Tomohiro Nishinaka
   Department   School of Medicine(Tokyo Women's Medical University Hospital), School of Medicine
   Position   Visiting Professor
Article types Original article
Language English
Peer review Peer reviewed
Title Circadian variation of motor current observed in fixed rotation speed continuous-flow left ventricular assist device support.
Journal Formal name：Journal of Artificial Organs
Abbreviation：J. artif. organs
ISSN code：14347229/16190904
Domestic / ForeginDomestic
Publisher Springer Japan KK
Volume, Issue, Page 17(2),pp.157-161
Author and coauthor SUZUKI KENJI†, NISHINAKA Tomohiro, MIYAMOTO Takuma, ICHIHARA Yuki, YAMAZAKI Kenji
Publication date 2014/07
Summary The algorithm for the physiological control provided by left ventricular assist devices (LVADs) has been controversial. In particular, little is known about the physiological control algorithm (such as for achieving physiological circadian rhythms) in continuous-flow LVADs. To investigate the existence of circadian variation, we retrospectively evaluated the LVAD flow-correlated motor current of patients supported by continuous-flow LVADs. The motor current and the pump speed were collected from the external controller every 10 min after device implantation, and the data were divided for every 30-day period, which began on midnight on the first post-operative day. The subjects were 18 patients (mean age 37.7, mean body surface area 1.71 m(2) at the time of operation) with dilated cardiomyopathy or dilated phase of hypertrophic cardiomyopathy. As of August 1, 2013, the patients' median support duration was 889 days. The mean calculated dominant period of motor current variation was 24.0 h and the mean amplitude was 11.7 mA for the entire duration. The amplitude of the motor current circadian variation tended to be increased until around the fifth month. The motor current had a tendency to be relatively low during the night time and high during the day time. A significant difference was found between the night-time and day-time mean motor current for the entire duration (p < 0.05). In conclusion, the circadian variation of the motor current could be observed over long term in patients with fixed rotation speed continuous-flow LVAD support.
DOI 10.1007/s10047-014-0762-4
PMID 24715349