Spectral analysis of atrial electrograms

Spectral analysis using a Fourier transform was performed on extracellular waveforms recorded in canine crista terminalis. For longitudinal propagation, the power spectrum showed a smooth decline and the bandwidth ranged between 1000 and 2400 Hz. For transverse propagation, the spectrum showed multiple lobes and the bandwidth ranged between 1000 and 3600 Hz. The effects of distance between electrode and preparation, as well as prematurity and (K+1) level of the bathing solution were studied in nine preparations. The bandwidth was decreased by 70% to 93% as the electrode was moved 2 mm away from the preparation. Factors that decrease the nonproduction speed, such as prematurity and decrease in (K+1), also decreased the bandwidth.<>