A medical apparatus includes a medical assist device to process signals to relating biological functions. A first lead is operatively connected to the medical assist device, the first lead having a distal end and a proximal end. A second lead is operatively connected to the medical assist device, the second lead having a distal end and a proximal end. The first electrode is operatively connected to the distal end of the first lead, and a second electrode is operatively connected to the distal end of the second lead. A filter circuit is operatively connected near the distal end of the first lead and the distal end of the second lead. A compensation circuit, operatively connected to the first lead, provides a compensation voltage to enable the filter to effectively block changing magnetic fields induced current in the second lead from passing through the second electrode of the distal end of the second lead.