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Figure

Figure 7: Principles of cardiogoniometry

A) Four electrodes are placed at four points on the patient’s thorax as follows: Point 1 (green) at point V4 of Wilson, i.e. in the 5th intercostal space in the mid-clavicular line; point 2 (white) sagittal to electrode 1 on the back (point V8 of Wilson); point 3 (yellow) is located perpendicularly above electrode 1 at 0.7 times the distance between points 1 and 2; point 4 (red) is placed to the right of point 3 at the same distance as between points 1 and 3. The leads are defined as follows: 4-2 D (dorsal), 4-1 A (anterior), 2-1 I (inferior), 4-3 Ho (horizontal), 3-1 Ve (vertical). B) Points 4-2-1 define the oblique sagittal plane OSP (red); points 4-3-1 define the frontal plane (yellow). The third plane (blue) is orthogonal to the two other planes and contains point 3; it is the sagittal plane perpendicular to the OSP. Projection x is oriented in an antero-dorsal direction and lies in the OSP and the sagittal plane perpendicular to the OSP. Projection y is oriented in a baso-apical direction and lies in the OSP (4-2-1) and the frontal plane (4-3-1). Projection z is oriented in a supero-inferior direction relative to the OSP and lies in the frontal plane (4-3-1) and the sagittal plane perpendicular to the OSP. C) Vector loops from projections x, y and z can be calculated within a Cartesian coordinate system. Figure shows R-Loops (blue) and T-loops (green) of 12 heart cycles and maximum vectors of both (red), calculated on median cycle.