The effect of severe brainstem injury on heart rate and blood pressure oscillations.
To determine whether an intact brainstem is essential for the generation of neurogenically mediated fluctuations of R-R intervals and blood pressure, three patients with cerebellar lesions causing severe brainstem compression or death, one patient with a large pontine infarct and one patient with a pontine haemorrhage, were studied. Time-frequency maps (based on a modified Wigner distribution) were constructed from blood pressure and R-R interval signals in these patients with brainstem injury and were compared with maps of normal control subjects. Low frequency sympathetically mediated rhythms (0.01-0.12 Hz) in systolic and diastolic pressure remained detectable but attenuated in patients with brainstem injury whereas there was an almost complete loss of normal R-R intervals rhythmicity over 0.01 to 0.5 Hz range. These data suggest that fluctuations in R-R intervals require an intact brainstem, whereas low frequency approximately 0.06 +/- 0.02 Hz blood pressure rhythms may be preserved by spinal sympathetic circuitry.
Novak
V
V
Department of Neurosciences, Sir Mortimer B. Davis Jewish General Hospital, Montreal, Quebec, Canada.
Novak
P
P
deMarchie
M
M
Schondorf
R
R
D000368:Aged; D000369:Aged, 80 and over; D001683:Biological Clocks / Q000502:physiology*; D001794:Blood Pressure / Q000502:physiology*; D001933:Brain Stem / Q000293:injuries / Q000502:physiology* / Q000503:physiopathology; D016022:Case-Control Studies; D002543:Cerebral Hemorrhage / Q000503:physiopathology*; D005260:Female; D006339:Heart Rate / Q000502:physiology*; D006801:Humans; D008297:Male; D009408:Nerve Compression Syndromes / Q000503:physiopathology*; D011149:Pons / Q000503:physiopathology