Abstract. Heart rate variability (HRV) reflects the neural regulation of normal pacemaker tissue, but the autonomic nervous regulation of abnormal atrial foci originating outside the sinus node has not been well evaluated. We compared the respiration-synchronous HRV and pulse plethysmogram (PPG) of the paroxysmal ectopic atrial tachycardia(PAT) and the normal sinus rhythm(NSR) in a healthy subject.

Method and Results. Electroencephalogram, electrooculogram, electrocardiogram, respiration wave (RW), PPG were recorded using the polygraph system. The data was acquired and digitized at 400Hz. The frequency domain analysis was carried out by autocorrelation-FFT method in the 180sec epochs. When comparing the power spectra computed from RW and heart rate time domains, no detectable high frequency component (0.24+/-0.03Hz) corresponding to the cardio-pulmonary vagal reflex was observed in all epochs during PAT, whereas the clear component appeared in NSR. The amplitude fluctuations of PPG in the mid frequency range (0.078+/-0.011) known as Mayer waves, was unchanged during both PAT and NSR.

Conclusions. PAT does not receive the physiological modulation by the respiratory vagal reflex. However, frequency characteristics of pulse wave through baroreceptor reflex concerning the respiration were observed as well as NSR. Traditional analysis of HRV in absolute units may be able to document the specific autonomic disturbance in PAT.