Recovery of cardiac autonomic responsiveness with low-intensity physical training in patients with chronic heart failure.
BACKGROUND
A gradual worsening of autonomic control of cardiovascular function accompanies the progression of heart failure. Exercise training modulates autonomic balance, and may affect the prognosis of the disease.


OBJECTIVE
The sympathovagal balance was studied after 3 months of low-intensity rehabilitation compared with conventional therapy in 45 patients with heart failure (52% ischemic, 48% idiopathic), of whom 30 underwent rehabilitation and 15 did not. In 11 rehabilitated patients we also studied the effects on autonomic profile of 6 additional months of home-based training. Rehabilitated and non-rehabilitated patients had similar NYHA class, ejection fraction, exercise pVO2; 50% assumed carvedilol (39+/-5 mg/day).


RESULTS
Autoregressive power spectral density of RR intervals variability were assessed during 10 min of: (1) supine rest and free breathing; (2) supine rest and breathing at 20 acts/min (=vagal stimulus); (3) standing (=sympathetic stimulus). During each period, the ratio LF/HF of the individual autospectrum indicated the sympathovagal balance. After 3 months of rehabilitation, pVO2 increased (20%); LF/HF at rest was unchanged (8.7+/-1.2 vs. 9.2+/-1.2); it decreased with controlled breathing (-18%) and increased during standing (+79%) (P<0.05). These changes were more evident after 6 months of home-based training, when pVO2 was still high: LF/HF at rest was reduced (5.4+/-0.9 vs. 8.5+/-2.1), decreased during controlled breathing (-17%) and increased during standing (87%) (P<0.05). No changes in any variable were seen in non-rehabilitated patients.


CONCLUSIONS
A low intensity rehabilitation program restores autonomic tone and reactivity to vagal and sympathetic stimuli. Some of these effects are already evident after the initial hospital-based phase.
Malfatto
Gabriella
G
Divisione di Cardiologia, Istituto Scientifico Ospedale San Luca, Istituto Auxologico Italiano IRCCS, via Spagnoletto, 3-20147, Milan, Italy. malfi@auxologico.it
Branzi
Giovanna
G
Riva
Beatrice
B
Sala
Luca
L
Leonetti
Gastone
G
Facchini
Mario
M
D000368:Aged; D015308:Anaerobic Threshold / Q000502:physiology; D001341:Autonomic Nervous System / Q000502:physiology*; D002908:Chronic Disease; D005081:Exercise Therapy; D017079:Exercise Tolerance / Q000502:physiology; D005260:Female; D006321:Heart / Q000294:innervation* / Q000503:physiopathology; D006333:Heart Failure / Q000503:physiopathology* / Q000628:therapy*; D006339:Heart Rate / Q000502:physiology; D006801:Humans; D008297:Male; D008875:Middle Aged; D020127:Recovery of Function / Q000502:physiology*; D013318:Stroke Volume / Q000502:physiology; D013995:Time; D016896:Treatment Outcome