The T wave abnormality in the magnetocardiogram.

The T wave changes in left ventricular hypertrophy and old inferior wall myocardial infarction were studied by the isomagnetic map to compare with those in the isopotential map. The isomagnetic map could detect the instantaneous current source, and the abnormal repolarization vector was more frequently observed in the isomagnetic map than in the isopotential map. The multiple dipoles were more frequently observed in the isomagnetic map, which has been difficult to detect by the isopotential map. The present study showed that repolarization in ventricular hypertrophy and myocardial ischemia is very complex and both normal and abnormal repolarization vectors are present, which might be opposite in direction. In some cases, these vectors were summated and only one dipole could be shown in the electrocardiogram or isopotential map. These results suggest that the magnetocardiogram is useful in detecting opposing current dipoles tangential to the heart.