The use of Fourier transform and spectral analysis in the detection of distension-induced gastric arrhythmias in dyspeptic patients.

The electrogastrograms of a cohort of normal controls and a group of functional and postvagotomy dyspeptic patients, recorded under conditions of varying gastric distension applied via a gastric barostat, have been captured and stored on a portable PC. Retrospective quantitative and qualitative analysis of the waveforms have been carried out in the frequency domain. Gastric distension induced a reduction in gastric baseline frequency levels, which recovered after removal of the bolus. Controlled distension at a moderate level (240-480 ml) caused more symptoms in patients than in controls, but did not seem to affect the electrogastrograms. However, under conditions of high gastric distension (> 480 ml), there was a significant difference between the controls and patients predominant electrogastrographic frequencies (mean difference = 0.013 Hz; 95% CL = 0.001 Hz to 0.025 Hz; p = 0.014). We conclude that functional and postvagotomy dyspeptic patients have greater gastric electrical instability than controls, which seems to be more apparent under conditions of high gastric distension. The use of the Fourier transform and running spectral analysis method of analysis allowed this difference to be detected and measured.