Altered baroreflex gain during voluntary breathing in chronic heart failure.
BACKGROUND
We assessed the behavior of the baroreflex (BR) gain in chronic heart failure (CHF) patients using the spectral analysis method during application of a forcing stimulus, i.e. respiration.


METHODS
Simultaneous RR interval and arterial pressure fluctuation recordings were obtained during two random-order periods of voluntary paced-breathing (0.15 Hz and 0.25 Hz) in seven patients with moderate CHF (NYHA class II/III; EF, 30+/-9%; peak VO(2), 18+/-5 ml kg(-1) min(-1)) and six age-matched controls. BR gain was assessed in the time (sequential method) and frequency (cross-spectral gain in the low and high frequency) domains.


RESULTS
Slower breathing was associated with a BR gain decrease in CHF patients whereas a BR gain increase was evidenced in controls (BR gain: 6+/-5 ms mmHg(-1) at 0.25 Hz vs. 4+/-3 ms mmHg(-1) at 0.15 Hz, P<0.05 in CHF; BR gain: 12+/-7 ms mmHg(-1) at 0.25 Hz vs. 15+/-7 ms mmHg(-1) at 0.15 Hz, P<0.05 in controls).


CONCLUSIONS
Voluntary breathing, which involves cortical centers in the brain, had major effects on cardiovascular system controller gain in CHF patients, indicating an impairment of the central neural regulation of the autonomic outflow.
Pharmacologie Clinique, Hôpital Henri Mondor, Créteil, France. luarence.magnin@psl.ap-hop-paris.fr
L
L
Mangin
A
A
Monti
C
C
Médigue
I
I
Macquin-Mavier
M
M
Lopes
P
P
Gueret
A
A
Castaigne
B
B
Swynghedauw
P
P
Mansier
D000328:Adult; D001341:Autonomic Nervous System / Q000503:physiopathology; D001676:Biofeedback, Psychology / Q000502:physiology; D001794:Blood Pressure / Q000502:physiology; D002908:Chronic Disease; D005260:Female; D006333:Heart Failure / Q000175:diagnosis / Q000503:physiopathology*; D006801:Humans; D008297:Male; D008875:Middle Aged; D011311:Pressoreceptors / Q000503:physiopathology*; D012123:Pulmonary Ventilation / Q000502:physiology*