Abstract: A power control system and method controls a power generator to vary the duty cycle of a power output provided to a delivery instrument for delivering that power to a site in a patient for ablation. The peak power can be raised and the duty cycle lowered to result in deeper lesions. However, the effective power is controlled so that it does not exceed a predetermined level. A power output having a higher peak power for producing deeper lesions can be obtained by using a lower duty cycle having a longer "off" period in order to deliver more power to the ablation site without overheating the delivery instrument. The maximum peak power that may be selected is determined in accordance with the structural limitations of the delivery instrument. The temperature of the delivery instrument is monitored, and the duty cycle is lowered when the temperature exceeds a predetermined maximum limit. After the instrument has cooled sufficiently, the duty cycle is then increased to its previous level.

Abstract: A catheter adapted to perform electrophysiological procedures comprises a body member, a manipulation handle attached to the proximal end of the body member for applying torque to the body member, the handle having a control knob adapted for control movements in a first plane and in a second plane simultaneously. A deflection control line is attached at its distal end to the distal portion of the catheter and its proximal end attached to the control device of the handle so that tension applied to the control line by sliding the control knob causes deflection of the distal portion of the catheter. A stiffening member is disposed within the body member of the catheter and is slidable, said stiffening member providing increased rigidity to the portion of the body member in which the stiffening member is located. Rotation of the control knob controls the position of the stiffening member in the body member.

Abstract: An electrogram analysis system and method for determining the quality of information gathered from electrical signals in biological tissue. The system comprises a catheter having an array of at least two electrodes at its distal end, the electrodes detecting electrical signals emanating from the site of origin and providing relayed signals to a processor. The processor processes the relayed signals into waveforms and computes a quality of the relayed signals. The quality of the relayed signals is used to select higher quality signals for further analysis, such as site of origin determination and mapping. The relayed signals from the electrodes may also be used to determine a quality for a particular electrode channel. When the invention is used in cardiac applications, the relayed signal quality may comprise two components--a channel quality and a beat quality.

Abstract: A steerable catheter comprising a resilient body member, a manipulation handle attached to the proximal end of the body member, a control wire extending from the handle to the distal end of the catheter for deflection control, and a pulley mechanism for controlling the movement of the control wire. Longitudinal movement of a slide element in the handle causes movement of the control wire and control over the deflection of the distal end of the catheter. The pulley mechanism is connected between the slide element and the control wire to provide greater mechanical advantage to effect deflection of the body member while enhancing deflection control resolution. A stiffening member is also disposed in the catheter body member and its position is controlled by the rotational motion of the slide element. The position of the pulley mechanism is not affected by rotational motion of the slide element.

Abstract: An energy delivery system and method controls the frequency of the power driving an ultrasonic device to achieve more efficient power delivery. During operation of the ultrasonic device to deliver power to a patient site, the system and method automatically sweeps the drive power through a frequency range, locates the series and parallel resonance frequencies, calculates the average of those frequencies and locks the power generator at that average frequency to drive the crystal. This frequency sweep procedure occurs automatically when the ultrasonic crystal is located at the patient site and the power generator operator presses the power-on switch to apply power. The method of tuning the power generator thus occurs when the crystal is at the site temperature and is transparent to the operator. The application of an external bio-layer to the crystal increases its bandwidth and its robustness.

Abstract: A steerable catheter comprising a resilient deflectable body member having an expandable electrode array at the distal end thereof, and a manipulation handle attached to the proximal end of the body member, the handle including an array deployment device. A mandrel is movable through the shaft of the catheter by control movements at the handle to deploy the array or collapse the array as selected. A displacement compensation system is operatively connected to the mandrel such that when the array is expanded, the compensation system biases the mandrel so keep the array expanded, even during instances of deflection of the distal end. Similarly, the displacement compensation system biases the mandrel to keep the array collapsed when that configuration is selected, even during instances of straightening of the catheter. The displacement compensation system also compensates for overturning the control device in the handle to protect the array and deployment systems.

Abstract: A locking mechanism for a steerable catheter, the catheter comprising a resilient body member having a restoring force that tends to maintain the body member at a predetermined orientation, and a manipulation handle including a control element and a second element movable in relation to one another and adapted for controlling the orientation of the body member. The locking mechanism maintains the selected deflection of the body member against the restoring force but permits a physician to overcome the locking force by moving the control element. The locking mechanism does not interfere with the other control movement of the handle. The locking device has a biasing member and a contact member mounted between the control element and the second element. The biasing member urges the contact member into frictional contact with one of the elements for holding the control element at the selected longitudinal position.

Abstract: A catheter adapted to perform electrophysiological procedures comprises a body member, a manipulation handle attached to the proximal end of the body member for applying torque to the body member, the handle having a control knob adapted for control movements in a first plane and in a second plane simultaneously. A deflection control line is attached at its distal end to the distal portion of the catheter and its proximal end attached to the control device of the handle so that tension applied to the control line by sliding the control knob causes deflection of the distal portion of the catheter. A stiffening member is disposed within the body member of the catheter and is slidable, said stiffening member providing increased rigidity to the portion of the body member in which the stiffening member is located. Rotation of the control knob controls the position of the stiffening member in the body member.

Abstract: A catheter includes a piezoelectric transducer mounted to the distal end of a catheter. In one embodiment, the piezoelectric transducer has the shape of a cylinder and in another embodiment, a convex shape with a mounting flange. In the cylindrical shape, a plurality of surface mounted temperature sensors are disposed within the piezoelectric transducer. The sensors are electrically insulated and a sealing technique prevents the leakage of body fluids from penetrating the interior of the catheter through the sensor bores. The cylindrical transducer is supported on mounting members so that it is accurately mounted and sealed while at the same time, the material used does not significantly dampen the transducer. The convex shape includes a temperature sensor at its tip.

Abstract: A system for monitoring temperature comprising a first thermocouple temperature sensor mounted to a catheter, the catheter also having a connector with a plurality of connecting devices for making the thermocouple signals available to external equipment. The connecting devices are formed of a material dissimilar to at least one of the thermocouple leads such that a second thermocouple is created at the connection point. The second thermocouple produces a second temperature signal that combines with the signal from the first thermocouple. A reference temperature sensor is mounted at the connector to sense the temperature at the connector and provide a reference temperature signal for use by a processor in correcting the combined temperature signal to derive the first thermocouple signal received from the connector.

Abstract: Electrophysiology catheter apparatus including at least one retractable control wire with a preformed curved resilient foot formed at the distal extremity, slidably advanced and retracted within a longitudinal lumen of a catheter tube for controllably anchoring to a selected endocardial heart tissue. The proximal end of the control wire is formed with a handle to be grasped to slidably advance the preformed resilient foot beyond the distal tip of a catheter to project laterally to contact the adjacent tissue.

Abstract: A catheter adapted to perform electrophysiological procedures comprises a body member, a manipulation handle attached to the proximal end of the body member for applying torque to the body member, the handle having a control knob adapted for control movements in a first plane and in a second plane simultaneously. A deflection control line is attached at its distal end to the distal portion of the catheter and its proximal end attached to the control device of the handle so that tension applied to the control line by sliding the control knob causes deflection of the distal portion of the catheter. A stiffening member is disposed within the body member of the catheter and is slidable, said stiffening member providing increased rigidity to the portion of the body member in which the stiffening member is located. Rotation of the control knob controls the position of the stiffening member in the body member.