A. Sciacca

Analysis of high-resolution atrial activation: Report on 403 cases

The findings of a study carried out on a sample of 403 P waves, selected over the 50 to 300 Hz frequency range, by a portable microcomputer system capable of averaging 512 P waves, are reported. Detailed analysis of P waves was attempted in healthy subjects and in patients affected by pathologic processes where atrial involvement had been observed. An attempt was made to individualize P wave parameters which may be associated with these pathologic conditions. On each atrial signal a 512-point fast Fourier transform was used. The original sample was divided into 18 classes, and the mean values of some parameters of each class were computed. The results of fast Fourier transform computing and of the mean values of parameters for both patients and healthy subjects show two different behaviors with respect to the amplitude-frequency relationships and mean peak-to-peak amplitude, respectively. The present results indicate that this technique may be useful for further detailed analysis of P waves.

High Resolution Recordings of Atrial Flutter

We present high resolution tracings of atrial flutter which, to our knowledge, have not been previously described. Two patients have been studied; in both cases atrial activity was made by waves similar to each other, differing only in voltage. We discuss the nature of these waves, which are probably related to continuous atrial activity, with a segregation into small and large waveform activity. It is concluded that high resolution recordings may be valid support for the interpretation of atrial flutter activity.