Quantitative left ventricular rotational mechanics in Duchenne and Becker muscular dystrophy patients

Wang et al. Journal of Cardiovascular Magnetic Resonance 2015, 17(Suppl 1):Q34 http://www.jcmr-online.com/content/17/S1/Q34 WALKING POSTER PRESENTATION Open Access Quantitative left ventricular rotational mechanics in Duchenne and Becker muscular dystrophy patients Zhe Wang 2,1* , Meral Reyhan 2,3 , Nancy Halnon 4 , Sarah N Khan 2 , Paul J Finn 2 , Pierangelo Renella 5 , Daniel B Ennis 2,1 From 18th Annual SCMR Scientific Sessions Nice, France. 4-7 February 2015 Background Duchenne/Becker muscular dystrophy (D/BMD) is asso- ciated with early onset cardiomyopathy, with cardiac fibro- sis amongst the earliest manifestations. Changes in conventional estimates of cardiac function (e.g. ejection fraction, EF) may occur late in Duchenne and Becker mus- cular dystrophy (DMD/BMD). Cardiac MRI tagging is a noninvasive imaging biomarker for quantifying ventricular dysfunction in DMD/BMD cardiomyopathy. In particular, estimates of ventricular rotational mechanics (e.g. peak twist or normalized untwisting rate) may provide insight to early ventricular dysfunction. Furthermore, myocardial fibrosis in DMD/BMD patients is frequently reported and could significantly impact LV rotational mechanics. How- ever, the functional consequences of myocardial fibrosis in these patients are incompletely understood. The objective of this study was to quantify LV rotational mechanics in pediatric DMD/BMD patients with normal EF (N-EF) or low EF (L-EF) and with (f+) or without (f-) fibrosis. Methods Seventeen (N=17) male pediatric subjects (13.7±4.5 years old) genetically diagnosed with DMD/BMD consented to participate in an IRB approved study. Each patient under- went a cardiac 3T MRI exam that included evaluation of functional status with cine MRI, cardiac tagging MRI, and ventricular scar evaluation. Ten (M=10) non-aged- matched (29±4.3 years old) healthy volunteers were also evaluated to provide context for interpreting the pediatric data. LV mass, LVESV, LVEDV, and LVEF were calcu- lated. The normal EF cut-off was >55.9% for 8-15 year- olds (Danielle et. al. JMRI 2009, 29: :552-559) and >53.2% for 16-20 year-olds (Sarikouch et. al. Circulation 2010 Jan;3(1):65-76). The presence or absence of myocardial fibrosis was determined by consensus agreement. Compar- isons were made using t-tests with Holm-Sidak correction. Results The volunteers had LV peak twist (LV-PT) of 12.2 ± 2.6° and lower LV normalized untwist rate (LV-NUR) -12.5 ± 2.1° s -1 . The table shows lower LV-PT and LV-NUR in the EF-n/f- group compared to controls. LV-PT and LV-NUR significantly decreased in the N-EF/f+ group. LV-PT and LV-NUR were further decreased in the L-EF/f+ and were lowest in the L-EF/f+ group. T-tests with Holm-Sidak cor- rection showed significant difference between L-EF/f- and L-EF/f+ in LV-PT. No significant difference was detected for LV-NUR. Conclusions LV-PT and LV-NUR are lower in patients with DMD/ BMD despite normal EF, compared to the healthy volun- teers. Both low EF and the presence of fibrosis are asso- ciated further decreased LV-PT and LV-NUR. Fibrosis alone has a significant effect on LV rotational mechanics and should be further evaluated. Table 1 Normal (EF-N) Fibrosis (-) LV-PT: 9.3± 2.2° Abnormal (EF-L) N=6 LV-NUR: -11.1± 3.2° s-1 Fibrosis (+) LV-PT: 7.8± 2.2° LV-NUR: -9.1± 2.2° s-1 LV-PT: 8.7± 1.4° N=2 LV-NUR: -10.5± 1.2° s-1 N=6 LV-PT: 5.3 ±0.5° N=3 LV-NUR: -8.3± 0.5° s-1 Radiological Sciences, University of California Los Angeles, Los Angeles, CA, USA Full list of author information is available at the end of the article © 2015 Wang et al; licensee BioMed Central Ltd. This is an Open Access article distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/4.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited. The Creative Commons Public Domain Dedication waiver (http:// creativecommons.org/publicdomain/zero/1.0/) applies to the data made available in this article, unless otherwise stated.