QRS prolongation in myotonic muscular dystrophy and diffuse fibrosis on cardiac magnetic resonance

Saman Nazarian, David A. Bluemke, Kathryn R. Wagner, Menekhem M. Zviman, Evrim Turkbey, Brian S. Caffo, Monda Shehata, David Edwards, Barbara Butcher, Hugh Calkins, Ronald D. Berger, Henry R. Halperin, Gordon F. Tomaselli

Research output: Contribution to journalArticlepeer-review

12 Scopus citations


Current noninvasive surrogates of cardiac involvement in myotonic muscular dystrophy have low positive predictive value for sudden death. We hypothesized that the cardiac MR signal-to-noise ratio variance (SNRV) is a surrogate of the spatial heterogeneity of myocardial fibrosis and correlates with electrocardiography changes in myotonic muscular dystrophy. The SNRV for contrast enhanced cardiac MR images was calculated over the entire left ventricle in 43 patients with myotonic muscular dystrophy. All patients underwent standard electrocardiography, and a subset of 23 patients underwent signal averaged electrocardiography. After correcting for body mass index, age, and ejection fraction, SNRV was predictive of QRS duration on standard electrocardiography (1.35-msec increased QRS duration/unit increase in SNRV, P < 0.001). SNRV was also predictive of the low-amplitude late-potential duration (1.49-msec increased low-amplitude late-potential duration/unit increase in SNRV, P < 0.001). Ten-fold cross-validation yielded an area under the receiver operating characteristic curve of 0.87 for the predictive value of SNRV for QRS duration greater than 120 msec. The SNRV of the left ventricle is associated with QRS prolongation, likely due to late depolarization of tissue within islands of patchy fibrosis. The association of SNRV with future clinical events warrants further study.

Original languageEnglish (US)
Pages (from-to)107-114
Number of pages8
JournalMagnetic resonance in medicine
Issue number1
StatePublished - Jul 2010


  • Atrioventricular block
  • Electrocardiography
  • Magnetic resonance imaging
  • Myocardial fibrosis
  • Myotonic muscular dystrophy

ASJC Scopus subject areas

  • Radiology Nuclear Medicine and imaging


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