Changes of autonomic information flow due to idiopathic dilated cardiomyopathy.
Risk stratification of patients with idiopathic dilated cardiomyopathy (IDC) is an epidemiologically relevant question. But the results based on conventional heart rate variability (HRV) analysis are still unsatisfactory. The adjustments within the cardiovascular system incorporate nonlinear and complex mechanisms of information exchange which may have additional prognostic value. It is an objective of the present work to evaluate the prognostic value of autonomic information flow (AIF) measures in IDC patients compared to conventional HRV measures in a first explorative study. Holter recordings of 32 patients with idiopathic dilated cardiomyopathy (IDC) and 12 normal subjects (NRM) were analyzed. The IDC patients consisted of two groups: 10 high risk (HR) patients, after aborted sudden cardiac death (SCD); 22 low risk (LR) patients, without SCD. Sensitivity, specificity, positive predictive value, negative predictive value and ROC characteristics of a comprehensive set of AIF measures, organized according to the conventional HRV standards, and conventional HRV measures were investigated. The significant risk predictors were evaluated by Spearman's rank correlation. While the only traditional HRV measure discriminating IDC patients from NRM was ln(LF) most of the AIF measures had a discriminatory value. Concerning the prognosis of the IDC patients by conventional HRV we found that SDNN and all frequency band measures (lnHF, lnLF, lnVLF) significantly discriminated HR from LR. Among the AIF measures the time shift related peak decay (PD(dHF)) reflecting the HF band information flow had a prognostic value. PD(dHF) was identified as a promising candidate which might improve the predictive value of traditional HRV analysis, predominantly represented by SDNN. A subsequent comprehensive clinical study is necessary to validate this hypothesis.
Dep. ESAII, Centre for Biomedical Engineering Research, Technical University of Catalonia, Barcelona, Spain.
Manuel
M
Palacios
Holger
H
Friedrich
Christine
C
Götze
Montserrat
M
Vallverdú
Antonio Bayes
AB
de Luna
Pere
P
Caminal
Dirk
D
Hoyer
D000328:Adult; D001341:Autonomic Nervous System / Q000503:physiopathology*; D002311:Cardiomyopathy, Dilated / Q000503:physiopathology*; D016022:Case-Control Studies; D006339:Heart Rate / Q000502:physiology; D006801:Humans; D012307:Risk Factors; D018709:Statistics, Nonparametric