Nevrokard^{®} LTaHRV is a software package designed to perform analysis of segmented ECG data (from 1 min. up to 120 hrs (5 days)) in the time and frequency domains. It is complementary to Nevrokard^{®} aHRV Analysis software which works on files of the same length, but performs somewhat different types of analysis with more emphasis on the time domain and does not use file segments. It consists of two software modules:


An ECG file recorded by any acquisition system or an ASCII RR interval table file is required. The software is compatible with ECG and RRI files in several different formats (see Data Formats). 
Detection of R waves, calculation of RR intervals: 
ECG and RRI files may be edited: 
All timedomain displays and calculations will be done either in the RR or HR mode 
Premature heart beats can be edited out of RRI files manually or automatically. The number of preceding beats on which correction is based, the parameters defining abnormal beats and the method of correction (deletion, interpolation) can be selected. 
TIME DOMAIN ANALYSIS 
Either whole recordings or zoomed segments of recordings can be analyzed both in time and frequency domains. Segments may be either adjacent (continuous) or overlapping; the user selects the segment length (in time units) and the number of FFT data points for spectral analysis. If overlapping of segments is enabled, any percentage of overlapping between 1 and 100 percent can be selected in steps of 1 percent. 

FREQUENCY DOMAIN ANALYSIS 
Waterfall Graph:
Waterfall graph is a 

Surface Graph: Surface
graph is a 3D 
Contour Graph: a 3D
graph displaying 
FSDmax Graph: displays
changes of 
Power Graph: displays
changes of the 
Stacked Power Graph: displays
changes 
Spectral
Results Graph: displays
changes of the LF/HF Power ratio, LF/(LF+HF) Power ratio,
HF/(LF+HF) Power ratio,CCVLF
(Coefficient of Component Variance for LF) and CCVHF (Coefficient of Component Variance for HF)
in consecutive
time segments. 
Grouped Graphs: a
group of four graphs 
RESULTS: a single
table containing all the 
OUTPUT OF ANALYSIS 
