The immediate and delayed effects of different types of vagotomy on human gastric myoelectrical activity.

The immediate and delayed effects of different types of vagotomy on the antral myoelectrical activity have been studied in 52 patients who had previously undergone either highly selective vagotomy (HSV) or truncal vagotomy and pyloroplasty (TV + P) for the treatment of chronic duodenal ulceration up to eight years previously. The frequency of the electrical activity was not statistically different between the two types of operation. After HSV the triphasic waveshape of the antral myoelectrical activity was retained; it was recorded more frequently in the delayed tests (98.0 plus or minus 1-7%) of the recording period than in immediate tests (74-7 plus or minus 6-5%) whereas mean amplitude in the immediate tests (1-59 plus or minus 0-13 mV) was not significantly changed in the delayed tests (1-49 plus or minus 0-08mV). After TV + P the waveform was more sinusoidal in shape, being recorded more often in the delayed tests (91-7 plus or minus 2-7%) than in the immediate tests (41-4 plus or minus 8-9%) although the mean amplitude between the immediate (0-090 plus or minus 0-06 mV) and delayed tests (0-94 plus or minus 0-07 mV) was not significantly different. The only significant change in the myoelectrical activity with the passage of time after vagotomy was an increase in the percentage activity.