A 38-year-old woman with idiopathic scoliosis (right convex thoracic scoliosis, 78 degrees; left convex lumbar curvature, 75 degrees) died suddenly. Forensic autopsy and histopathologic examination revealed chronic congestive oedema, numerous cavities and atrophic changes of heart. These changes, including both respiratory changes and biventricular failure caused by hypoplastic cardiac changes, were due to a deformed thoracic cage. This case illustrates that not only abnormalities of respiratory function and cor pulmonare, but also hypoplastic cardiac changes, may cause sudden death in a patient with untreated scoliosis.