Intra- and interpersonal variation in body surface potentials of healthy subjects

Figure 1. Setup of the torso electrodes from the 67-lead body surface mapping (BSPM) system, and the study workflow showing the procedures performed at baseline and a week later during follow-up BSPM. 3D = 3-dimensional.

Figure 2. Data analysis methods per condition for depolarization and repolarization analyses. Data analysis of the effect of normal respiration (upper left panel), reclined position (upper right panel), increased heart rate (lower left panel), and repeated electrode placement (lower right panel) is presented. Examples of median beats during inspiration (gray), expiration (dashed line), reclined position (orange), supine position (blue), and repeated electrode placement (yellow) are shown. The regression models for depolarization and repolarization are shown in the upper row of the left lower panel. The yellow dots represent the R-, S-, and T-wave amplitudes (in millivolts) derived from the signals in the bottom row, and the black dot represents the median beat during the supine position. Median beats are shown for the different heart rate intervals during the first 15 seconds (dark blue) directly after exercise until the last 15-second interval (red). The signals visualized are from lead 45 of subject 4.

Figure 3. Heatmaps of the signal variation in R-wave amplitude between the 2 median beats during the supine position (first row), normal respiration (second row), reclined position (third row), and repeated electrode placement (third row) for all subjects (left column), males (middle column), and females (right column). The black dots represent the 64 torso electrodes (see Figure 1), and the white dots represent the standard positions of precordial leads V1–V6. Blue represents an R-wave amplitude decrease and red an increase.

Figure 4. Heatmaps of the signal variation in S-wave amplitude between the 2 median beats during the supine position (first row), normal respiration (second row), reclined position (third row), and repeated electrode placement (third row) for all subjects (left column), males (middle column), and females (right column). The black dots represent the 64 torso electrodes (see Figure 1), and the white dots represent the standard positions of precordial leads V1–V6. Blue represents an S-wave amplitude that became more negative and red an S-wave amplitude that became less negative.

Figure 5. Heatmaps of the signal variation in T-wave amplitude between the 2 median beats during the supine position (first row), normal respiration (second row), reclined position (third row), and repeated electrode placement (third row) for all subjects (left column), males (middle column), and females (right column). The black dots represent the 64 torso electrodes (see Figure 1), and the white dots represent the standard positions of precordial leads V1–V6. Blue represents an T-wave amplitude that became less positive or more negative and red a T-wave amplitude that became more positive or less negative.

Figure 6. Heatmaps of the regression coefficients for the change in the amplitude of the R wave (first row), S wave (second row), and T wave (third row) due to an increased heart rate for all subjects (left column) and specifically for males (middle column) and females (right column). The black dots represent the 64 torso electrodes (see Figure 1), and the white dots represent the standard positions of precordial leads V1–V6. The heatmaps show a negative (blue) or positive (red) relation (regression coefficient) between amplitude and an increased heart rate.