On the precision of automated activation time estimation.
We examined how the assignment of local activation times in epicardial and endocardial electrograms is affected by sampling rate, ambient signal-to-noise ratio, and sinx/x waveform interpolation.  Algorithms used for the estimation of fiducial point locations included dV/dtmax, and a matched filter detection algorithm.  Test signals included epicardial and endocardial electrograms overlying both normal and infarcted regions of dog myocardium.  Signal-to-noise levels were adjusted by combining known data sets with white noise "colored" to match the spectral characteristics of experimentally recorded noise.  For typical signal-to-noise ratios and sampling rates, the template-matching algorithm provided the greatest precision in reproducibly estimating fiducial point location, and sinx/x interpolation allowed for an additional significant improvement.  With few restrictions, combining these two techniques may allow for use of digitization rates below the Nyquist rate without significant loss of precision.
Kaplan
D T
DT
Harvard-MIT Division of Health Sciences and Technology, Cambridge, Massachusetts 02139, USA.
Smith
J M
JM
Rosenbaum
D S
DS
Cohen
R J
RJ
D000465:Algorithms; D000818:Animals; D004195:Disease Models, Animal; D004285:Dogs; D004594:Electrophysiology; D004699:Endocardium / Q000502:physiology / Q000503:physiopathology*; D006329:Heart Conduction System / Q000502:physiology / Q000503:physiopathology; D009203:Myocardial Infarction / Q000175:diagnosis / Q000503:physiopathology*; D009206:Myocardium / Q000473:pathology; D010496:Pericardium / Q000502:physiology / Q000503:physiopathology*; D012815:Signal Processing, Computer-Assisted