An atrial myxoma is a benign tumor of the heart that usually occurs in one of the two atria of the heart and grows on the wall separating the two atria. Although they rarely become malignant, they frequently cause complications in heart function and can result in death. The tumor can interfere with the operation of the heart valves, and pieces of it can become detached and form blockages which could lead to heart attack, pulmonary embolism or stroke. However, because of its nature, the symptoms can often be intermittent or are relieved when the patient changes position.