J Korean Pediatr Soc.  1979 Jan;22(1):13-19.

The Electrocardiographic and Vectorcardiographic Findings of Tetralogy of Fallot

• Hong CY
• Choi JY

Abstract

The electrocadiographic and vectorcardiographic findings were reviewed in 49 cases of tetralogy of Fallot, confirmed by cardiac catheterization and angiocardiographic findings and/or, by surgery. In most cases, the electrocardiographic findings were right axis deviation and right ventricular hypertrophy. Vectorcardiographic findings were as following; 1) The initial vector directed to anterior and slightly left or right. 2) The maximum vector directed to right, anterior or posterior and inferior. 3) The terminalvector directed to right, posterior and inferior. 4) The loop inscription of horizontal plane and frontal plane were mainly clockwise. Five cases out of 49 showed somewhat atypical electrocardiographic findimgs. In 2 cases, rS pattern all through the chest leads were observed and in another 2, right chest leads showed the RS pattern(predominantly S) and left chest leads showed the not tall R waves and in the remaining 1, left axis deviation was noticed. The vectorcardiogram of these 5 cases showed the less Rx and Qz, larger Sx and Rz. In horizontal plane, main area is shifted to the third quadrant and direction of the maximum vector is right, posterior and inferior, and the inscription of loop is counterclockwise or figure of 8. The vectorcardiographic findings of tetralogy of Fallot which showed rS pattern were not different from those of single ventricle which showed rS pattern all through the precordial leads. Counterclockqwise or figure of 8 herizontal inscription is known to suggest mild tetralogy of Fallot but counterclocwise or figure of 8 inscription with small Rz and Qz may suggest severe tetralogy of Fallot.

MeSH Terms

Axis, Cervical Vertebra
Cardiac Catheterization
Cardiac Catheters
Electrocardiography*
Hypertrophy, Right Ventricular
Tetralogy of Fallot*
Thorax