Abstract 11319: A Mitochondrial DNA (OPA1) Deletion Mutation Presenting With Cardiomyopathy and Disproportionate Dyspnea - First Human Case
Introduction: Mitochondrial DNA (mtDNA) depletion syndrome (MDS), a group of autosomal recessive disorders, is characterized by a paucity of mtDNA. MDS is a phenotypically heterogeneous disorder which commonly presents as: hepatocerebral, myopathic and encephalomyopathic. We report cardiovascular and neurological investigations in a patient with an uncommon phenotypic manifestation of cardiomyopathy associated with MDS.
Case report: A 58-year-old man with nonischemic cardiomyopathy, ambulatory NYHA class III-IV and progressive dyspnea for 3 years was referred for electrophysiology evaluation and CRT-D implant. Family history significant for sudden death in father and two brothers. Echocardiography showed LV dilation and global hypokinesia, EF 0.30; coronary angiography showed no significant CAD. Minimal improvement in functional status and EF despite maximal medical therapy. Physical examination revealed an alert, tachypneic patient with no signs of cardiac failure and a normal BNP of 69. EKG showed sinus rhythm with wide left bundle branch block. ABG evaluation showed uncompensated respiratory alkalosis but normal O2 saturation and CXR. Patient underwent CRT-D implantation with immediate improvement of EF to 0.50 but mild clinical symptom improvement. Dizziness, extreme fatigue and severe dyspnea continued at rest with leg paresthesias. Pulmonary, hematologic and endocrinologic evaluations were unremarkable. EMG and nerve conduction positive for right biceps brachii myotonic discharges suggestive of a myopathic process. No signs of a neuromuscular junction disorder with normal phrenic nerve conduction study. Muscle biopsy specimen demonstrated mitochondrial myopathy. Nuclear DNA mitochondrial DNA analysis positive for variant of unknown signficance (c10orf2) and OPA 1 deletion mutation. Coenzyme Q 160 BID begun and cardiac medications were discontinued with minimal improvement in symptoms. The patient is undergoing evaluation with a medical geneticist.
Summary: This is the first reported case of mtDNA-associated cardiomyopathy in a patient who presented with NICM and LBBB. Lack of clinical response after CRT-D therapy despite objective improvement in LV function prompted an extensive evaluation.
Author Disclosures: A. Lee: None. L. Norton: None. R. Vagelos: None. P. Zei: None.
- © 2014 by American Heart Association, Inc.