Cardiac autonomic nervous function during long-term nonpulsatile left heart bypass.
We investigated the changes in cardiac autonomic nervous activities during long-term nonpulsatile left heart bypass (NLHB) by analyzing heart rate variability. A pulsatile ventricular assist device was installed in 3 goats, and pulsatile left heart bypass (PLHB) was conducted for 2 weeks. Then, NLHB was maintained for the following 4 weeks. The segmental data of the R-R intervals (R-Rs) was analyzed by maximum entropy spectral analysis. Changes in evaluated parameters from the last week of PLHB to the 4th week of NLHB were as follows: the mean R-Rs increased from 511 ms to 692 ms; the coefficient of variation of R-R increased from 10.2 to 14.1%; the power of the low frequency band (LF) increased from 747 ms2 to 2,855 ms2; the power of the high frequency band (HF) increased from 512 ms2 to 1,270 ms2; and the ratio of LF to HF increased from 2.6 to 6.5. These results indicated that the cardiac autonomic nervous activity, both sympathetic and parasympathetic, increased during long-term NLHB.
Nishinaka
T
T
Department of Artificial Organs, National Cardiovascular Center, Osaka, Japan. nishinak@ri.ncvc.go.jp
Tatsumi
E
E
Nishimura
T
T
Taenaka
Y
Y
Masuzawa
T
T
Nakata
M
M
Takano
H
H
Koyanagi
H
H
D000704:Analysis of Variance; D000818:Animals; D001011:Aorta / Q000502:physiology; D001341:Autonomic Nervous System / Q000502:physiology*; D001775:Blood Circulation / Q000502:physiology; D001794:Blood Pressure / Q000502:physiology; D006041:Goats; D018611:Heart Bypass, Left; D006329:Heart Conduction System / Q000502:physiology*; D006339:Heart Rate / Q000502:physiology; D008137:Longitudinal Studies; D008323:Mammary Arteries / Q000502:physiology; D010275:Parasympathetic Nervous System / Q000502:physiology; D011673:Pulsatile Flow / Q000502:physiology; D012815:Signal Processing, Computer-Assisted; D013564:Sympathetic Nervous System / Q000502:physiology; D013997:Time Factors