[Spatial ventricular gradient studied by computerized vectorcardiography. Normal and pathological values. Interpretation and clinical evaluation].

The ventricular gradient is a reflection of uneven ventricular repolarisation. Until recently is was only appreciated in the frontal plane of the classical electrocardiogramme and expressed as the sum of the vectors representing the surfaces under the QRS complex and T wave. We used computerised vectorcardiography to obtain a more exact evaluation of the size and spatial orientation of the vector gradient. The spatial vector gradient was calculated in a control group and in a number of pathological conditions. The reference values were established in 70 normal subjects with a mean age of 36 +/- 21 years: 0.092 +/- 0.016 m V.s for amplitude: 38.4 degrees +/- 6.1 for thesite and 21.6 degrees +/- 8.7 for the azimuth. The size and spatial orientation of the ventricular gradient can be used to define normal limits and to distinguish subgroups by using the values of the site and azimuth. The spatial ventricular gradient is a new approach to defining the limits of normality in poorly understood abnormalities of ventricular repolarisation. It may also be useful in the comprehension of certain forms of cardiac arrhythmia related to desynchronisation of ventricular repolarisation.