2208 results about "Maximum temperature" patented technology

Apparatus for forming a lesion in body tissue includes a probe having an active region with an electrode for contacting tissue to be treated, and an inactive region including an insulative sleeve around a portion of the electrode. The temperature of the inactive region is monitored using a temperature sensor. A controller supplies radio frequency energy to the electrode and samples signals from the temperature sensor. By performing a calculation using the sampled signals and a predetermined inactive region threshold temperature, and by adjusting the supplied radio frequency power, the inactive region of the probe can be maintained at or below an inactive region maximum temperature while the controller continues to supply radio frequency energy to the electrode. The probe has a second temperature sensor, mounted at a distal end of the electrode, the controller being configured to reduce the supplied radio frequency power when the electrode temperature reaches a predetermined maximum electrode temperature.

Systems and methods for estimating tissue parameters, including mass of tissue to be treated and a thermal resistance scale factor between the tissue and an electrode of an energy delivery device, are disclosed. The method includes sensing tissue temperatures, estimating a mass of the tissue and a thermal resistance scale factor between the tissue and an electrode, and controlling an electrosurgical generator based on the estimated mass and the estimated thermal resistance scale factor. The method may be performed iteratively and non-iteratively. The iterative method may employ a gradient descent algorithm that iteratively adds a derivative step to the estimates of the mass and thermal resistance scale factor until a condition is met. The non-iterative method includes selecting maximum and minimum temperature differences and estimating the mass and the thermal resistance scale factor based on a predetermined reduction point from the maximum temperature difference to the minimum temperature difference.

An embodiment of the invention includes a surgical device for coagulating soft tissue such as atrial tissue in the treatment of atrial fibrillation, atrial flutter, and atrial tachycardia; tendon or ligament shrinkage; or articular cartilage removal. The surgical device integrates a suction mechanism with the coagulation mechanism improving the lesion creation capabilities of the device. The surgical device comprises an elongate member having an insulative covering attached about conductive elements capable of coagulating soft tissue when radiofrequency or direct current energy is transmitted to the conductive elements. Openings through the insulative covering expose regions of the conductive elements and are coupled to lumens in the elongate member which are routed to a vacuum source. Suction causes the soft tissue to actively engage the opening thus the integrated, exposed conductive elements to facilitate the coagulation process and ensure the lesions created are consistent, continuous, and transmural. The embodiments of the invention can also incorporate cooling mechanisms associated with the conductive elements and coupled to a fluid source to passively transport fluid along the contacted soft tissue surface to cool thus pushing the maximum temperature deeper into tissue.