Electrosigmoidogram, electrorectogram and their relation.

The electric activity of the sigmoid colon (electrosigmoidogram=ESG) and rectum (electrorectogram=ERG) and their relationship was studied in nine patients. Slow waves or pacesetter potentials (PPs) of the sigmoid colon and rectum were recorded. The PP frequency and amplitude of the electrorectograms were higher (p less than 0.05) than electrosigmoidograms. Balloon distention of the sigmoid colon or rectum increased the frequency, amplitude and velocity of PPs and APs proximal to the balloon and led to their decrease distally. These effects were enhanced with increased balloon distention until the balloon was expelled. Balloon distention of the sigmoid colon did not affect the rectal electromechanical activity and vice versa. This study suggests that the movement of the sigmoid colon or rectum is of the "mass type".