Atrial myxoma

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.
A tumor can often be detected with a stethoscope as the movement of the tumor during heart function has a distinct "plop" sound. Echocardiogram, Doppler study, and radiological investigation can also be useful. Blood tests show a pattern of low red blood cell count, decreased white blood cell count and increased sed rate.
The tumor should be surgically removed, and if necessary the mitral valve can be replaced at the same time. Care must be taken to remove the entire tumor as it can regrow if a part is missed.
Atrial myxoma at NIH
Atrial myxoma at Wikipedia
Atrial myxoma