Method for the analysis of the entrainment between heart rate and ventilation rate

A digital computer program was developed which allows to continuously represent the relation between heart rate and ventilation rate. Using this program, experiments in anesthetized rabbits were performed. We found periods of synchronization, periods of transient entrainment and escape, and periods of complete desynchronization. By testing the respective roles for the entrainment mechanism of ventilation rate and heart rate it was found that spontaneous adjustments of the ventilation rate play a more pronounced role. Thus, as soon as spontaneous or induced variations of the heart rate and/or the ventilation rate shift both rhythms close to synchronization, variations of the ventilation pattern, which seem to be of reflex nature, tend to induce entrainment.