[Integral ECG and ventricular gradients, differential ECG, their diagnostic potentials]

Synchronous recording of the integral ECG (IECG), ECG and is first derivative (DECG), made according to the original method, shows that the measurement of the amplitude of IECG elements can substitute the difficult calculations of the area of ECG waves, required for the determination of AQRS, AT and the ventricular gradient (G). On this basis the normal dimensions and directions of the AQRS, AT, G vectors were calculated in the frontal and horizontal planes, the typical changes were recorded in the blocks of the His' bundle, ischaemic heart disease and myocardial infarction. The offered methods of calculation make easily accessible the determinations of G in the right-angle system of coordinates, open new possibilities of the quantitative assessment of ST segment displacement. Recording of DECG permits one to detect P waves in those cases when they coincide with the QRS complex, with ST--T interval, which helps differential diagnosis of rhythm disorders of the heart.