An octaxial reference system derived from a nonequilateral triangle for frontal plane vectorcardiography

The weight of evidence indicates that the frontal plane triangle commonly used in electrocardiography is not equilateral from the electrical standpoint.1–5 This triangle is scalene as illustrated in Fig. 1, a. Such a triangle should be more representative of the true situation pertaining to the electrical field of the heart than is the equilateral triangle. It is the purpose of tis paper to illustrate the use of this nonequilateral triangle and an octaxial system derived from it for the estimation of the direction and magnitude of mean QRS and T vectors in the frontal plane.