Fresh tissues were taken for light microscopy from the trabeculae cameae at the right ventricular base, apex, left ventricular base, and apex of four normal canine hearts and nine whose pulmonary artery had been banded for 7 to 48 weeks. After banding, the width of the intercalated disc at the right base, 1.34 ± 0.10 /x (mean ± SE), was greater than at the right apex, 1.02 ± 0.09 fi (P< 0.002);...
