Abstract: A method and system for assessing lesion formation in tissue is provided. The system includes an electronic control unit (ECU). The ECU is configured to acquire values for first and second components of a complex impedance between the electrode and the tissue, and to calculate an index responsive to the first and second values. The ECU is further configured to process the ECI to assess lesion formation in the tissue.

Abstract: A catheter includes a handle that advantageously limits the amount of torque that can be imparted to the body of the catheter. This advantageously reduces the likelihood of catheter failure, damage to tissue, or damage to medical devices introduced into the vasculature via the catheter. The catheter handle includes a grip portion that the practitioner manipulates in order to impart a torque and a torque transmitting portion operably coupled thereto that transmits the torque to the catheter body. A torque limiting mechanism decouples the torque transmitting portion from the grip portion, the body, and/or any pull wires when the torque imparted to the grip portion exceeds a torque threshold, thereby preventing excessive torques from being transmitted to the catheter body and/or pull wires. A practitioner may be able to adjust the torque threshold and may be able to disable the torque limiting mechanism.

Abstract: A body-surface mapping system is disclosed that uses a plurality of electrodes to map at least a portion of a human torso without having to adjust the positions of the electrodes. The body-surface mapping system energizes groupings or regions of electrodes, then compares and adjusts the current driven through each grouping or region of electrodes to produce near-uniform fields. The electrodes of the body-surface mapping system may be interconnected by wires capable of sensing interelectrode distances, such that the system can reconstruct a detailed model of a patient's torso surface. The body-surface mapping system may also use a catheter in addition to the body surface electrodes to compute both endocardial and epicardial voltage distributions.

Abstract: A system and method for assessing a degree of coupling between an electrode and tissue in a body is provided. Values for first and second components of a complex impedance (e.g., resistance and reactance or impedance magnitude and phase angle) between the electrode and the tissue are obtained. These values are used together with a standardization value indicative of a deviation from a reference standard by a parameter associated with at least one of the body, the electrode and another component of the system to calculate a coupling index that is indicative of a degree of coupling between the electrode and the tissue. The coupling index may be displayed to a clinician in a variety of ways to indicate the degree of coupling to the clinician. The system and method find particular application in ablation of tissue by permitting a clinician to create lesions in the tissue more effectively and safely.

Abstract: A method and system for assessing lesion formation in tissue is provided. The system includes an electronic control unit (ECU). The ECU is configured to acquire values for first and second components of a complex impedance between the electrode and the tissue, and to calculate an index responsive to the first and second values. The ECU is further configured to process the ECI to assess lesion formation in the tissue.

Abstract: A system and method for assessing a degree of coupling between an electrode and tissue in a body is provided. Values for first and second components of a complex impedance (e.g., resistance and reactance or impedance magnitude and phase angle) between the electrode and the tissue are obtained. From these values, a coupling index is calculated that that is indicative of a degree of coupling between the electrode and the tissue. The coupling index may be displayed to a clinician in a variety of ways to indicate the degree of coupling to the clinician. The system and method find particular application in ablation of tissue by permitting a clinician to create lesions in the tissue more effectively and safely.

Abstract: A pacemaker is disclosed that includes circuitry for monitoring the current and/or voltage delivered to the heart during a pacing pulse. A microprocessor connects to the monitoring circuitry and analyzes the current (and/or voltage) to determine when capture occurs. When capture occurs, the microprocessor terminates the pacing pulse to save energy. Conversely, if capture does not occur within a predetermined maximum time period, or if the pacing pulse amplitude falls below a predetermined threshold value, the processor immediately causes a safety pulse to fire to insure a regular beating of the heart. By monitoring the current and/or voltage delivered, and by permitting the pacing pulse width to be variable, the pacemaker of the present invention can closely track the pacing threshold of the patient with a minimum expenditure of energy.