A comparison of high frequency vs. low frequency gastric stimulation in treating gastroparesis

Gastric electrical stimulation (GES) is a new therapeutic option for treatment of gastroparesis. We report our experience with the 4 diabetic patients (2M, 2F, mean age: 32 years) who received both low frequency stimulation (LFS) and high frequency stimulation (HFS) for 2 months to 2 years. LFS always preceded the HFS. LFS was applied at the stomach´s intrinsic frequency of 3 cycles/min (cam) via a pair of electrodes surgically placed on the serosa of the mid-body of the stomach and connected to an external stimulator. HFS (12 cpm) was applied to the electrodes surgically positioned at 9 to 10 cm from the pylorus on the greater curvature of the ant rum and connected to a neurostimulator implanted in a pocket under the abdomen. In addition, 2 to 3 pairs of temporary pacing wires were placed on the serosa of the stomach along the greater curvature for measuring myoelectric activity of the stomach. Severity of nausea and vomiting were graded using a 5-point scale (0 to 4) and gastric emptying was evaluated using a 4-hour scintigraphy at baseline and during GES. Spectral analysis of the serosal recordings of gastric myoelectric activity showed that LFS not HFS entrained the gastric slow waves. Both LFS and HFS increased the amplitude of gastric slow waves. Mean total symptom score reduced from 5.5 to 2.25 by LFS and from 6.35 to 2.5 by HFS. The improvement in GE is 62% by LFS and overall no change by HFS. The following conclusions were drawn: 1) LFS improved GE by 60%, entrained gastric slow waves and reduced symptoms by 60%, 2) High frequency GES improved nausea and vomiting (60%) without changing GE or frequency of electric activity, 3) Important differences exist between these 2 methods of GES.