title: A beat-by-beat analysis of electrocardiograms from cardiac transplant recipients.
abstract: A software system is described for producing a beat-by-beat analysis of the electrocardiograms from patients after heart transplantation. Pacemaker spikes are automatically detected and eliminated from the signals. R waves are located by a robust and accurate two-step algorithm. Based on the variable length of single heart beats, the Fourier coefficients of three orthogonal surface leads and of two intracardiac leads are calculated beat-by-beat. Power spectra are then obtained by combining contributions from the variable fundamental frequency and its multiples (harmonics) into fixed frequency classes of 1 Hz width and averaging over 60-120 cardiac cycles. Additionally, averaged beat-by-beat power spectra are calculated for windowed QRS complexes and T waves. As by-products, single beat quantities, such as R-R and R-T intervals, averaged signals for all leads, and the orientational autocorrelation function of the electrical vector of the heart, are obtained. Following beat-by-beat evaluation, mean values and standard deviations are obtained for all quantities.
authors.affiliation: 2nd Department of Surgery, University of Vienna, Austria.
authors.forename: W
authors.initials: W
authors.lastname: Schreiner
authors.forename: G
authors.initials: G
authors.lastname: Laufer
authors.forename: M
authors.initials: M
authors.lastname: Neumann
authors.forename: R
authors.initials: R
authors.lastname: Lahoda
authors.forename: W
authors.initials: W
authors.lastname: Premauer
authors.forename: F
authors.initials: F
authors.lastname: Merksa
authors.forename: H
authors.initials: H
authors.lastname: Teufelsbauer
authors.forename: W
authors.initials: W
authors.lastname: Röthy
authors.forename: A
authors.initials: A
authors.lastname: Laczkovics
authors.forename: E
authors.initials: E
authors.lastname: Wolner
mesh_terms: D000465:Algorithms; D000703:Analog-Digital Conversion; D003199:Computer Systems; D004562:Electrocardiography; D005500:Follow-Up Studies; D005583:Fourier Analysis; D006084:Graft Rejection / Q000502:physiology; D016027:Heart Transplantation / Q000502:physiology*; D006801:Humans; D012815:Signal Processing, Computer-Assisted; D012984:Software