Basic Technology of Voluntary Cardiorespiratory Synchronization in Electrocardiology

Ordinary respiration produces surprisingly large and highly variable changes in the electrocardiogram of many subjects, healthy as well as diseased. By responding voluntarily to a visual signal developed by special but simple electronic circuitry, or by a small computer, the subject can ``breathe with the lights'' and thus pace his breathing to an exact submultiple of his own heart rate without requiring forced breathing or constant respiratory rate. The flexible stationarity introduced by this technique allows two goals to be approached. One is the ``epitome'' electrocardiogram, a sequence of VCG-ECG patterns highly reproducible and highly characteristic of the individual as his heart responds to normal respiratory influences. The other is a set of indices characterizing quantitatively the physiological dynamics of the cardiorespiratory interaction in the individual. This pattern, expressed as respiratory heart-rate modulation index and pattern dynamics indices, may contain important medical indicators of autonomic and cardiovascular systems response status. The technology of producing these cardiorespiratory synchrograms (CRSG) is discussed with a brief outline of their medical and research utility.