A COHERENCE SPECTRAL ANALYSIS BETWEEN HEART RATE VARIABILITY AND BLOOD PRESSURE FLUCTUATION UNDER LEFT VENTRICULAR ASSISTANCE

Abstract

The purpose of this study is to identify the participation of the blood pressure to the heart rate variability which reflects the autonomic nerve response to the systemic ventricular assistance. For this purpose, the coherence of the blood pressure fluctuation against the heart rate was analyzed in long-term animal experiments using adult goats under the ventricular assistance of different driving modes. A high coherence was observed in 0.1Hz (Mayer wave) and 0.3 Hz (respiratory arrhythmia) under both synchronous and asynchronous modes. Especially, the coherence of systolic and pulse blood pressure was very high. The coherence of blood pressure against the heart rate reflects the participation of the blood pressure to the autonomic cardiovascular control mechanism. Therefore, this evidence indicates that the blood pressure has an influence on the autonomic nervous system which oscillates the heart rate. In addition, the power spectrum of systemic resistance, calculated from the cardiac output and the blood pressure, had only one spectral peak (0.05Hz) with high coherence against heart rate and blood pressure. It was concluded that the coherence spectral analysis could reveal the mechanism of the heart rate variability under ventricular assistance and furnish useful information concerning the driving mode of the ventricular assistance.