Pulmonary artery

Vectorcardiography

Cardiology

QRS complex

Blood pressure

Ligation

Anatomy

Internal medicine

Sagittal plane

Electrocardiography

Ventricular hypertrophy

Medicine

Right ventricular hypertrophy

Left ventricular hypertrophy

Muscle hypertrophy

Ventricle

Japanese Circulation Journal

Vectorcardiographic changes which appear in the ventricular hypertrophy of heart have been studies often by use of tetrahedral or cube system methods. But they have not been researched serially on the same subject from the beginning to the end of hypertrophy. Moreover, the vectorcardiograms recorded by htese methods have much deformation in their represented vectors compared with those of the theoretical electrical heart axes. Therefore I tried to study tthe vectorcardiographic changes in the ventricular hypertrophy by means of vectorpolyography having least deformation in represented vectors. The experimental hypertrophy of right or left heart ventricle were produced respectively by ligation of pulmonary or abdominal artery. The polyograms were taken spatially in three planes of frontal, horizontal and sagittal one, and the wire model was reconstructed from these polyograms in three planes for the benefit of observation of the changes in the represented vector loops. The roentgenograms were taken also in every cases. The data obtained in these procedures are compiled in table 1, 2, and 3. The results are as follows. CHANGES IN QRS-LOOP. -Changes in QRS-loop were observed not only in its terminal portion, but in the entire loop, especially in its mid-portion. The mid-portion of QRS-loop displaced from initial position to its right upper anterior in right ventricular hypertrophy, and to its left posterior in left ventricular hypertrophy. Namely, in vectorcaidiogram of right ventricular hypertrophy, the mid-portion in frontal plane displaced from initial position to the right, in horizontal plane to the right anterior, and in sagittal plane to the anterior, and in vectorcardiogram of left ventricular hypertrophy, that in frontal plane displaced to the left, in horizontal plane to the left posterior, and in sagittal plane to the posterior. These results could be explained by the rotation and variation of the QRS-loop before the procedure. Rotation of QRS-loop in right ventricular hypertrophy: The initial QRS-loop is rotated counterclockwise around ventrical axis after the procedure when viewed from the cranial side, clockwise around transverse axis when viewed from the right, and clockwise around anteroposterior axis when viewed from the front. Rotation of QRS-loop in left ventricular hypertrophy: The initial QRS-loop is rotated clockwise around vertival axis, counterclockwise around transverse axis, and couterclockwise around anteroposterior axis after the procedure when viewed from the same side as above mentioned. Variation of QRS-loop was observed mainly in the mid-portion of the loop. The QRS-loop budged or bended to right or anteriorly in right ventricular hypertrophy, and posteriorly in left ventriclar hypertrophy. INVERSION OF T-LOOP. - Inversions of T-loop were observed in about 1/3 of right or left ventricular hypertrophy, and began to appear usually within the same interval after procedure. It was also noted that there was gradual increase in the degree and appearance of inversion in proportion to the number of days after procedure. OPENING OF QRS-LOOP. - No apparent correlation could be observed between the opening of QRS-loop and the hypertrophy in these experiments. The most reasons of these changes of QRS-loop in the vectorcardiogram after the occurrence of ventricular hypertrophy were probably in the rotation, thickness of hypertrophied free ventricular wall and deformation of ventricle itself due to enlargement, hypertrophy, and other reasons, because we observed that the rotation or variation of QRS-loop was caused by rotation or deformation of heart ventricle in another experiments. Futhermore, the vectorcardiograms, obtained by calculation under the assumption that the subepicardial muscle surface in hypertrophied ventricle was activated later than that of normal ventricle, were very alike to these in this paper. These facts mean that the variation of VCG

Experimental Studies on the Ventricular Hypertrophy and Enlargement by means of Vectorcardiography : VENTRICULAR HYPERTROPHY AND ENLARGEMENT PRODUCED BY LIGATION OF PULMONARY OR ABDOMINAL ARTERY