The purpose of this work is to discuss the ability of
wavelet analysis and cross-spectral algorithm to follow up the
short-term cardiovascular function changes during cardiac
arrhythmia.
It was analyzed the (a) coherence between systolic blood pressure
(SBP) and cardiac oscillations in low frequency (LF) and high
frequency (HF) band; (b) fluctuations of phase; (c) heart rate
variability (HRV) and blood pressure variability (BPV) as a LF
power and HF power in frequency and time frequency domain.
The analysis was performed on blood pressure and
electrocardiogram signals from one rabbit anaesthetized,
paralyzed and mechanically ventilated with self-terminating
atrial and ventricular fibrillation after 7 minutes of cardiac
arrhythmia. Arrhythmia was preceded by a) decreased
coherence; b) increase in fluctuations of phase between
signals; c) increased spectral energy associated with respiratory
frequency in blood pressure signal; d) increased
sympathetic outflow to the heart and e) decreased HRV. Cardiac
arrhythmia was characterized mainly by increased LF power in
blood pressure and cardiac signal. During self-termination of
dysrhythmia a larger increased in total BPV and HRV was
recorded. These results suggest that important information about
both neuronal cardio-circulatory control and risk for
spontaneous arrhythmia might be provided by combined analysis
of frequency, phase, time-frequency analysis of blood pressure
and cardiac oscillation.