TY - JOUR
T1 - Abnormal awake respiratory patterns are common in chronic heart failure and may prevent evaluation of autonomic tone by measures of heart rate variability
AU - Mortara, Andrea
AU - Sleight, Peter
AU - Pinna, Gian Domenico
AU - Maestri, Roberto
AU - Prpa, Alexander
AU - La Rovere, Maria Teresa
AU - Cobelli, Franco
AU - Tavazzi, Luigi
PY - 1997/7/1
Y1 - 1997/7/1
N2 - Background: Reduced heart rate variability, particularly in the very- low-frequency (VLF) spectral band, has been found to be a marker for poor prognosis in patients after myocardial infarction, but the origin of the VLF oscillations is unclear. In this study, we demonstrate that the power of cardiovascular oscillations in the VLF band in awake patients with mild to severe chronic heart failure is greatly increased by the common occurrence of unrecognized irregularity of breathing, which may confound the use of heart rate variability measures as indexes of autonomic tone or prognosis. Methods and Results: Among 110 consecutive patients referred for consideration of transplantation, 90 were in sinus rhythm, of whom 10 were excluded as unstable. The remaining 80 patients underwent recordings of ECG, beat-to- beat arterial oxygen saturation (SaO2), and respiration during both spontaneous and controlled breathing. During spontaneous awake breathing, 64% showed periodic breathing or Cheyne-Stokes respiration (CSR), which was associated with dominant power in the VLF band of all signals. This VLF power accounted for 55%, 77%, and 87% of heart rate variability, respectively, in patients with normal breathing, periodic breathing, and CSR. It was reduced by 48% and 62%, respectively, during controlled breathing in patients with periodic breathing or CSR. Controlled ventilation also improved oxygen saturation and markedly reduced its variability. Conclusions: Breathing disorders are surprisingly common in awake patients with poor left ventricular function and produce large VLF oscillations in heart rate variability. If measures of heart rate variability are used for prognostic purposes during both short-term and long-term recordings, the confounding effects of variable respiratory patterns should be excluded. Respiratory rehabilitation might help control potentially hazardous surges in sympathetic tone.
AB - Background: Reduced heart rate variability, particularly in the very- low-frequency (VLF) spectral band, has been found to be a marker for poor prognosis in patients after myocardial infarction, but the origin of the VLF oscillations is unclear. In this study, we demonstrate that the power of cardiovascular oscillations in the VLF band in awake patients with mild to severe chronic heart failure is greatly increased by the common occurrence of unrecognized irregularity of breathing, which may confound the use of heart rate variability measures as indexes of autonomic tone or prognosis. Methods and Results: Among 110 consecutive patients referred for consideration of transplantation, 90 were in sinus rhythm, of whom 10 were excluded as unstable. The remaining 80 patients underwent recordings of ECG, beat-to- beat arterial oxygen saturation (SaO2), and respiration during both spontaneous and controlled breathing. During spontaneous awake breathing, 64% showed periodic breathing or Cheyne-Stokes respiration (CSR), which was associated with dominant power in the VLF band of all signals. This VLF power accounted for 55%, 77%, and 87% of heart rate variability, respectively, in patients with normal breathing, periodic breathing, and CSR. It was reduced by 48% and 62%, respectively, during controlled breathing in patients with periodic breathing or CSR. Controlled ventilation also improved oxygen saturation and markedly reduced its variability. Conclusions: Breathing disorders are surprisingly common in awake patients with poor left ventricular function and produce large VLF oscillations in heart rate variability. If measures of heart rate variability are used for prognostic purposes during both short-term and long-term recordings, the confounding effects of variable respiratory patterns should be excluded. Respiratory rehabilitation might help control potentially hazardous surges in sympathetic tone.
KW - Autonomic
KW - Heart failure
KW - Heart rate
KW - Nervous system
KW - Respiration
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M3 - Article
C2 - 9236441
AN - SCOPUS:0030854769
VL - 96
SP - 246
EP - 252
JO - Circulation
JF - Circulation
SN - 0009-7322
IS - 1
ER -