title: Adding "hemodynamic and fluid leads" to the ECG. Part I: the electrical estimation of BNP, chronic heart failure (CHF) and extracellular fluid (ECF) accumulation.
abstract: OBJECTIVE
  In primary care the diagnosis of CHF and ECF accumulation is no triviality. We aimed to predict plasma BNP, CHF and ECF accumulation with segmental impedance spectroscopy while using and extending the electrodes of the conventional electrocardiography.
  
  
  METHODS
  Three combined multiple electrodes were added to the 15 lead ECG for segmental impedance spectroscopy and for measuring the maximal rate of segmental fluid volume change with heart action at the thorax and the legs. The obtained signals were analyzed by partial correlation analyses in comparison with plasma BNP, CHF classes, ejection fraction by echocardiography and cardiac index by double gas re-breathing. 119 subjects (34 healthy volunteers, 50 patients with CHF, NYHA classes II to IV and 35 patients without CHF) were investigated.
  
  
  RESULTS
  The maximal rate of volume change with heart action at the thorax and at the legs, as well as the ECF/ICF ratio at the legs contribute equally and independently to the prediction of BNP and heart failure in an unknown test sample of 49 patients (multiple r=0.88, p<0.001). The ROC-curve for the predicted plasma BNP>400 pg/ml gave an AUC=0.93. The absence or the presence of heart failure could be predicted correctly by a binomial logistic regression in 92.9 and 87.5% of cases, respectively.
  
  
  CONCLUSIONS
  The methodology, which is based on inverse coupling of BNP release and of maximal blood acceleration and on sensitive detection of ECF overload, could enable the diagnosis of CHF with useful sensitivity and specificity while writing a routine-ECG.
authors.affiliation: Institute for Cardiovascular and Metabolic Medicine, Mariatrosterstrasse 67, A8043 Graz, Austria. Electronic address: falko.skrabal@medunigraz.at.
authors.forename: Falko
authors.initials: F
authors.lastname: Skrabal
authors.affiliation: Institute for Cardiovascular and Metabolic Medicine, Mariatrosterstrasse 67, A8043 Graz, Austria.
authors.forename: Georg P
authors.initials: GP
authors.lastname: Pichler
authors.affiliation: Krankenhaus Barmherzige Brüder, Marschallgasse, Teaching Hospital Medical University Graz, Austria.
authors.forename: Gerfried
authors.initials: G
authors.lastname: Gratze
authors.affiliation: Krankenhaus Barmherzige Brüder, Marschallgasse, Teaching Hospital Medical University Graz, Austria.
authors.forename: Albert
authors.initials: A
authors.lastname: Holler
mesh_terms: D000328:Adult; D000368:Aged; D000465:Algorithms; D002307:Cardiography, Impedance / Q000379:methods*; D002908:Chronic Disease; D003936:Diagnosis, Computer-Assisted / Q000379:methods; D004569:Electroencephalography / Q000379:methods*; D005260:Female; D006333:Heart Failure / Q000150:complications / Q000175:diagnosis* / Q000503:physiopathology*; D006801:Humans; D008297:Male; D008875:Middle Aged; D020097:Natriuretic Peptide, Brain / Q000097:blood*; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D014883:Water-Electrolyte Imbalance / Q000175:diagnosis* / Q000209:etiology / Q000503:physiopathology*
chemical_list: D020097:Natriuretic Peptide, Brain
keywords: Atrial natriuretic peptide; Bioimpedance spectroscopy; Congestive heart failure; Contractility; Electrocardiography