Figure legend
A-a) The widespread malignant tumor appeared as a light-yellow color. A-b, c) Histology showing that the malignant tumor cells had invaded a large amount of the right atrium (hematoxylin-eosin stain, magnification x40, x100).
B-a) Atrial tachycardia with 3:1 conduction. B-b) Atrial fibrillation.