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CLINICAL RESEARCH

Circumferential Strain Analysis Identifies Strata of Cardiomyopathy in Duchenne Muscular Dystrophy

A Cardiac Magnetic Resonance Tagging Study

Kan N. Hor, MD^_*, Janaka Wansapura, PhD, Larry W. Markham, MD, Wojciech Mazur, MD, Linda H. Cripe, MD^_*, Robert Fleck, MD, D. Woodrow Benson, MD, PhD^_* and William M. Gottliebson, MD^_*,_*

^_* Department of Cardiology, Cincinnati Children's Hospital Medical Center, Cincinnati, Ohio
Department of Radiology, Cincinnati Children's Hospital Medical Center, Cincinnati, Ohio
Department of Pediatric Cardiology, Vanderbilt University, Nashville, Tennessee
Christ Hospital, Cincinnati, Ohio

Manuscript received June 17, 2008; revised manuscript received October 31, 2008, accepted December 18, 2008.

^_* Reprint requests and correspondence: Dr. William M. Gottliebson, Cincinnati Children's Hospital Medical Center, Division of Cardiology, 3333 Burnet Avenue, Cincinnati, Ohio 45229-3039 (Email: bill.gottliebson{at}cchmc.org).

Objectives: This study sought to evaluate the natural history of occult cardiac dysfunction in Duchenne muscular dystrophy (DMD).

Background: Duchenne muscular dystrophy is characterized by progressive cardiac dysfunction and myocardial fibrosis late in the disease process. We hypothesized that left ventricular myocardial peak circumferential strain (_cc) would decrease in DMD before global systolic functional abnormalities regardless of age or ventricular ejection fraction (EF).

Methods: We evaluated cardiac magnetic resonance image (MRI) data from 70 DMD patients and 16 aged-matched control subjects. Standard imaging data included steady-state free precession short-axis cine stack images, cine myocardial tagged images, and myocardial delayed enhancement (MDE) (an indicator of myocardial fibrosis) sequences. Analysis was performed with QMASS (Medis Medical Imaging Systems, Leiden, the Netherlands) and HARP (Diagnosoft, Palo Alto, California) software. The DMD patient data were subdivided by age (<10 or >10 years), EF (>55% or <55%), and the presence or absence of MDE.

Results: The DMD patients with normal EF had reduced _cc at an early age (<10 years) compared with control subjects (p < 0.01). The DMD patients age >10 years with normal EF had further decline in _cc compared with younger DMD patients (p < 0.01). There was further decline in _cc with age in patients with reduced EF (p < 0.01) without MDE. The oldest patients, with both reduced EF and positive MDE, exhibited the lowest _cc. None of the patients had ventricular hypertrophy.

Conclusions: Myocardial strain abnormalities are prevalent in young DMD patients despite normal EF, and these strain values continue to decline with advancing age. Strain analysis in combination with standard MRI and MDE imaging provides a means to stratify DMD cardiomyopathy.

Key Words: cardiac magnetic resonance imaging • circumferential strain • Duchenne muscular dystrophy

Abbreviations and Acronyms   DMD = Duchenne muscular dystrophy   ECG = electrocardiogram   cc = circumferential strain   EF = ejection fraction   MDE = myocardial delayed enhancement   MRI = magnetic resonance imaging/image   SSFP = steady-state free precession   TTE = transthoracic echocardiogram

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J. Am. Coll. Cardiol. 2009 53: A25. [Full Text] [PDF]