We describe the case of a 58-year-old man who underwent coronary artery bypass grafting with an unremarkable transesophageal echocardiogram. Three years later he underwent a routine transthoracic echocardiogram that was normal. Eleven months later he presented with dyspnea and right-sided heart failure. Transthoracic echocardiogram showed a large mass located in the right atrium in which the base was inserted by the junction of the inferior vena cava and coronary sinus. Pathology showed a myxoma that measured 15 x 3 cm implying a growth rate of 1.36 x 0.3 cm/month.