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The electrocardiograms and the vectocardiograms of 26 childrens, up to 3 years of age, affected by A-V canal, were been analyzed. The pattern of QRS loop in the 3 planes, the voltage of right maximum spatial vector (RMSV) and left maximum spatial vector (LMSV), their projection onto the horizontal (azimuth) and frontal plane (elevation) were related to right ventricular systolic pressure. The qualitative and quantitative evaluation of VCG Showed a better correlation with the haemodynamic data than the electrocardiogram. In all but 3 cases, the high frequency of superior orientation and counterclockwise rotation of QRS loop in the frontal plane was found; moreover the good correlation of right ventricular systolic pressure to the rotation of QRS loop on the horizontal plane was also confirmed. In fact, the latter was counterclockwise in the cases with a low pressure, whereas it became clockwise in those with higher pressure. Moreover a good direct correlation of the right ventricular pressure with forward orientation of LMSV on the horizontal plane was found. In differential diagnoses with other congenital heart diseases with superior orientation and anticlockwise rotation on the frontal plane, useful results were obtained by using the calculation of elevation time (the interval between point 0 and intersection of the QRS loop with the axis) which is significantly lower in the A-V canal. Terminal forces directed posteriorly and to the right and with a delay no longer than 0,03 inches do not warrant the diagnosis of left anterior hemiblock with a right bundle branch block associated. On the contrary, on the basis of anatomical and electrophysiologic studies we believe that in this disease there is an asinchrony in the activation i.e. the postero-inferior region, then the left lateral wall and finally the tree high part of right ventricle wall are sequentially activated.

The vectorial and morphological variations of the VCG (Frank method) during the first seven days of life of sixteen normal newborn infants were analyzed. A byphasic distribution of the QRS vectors in the horizontal plane was found at birth. Successive observations showed a rising of initial forces of left septal activation and a slight increase of left parietal forces. The T loop variations were more remarkable, being probably correlated with rapid postnatal hemodynamic modifications. After a few days the T loop was oriented posteriorly and to the left, not changing this direction for many year. The P loop did not differ from the adult's in the majority of cases. Sometimes it showed a figure-or-eight rotation in the horizontal plane, probably due, according to the authors, to a different pathway of atrial activation.

36 patients, less than two years old, affected by Fallot's tetralogy were studied by vectorcardiography. The configuration of the QRS loop in the three orthogonal planes, the voltage of the 0.10 sec spatial vector, RMSV and LMSV vectors, and their azimuth and elevation were evaluated. Such data have been correlated to arterial oxygen saturation. Qualitative analysis showed a clockwise or figure eight QRS loop on the H and F planes in the great majority of cases; and only in a counterclockwise loop on the H plane was the suspicion of an arterial oxygen saturation greater than 85% especially in cases older than two months. The terminal forces of the QRS loop on the H plane were always directed under the O point, Whereas in the valvular pulmonary stenosis, terminal forces are generally superior to the O point. Quantitative analysis demonstrated the constant increase of the RMSV and the direct relationship of the LMSV to arterial oxygen saturation, and so it was the principal parameter for evaluation of the left ventricular volume and the size of pulmonary flow and the degree of pulmonary stenosis. The relationship between the azimuth of 0.01 sec spatial vector to O2 saturation was highly significant, showing a progressive anterior development of the former, as the latter increased.

Eighty-one patients suffering from pulmonary stenosis with intact interventricular septum were divided into two groups according to their age: Group I (greater than 2 years), Group II (less than 2 years). In Group I, patients with RVSP up to 50 mmHg have been included in subgroup A; patients with RVSP from 50 to 90 mmHg in subgroup B, patients with RVSP greater than 90 mmHg in subgroup C. In Group II forms with RVSP less than or equal to 60 mmHg have been considered moderate and forms with RVSP greater than 60 mmHg severe. The rotation and duration of the QRS loop on the various planes, presence of a terminal slowing, the ratios 0,01"/LMSV and 0,02"/LMSV, the LMSV and the RMSV in order to assess the most significant vcgraphic parameters to predict severity of the stenosis have been analysed. A fair correlation has been found between RMSV and RVSP (r = 0,55 in Group I; r = 0,54 in Group II). The AA. conclude that a counterclockwiseloop on the H plane and the presence of a terminal slowing are the most reliable parameters for recognizing the light forms, while the clockwise loop on the H plane and a markedly increased voltage of RMSV indicate more severe stenosis.

The value of the electrocardiogram and vectorcardiogram for the diagnosis of congenital heart diseases with VSD and pulmonary obstruction is illustrated. Three types of electrocardiographic pattern are encountered: 1) pressure overload to the right ventricle (Tetralogy of Fallot, DORV, TGA); 2) left ventricular hypertrophy (TA, UH with outlet chamber to the right); 3) Inversion of septal activation (Correct TGA, UH with outlet chamber to the left). In the diagnosis of the anomalies of the first group, absence of P wave alteration, downward and rightward QRSA, lack of s wave in AVF and terminal forces of the QRS loop under the O point suggest Tetralogy of Fallot. In DORV and TGA the QRSA may be directed upward to the right or to the left and P wave may show overload pattern of the right ventricle. Moreover, in DORV conduction delays on the right bundle branch and/or increased voltage of the R wave in V1 may be observed. In diagnosis between TA and UH with outlet chamber to the right, a leftward displacement of QRSA, an overload pattern of RA and absence of clockwise rotation of the QRS loop on the H plane suggest the former disease. These electrocardiographic data, as well as pathological considerations, made us keep these two form distinct from a clinical point of view. Finally, recording of LV potentials in V1 or to its right with AV conduction abnormalities are typical of corrected TGA; in UH with outlet chamber to the left no conduction defects are observed. In UH with outlet chamber anterior o slightly to the left, ECG pattern is rS on all the praecordial leads and a left posterior hemiblock is present in 40% of the cases of second type.

Balloon aortography is a new technique for the angiographic study of pulmonary atresia with ventricular septal defect. A Swan-Ganz angiographic catheter is employed, whose balloon is inflated to stop blood flow in the descending aorta, thus ensuring the opacification of the pulmonary circulation. By this method we have studied 18 patients. Anatomic details of the pulmonary arterial circulation were obtained in all. No complications occurred. Balloon aortography is a simple and safe technique for the routine study of patients with pulmonary atresia and ventricular septal defect, whereas selective injection in collateral arteries or pulmonary veins, which carries more risk and is more complex, should be adopted only in selected cases.

We have evaluated the diagnostic accuracy of subxyphoid 2-dimensional (2-D) echocardiography in Fallot's tetralogy by employing two planes defined as left anterior oblique (LAO) and right anterior oblique (RAO), similar to the respective angiographic axial projections. Echocardiographic and angiographic findings were compared in 39 patients. The pulmonary branches, the trunk, the infundibulum, the septal defect and the aorta were identified in all cases, the pulmonary valve in 97% and associated defects in 71%. The LAO view was best suited for an overall diagnosis and for the visualization of the left pulmonary branch, of the pulmonary anulus, and of the overriding of the aorta. The RAO proved optimal for the evaluation of the right pulmonary branch, of the infundibulum and of the relationship between ventricular septal defect and adjacent structures. It is concluded that the subxiphoid approach is a valuable technique for the 2-D echocardiographic evaluation of Tetralogy of Fallot.

A group of 37 patients, less than 2 years old, with a ventricular septal defect of variable degree, and a left to right shunt, were studied by vectorcardiography. The duration, the direction and the aspect of the QRS loop on the three orthogonal planes, the voltage of the 0.01; 0.02; 0.04 vectors, the right and the left maximum spatial vectors and their projection on the H and F planes were analyzed and correlated to the right ventricular systolic pressure and Qp/Qs. A clockwise or an eight-type loop on the frontal plane, regardless of RVSP, was observed; on the H plane the loop is, usually, counterclockwise when the pressure is low or medium, and can be of the eight-type but never clockwise when the pressure is systemic. Very interestingly, the quantitative analysis showed a consistent increase of the LMSV. A progressive relationship between the spatial vectors and the right ventricular pressure was noted. The diagnosis of combined ventricular hypertrophy depend upon the following findings: the majority of cases showed a large, counterclockwise and anterior QRS loop on the H with the maximum vector to the left and anteriorly; in all cases the 0.01; 0.02; 0.04 vectors were enlarged, thus warranting the diagnosis of combined ventricular hypertrophy in the first few months of life. 4 cases with low RVSP presented increased initial forces to the right and anteriorly directed, while the major portion of the loop was in the left posterior quadrant on the H plane, with a counterclockwise direction. In our view, the differential diagnosis between this type of aspect and that of diastolic overload of the left ventricle can rest only on the increased voltage of the 0,02 vector which means both systolic and diastolic overload of the right ventricle when accompanied by an increased 0.01 vector which indicates volume overload of left ventricle. Likewise only a quantitative analysis can help in differentiating a combined ventricular hypertrophy from a normal tracing in children under 6 months who show an eight-type loop on the H plane with initial and medium vectors directed anteriorly to the left and counterclockwise, and terminal vectors to the right, posteriorly and clockwise, or in those cases with an anterior clockwise loop on the H plane. Moreover, in the first month of life, the VCG of large VSD with increased pulmonary flux and pressure, can be differentiated from the normal by the QRS loop on the H plane which is clockwise, with initial vectors directed to the left and anteriorly with increased LMSV.