Hydatid disease is a parasitic disease with a high incidence in pastoral
areas in Tibet. The heart is an uncommon location of echinococcosis and
involvement of the interventricular septum is even rarer. This disease
can remain asymptomatic for a long time, but may result in cardiac
tamponade and sudden death. We report a 55-year-old woman who was
diagnosed with a giant cardiac hydatid cyst involving the
interventricular septum associated with complete right bundle branch
block. However, owing to insufficient treatment, spontaneous rupture of
the cardiac hydatid cyst occurred 6 months after diagnosis, which caused
sudden death of the patient.