Nevertheless, thorough examination of the signals of the bottom of the LA showed double signals directly opposite to the entire CS: one sharper signal simultaneous to the recorded signal in CS (encircled in Figure 1) and in addition highly fractionated signals, which presented a sequence proximal to distal (see stars and arrows in Figure 1). Examination of the propagation pattern of the adjacent LA led to the conclusion that the sharper component presented a near field signal of the LA endocard and the low voltage fractionated signal presented a far field signal of epicardial myocardial sleeves, i.e. CS musculature.
Figure 1 Signals on the grid catheter on the bottom of the LA opposite to CS with two components. Sharp signals simultaneously to the signals on the decapolar catheter (rather posteriorly, encircled). Highly fractionated signals with a sequence proximal to distal (stars and arrows). Blue globes represent exemplary points with double signals adjacent the entire CS. White globes show the exits into the LA and RA.