Gastric electrophysiology

INTRODUCTION: The mechanical activity of the stomach is mediated by electrical signals. Circular smooth muscle contractions and propagation of peristaltic waves occur during plateau/action potentials and are linked to slow waves generated by interstitial cells of Cajal. These electrical activities form the basis of gastric electrophysiology (EP). Test meals elicit three per minute peristaltic contractions. In contrast, test meals may evoke gastric dysrhythmias in patients with gastroparesis and chronic unexplained nausea. Postprandial gastric myoelectrical activity (GMA) can be recorded with noninvasive electrogastrogram (EGG) and body surface gastric mapping (BSGM). AREAS COVERED: This article overviews gastric slow waves, the electrical event that controls 3 cycles per minute (cpm) peristaltic contractions, their cellular origin, propagation patterns, electro-contractile coupling of smooth muscle cells, and modulation by the nervous system and hormones. EXPERT OPINION/COMMENTARY: Gastric EP is a growing field with a 100-year-old history. Studies of dysrhythmic GMA in a variety of nausea conditions stimulated recent interest in gastric EP. Conventional EGG recordings use three electrodes with a single channel GMA signal recording. BSGM uses 64 electrodes with multiple channel recordings, providing various phenotypes, new diagnostic categories and new approaches to therapy for gastric motility disorders.