Dramatic improvement in mitochondrial cardiomyopathy following treatment with idebenone.

Idebenone, a synthetic analogue of coenzyme Q10, has been shown to improve cardiac function in patients with Friedreich ataxia and a deficiency of respiratory chain complexes I-III. We describe a woman with severe combined right and left heart failure due to a mitochondrial cardiomyopathy. The patient underwent an endomyocardial biopsy as part of an evaluation for cardiac transplantation. It showed severely decreased respiratory complex activities dependent on CoQ, pointing to CoQ depletion. Following idebenone treatment there was a dramatic improvement in her clinical status with resolution of the heart failure.