title: Comparison of wavelet transform modulus maxima and multifractal detrended fluctuation analysis of heart rate in patients with systolic dysfunction of left ventricle.
abstract: BACKGROUND
  In recent years the WTMM (wavelet transform modulus maxima) and MDFA (multifractal detrended fluctuation analysis) methods have become widely used techniques for the determination of nonlinear, multifractal heart rate (HR) dynamics. The purpose of our study was to compare multifractal parameters of heart rate calculated using both methods in a group of 90 patients with reduced left ventricular systolic function (rlvs group) and in a group of 39 healthy persons (nsr group).
  
  
  METHODS
  For each subject from the rlvs group (LVEF < or =40%) and the nsr group, a 24-hour ECG Holter monitoring was performed. The width of the multifractal spectrum and global Hurst exponent were calculated by means of WTMM and MDFA methods for 5-hour daytime and nighttime subsets.
  
  
  RESULTS
  The width of the multifractal spectrum was significantly lower and the Hurst exponent was significantly higher in rlvs group in comparison to nsr group both during diurnal activity and nocturnal rest according to MDFA and only during diurnal activity according to WTMM method. In both groups we observed significant differences of the multifractal spectrum width and the global Hurst exponent between the nighttime and daytime recordings.
  
  
  CONCLUSIONS
  MDFA seems to be more sensitive as compared with WTMM method in differentiation between multifractal properties of the heart rate in healthy subjects and patients with left ventricular systolic dysfunction.
authors.affiliation: First Department of Cardiology Medical University of Gdansk, Poland. rgal@amg.gda.pl
authors.forename: Rafal
authors.initials: R
authors.lastname: Galaska
authors.forename: Danuta
authors.initials: D
authors.lastname: Makowiec
authors.forename: Aleksandra
authors.initials: A
authors.lastname: Dudkowska
authors.forename: Andrzej
authors.initials: A
authors.lastname: Koprowski
authors.forename: Krzysztof
authors.initials: K
authors.lastname: Chlebus
authors.forename: Joanna
authors.initials: J
authors.lastname: Wdowczyk-Szulc
authors.forename: Andrzej
authors.initials: A
authors.lastname: Rynkiewicz
mesh_terms: D000368:Aged; D016022:Case-Control Studies; D002940:Circadian Rhythm; D004562:Electrocardiography / Q000379:methods; D015716:Electrocardiography, Ambulatory / Q000379:methods*; D005260:Female; D054143:Heart Failure, Systolic / Q000175:diagnosis*; D006339:Heart Rate / Q000502:physiology*; D006801:Humans; D008297:Male; D008875:Middle Aged; D015999:Multivariate Analysis; D011336:Probability; D012016:Reference Values; D018570:Risk Assessment; D012680:Sensitivity and Specificity; D012815:Signal Processing, Computer-Assisted; D018487:Ventricular Dysfunction, Left / Q000175:diagnosis*