Impairment of heart rate variability during paclitaxel therapy.
BACKGROUND
Paclitaxel, which has been reported to be effective in treating metastatic breast carcinoma and advanced ovarian carcinoma, has been associated with cardiac side effects. Therefore, the effect of paclitaxel on cardiovascular autonomic regulation was studied.


METHODS
Twenty-four-hour ambulatory electrocardiogram measurements were recorded twice from 14 women with breast or ovarian carcinoma: once before paclitaxel treatment and once on the day after the second chemotherapy course. Heart rate variability (HRV) was assessed with spectral analysis. For the frequency domain analysis, HRV was assessed in the very low (0.005-0.040 hertz [Hz]), low (0.040-0.150 Hz), and high frequency (0.150-0.400 Hz) spectral components.


RESULTS
The ratio between low frequency and high frequency HRV decreased (daytime values of 2.7% [standard deviation (SD) 1.6] vs. 1.7% [SD 0.91; P = 0.0098) after 2 courses of paclitaxel. The circadian fluctuation of HRV also decreased in all studied frequency components.


CONCLUSIONS
The observed changes in spectral characteristics suggest that autonomic modulation of the heart rate is impaired after paclitaxel therapy. However, from these data it is not clear whether the observed changes are permanent or whether autonomic cardiac function returns to normal some time after treatment. Further studies are needed to examine whether these indices based on HRV can be used to detect those patients at risk for cardiac side effects during chemotherapy.
Ekholm
E M
EM
Department of Obstetrics and Gynecology, University of Turku, Finland.
Salminen
E K
EK
Huikuri
H V
HV
Jalonen
J
J
Antila
K J
KJ
Salmi
T A
TA
Rantanen
V T
VT
D000328:Adult; D000368:Aged; D000704:Analysis of Variance; D000972:Antineoplastic Agents, Phytogenic / Q000009:adverse effects*; D000971:Antineoplastic Combined Chemotherapy Protocols / Q000627:therapeutic use; D001341:Autonomic Nervous System / Q000187:drug effects*; D001943:Breast Neoplasms / Q000188:drug therapy; D002277:Carcinoma / Q000188:drug therapy / Q000556:secondary; D002940:Circadian Rhythm; D015716:Electrocardiography, Ambulatory / Q000187:drug effects; D005260:Female; D005500:Follow-Up Studies; D006329:Heart Conduction System / Q000187:drug effects*; D006339:Heart Rate / Q000187:drug effects*; D006801:Humans; D008875:Middle Aged; D010051:Ovarian Neoplasms / Q000188:drug therapy; D017239:Paclitaxel / Q000009:adverse effects*; D012307:Risk Factors; D012815:Signal Processing, Computer-Assisted
D000972:Antineoplastic Agents, Phytogenic; D017239:Paclitaxel