Frequency-domain analyses of RR intervals are used widely to estimate levels of autonomic
neural traffic to the human heart. Because respiration modulates autonomic activity, we …

RR interval variability (RR variability) is increasingly being used as an index of autonomic
activity. High-frequency (HF) power reflects vagal modulation of the sinus node. Since vagal …

A complex demodulation (CDM) method for continuous assessment of frequency shifts and
time-dependent changes in amplitude in the rhythmic components existing in predefined …

Background—Survival of post–myocardial infarction patients is related inversely to their
levels of very-low-frequency (0.003 to 0.03 Hz) RR-interval variability. The physiological …

Background One of the principal explanations for respiratory sinus arrhythmia is that it
reflects arterial baroreflex buffering of respiration-induced arterial pressure fluctuations. If …

Frequency analysis of the electrocardiographic RR interval is a common method of
quantifying autonomic outflow by measuring the beat-to-beat modulation of the heart (heart …

BACKGROUND: Power spectral analysis of heart rate variability (HRV) has been used to
indicate cardiac autonomic function. High-frequency power relates to respiratory sinus …

Electrocardiographic RR intervals fluctuate cyclically, modulated by ventilation, baroreflexes,
and other genetic and environmental factors that are mediated through the autonomic …

We studied the influence of three types of breathing [spontaneous, frequency controlled
(0.25 Hz), and hyperventilation with 100% oxygen] and apnea on RR interval …

Cardiac neural control can be estimated by frequency domain characterization of RR
interval variations. This technique may become a clinical tool, as autonomic dysfunction is …