability.
  
  
  METHODS
  Four members of a family affected by myotonic dystrophy are reported, which underwent a cardiological examination including invasive electrophysiological study and prolonged follow-up. Other 3 members of the same family had died suddenly. No clinical data are available for 2 of these patients, while paroxysmal atrial flutter and non sustained ventricular tachycardia had been detected at Holter in the third one.
  
  
  RESULTS
  Signs of atrioventricular conduction impairment, poorly predictable with non invasive electrocardiography, were found in the 4 patients undergoing intracardiac electrophysiologic study. In 2/4 patients, both having dizzy spells and the most impaired atrioventricular conduction, a pace-maker was implanted. Polymorphic, non sustained ventricular response was induced in 2/4 patients, 1 of them with spontaneous high grade ventricular arrhythmias.
  
  
  CONCLUSIONS
  The respective role of atrioventricular conduction impairment and ventricular vulnerability in determining sudden death has not been stated so far in these patients. The observed polymorphic non sustained response should not be "a priori" disregarded as aspecific, since it could be the electrophysiological counterpart of a peculiar anatomic arrhythmogenic substrate. A comprehensive study, including invasive electrophysiology, is advisable in all patients with myotonic dystrophy whenever a member of their family presents with cardiac involvement, to assess the most probable life-threatening arrhythmogenic mechanism.
authors.affiliation: Fisiologia Clinica, Università Cattolica del Sacro Cuore, Policlinico A. Gemelli, Roma, Italy.
authors.forename: G
authors.initials: G
authors.lastname: Melillo
authors.forename: M P
authors.initials: MP
authors.lastname: Ruggieri
authors.forename: G
authors.initials: G
authors.lastname: Magni
authors.forename: P V
authors.initials: PV
authors.lastname: Fragola
authors.forename: G
authors.initials: G
authors.lastname: Antonini
authors.forename: R
authors.initials: R
authors.lastname: Vichi
authors.forename: D
authors.initials: D
authors.lastname: Cannata
authors.forename: R R
authors.initials: RR
authors.lastname: Fenici
mesh_terms: D000293:Adolescent; D000328:Adult; D016757:Death, Sudden, Cardiac / Q000209:etiology*; D004452:Echocardiography; D004562:Electrocardiography; D015716:Electrocardiography, Ambulatory; D004594:Electrophysiology; D005260:Female; D005500:Follow-Up Studies; D006327:Heart Block / Q000209:etiology; D006329:Heart Conduction System / Q000503:physiopathology*; D006352:Heart Ventricles / Q000503:physiopathology; D006801:Humans; D008297:Male; D008875:Middle Aged; D009223:Myotonic Dystrophy / Q000235:genetics / Q000503:physiopathology*; D010375:Pedigree; D013997:Time Factors