Abstract:
A system and method for cardiac diagnosis and treatment inserts the distal end of a catheter (18) into a heart chamber. The distal end of the catheter (18) supports at least one electrode (22). The catheter (18) has a fluid flow conduit (62) extending through it. The conduit (62) has a valve (156) that prevents fluid flow from the heart chamber into the conduit (62) in response to in vivo pressure generated during heart systole and diastole. The valve (156) permits fluid flow from the conduit (62) into the heart at a pressure above the in vivo pressure. In use, the catheter (18) locates the electrode (22) in contact with a portion of the endocardium, and fluid is conducted from an external source through the conduit (62) at a pressure above the in vivo pressure to flush the area surrounding the electrode (22).
Abstract:
Systems (10) for ablating tissue measure the current and voltage delivered to the associated electrode assembly (16) and generate measured current and voltage signals. The systems (10) divide the measured voltage signal by the measured current signal to derive a measured tissue impedance signal. The systems (10) perform control functions based upon the measured tissue impedance signal.
Abstract:
A combination catheter for both detecting monophasic action potentials and ablating surface tissue in an in vivo heart of a patient is provided. The apparatus includes a catheter probe having a terminal tip portion (10) and an electrode (20) carried on the tip such that a portion of the tip electrode (20) is exposed to ambient. A reference electrode (50) is spaced along the tip from the first electrode for supplying a reference potential signal. An ablating electrode (30) is located adjacent to but electrically insulated from both the tip (20) and reference (50) electrodes for providing electromagnetic energy to the tip. The electrodes are electrically connected to the proximal end of the catheter through individual conductors or wires (22, 32 and 50) that run through an insulated cable. An electronic filter is provided to permit the recording of MAPs during ablation without radiofrequency interference. The catheter may also include standard mapping and/or pacing electrodes (80) and (75) respectively. The catheter may further include a steering mechanism for positioning the catheter at various treatment sites in the heart, and a structure for holding the tip electrode in substantially perpendicular contact with heart tissue with a positive pressure, and for spacing the reference electrode from the heart tissue.
Abstract:
An electrode assembly for use in inter-ventricular cardiac mapping includes one or more elongated splines (76) each of which carries a plurality of spaced apart electrodes (22) thereon. The body of each spline is formed of a plurality of alternating electrically conductive layers (86, 98) and the electrically nonconductive layers (88, 100). A separate electrically conductive pathway (94, 102) is provided to connect each of the electrodes to a different one of the conductive layers. Each of the layers is electrically connected to an electrical signal processing device (92) so that signals provided by each of the electrodes can be processed.
Abstract:
An improved assembly (10) for steering and orienting a functional element (20) at the distal end of a catheter tube (12) holds the functional element (20) with its major axis aligned with the axis of the catheter tube (12) for convenient steering to a tissue site. The mechanism can also pivot the functional element (20) in response to an external force to orient the major axis of the functional element generally parallel to the plane of the tissue site, without bending the catheter tube (12).
Abstract:
An improved assembly (10) for steering and orienting a functional element (20) at the distal end of a catheter tube (30) which holds the functional element (20) with its major axis (24) aligned with the axis of the catheter tube (30) for convenient steering to a tissue site (28). The mechanism can also pivot the functional element (20) in response to an external force to orient the major axis (24) of the functional element (20) generally parallel to the plane of the tissue site (28), without bending the catheter tube (30).
Abstract:
Systems for ablating tissue control radiofrequency power to an ablation electrode (16) by relying upon actual phase sensitive power measurements (72), unaffected by phase shifts between radiofrequency voltage and current. The systems also detect these phase differences (70), if they develop and integrate this factor (30) in making their control decisions.
Abstract:
An antenna assembly (10) has an energy propagating region (16) that is encapsulated in a material having a high dielectric constant for minimizing the loss of dissipating conductive heat patterns about the energy propagating region (16).
Abstract:
A catheter (10) has an electrode tip assembly (16) that is bendable at the selection of the user in two different directions. The electrode tip assembly (16) assumes a different predetermined curve configuration when bent in the two directions.