We observed cardiac prolapse following right pneumonectomy in which the patient experienced a 90 degree rotation of the heart and compression of right ventricular outflow tract from behind by the aorta, which led to an increase in right atrial pressure and a decrease of pulmonary artery pressure and cardiac output. Compression of the right ventricular outflow tract by the base of the aorta was observed as an additional shock inducing factor in right cardiac prolapse.