Body surface mapping of cardiac activity after partial left ventriculectomy

MECG measurements were performed using 35 electrodes in 10 patients operated with partial left ventriculectomy (PLV). Body surface ECG signals were recorded and five measurements were done: prior to PLV, second, third, fourth and fifth postoperative day. This work was concentrated on the following mapping methods: average isopotential ST segment maps (STM), QRS interval isointegral maps (QRM) and isochronal activation maps (IAM). STMs of the patients show a great positive area (elevation) over the anterior aspect of the heart and a great negative area (depression) over the lateral and posterior aspect of the heart before the operation. After the operation, the ST elevation over the anterior, lateral and posterior aspect of the heart was reduced. A substantial positive value over the excised area of the heart was present also on the end of the postoperative monitoring interval. Minimal and maximal values of the QRMs were smaller and also show some kind of normalisation. The area of the left ventricle, where PLV was performed, was carefully analysed for any changes of activation time for different heart regions. IAMs indicate that the start of the first activation was quite stable and in accordance with the position of the QRMs minimum.