Abstract: Devices, systems and methods are disclosed for the ablation of tissue. Embodiments include an ablation catheter which has an array of ablation elements attached to a deployable carrier assembly. The carrier assembly can be constrained within the lumen of a catheter, and deployed to take on an expanded condition.

Abstract: Systems and methods for assessing electrode position, including positioning a plurality of electrodes within a heart and proximate a pulmonary vein; obtaining an impedance measurement from each of the plurality of electrodes; determining whether any of the plurality of electrodes is located within the pulmonary vein based at least in part on the obtained impedance measurements; and generating an indication if at least one of the plurality of electrodes is determined to be located within the pulmonary vein.

Abstract: A method and system for detecting microbubble formation during a radiofrequency ablation procedure. The method includes measuring an impedance of a pair of electrodes, at least one electrode in the pair of electrodes being coupled to a treatment assembly of a medical device. Radiofrequency ablation energy is transmitted between the pair of electrodes. The transmission of radiofrequency ablation energy between the pair of electrodes is terminated when after a predetermined period of time the measured impedance in either of the electrodes in the pair of electrodes is a predetermined percentage above a measured minimum impedance and a measured power is above a predetermined power threshold. An alert is generated indicating at least one of the formation and release of microbubbles proximate the pair of electrodes.

Abstract: Systems and methods for assessing tissue contact, including positioning an electrode adjacent a tissue region; delivering radiofrequency energy to the electrode, wherein the delivered radiofrequency energy is sufficient to ablate at least a portion of the tissue region; obtaining a plurality of impedance measurements from the electrode during the delivery of the radiofrequency energy; calculating a change in the impedance measurements over a pre-determined time period; and generating an alert if the calculated change is less than a pre-defined value.

Abstract: A method and system for detecting a short circuit during a radiofrequency ablation procedure. The method includes measuring an impedance of a pair of electrodes coupled to a treatment assembly of a medical device. Radiofrequency ablation energy is transmitted between the pair of electrodes. The transmission of radiofrequency ablation energy between the pair of electrodes is terminated when after a predetermined period of time the measured impedance in either of the electrodes in the pair of electrodes is below a predetermined threshold impedance value. An alert is generated indicating a short circuit between the pair of electrodes.

Abstract: Devices, systems and methods are disclosed for the ablation of tissue. Embodiments include an ablation catheter which has an array of ablation elements attached to a deployable carrier assembly. The carrier assembly can be constrained within the lumen of a catheter, and deployed to take on an expanded condition.

Abstract: An atrial ablation catheter and methods for its use. The endocardial catheter includes an electrode array particularly adapted to locate and ablate foci of arrhythmia which are required for sustained atrial fibrillation is provided. The array is easily deployed and retracted from the catheter, and presents a distally oriented electrode array that can be pressed against the wall of the atrium.

Abstract: A method of assessing a tissue ablation treatment, including positioning a medical device adjacent a target tissue; measuring a first impedance magnitude a first frequency with the medical device; measuring a first impedance phase at a second frequency with the medical device; ablating at least a portion of the target tissue with the medical device; measuring at second impedance magnitude at a third frequency with the medical device; measuring a second impedance phase at a fourth frequency with the medical device; comparing at least one of (i) the first and second impedance magnitudes and (ii) the first and second impedance phases; and providing an indication of the efficacy of the ablation treatment based at least in part on the comparison.

Abstract: A medical method, device, and system are provided, including advancing an ablation element of a medical device into contact with tissue to be treated, selecting a power level of energy to ablate the tissue, delivering energy at the selected power level to the ablation element, determining whether the ablation element is in continuous contact with the tissue, and reducing the selected power level when the ablation element ceases to be in continuous contact with the tissue.

Abstract: A medical method, device, and system are provided, including advancing an ablation element of a medical device into contact with tissue to be treated, selecting a power level of energy to ablate the tissue, delivering energy at the selected power level to the ablation element, determining whether the ablation element is in continuous contact with the tissue, and reducing the selected power level when the ablation element ceases to be in continuous contact with the tissue.

Abstract: A method of assessing lesion quality of an ablated tissue region comprising ablating at least a portion of the tissue region. The reactance of the ablated tissue region is measured. The lesion quality of the ablated tissue region is determined based on the measured reactance.

Abstract: A medical device is provided, including an ablation system with a generator, at least one ablation element, a patient return electrode, and a feedback system to verify and monitor the electrical connection between the generator and the patient return electrode, as well as contact of the patient return electrode with the patient. If an electrical connection is absent, intermittent, or of low quality, the medical device may also provide notice, a warning or alarm, and may also automatically cease ablation occurring at that time.

Abstract: Devices, systems and methods are disclosed for the ablation of tissue. Embodiments include an ablation catheter that has an array of ablation elements attached to a deployable carrier assembly. The carrier assembly can be constrained within the lumen of a catheter, and deployed to take on an expanded condition. The carrier assembly includes multiple electrodes that are configured to ablate tissue at low power. Additional embodiments include a system that includes an interface unit for delivering one or more forms of energy to the ablation catheter.

Abstract: Devices, systems and methods are disclosed for the ablation of tissue. Embodiments include an ablation catheter which has an array of ablation elements attached to a deployable carrier assembly. The carrier assembly can be constrained within the lumen of a catheter, and deployed to take on an expanded condition.

Abstract: An atrial ablation catheter and methods for its use. The endocardial catheter includes an electrode array particularly adapted to locate and ablate foci of arrhythmia which are required for sustained atrial fibrillation is provided. The array is easily deployed and retracted from the catheter, and presents a distally oriented electrode array that can be pressed against the wall of the atrium.

Abstract: A radio frequency tissue ablation system with a radio frequency generator, the generator comprising a radio frequency source, at least four independently controllable radio frequency outputs, a user interface and a controller configured to delivery radio frequency energy from the radio frequency source to the radio frequency outputs in one of at least two different output configurations in response to a configuration selection made through the user.

Abstract: An atrial ablation catheter and methods for its use. The endocardial catheter includes an electrode array particularly adapted to locate and ablate foci of arrhythmia which are required for sustained atrial fibrillation is provided. The array is easily deployed and retracted from the catheter, and presents a distally oriented electrode array that can be pressed against the wall of the atrium.

Abstract: The efficacy of a lesion produced between a pair of ablation electrodes is assessed by analyzing the time it takes for a pulse of energy to travel from one electrode to the other. During a first time period, a first pulse of energy is applied to a first electrode. The time it takes for the pulse to conduct through the tissue to a second electrode is determined. During a time period subsequent to the first time, a subsequent pulse of energy is applied to the first electrode and the time it takes for the subsequent pulse to conduct through the tissue to the second electrode is determined. Changes in the conduction times are monitored by calculating the difference between consecutive conduction times and comparing the difference to a preset value. If the difference is below the preset value the lesion is considered adequate.

Abstract: A catheter carries a plurality of electrodes, each with multiple thermal sensors attached and is used to position the electrodes proximal biological tissue. A processor responsive to each of the thermal sensors determines the temperature at the thermal-sensor/electrode junction. A display provides a graphic representation of the temperatures of the thermal-sensor/electrode junctions. An exemplary representation is a bar graph having the temperature of one thermal sensor at one end and the temperature of another thermal sensor at the other end. The length of the bar graph combined with the position of the bar graph relative to a temperature range region provides an indication of the position of the thermal-sensor/electrode junctions relative to the biological tissue. The processor also monitors the spread between the sensor temperatures and compares it to a threshold value. Base on the result of the comparison, the processor controls the power applied to the electrode.

Abstract: Upon initial use of a catheter, a power control system writes data indicative of the date/time of the initial use to a memory device carried by the catheter. During continued use of the catheter the power control system periodically determines the difference between the stored date/time and the current date/time. For electrophysiological catheters, the power control system allows for an electrical interface with the catheter electrodes only when the difference is less than a set time period. The electrical interface may include the provision of ablation energy from the power control system to the electrodes or the receipt of signals from the electrodes indicative of electrical activity sensed by the electrodes. Alternatively, the power control system may provide a visual or audible overtime indication when the difference is greater than the set time period.