The role of Imaging in Characterizing the Cardiac Natural History of
Duchenne Muscular Dystrophy
Abstract
Duchene muscular dystrophies (DMD) is a rare but devastating disease
resulting in progressive loss of ambulation, respiratory failure,
DMD-associated cardiomyopathy (DMD-CM) and premature death. The use of
corticosteroid and supportive respiratory care has improved outcomes,
such that DMD-CM is now the leading cause of death. Historically, most
programs have focused on the skeletal myopathy with less attention to
the cardiac phenotype. This omission is rather astonishing since boys
with DMD possess an absolute genetic risk of developing cardiomyopathy.
Unfortunately, heart failure signs and symptoms are vague due to
skeletal muscle myopathy leading to limited ambulation and traditional
assessment of cardiac symptoms by the New York Heart Association
classification is of limited utility even in advance stages.
Echocardiographic assessment can detect cardiac dysfunction late in the
disease course, but this has proven to be a poor surrogate marker of
early cardiovascular disease and an inadequate predictor of DMD-CM.
Indeed, one explanation for the paucity of cardiac therapeutic trials
for DMD-CM has been the lack of a suitable end-point. Improve outcomes
requires a better proactive treatment strategy, however the barrier to
treatment is lack of a sensitive and specific tool to assess efficacy of
treatment. The use of cardiac imaging has evolve from echocardiography
to cardiac magnetic resonance imaging to assess cardiac performance. The
purpose of this article is to review the role of cardiac imaging in
characterizing the cardiac natural history of DMD-CM, highlighting the
prognostic implications and an outlook on how this field might evolve in
the future.