[Evaluation of left ventricular asynergy by two-dimensional echocardiography: comparison between fixed external axis...

Detection and quantitative estimation of segmental asynergy in the infarcted area has been impeded by the rotation and anterior movement of the heart during systole. In the present communication, we compared the two measurements determined by the floating and fixed external axis systems. The former takes into account of the effect of cardiac movement. Furthermore, we assessed which system is superior by the left ventriculographic and coronary arteriographic analyses. The materials consisted of 24 cases of myocardial infarction. There was no significant difference between the two systems in the estimation of the number of asynergic segments or between echocardiographic and ventriculographic findings. The floating axis system had a tendency to underestimate asynergy, so that the number of hypokinetic segment estimated by the floating system was greater than that by the fixed external axis system. Therefore, the fixed external axis system was superior to the floating axis system in determining the causative coronary artery.