ECG toolbox I

g.ECGtoolbox is a software package for ECG data processing and analysis. — The investigation of patterns and signal features of ECGs allows to observe noninvasively brain and heart functions and disfunctions.

The graphical user interface for g.ECGtoolbox enables you to investigate all important time and frequency domain features of your electrocardiogram (ECG) data such as RR intervals or HRV maps. You can load and save your preferred processing steps as a script program and automatically process your data in batch mode.

The g.ECGtoolbox can be ordered in two parts:

Time Domain: 

• Tachogram , Resampled tachogram, histogram of RR intervals
• Time domain measures and statistics: MeanRR, MeanHR, MaxRR, MinRR, MinMaxRRDiff,SDNN, SDHR
• Segemented measures: SDANN, SDNNindex
• RR difference measures: RMSSD, SDSD, NN50, pNN50
• Geometric measures: HRVindex 

Frequency domain:

• Power spectral density of resampled tachogram
• Absolute measures of spectral power distribution (ULF, VLF, LF, HF)
• Relative measures of spectral power distribution (LFnorm, HFnorm, LF/HF)

Time-Frequency Evolution of HRV:

Starting from noisy raw ECG data, QRS complexes are automatically detected and indicated in the data editor with attribute QRS. An intelligent algorithm assigns the attribute QRSBAD to R-peaks that are not detected securely. These markers can now be corrected visually or (if necessary) excluded from further analyses. Time courses of tachogram and RR-intervals can also be displayed for visual inspection. 




 

Time domain measures such as the evolution of the mean RR intervals NN50, the number of RR intervals differing by more than 50 ms, ... 

Segmented Measures such as SDANN, the standard deviation of the averages of RR intervals in all segments of the recording, ...

Geometric Measures such as HRVindex yielding the total number of RR intervals divided by the number of RR intervals, ...



 

ECG data analysis in the frequency domain allows you to investigate heart rate variability oscillations at different frequencies. These oscillations are originated by different physiological systems. The parasympathetic and sympathetic systems modulate the heart rate variability. High frequency oscillations (about 0.2-0.35 Hz) are vagally mediated and low frequency oscillations (around 0.1 Hz) are due to both parasympathetic and sympathetic systems. The respiratory sinus arrhythmia (RSA) is vagally mediated and has a frequency synchronous to the respiratory cycle (between 0.2 and 0.35 Hz). Very low frequency components are associated with slow regulation mechanisms such as humoral and thermoregulation factors.

Absolute Measures such as the 4 main spectral components (ULF, VLF, LF, HF) are extracted from a calculated spectrum, ... 

Relative Measures such as the ratio of LF/HF or LF normalized by the total power TP, ...

To simplify the data analysis and interpretation of the ECG data HRV maps allow to estimate the PSD (power spectral density) for a certain segment. Then the segment is shifted by a specific stepsize and the PSD is calculated again. This yields a comprehensive time-frequency analysis plot over the recording time. High power values are indicated in red, low power values are shown in blue.

In addition to the time frequency plot, the time course of the spectral components ULF, LF, HF, VHF are also displayed in the protocol.
 

WINNER of the CinC Challenge 2006

ECG-Toolbox brochure (PDF 1.5 MByte)

g.BSanalyze brochure (PDF 5.7 MByte)