SYSTEM AND METHOD FOR MEASUREMENT OF AN IMPEDANCE USING A CATHETER SUCH AS AN ABLATION CATHETER
First Claim
1. A catheter, comprising:
- an elongated shaft having a proximal end and a distal end;
an electrode disposed at said distal end;
a source lead electrically connected to said electrode and extending through said shaft to said proximal end; and
a sense lead, different from said source lead, electrically connected to said electrode and extending through said shaft to said proximal end.
1 Assignment
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Accused Products
Abstract
A catheter and patch electrode system is provided for use with an apparatus, such as an ablation generator, having a 4-wire interface for improved impedance measurement. The 4-wire interface includes a pair of source connectors across which an excitation signal is produced and a pair of sense connector wires across which the impedance is measured. The RF ablation generator may also produce an ablation signal across a source wire and an indifferent return patch electrode. The system further includes a cable that connects the generator to a catheter. The catheter includes a shaft having a proximal end and a distal end, with an ablation tip electrode disposed at the distal end. A source lead is electrically coupled to the tip electrode and extends through the shaft to the proximal end where it is terminated. An optional sense lead is also electrically coupled to the tip electrode and extends through the shaft to the proximal end. The system further includes a source return (e.g., skin patch) and a sense return (e.g., skin patch), either or none of which may be combined with the indifferent return, and if used may be placed on opposite sides of the patient for improved performance. The impedance sensor circuit produces an excitation signal across the source connectors, which is then carried to the catheter by the cable, then to the tip electrode, travels through the complex load (tissue volume), and returns to the generator via a patch electrode. The impedance is measured by observing the voltage drop across the sense connectors caused by the excitation signal.
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Citations
26 Claims
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1. A catheter, comprising:
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an elongated shaft having a proximal end and a distal end; an electrode disposed at said distal end; a source lead electrically connected to said electrode and extending through said shaft to said proximal end; and a sense lead, different from said source lead, electrically connected to said electrode and extending through said shaft to said proximal end. - View Dependent Claims (2, 3, 4, 5, 6, 7)
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8. A catheter system for use with an apparatus having a four-wire interface including positive and negative source connectors across which is produced an excitation signal and positive and negative sense connectors, said system comprising:
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a catheter comprising an elongated shaft having a proximal end and a distal end, a tip electrode disposed at said distal end, a source lead electrically connected to said tip electrode and extending through said shaft to said proximal end and configured for connection to said positive source connector to receive said excitation signal, said electrode being further configured for connection to said positive sense connector; a source return configured for connection to said negative source connector; a sense return configured for connection to said negative sense connector; wherein said apparatus is configured to determine an impedance between said sense connectors. - View Dependent Claims (9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25)
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26. An RF ablation generator having a four-wire impedance measurement interface, comprising:
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an RF power source configured to produce an RF ablation signal across positive and negative source connectors; an excitation signal source configured to produce an excitation signal across said source connectors; and a complex impedance sensor coupled said positive and negative source connectors and to positive and negative sense connectors different from said source connectors and configured to determine a complex impedance across said sense connectors when said excitation signal is generated.
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Specification