Gastric pacemaker rhythm in conscious dog.

The pacemaker rhythm in the stomach of six healthy conscious dogs was studied by means of the measurement of sequential electrical control activity (ECA) intervals. Only the rhythm originating in the normal pacemake area was studied. An electrical response activity (ERA) score was used to assess contractile activity. Whereas substantial shortening of nonectopic ECA intervals did not occur, contraction-related interval lengthening was a characteristic phenomenon. The temporal relations between ERA scores and interval durations were found to be dependent on the gastric level at which the signals were derived. The activity front of the interdigestive myoelectric complex (IDMEC) appeared to be correlated with the periodic occurrence of considerably prolonged intervals; this sign could be used for recognition of the IDMEC. The motor quiescence phase of the IDMEC was correlated with small interval-to-interval variation, as was the early postprandial phase.