Cooley R L, Montano N, Cogliati C, van de Borne P, Richenbacher W, Oren R, Somers V K
Department of Internal Medicine, College of Medicine, University of Iowa, Iowa City 52242, USA.
Circulation. 1998 Aug 11;98(6):556-61. doi: 10.1161/01.cir.98.6.556.
Short-term variability of RR interval and blood pressure occurs predominantly at low frequency (LF; approximately 0.1 Hz) and high frequency (approximately 0.25 Hz). The arterial baroreflex is thought to be the predominant determinant of the LF component of RR variability. Patients with severe congestive heart failure (CHF) have an attenuated or absent LF oscillation in RR variability. The left ventricular assist device (LVAD) offers a unique possibility for analysis of spectral oscillations in RR interval independent of any effects of blood pressure that influence these oscillations via the baroreflex.
We performed spectral analysis of RR, blood pressure, and respiration in 2 patients with CHF before and after LVAD implantation. LF components of the RR-interval and blood pressure variability were absent in both CHF patients before LVAD implantation. After LVAD implantation, spectral analysis of the RR interval showed restoration of a clear and predominant LF oscillation in the native hearts of both patients, with no such oscillation evident in the blood pressure profile.
During total circulatory support with the LVAD, the LF oscillation in RR interval of the native heart, absent in CHF, is restored. This LF oscillation in RR interval occurs in the absence of LF oscillations in blood pressure and thus is unlikely to be explained by baroreflex mechanisms. Hence, the absence of LF oscillation in the RR interval in CHF is functional and is reversible by LVAD circulation. The presence of a predominant LF oscillation in RR interval independent of any oscillation in blood pressure suggests that the LF oscillation is a fundamental property of central autonomic outflow.
RR间期和血压的短期变异性主要发生在低频（LF；约0.1赫兹）和高频（约0.25赫兹）。动脉压力反射被认为是RR变异性LF成分的主要决定因素。严重充血性心力衰竭（CHF）患者的RR变异性中LF振荡减弱或消失。左心室辅助装置（LVAD）为分析RR间期的频谱振荡提供了独特的可能性，不受通过压力反射影响这些振荡的任何血压影响。
我们对2例CHF患者在植入LVAD前后的RR、血压和呼吸进行了频谱分析。在植入LVAD前，两名CHF患者的RR间期和血压变异性的LF成分均缺失。植入LVAD后，RR间期的频谱分析显示，两名患者的天然心脏中均恢复了清晰且占主导地位的LF振荡，而血压曲线中未出现这种振荡。
在使用LVAD进行全循环支持期间，CHF患者天然心脏中RR间期的LF振荡得以恢复。RR间期的这种LF振荡在血压无LF振荡的情况下出现，因此不太可能由压力反射机制解释。因此，CHF患者RR间期LF振荡的缺失是功能性的，可通过LVAD循环逆转。RR间期存在占主导地位的LF振荡，与血压的任何振荡无关，这表明LF振荡是中枢自主神经输出的基本特性。
