Intravenous leiomyomatosis (IVL) is a rare benign neoplasm which originates from the smooth muscle cells and is usually confined to the pelvic venous system. Rarely, intracaval and intracardiac extension has been described. Death can occur as a result of intracardiac involvement. We reported 4 cases of IVL with right heart involvement (intracardiac leiomyomatosis, ICL). Three of them suffered recurrent sudden syncope, and the other one was totally asymptomatic. All of them were successfully treated through one-stage operation under extracorporeal circulation.