Rapid progression of neuromuscular disorder related cardiomyopathy in a young patient.

An 11-year and 3-month-old boy with a neuromuscular disorder was admitted for dyspnea. Echocardiography revealed severe left ventricular dysfunction with an ejection fraction (EF) of 17%. However, the EF had been 57% when the patient was 10 years and 9 months old. The patient's clinical condition became refractory, and he died on the 155th day of hospitalization. Speckle-tracking analysis was retrospectively performed, which demonstrated that the global radial strain was within the normal range; however, the global longitudinal and circumferential strains were lower -than -normal 10 years and 9 months of age. Adult neuromuscular disorder-related secondary cardiomyopathy generally progresses slowly, although progression depends on the age of onset of cardiomyopathy.