Gastric myoelectrical activity in patients with gastric outlet obstruction and idiopathic gastroparesis.

Objective: The cause of gastroparesis may be uncertain in some patients. Mechanical obstruction of the stomach or duodenum should be excluded in patients with idiopathic gastroparesis. The objective of this study was to compare gastric myoelectrical activity in patients with idiopathic gastroparesis with that of patients with gastroparesis due to mechanical obstruction of the stomach or duodenum.
Methods: Electrogastrography techniques were used to record gastric myoelectrical activity in 20 patients with idiopathic gastroparesis and in nine patients with gastroparesis secondary to gastric outlet obstruction. Four of these nine patients initially were thought to have idiopathic gastroparesis. Electrogastrograms (EGGs) were recorded from 29 healthy subjects who served as controls. EGGs were recorded for 20-30 min 2 h after a standard 200-Kcal meal and were analyzed visually and by computer.
Results: Patients with gastroparesis due to outlet obstruction had high-amplitude and excessively regular 3-cycles-per-minute (cpm) EGG patterns, whereas patients with idiopathic gastroparesis had primarily 1- to 2-cpm patterns and little 3-cpm EGG activity. The percentage of total EGG power in the 3-cpm range was approximately 50% in patients with gastric outlet obstruction compared with 20% in patients with idiopathic gastroparesis (p < 0.001). The percentage of EGG power in the normal 3-cpm range was greater in the obstructed patients (50%) than in the healthy controls (35%; p < 0.052).
Conclusions: Gastric myoelectrical patterns recorded in the EGG distinguish mechanical and idiopathic causes of gastroparesis and may be useful in evaluating patients with nausea, vomiting, and gastroparesis of unknown cause.