Please click here to obtain permission to reproduce this image.
Click on image to view larger version.
Figure 3 Frequency components of the heart rate variability signal, 24-h average and at 30-min intervals before the onset of sustained ventricular tachycardia. (a) Total power (TFP). (b) Ratio of low to high frequency power (LFP/HFP). (c) Low frequency power. (d) High frequency power. (e) Normalized low frequency power. (f) Normalized high frequency power. *p < 0.05 for comparison 30-min versus 24-h average. **p < 0.01 compared to the 24-h average. nu = normalized units. Significance of changes during 2-h period before ventricular tachycardia was assessed by analysis of variance and is discussed in the text.
|
