Abstract 14069: Cardiac Transplantation Unmasks Profound Muscle Weakness and Leads to Diagnosis of a Rare Cardiomyopathy
A 27 year old female presented with symptoms of heart failure. Work-up revealed an LVEF of 25% with a dilated ventricle, no evidence of CAD; MRI findings were suggestive of a viral myocarditis. She had severe functional impairment (peak VO2 7.3 ml/kg/min), and underwent transplantion. Subsequently, she developed progressive muscle weakness. The allograft was noted to be functioning well. Serum CK levels were elevated at 800 U/L (normal 30- 220), and increased subsequently to >1,000; aldolase was 32 (normal 0-7.6), pointing to a peripheral muscle abnormality. She was taken off pravastatin, and prednisone levels were increased at first due to concern for an inflammatory myopathy. However, her symptoms worsened, and concerns for an inherited myopathy were raised, leading to a left deltoid biopsy. This was noted to be diffusely abnormal (A), with fibers displaying increased mitochondrial content; electron microscopy revealed mitochondria with widespread, marked morphologic abnormalities (B). Electron miscroscope pictures of tissue from the patient’s explanted heart were reviewed, and showed increased numbers of abnormal mitochondria with dense inclusions (C). The presence of abnormal mitochondria in both cardiac and skeletal muscle was consistent with a primary mitochondrial disorder. A genetics consultation was sought. Reviewing her family history, evidence of lactic acidosis, and physical exam findings that included bilateral ptosis, it was felt that her presentation was most consistent with Kearns-Sayre Syndrome. Mitochondrial genome analysis for muscle and blood samples is pending at time of submission; results of this testing will help clarify the diagnosis. Initial treatment with ubiquinol and levocarnitine was initiated, with improvement in symptoms and decrease in lactic acidosis. This case illustrates that the presence of data that does not fit with or challenges an accepted diagnosis should prompt a reexamination of the assumptions.
- © 2013 by American Heart Association, Inc.