Figure 5.

Architecture of atrial musculature. Upper left: main atrial muscular bundles from anterior view. Lower left: transection of the Bachmann's bundle, postero-superior interatrial bundle, and the septopulmonary bundle enables visualization of the septoatrial bundle. Upper right: main atrial muscular bundles from posterior view with slight rightward tilting—the stars denote epicardial connections of the right PVs with the right atrium and left atrium posterior wall. Lower right: transection of the septopulmonary bundle coursing epicardially enables visualization of the septoatrial bundle and neighbouring fat inter-position. PV, pulmonary vein.