The Ventricular Gradient Revisited: Relation to the Area Under the Action Potential

The ventricular gradient G is shown to be related to the area μ under the cellular action potential. For ac-coupled amplifiers, μ is calculated by taking the resting potential for each cell to be zero. The contribution to G for a small volume of the heart is then proportional to the gradient of μ weighted by the transfer impedance or lead field Z. An expression is developed which relates the secondary T wave to the QRS complex and the shape of the action potential. This expression is evidently equivalent to a procedure originally proposed by Abildskov et al. [6].