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Comparison of different methods for assessing sympathovagal balance in chronic congestive heart failure secondary to coronary artery disease
Adamopoulos S, Piepoli M, McCance A, Bernardi L, Rocadaelli A, Ormerod O, Forfar C, Sleight P, Coats AJ
The American Journal of Cardiology 1992 Dec 15;70(20):1576-1582
clinical trial
2/10 [Eligibility criteria: No; Random allocation: Yes; Concealed allocation: No; Baseline comparability: No; Blind subjects: No; Blind therapists: No; Blind assessors: Yes; Adequate follow-up: No; Intention-to-treat analysis: No; Between-group comparisons: No; Point estimates and variability: No. Note: Eligibility criteria item does not contribute to total score] *This score has been confirmed*

Twenty-five patients (aged 62 +/- 2 years) with stable, moderate to severe ischemic congestive heart failure (CHF) (New York Heart Association class II/III: 15/10; ejection fraction 21.6 +/- 2%; and peak oxygen uptake 13.6 +/- 0.7 ml/kg/min) were studied to evaluate the ability of different methods to characterize autonomic tone in chronic CHF. Sympathovagal balance was assessed by: (1) heart rate variability in the time domain, assessed by the SD of RR intervals; (2) heart rate variability in the frequency domain, assessed by low- (0.03 to 0.14 Hz) and high- (0.18 to 0.40 Hz) frequency components of heart rate variability by autoregressive power spectral analysis; (3) 24-hour, daytime and nighttime heart rate; (4) submaximal heart rate during upright bicycle exercise, with respiratory gas analysis to obtain peak oxygen uptake; and (5) radiolabeled norepinephrine spillover. These methods did not correlate, with the exception of day and nighttime heart rate (r = 0.74; p < 0.001) and the expected inverse correlation between low and high frequency (r = -0.92; p < 0.001). No method correlated significantly with peak oxygen uptake, exercise tolerance or ejection fraction. After 8 weeks of physical training at home, all methods showed improvement in autonomic balance: increases in SD of RR intervals (+21%; p < 0.02) and high frequency (+41%; p < 0.007), and decreases in low frequency (-19%; p < 0.002), low-/high-frequency ratio (-48%; p < 0.03), norepinephrine spillover (-28.9%; p < 0.03), 24-hour heart rate (-2.7%; p < 0.005) and submaximal heart rate (-10.8%; p < 0.01). However, neither the absolute values nor percent changes of the individual measures of autonomic function after training showed a significant correlation between each other. In patients with CHF, the individual parameters of autonomic control reflect different aspects of circulatory control. A comprehensive description of autonomic tone probably needs multiple methods.
With permission from Excerpta Medica Inc.

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