[Long-term follow up of QRS axis deviation]

It has been already described that the average axis of QRS complex is deviated by aging as well as various diseases, such as ventricular overload or bundle branch block. In this study, we first tested the hypothesis that the extra-cardiac factor changes with aging, such as the body shape or diaphragm position, which are represented by body weight (WT) and/or cardiac-thoracic ratio (CTR), are the main cause of QRS axis deviation. In 28 cases including 1 right (RAD) and 27 left axis deviation (LAD) patients whose QRS axis have been deviated during observed periods, WT and X-ray CTR were compared to the degree of axis deviation. Unfortunately no clear relationship was found among these parameters. On the other hand, in 8 cases out of 27 LAD patients, confirmed or suspected left anterior hemiblock (LAH) was found by vector electrocardiogram. Pathological studies showed that the degeneration of the stimulation pathway occurred with aging and it caused the bundle branch block. Therefore, we conclude that the degenerative change in left anterior stimulation pathway by aging should be, at least, one of the cause of the QRS axis deviation.