Patents Assigned to American Cardiac Ablation Co., Inc.
  • Patent number: 6050267
    Abstract: A system for detecting the position of a catheter in a patient includes three sets of excitation electrodes, with one set disposed in each of three intersecting axes. A signal processor measures a voltage indicative of impedance between a detection electrode disposed on the catheter and each of the three sets of excitation signals in order to determine the X coordinate, Y coordinate and Z coordinate of the catheter. The detected position of the catheter is recorded and the detection of subsequent catheter positions is performed relative to the recorded catheter position. The difference between subsequent catheter positions and the recorded position relative to the X, Y and Z axes is displayed in order to facilitate repositioning of the catheter at the recorded position. Excitation electrode embodiments utilizing as few as four excitation electrodes are disclosed. The excitation electrodes may be surface, subcutaneous or intracardiac electrodes.
    Type: Grant
    Filed: February 4, 1998
    Date of Patent: April 18, 2000
    Assignee: American Cardiac Ablation Co. Inc.
    Inventors: Paul C. Nardella, Thomas A. Wrublewski
  • Patent number: 5944022
    Abstract: A system for detecting the position of a catheter in a patient includes three sets of reference electrodes, with one set disposed on each of the mutually orthogonal X, Y and Z axes. A signal processor measures the differential voltage indicative of impedance between a detection electrode disposed on the catheter and each electrode of each of the three sets of reference electrodes in order to determine the X coordinate, Y coordinate and Z coordinate of the catheter. The detected position of the catheter is recorded and the detection of subsequent catheter positions is performed relative to the recorded catheter position. The difference between subsequent catheter positions and the recorded position relative to the X, Y and Z axes is displayed in order to facilitate re-positioning of the catheter at the recorded position. Optional EKG and/or respiratory sensors may be used to synchronize the catheter position detection in order to reduce detection inaccuracies due to EKG and/or respiratory artifacts.
    Type: Grant
    Filed: April 28, 1997
    Date of Patent: August 31, 1999
    Assignee: American Cardiac Ablation Co. Inc.
    Inventors: Paul C. Nardella, Thomas A. Wrublewski
  • Patent number: 5437662
    Abstract: An electrosurgical probe is disclosed which provides the ability to both cut and cauterize tissue. The probe includes at least one cauterization electrode mounted upon a distal portion of the electrode and adapted to deliver electrosurgical energy to tissue. Further, a central lumen is disposed within the probe. The lumen is adapted to accommodate the flow of fluid from a remote source to tissue through an outlet port in the distal end of the probe. Also, the lumen houses a cutting electrode which is selectively deployable. Both cauterization and coagulation can be conducted in a bipolar mode. The flow of fluid through the lumen serves to limit the heat transfer from the cauterization electrode to adjacent tissue to an extent sufficient to prevent the sticking of tissue to the probe. A feedback system is also provided to optimize the electrode temperature.
    Type: Grant
    Filed: February 17, 1994
    Date of Patent: August 1, 1995
    Assignee: American Cardiac Ablation Co., Inc.
    Inventor: Paul C. Nardella
  • Patent number: 5383876
    Abstract: An electrosurgical probe is disclosed which provides the ability to both cut and cauterize tissue. The probe includes at least one cauterization electrode mounted upon a distal portion of the electrode and adapted to deliver electrosurgical energy to tissue. Further, a central lumen is disposed within the probe. The lumen is adapted to accommodate the flow of fluid from a remote source to tissue through an outlet port in the distal end of the probe. Also, the lumen houses a cutting electrode which is selectively deployable. Both cauterization and coagulation can be conducted in a bipolar mode. The flow of fluid through the lumen serves to limit the heat transfer from the cauterization electrode to adjacent tissue to an extent sufficient to prevent the sticking of tissue to the probe. In another embodiment the probe is adapted only for cauterization and does not include a cutting electrode.
    Type: Grant
    Filed: March 22, 1994
    Date of Patent: January 24, 1995
    Assignee: American Cardiac Ablation Co., Inc.
    Inventor: Paul C. Nardella
  • Patent number: 5357956
    Abstract: An ablation catheter has an ablation electrode at a distal end coupled to an ablation power source through a low impedance coupling. The ablation electrode also functions as a sensing electrode, for monitoring the endocardial signal and preferably also tissue impedance during the ablation procedure, and is coupled to an electrode monitor through a high impedance coupling. A timing element operates a plurality of switches to selectively isolate, dampen, or interconnect various signal paths during plural repetitive non-overlapping ablation and quiescent intervals which alternate at a rate substantially above a Nyquist sampling rate. RF energy is delivered to the ablation site during the ablation intervals. The local endocardial signal is measured during the quiescent intervals.
    Type: Grant
    Filed: November 13, 1992
    Date of Patent: October 25, 1994
    Assignee: American Cardiac Ablation Co., Inc.
    Inventor: Paul C. Nardella
  • Patent number: 5341807
    Abstract: A multi-electrode cardiac catheter has pairs of electrodes connected to sensing circuitry to produce a differential signal. The sensing output is sharply defined and self-normalizing. Preferably a catheter ablation tip electrode is an electrode of one pair, and the differential signal becomes non-zero when the tip contacts surrounding tissue. The shape of the differential signal provides information on the degree of electrode contact, as well as on the on the amount of locally-sensed tissue impedance change. The signal may be used as a trigger enable signal for a cardiac ablation catheter, and the applied level of RF power may be controlled based on the indicated degree of electrode contact and value of tissue impedance.
    Type: Grant
    Filed: June 30, 1992
    Date of Patent: August 30, 1994
    Assignee: American Cardiac Ablation Co., Inc.
    Inventor: Paul C. Nardella
  • Patent number: 5342357
    Abstract: An electrosurgical probe is disclosed which provides the ability to both cut and cauterize tissue. The probe includes at least one cauterization electrode mounted upon a distal portion of the electrode and adapted to deliver electrosurgical energy to tissue. Further, a central lumen is disposed within the probe. The lumen is adapted to accommodate the flow of fluid from a remote source to tissue through an outlet port in the distal end of the probe. Also, the lumen houses a cutting electrode which is selectively deployable. Both cauterization and coagulation can be conducted in a bipolar mode. The flow of fluid through the lumen serves to limit the heat transfer from the cauterization electrode to adjacent tissue to an extent sufficient to prevent the sticking of tissue to the probe. A feedback system is also provided to optimize the electrode temperature.
    Type: Grant
    Filed: November 13, 1992
    Date of Patent: August 30, 1994
    Assignee: American Cardiac Ablation Co., Inc.
    Inventor: Paul C. Nardella
  • Patent number: 5334193
    Abstract: A thin, elongate and flexible ablation catheter, suitable for delivery to an internal organ, comprises a fluid delivery lumen centrally located within the catheter, and first and second electrodes disposed on an outer surface of the catheter. The electrodes preferably are helically oriented about the catheter. At least one of the electrodes is in communication with a source of electrosurgical energy so as to deliver ablative electrosurgical energy to tissue. The lumen communicates with a fluid supply source such that fluid is conveyed through the lumen and is discharged to adjacent tissue during the delivery of ablative energy. The fluid delivered through the lumen assists in optimizing the electrode temperature. A method and apparatus is also provided to regulate the fluid flow rate based on monitored electrode temperature and/or tissue impedance.
    Type: Grant
    Filed: November 13, 1992
    Date of Patent: August 2, 1994
    Assignee: American Cardiac Ablation Co., Inc.
    Inventor: Paul C. Nardella
  • Patent number: 5293868
    Abstract: A cardiac ablation catheter includes a distal, energy delivering electrode and at least one sensing electrode proximal to the energy delivering electrode. The catheter communicates with an electrosurgical generator which provides electrical energy, such as a radio frequency energy, to the distal electrode. The sensing electrodes communicate with a monitor for recording electrical signals within the heart. One or more resistors is positioned adjacent each sensing electrode, and in series with a conductor associated with the sensing electrode, to reduce or eliminate any current tending to be emitted through the sensing electrodes as a result of delivery of electrical current through the distal electrode.
    Type: Grant
    Filed: June 30, 1992
    Date of Patent: March 15, 1994
    Assignee: American Cardiac Ablation Co., Inc.
    Inventor: Paul C. Nardella