Cardiac magnetic resonance imaging and management of dilated cardiomyopathy in a Duchenne muscular dystrophy manifesting carrier

Abstract

JO N 3055 muscles. Most DMD boys initially present delayed motor milestones, elevated serum creatine kinase (CK), respiratory impairment and 25 % of those surviving the age of 15 present dilated cardiomyopathy and arrhythmias [3, 4, 8, 10]. Echocardiography describes left ventricular dysfunction, but cardiac magnetic resonance (CMR) can detect the earliest signs of cardiomyopathy: occult regional cardiac asynergy; tissue degeneration; fibrosis [1, 9, 12]. Standard therapy for heart failure is effective in DMD cardiomyopathy [7, 10]. Female carriers show a mosaic pattern of dystrophin-positive and dystrophin-negative muscular fibres. About 50 % of patients present skeletal muscular symptoms and 18 % present dilated cardiomyopathy, because of a “skewed Xinactivation”, with most cells having an active faulty X-chromosome [5, 6]. A 27-year old woman was referred to our hospital in 2005 because of fatigue, effort dyspnoea (NYHA class IIb), episodes of palpitations and near syncope. Two brothers with a typical history of DMD without heart involvement died in their teens due to respiratory failure. Her asymptomatic 6year old daughter had a mild increase of CK (640 U/L). DNA analysis revealed dystrophin gene deletion of exons 3–17. Electromyography showed small duration motor unit potentials and reduced amplitude interference pattern during voluntary contraction. In 2003, she had already been diagnosed with a dilated cardiomyopathy, with an echocardiographic ejection fraction (EF) of 40 %, treated discontinuously with carvedilol 6.25 mg b.i.d. She was a smoker (5 cigarettes/d) and showed only calf pseudohypertrophy. She had high plasmatic concentrations of CK (1745 U/L, n.v. 22– 269), normal levels of cardiac troA. Barison G. D. Aquaro C. Passino M. Falorni A. Balbarini M. Lombardi L. Pasquali M. Emdin G. Siciliano