[II-AHAJS-1] Challenging in diagnosis and management of mitochondrial cardiomyopathy
Mitochondrial cardiomyopathy (MCM) is defined as a disorder of oxidative phosphorylation in the myocardium due to genetic mutations. In clinical, it is usually recognized as a serious cardiac complication in mitochondrial diseases. Also, it could be a causative disorder of “unknown” cardiomyopathy including lethal infantile cardiomyopathy. To date, we have provided an advanced diagnostic system using the trinity of biochemical, genetic, and pathological examinations using biopsied myocardium, cultured skin fibroblast, and blood samples. Most cases were diagnosed by respiratory chain enzymatic assay in biopsied myocardium, while oxygen consumption rate in cultured skin fibroblast has emerged as a substitute diagnostic tool. Recently, we have provided an immunohistopathologic study using paraffin-embedded samples of the myocardium. The management of MCM has been challenging. In common mitochondrial disease, the progression of cardiac complications has unique characteristics and attention should be paid to the type of cardiomyopathy, serial changes in the electrocardiogram, and cardiac function. In some lethal infantile MCM, a mitochondrial rescue regimen could be life-saving. Also, we would like to discuss the lethal arrhythmia in patients with suspected MCM.