[Left anterior hemiblock (left axis deviation) in the ECG of children before and after heart surgery]

In this study 18 248 ECG's were reviewed. In 212 children were found an extreme left axis deviation (or left anterior hemiblock) in ECG. In 44 (or 21%) exists an extreme left axis deviation before or after operation on congenital heart malformations. In 24 children this pathological deviation of the heart axis first appeared post-surgically. After critical analysis, however, it became apparent that it was factually correct to speak of a left anterior hemi-block in only 10 cases. This terminology was especially encountered after repair of ventricle-septal defects and total corrections of Tetralogy of Fallot, if at the same time a right bundle branch block existed in the sense of a bifascicular block. Some cases are especially difficult to judge; namely those in which on the basis of the heart defect itself, an extreme left axis deviation is likely to exist before surgery, as for example in endocardial cushion defects. Also, it is possible that an extreme left axis deviation could be reversed in the normal QRS-angle after operation.