Cardiac conduction disorders as markers of cardiac events in myotonic dystrophy type 1

Hideki Itoh, Takashi Hisamatsu, Takuhisa Tamura, Kazuhiko Segawa, Toshiaki Takahashi, Hiroto Takada, Satoshi Kuru, Chizu Wada, Mikiya Suzuki, Shugo Suwazono, Shingo Sasaki, Ken Okumura, Minoru Horie, Masanori P. Takahashi, Tsuyoshi Matumura

Research output: Contribution to journalArticlepeer-review

8 Citations (Scopus)


BACKGROUND: Myotonic dystrophy type 1 involves cardiac conduction disorders. Cardiac conduction disease can cause fatal arrhythmias or sudden death in patients with myotonic dystrophy type 1. METHODS AND RESULTS: This study enrolled 506 patients with myotonic dystrophy type 1 (aged ≥15 years; >50 cytosine-thymine-guanine repeats) and was treated in 9 Japanese hospitals for neuromuscular diseases from January 2006 to August 2016. We investigated genetic and clinical backgrounds including health care, activities of daily living, dietary intake, cardiac involvement, and respiratory involvement during follow-up. The cause of death or the occurrence of composite cardiac events (ie, ventricular arrhythmias, advanced atrioventricular blocks, and device implantations) were evaluated as significant outcomes. During a median follow-up period of 87 months (Q1–Q3, 37–138 months), 71 patients expired. In the univariate analysis, pacemaker implantations (hazard ratio [HR], 4.35; 95% CI, 1.22–15.50) were associated with sudden death. In contrast, PQ interval ≥240 ms, QRS duration ≥120 ms, nutrition, or respiratory failure were not associated with the incidence of sudden death. The multivariable analysis revealed that a PQ interval ≥240 ms (HR, 2.79; 95% CI, 1.9–7.19, P<0.05) or QRS duration ≥120 ms (HR, 9.41; 95% CI, 2.62–33.77, P < 0.01) were independent factors associated with a higher occurrence of cardiac events than those observed with a PQ interval <240 ms or QRS duration <120 ms; these cardiac conduction parameters were not related to sudden death. CONCLUSIONS: Cardiac conduction disorders are independent markers associated with cardiac events. Further investigation on the prediction of occurrence of sudden death is warranted.

Original languageEnglish
Article numbere015709
JournalJournal of the American Heart Association
Issue number17
Publication statusPublished - Sept 1 2020


  • Conduction disturbance
  • Myotonic dystrophy
  • Sudden death
  • Ventricular tachycardia

ASJC Scopus subject areas

  • Cardiology and Cardiovascular Medicine


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