Long-term effects of gastric stimulation on gastric electrical physiology.

INTRODUCTION: This study evaluates the modeling of gastric electrophysiology tracings during long-term gastric electrical stimulation for gastroparesis. We hypothesized that serosal electrogastrogram may change over time representing gastric remodeling from gastric stimulation. PATIENTS: Sixty-five patients with gastroparesis underwent placement of gastric stimulator for refractory symptoms. Mean age at initial stimulator placement was 44 years (range, 8-76), current mean age was 49, and the majority of the subjects were female (n = 51, 78 %). Only a minority had diabetes-induced gastroparesis (n = 16, 25 %); the remainder were either idiopathic or postsurgical. METHODS: At the time of stimulator placement, electrogastrogram was performed after the gastric leads were placed but before stimulation was begun. Patients underwent continuous stimulation until pacer batteries depleted. At the time of replacement, before the new pacemaker was attached, electrogastrogram was again performed. RESULTS: After a mean of 3.9 years of stimulation therapy, the mean of baseline frequency before stimulation therapy was 5.06 cycles/min and declined to 3.66 after replacement (p = 0.0000002). The mean amplitude was 0.33 mV before stimulation therapy and decreased to 0.31 mV (p = 0.73). The frequency/amplitude ratio was 38.4 before stimulation therapy and decreased to 21.9 (p = 0.001). CONCLUSION: Long-term gastric electrical stimulation causes improvement in basal unstimulated gastric frequency to near normal.