Hexaxial reference system
- 2. TRIAXIAL REFERENCE SYSTEM Standard lead • The lead axes of the three standard leads form an equilateral triangle. • This constitutes Einthoven's equilateral triangle, each angle of the triangle being 60°
- 4. TRIAXIAL REFERENCE SYSTEM • The lead axes of Einthoven's triangle may be transposed so that they bisect each other while maintaining their orientation. • These three lead axes thus form a triaxial reference system with each lead axis being theoretically separated from the other by 60°
- 7. TRIAXIAL AND HEXAXIAL SYSTEM Unipolar lead The unipolar extremity leads are so constructed that their lead axes geometrically bisect the angles of the equilateral triangle formed by the standard leads • Each electrode of these unipolar leads is a positive electrode. • These leads, too, may be transposed so that they bisect each other while maintaining their orientation
- 8. TRIAXIAL AND HEXAXIAL SYSTEM • They also form a triaxial reference system with each lead axis separated from the other by 60° • When these two triaxial reference systems are combined and superimposed upon each other, they form a hex-axial reference system • Each lead axis is then separated from its two neighbouring axes by 30° • This hexaxial reference system is used for graphing the mean manifest frontal plane electrical axes.
- 10. HEXAXIAL SYSTEM • Naming the degrees • By an irrational and confusing convention, the degrees in the upper hemisphere of the hexaxial reference system are labelled negative degrees, whereas those in the lower half are labelled positive degrees.
- 11. HEXAXIAL SYSTEM • Thus, beginning with the positive pole of standard lead I, which is labelled 0°, and progressing clockwise, the leads are labelled sequentially +30°, +60°, +90°, +120°, +150° and +180°. • Beginning at 0° and progressing counterclockwise, the leads are labelled sequentially -30°, 60°, 90°, -120°, -150° and - 180°. The 180° position may be termed + or - 180°.
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