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Increased heterogeneity of ventricular repolarization in myotonic dystrophy type 1 population

Vincenzo Russo1, Andrea Antonio Papa1, Anna Rago1

  • 1Cardiomyology and Medical Genetics, Department of Experimental Medicine, Second University of Naples and Monaldi Hospital, Naples, Italy.

Acta Myologica : Myopathies and Cardiomyopathies : Official Journal of the Mediterranean Society of Myology
|March 28, 2017
PubMed

Insights

Myotonic dystrophy type I (DM1) patients show increased ventricular repolarization heterogeneity, indicated by higher QTc dispersion, JTc dispersion, and transmural dispersion of repolarization. This occurs even with normal heart function, suggesting a risk for arrhythmias.

Area of Science:

  • Cardiology
  • Genetics
  • Electrophysiology

Background:

  • Sudden cardiac death in myotonic dystrophy type I (DM1) is linked to arrhythmias, even with preserved cardiac function.
  • Ventricular repolarization heterogeneity is a potential substrate for malignant arrhythmias.

Purpose of the Study:

  • To investigate ventricular repolarization heterogeneity in DM1 patients with preserved systolic and diastolic function.
  • To assess QTc dispersion (QTc-D), JTc dispersion (JTc-D), and transmural dispersion of repolarization (TDR) in this cohort.

Main Methods:

  • Compared 50 DM1 patients (normal cardiac function) with 50 age/sex-matched healthy controls.
  • Measured electrocardiographic parameters including QRS duration, QT/JT intervals, QTc-D, JTc-D, and TDR.

Main Results:

  • DM1 patients exhibited significantly increased QTc-D (p=0.03), JTc-D (p=0.001), and TDR (p=0.004) compared to controls.
  • These findings indicate heightened regional and transmural ventricular repolarization heterogeneity.

Conclusions:

  • DM1 patients with preserved cardiac function demonstrate significant ventricular repolarization abnormalities.
  • Increased repolarization dispersion may predispose DM1 patients to life-threatening arrhythmias.

Keywords:
JTc dispersionQTc dispersionarrhythmiasmyotonic dystrophyrepolarizationsudden cardiac death

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