Nitric oxide and cardiac parasympathetic control in human heart failure

2002 ◽  
Vol 102 (4) ◽  
pp. 397-402 ◽  
Author(s):  
Saqib CHOWDHARY ◽  
G. Andre NG ◽  
Sarah L. NUTTALL ◽  
John H. COOTE ◽  
Hamish F. ROSS ◽  
...  
Keyword(s):  
Heart Failure ◽  
Heart Rate ◽  
Heart Rate Variability ◽  
High Frequency ◽  
Human Heart ◽  
Baroreflex Sensitivity ◽  
No Production ◽  
Human Heart Failure ◽  
Heart Failure Patients ◽  
Parasympathetic Control

Cardiac parasympathetic control has prognostic significance in heart failure, but the control mechanisms of this system remain poorly defined. We have demonstrated previously a facilitatory role for nitric oxide (NO) in the parasympathetic control of heart rate in young healthy human subjects. In view of the complex abnormalities of regional NO activity observed in chronic heart failure, we now aim to establish if this mechanism is active in subjects with this condition. Groups of 12heart failure patients [NYHA class II-III; mean age 52 years (range 38-67 years)] and 12 age/sex-matched healthy control subjects [mean age 50 years (range 36-62 years)] were studied. Heart rate variability and baroreflex sensitivity were measured during inhibition of endogenous NO production with NG-monomethyl-l-arginine (l-NMMA; 3mgċh-1ċkg-1) and during administration of an equipressor dose of the control vasoconstrictor phenylephrine (12-36μgċh-1ċkg-1). Basal levels of nitrate+nitrite were measured in the plasma as an indication of systemic NO production. In the heart failure patients, despite an equal rise in blood pressure with both drugs, high-frequency indices of heart rate variability increased less with l-NMMA than with phenylephrine: RMSSD (root mean square of successive RR-interval differences) increased by 4±2 compared with 26±8ms (P < 0.001) and high-frequency power increased by 97±62 compared with 1372±861ms2 (P < 0.001). The increases in cross-spectral baroreflex sensitivity were also lower with l-NMMA than with phenylephrine [high-frequency α-index, 2.2±1.3 and 12.6±3.8ms/mmHg respectively (P < 0.001); low-frequency α-index, 1.3±0.9 and 4.3±1.7ms/mmHg respectively (P < 0.05)]. Healthy subjects showed a similar discrepancy in the response of high-frequency indices of heart rate variability to the two drugs, although baroreflex sensitivity responses were significantly different only for the high-frequency α-index. Levels of plasma nitrate+nitrite were significantly higher in the heart failure patients compared with controls. These data demonstrate that baroreflex-mediated cardiac parasympathetic activation in human heart failure, as in health, is dependent upon endogenous NO synthesis.

scholarly journals Clinical, hemodynamic, and microneurographic determinants of respiratory heart rate variability in human heart failure

1990 ◽  
Vol 15 (2) ◽  
pp. A149 ◽  
Author(s):  
Michael G. Kienzle ◽  
Clayton L. Birkett ◽  
D.James Mariano ◽  
William J. Berg ◽  
David W. Ferguson
Keyword(s):  
Heart Failure ◽  
Heart Rate ◽  
Heart Rate Variability ◽  
Human Heart ◽  
Human Heart Failure

Heart rate variability and baroreflex sensitivity are reduced in chronically undernourished, but otherwise healthy, human subjects

2003 ◽  
Vol 104 (3) ◽  
pp. 295-302 ◽  
Author(s):  
Mario VAZ ◽  
A.V. BHARATHI ◽  
S. SUCHARITA ◽  
D. NAZARETH
Keyword(s):  
Heart Rate ◽  
Heart Rate Variability ◽  
High Frequency ◽  
Baroreflex Sensitivity ◽  
Human Subjects ◽  
Normal Weight ◽  
Autonomic Nerve ◽  
Total Power ◽  
Healthy Human ◽  
Frequency Power

Alterations in autonomic nerve activity in subjects in a chronically undernourished state have been proposed, but have been inadequately documented. The present study evaluated heart rate and systolic blood pressure variability in the frequency domain in two underweight groups, one of which was undernourished and recruited from the lower socio-economic strata [underweight, undernourished (UW/UN); n = 15], while the other was from a high class of socio-economic background [underweight, well nourished (UW/WN); n = 17], as well as in normal-weight controls [normal weight, well nourished (NW/WN); n = 27]. Baroreflex sensitivity, which is a determinant of heart rate variability, was also assessed. The data indicate that total power (0–0.4Hz), low-frequency power (0.04–0.15Hz) and high-frequency power (0.15–0.4Hz) of RR interval variability were significantly lower in the UW/UN subjects (P<0.05) than in the NW/WN controls when expressed in absolute units, but not when the low- and high-frequency components were normalized for total power. Baroreflex sensitivity was similarly lower in the UW/UN group (P<0.05). Heart rate variability parameters in the UW/WN group were generally between those of the UW/UN and NW/WN groups, but were not statistically different from either. The mechanisms that contribute to the observed differences between undernourished and normal-weight groups, and the implications of these differences, remain to be elucidated.

scholarly journals Preprocessing Unevenly Sampled RR Interval Signals to Enhance Estimation of Heart Rate Deceleration and Acceleration Capacities in Discriminating Chronic Heart Failure Patients from Healthy Controls

2020 ◽  
Vol 2020 ◽  
pp. 1-10 ◽  
Author(s):  
Ping Cao ◽  
Bailu Ye ◽  
Linghui Yang ◽  
Fei Lu ◽  
Luping Fang ◽  
...  
Keyword(s):  
Heart Failure ◽  
Heart Rate ◽  
Heart Rate Variability ◽  
Chronic Heart Failure ◽  
Characteristic Curve ◽  
Clinical Analysis ◽  
Healthy Controls ◽  
Heart Failure Patients ◽  
Rr Interval ◽  
Frequency Components

Objective. The deceleration capacity (DC) and acceleration capacity (AC) of heart rate, which are recently proposed variants to the heart rate variability, are calculated from unevenly sampled RR interval signals using phase-rectified signal averaging. Although uneven sampling of these signals compromises heart rate variability analyses, its effect on DC and AC analyses remains to be addressed. Approach. We assess preprocessing (i.e., interpolation and resampling) of RR interval signals on the diagnostic effect of DC and AC from simulation and clinical data. The simulation analysis synthesizes unevenly sampled RR interval signals with known frequency components to evaluate the preprocessing performance for frequency extraction. The clinical analysis compares the conventional DC and AC calculation with the calculation using preprocessed RR interval signals on 24-hour data acquired from normal subjects and chronic heart failure patients. Main Results. The assessment of frequency components in the RR intervals using wavelet analysis becomes more robust with preprocessing. Moreover, preprocessing improves the diagnostic ability based on DC and AC for chronic heart failure patients, with area under the receiver operating characteristic curve increasing from 0.920 to 0.942 for DC and from 0.818 to 0.923 for AC. Significance. Both the simulation and clinical analyses demonstrate that interpolation and resampling of unevenly sampled RR interval signals improve the performance of DC and AC, enabling the discrimination of CHF patients from healthy controls.

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