| 摘要 |
<p>A catheter, used e.g. for cardiac ablation, has a handle, a shaft, and a J-bendable distal end containing tip and ring electrodes. The tip electrode is axially rotatable and has insulated and uninsulated portions. As the tip electrode is rotated, the impedance between it and a reference level is observed. When the impedance reaches a maximum, this indicates that the uninsulated portion lies against the tissue and the insulated portion faces the bloodstream. An electrogram can be taken from the electrode, or an ablation current can then be applied to it. Short circuiting of the signal or current through the blood is thus reduced.</p> |
