Abstract: An apparatus includes a generator including a control module that is operably coupled to a power module. The power module is configured to produce an electronic signal to be received by an ultrasonic energy delivery assembly. The ultrasonic energy delivery assembly is characterized by a natural frequency, and the electronic signal is characterized by a frequency. The control module is configured to send a control signal to the power module to randomly vary the frequency of the electronic signal within a range defined at least in part by the natural frequency.

Abstract: Methods, systems and devices for endometrial ablation. In accordance with a method, a working end of an RF ablation device is positioned in a patient uterus to contact endometrial tissue, the working end comprising a dielectric. Radiofrequency energy is applied for a first interval of time at constant power, the power being sufficient to capacitively couple current across the dielectric to the contacted endometrial tissue. A voltage parameter measured within the first interval, and radiofrequency energy is applied at a constant voltage over a second, treatment interval to ablate endometrial tissue, the constant voltage being related to the recorded voltage.

Abstract: A system and method are provided for assessing the compliance of internal patient tissue for purposes of catheter guidance and/or ablation procedures. Specifically, the system/method provides for probing internal patient tissue in order to obtain force and/or tissue displacement measurements. These measurements are utilized to generate an indication of tissue elasticity. In one exemplary embodiment, the indication of elasticity is correlated with an image of the internal tissue area and an output of this image including elasticity indications is displayed for a user.

Abstract: Methods, devices, and systems for predicting, diagnosing, and preventing adverse events during an ablation procedure are described. A method for providing ablation energy includes receiving a first signal based on biological activity of a tissue of a patient. The method further includes analyzing the first signal to yield a first data set, establishing a threshold parameter according to the first data set, and providing ablation energy for the ablation of a biological site.

Abstract: A pulse delivery system for producing a spark in tissue is disclosed. The system can include at least two electrodes having sharp surface features, where the at least two electrodes are electrically isolated from one another. The sharp features of the electrodes can be separated by a distance of about 2 to 20 mm. The system can also include a pulse generator for delivering pulsed voltage differences between the at least two electrodes. The pulsed voltage differences can producing a voltage difference ranging from about 2.5 kV to about 35 kV for a duration of about 50 ns to 3 ?s. The system can include a controller for determining whether the plurality of pulsed voltage differences produced a spark between the at least two electrodes. A method of producing a spark in tissue for both therapeutic and cosmetic, i.e., non-therapeutic, applications is also disclosed.

Abstract: An electrosurgical system includes an electrosurgical generator (1) including at least one source of radio frequency (RF) power, and a plurality of output connections (2, 3, 4), only one of the output connections at any one time being active in that it is able to receive radio frequency power from the source. The generator (1) includes selection means adapted to change the active output connection, and a controller adapted to control the supply of radio frequency power from the source to the active output connection. The system also includes a plurality of electrosurgical assemblies, each including an electrosurgical instrument (5, 6, 7) and a cable (8, 9, 10) connecting the electrosurgical instrument to one of the output connections (2, 3, 4). The electrosurgical instruments (5, 6, 7) each include a handswitch (17, 18, 19) adapted to send a signal to the generator (1) to change the active output connection.

Abstract: Disclosed herein are ablation systems and methods for providing feedback on lesion formation in real-time. The methods and systems assess absorptivity of tissue based on a degree of electric coupling or contact between an ablation electrode and the tissue. The absorptivity can then be used, along with other information, including, power levels and activation times, to provide real-time feedback on the lesions being created. Feedback may be provided, for example, in the form of estimated lesion volumes and other lesion characteristics. The methods and systems can provide estimated treatment times to achieve a desired lesion characteristic for a given degree of contact, as well as depth of a lesion being created. The degree of contact may be measured using different techniques, including the phase angle techniques and a coupling index.

Abstract: Devices and methods are disclosed for providing access to the pericardial cavity while reducing risk of myocardial damage. The methods include maintaining the positions of a puncture device and of a portion of a parietal pericardium relative to one other while delivering energy from the puncture device to create a channel through the pericardium. Additional embodiments disclosed include delivering a pulse or pulses of energy to the parietal pericardium and attempting to advance the puncture device through the parietal pericardium between deliveries of energy pulses.

Abstract: A method and apparatus for treating masses, such as prostate or breast cancer, or any other soft tissue cancerous or benign mass, employs a unique, three-dimensional software-controlled electronic amplifier array using arbitrary waveforms that dynamically and proportionally steer electrical currents by using two or more current vector paths, sequentially or simultaneously, through a mass containing electrically-conductive ionic solutions so as to obtain 100% thermal heating or hyperthermia through the mass, and destroying it with a minimally-invasive treatment which requires no radiation or chemotherapy which could be harmful to the patient.

Abstract: Treatment apparatus and methods for delivering energy at multiple selectable tissue depths as selected by a clinician. The treatment apparatus includes at least two electrodes that are electrically isolated from each other, which permits each electrode to be independently energized for selecting different treatment depths. The electrodes may be concurrently energized with high frequency energy of the same polarity in a monopolar mode to deliver energy at a relatively deep depth into a patient's tissue, or with high frequency energy of a different polarity in a bipolar mode to provide a shallower penetration depth. Alternatively, the depth of energy delivery may be modified by energizing less than all of the electrodes. The electrodes may be energized with high frequency energy of different phase relationships to deliver energy concurrently in both monopolar and bipolar modes with the phase difference determining a depth of energy delivery.

Abstract: The present disclosure relates to planar transformers including a plurality of circuit layers that are configured to reduce termination losses on at least one of the plurality of circuit layers. The plurality of circuit layers are stacked together in a first direction and include at least first and second circuit layers. The first and second circuit layers each include an electrically conductive trace forming at least one winding having a first termination portion and a second termination portion that are separated by a gap. The gaps of the first and second circuit layers are offset relative to each other in a second direction different from the first direction. The plurality of circuit layers may further include a third circuit layer, which includes an electrically conductive trace having a grounded portion that is disposed adjacent to at least one of the gaps of the first and second circuit layers.

Abstract: A sphincter tissue region is treated using a support structure sized for advancement into the anal canal. At least one electrode is carried by the structure. A mechanism is coupled to the electrode to move the electrode between a first position retracted in the support structure and a second position extended from the support structure through surface tissue to penetrate a subsurface tissue region at or near a sphincter in the anal canal. A cable is coupled to the electrode to conduct energy for application by the electrode to form a lesion in the subsurface tissue region.

Abstract: Electrosurgical systems and methods are described herein in which the temperature of a fluid within a body or joint space is determined and/or monitored despite the energy generated during treatment by an ablation probe. One or more temperature sensors are positioned along the probe proximally of the electrode assembly and measure the temperature of an electrically conductive fluid without being overly influenced by the surgical effect occurring proximate the electrode assembly. A controller automatically suspends energy delivery for one or more periods of time while the temperature is monitored.

Abstract: A control console is disclosed for controlling one or more medical devices. The control console communicates to at least one medical device, and at least one peripheral module associated with the medical device if needed. The control console has a microprocessor for processing data to direct an operation of the medical device.

Abstract: An electrosurgical system includes an energy applicator adapted to direct energy to tissue, an electrosurgical power generating source, and a surface-contact detection device. The surface-contact detection device is operably associated with the energy applicator. The surface-contact detection device is communicatively-coupled to the electrosurgical power generating source. The surface-contact detection device includes at least one optical transmitter to generate optical signals, a lens member configured to reflect optical signals generated by the optical transmitter when the lens member is disposed in contact with tissue, and at least one optical receiver to receive optical signals reflected by the lens member. The electrosurgical power generating source is adapted to transmit energy to the energy applicator when it is determined that the lens member is disposed in contact with tissue.

Abstract: A thermal ablation probe is described having one or more sensors for sensing at least one tissue parameter, such as temperature, fluctuation in temperature change, and/or rate of temperature change. The thermal ablation probe includes an elongated shaft and a head portion at a distal end of the elongated shaft. The head portion includes a sensing system having the one or more sensors for sensing the at least one tissue parameter. The head portion further includes one or more antennas configured to apply energy to tissue. The proximal end of the thermal ablation probe is configured for removable engagement with a thermal ablation system. The one or more sensors of the sensing system form at least one thermal ablation probe array or sensing platform. The thermal ablation probe array(s) can be in operative communication with a control system of the thermal ablation system for controlling the operation of the thermal ablation system in accordance with the at least one tissue parameter.

Abstract: A method of directing energy to tissue includes the initial steps of determining target tissue location and/or target tissue margins, positioning an ablation device for delivery of energy to target tissue, and introducing a material having a shape into a tissue region to be monitored. The material is adapted to change echogenic properties in response to heat. The method also includes the steps of applying energy to the ablation device, monitoring the material on a monitor, determining an echogenic response of the material, and terminating ablation if it is determined that the echogenic response of the material is outside a predetermined target tissue threshold.

Abstract: An electro-thermal apparatus configured to treat tissue is provided. The electro-thermal apparatus including an electrosurgical cable configured to couple to an electrosurgical energy source. The electrosurgical cable includes supply and return lines that are wound in a double helix arrangement around a dielectric insulator within the electrosurgical cable. An electro-thermal element is provided at a distal end of the electrosurgical cable. The electro-thermal element is in electrical communication with the supply and return lines via corresponding first and second conductive traces. The first and second conductive traces have a patterned geometry and resistivity configured to convert electrical energy provided by the supply and return lines to thermal energy for treating tissue.

Abstract: A method of directing energy to tissue includes the initial steps of determining target tissue location and/or target tissue margins, positioning an ablation device for delivery of energy to target tissue, and positioning one or more heat-sensitive optical probes into a tissue region to be monitored. Each heat-sensitive optical probe is adapted to utilize spectral properties of light to access one or more optical fiber portions of the heat-sensitive optical probe in response to heat.

Abstract: A medical device includes an energy-generating unit configured to produce energy for conduction through tissue to treat tissue. Waste heat produced by the energy-generating unit during energy production is conducted to tissue to facilitate treating tissue.

Abstract: An electrosurgical generator is disclosed. The generator includes a power supply operable to generate a DC voltage and a multi-pole, phase-shifted, pulse-width and/or frequency modulated RF output stage coupled to the power supply. The RF output stage includes a plurality of dual-pole circuits, each of the plurality of dual-pole circuits including first and second pairs of switching components. The generator also includes a controller configured to drive the first and second pairs of switching components of each of the plurality of dual-pole circuits at a predetermined phase-shifted frequency.

Abstract: Energy delivery systems and methods for treating tissue are disclosed that may include an energy generator, a cooled electrode device, and a controller connected to the energy generator. The controller may include a processor and may be configured to control power output by the cooled electrode device based on a measured impedance level of tissue at a target treatment site.

Abstract: A method and apparatus include determining a value of a parameter associated with operation of an electrosurgical probe having a particular probe design, and determining whether the value of the parameter is within a range of values that has been predetermined for the particular probe design to indicate that the probe is treating tissue in a desired manner. Power is delivered to the probe according to an algorithm based upon a determination that the value of the parameter is outside the range of values The algorithm delivers power in a pulsed profile including portions of low power and portions of high power. In one embodiment, the tissue treatment is ablation, the parameter is impedance, and the method limits tissue necrosis to less than 200 microns. In another embodiment, the tissue treatment is shrinkage, the parameter is temperature, and the method limits power delivery when the probe is not shrinking tissue.

Abstract: A method of modulating a physiological parameter of a patient is provided. The method includes disabling one or more pre-aortic ganglion cells within a pre-aortic ganglion and improving the physiological parameter. The method further includes destroying a pre-aortic ganglion cell to prevent regeneration.

Abstract: An electrosurgical system includes an electrosurgical probe connected to a control console, wherein the probe is capable of coagulating and ablating tissue depending on a selected operating mode. Before operating the system, probe-specific data stored in a memory device associated with the probe is read by a processing device in the console. The data includes source impedance values specific to a coagulation or cutting mode of operation. A constant duty cycle value for a modulated cutting mode also is provided. Depending on the operating mode selected, an RF generator adjusted to have a predetermined source impedance value provides a voltage value to the probe. During the duty-cycled mode, the RF generator generates an instantaneous voltage value output for a duty cycle portion that is less than 100% of a time period, which value is no less than a maximum continuous average voltage value for the electrosurgical probe.

Abstract: A surgical instrument includes a reusable base component including a handle and an electrically activatable modular component removably coupled to the base component. The modular component includes an end effector operable from the handle to treat tissue. The end effector is responsive to manipulation of the handle. A first energy storage component is disposed onboard the base component and is electrically coupled to a source of electricity. A second energy storage component is disposed onboard the modular component and is electrically insulated from the first energy storage component. The second energy storage component is arranged such that a current may be selectively induced in the modular component by delivery of electrical energy to the first energy storage component.

Abstract: Described herein is an apparatus for locally monitoring nerve activity that may be incorporated into a nerve ablation catheter. Such a catheter is equipped with magnetic sensing for both identifying nerves and assessing the success of the ablation. The catheter is also equipped with an ablation instrument for both stimulating and destroying nerve tissue.

Abstract: When a treatment instrument is connected to the corresponding device (electric scalpel device or ultrasonic wave generation device), the device (electric scalpel device or ultrasonic wave generation device) transmits information related to the type, mode, and setting of the treatment instrument to a system controller. Accordingly, if a new treatment instrument is used, the system controller can perform display information related to the new treatment instrument and control the new treatment instrument. Even when the system controller is used in combination with newly-developed electric cautery knife and other treatment instruments, the system controller can obtain fixed information related to the respective medical instruments, thus increasing the operationality. Even if wrong setting is performed outside the ratings of the instruments in the system controller, the instruments can be prevented from damage such as dielectric breakdown on the basis of the obtained fixed information.

Abstract: A system and method for optimizing tissue separation using modulated or duty cycle controlled waveforms on desiccated tissue, where the desiccated tissue has a high electrical impedance. In bipolar electrosurgical procedures, tissue separation is separated with the application of an electrical signal. When tissue does not completely separate and becomes desiccated, generator may generate a duty cycle controlled waveform with specified duty cycle and frequency or modulated waveform. Modulated waveform is generated by adding or multiplying one or more waveforms together. Modulated or duty cycle waveforms create power pulses with higher voltages and a low RMS value. Power pulses drive power and create heat in the high impedance tissue. The creation of heat helps to mobilize water content adjacent to the desiccated tissue. The heating and mobilization of water induces motion into the tissue and aids in the complete separation of tissue while keeping the RMS power low.

Abstract: Tissue ablation is carried out using insertion tube having at least one ablation electrode, a first temperature sensor disposed on the distal portion sufficiently proximate the ablation electrode to detect heat generated during the ablation procedure, a second temperature sensor disposed on the distal portion sufficiently distant from the ablation electrode to be unable to detect the heat, and electronic logic circuitry linked to the first temperature sensor and the second temperature sensor and programmed to compute a temperature differential between respective temperatures sensed by the first temperature sensor and the second temperature sensor when conveying the electromagnetic energy. Satisfactory contact status between the ablation electrode and the target tissue is indicated when the temperature differential exceeds a predetermined threshold.

Abstract: A system for performing an electrosurgical procedure at a surgical site is disclosed. The system includes a sensor configured to continually sense an electrical and/or a physical property of tissue at a surgical site and to generate a sensor signal as a function thereof. The system also includes a control module configured to process the sensor signal using a processor, an algorithm, and a map having one or more predetermined values. The control module is further configured to compare the sensor signal to a predetermined level to determine reliability of the sensor signal and to signal an electrosurgical generator in response to a reliable sensor signal such that the electrosurgical generator enters energy control mode, wherein the electrosurgical generator matches an output of the control signal with a predetermined value from the map.

Abstract: A system for providing feedback during an electrosurgical procedure on a target tissue is provided. The system includes an electrosurgical energy source; an electrode probe assembly connected to the electrosurgical energy source, wherein the electrode probe assembly includes at least one electrode assembly having a needle configured to deliver electrosurgical energy to the target tissue; at least one thermal feedback assembly connected to the electrosurgical energy source, wherein each thermal feedback assembly includes at least one temperature sensor assembly; and a hub configured to selectively support the electrode probe assembly and each thermal feedback assembly such that the needle of the electrode probe assembly and each temperature sensor assembly of each thermal feedback assembly are proximate one another when disposed proximate the target tissue.

Abstract: An apparatus comprises an external device for communication with an implantable device. The external device includes a communication circuit configured to receive a communication signal from at least one other device different from the implantable device, a locating circuit configured to determine a location of the external device using the received communication signal, and a control circuit electrically coupled to the communication circuit and the locating circuit. The control circuit is configured to determine whether the determined location imposes a limit on functionality of an implantable device, and provide user access to an implantable device feature according to the determined location.

Abstract: A system comprising a photoacoustic module, an ablation module, and a processor. The photoacoustic module includes a light emitter and an acoustic sensor. The acoustic sensor is configured to provide a sensor output corresponding to a modulated pressure detected in a target tissue in response to light from the emitter. The ablation module is associated with the photoacoustic module. The ablation module has an energy discharge port configured to contact the tissue at an ablation target and is configured to ablate the ablation target. The processor is coupled to the ablation module and coupled to the photoacoustic module. The processor is configured to execute an algorithm to provide an output signal indicative of the ablation progress and is configured to control the ablation module based on the sensor output.

Abstract: A surgical apparatus and method according to which a cable assembly is connected to a handpiece and includes a sensing element, and a member adapted to move relative to the sensing element to control the operation of a motor in the handpiece.

Abstract: The invention relates to an HF surgical instrument for treating, in particular for cutting and coagulating, biological tissue by means of an HF current. The HF surgical instrument comprises an HF generator for supplying an HF current to a cutting electrode and at least one control device for interrupting an HF current circuit. The control device comprises a current monitoring device, which detects the amplitude of the HF current and then generates a first switch-off signal when the HF current decreases over a defined period of time and/or the HF current falls below a threshold value characterizing a state of the treated tissue, as well as an arc monitoring device, which generates a second switch-off signal when an arc is formed between the cutting electrode and the tissue. The control device is configured in such a way that the HF current circuit is interrupted in response to the first switch-off signal or the second switch-off signal.

Abstract: A method of treating a complex rhythm disorder of a human heart includes identifying a region of a wall of the heart having an activation trail that is rotational or radially emanating, where the activation trail is indicative of the complex rhythm disorder and is based on activation times associated with one or more activations of the heart. A portion of the region is selected based on the activation trail and modified to affect the activation trail.

Abstract: A forceps includes an end effector assembly having first and second jaw members. One (or both) of the first and second jaw members is moveable relative to the other between a spaced-apart position and an approximated position for grasping tissue therebetween. One (or both) of the jaw members includes a jaw frame a disposable jaw housing and an elastomeric ring member. The disposable jaw housing is releasably engageable with the jaw frame. The elastomeric ring member is removably positionable about a distal end of the jaw housing. The elastomeric ring member is configured to define a gap distance between the first and second jaw members upon movement of the first and second jaw members to the approximated position.

Abstract: An electrosurgical system may generally first and second electrodes coupled to an energy source operative to generate and deliver pulses of a biphasic radio frequency (RF) waveform to treat undesirable tissue in a patient. The pulses may induce non-thermal cell death in the patient's tissue while causing no or minimal muscle contractions in the treated patient. The pulses may be grouped in bursts wherein the pulses within a burst repeat at a particular pulse frequency.

Abstract: A surgical instrument system includes a surgical instrument, a power supply, and an accessory. The surgical instrument has a first induction device positioned therein. The accessory is selectively operably couplable to the surgical instrument. The accessory includes a second induction device that is inductively coupled with the first induction device when the accessory is operably coupled to the surgical instrument such that the power supply provides power to the accessory.

Abstract: A method of performing an ablation procedure includes the steps of inserting an antenna assembly into tissue and supplying energy thereto for application to tissue. The method also includes the step of causing contact between a first material and at least one other material disposed within the antenna assembly to thermally regulate the antenna assembly. According to another embodiment, an ablation system includes an energy delivery assembly. A first chamber is defined within the energy delivery assembly and is configured to hold a first chemical. Another chamber is defined within the energy delivery assembly and is configured to hold at least one other chemical. The first chamber and the other chamber are configured to selectively and fluidly communicate with each other to cause contact between the first chemical and the at least one other chemical to cause an endothermic reaction and/or an exothermic reaction.

Abstract: A mechanism for authenticating a physiological sensor is disclosed. When a sensor is connected to a monitor, the monitor examines whether a first sensor-specific usage identifier of the connected sensor is consistent with a second sensor-specific usage identifier thereof. The first and second sensor-specific usage identifiers are indicative of the cumulative usage of the connected sensor, but may nevertheless be unequal. The first sensor-specific usage identifier is maintained in the sensor and the second sensor-specific usage identifier in a host memory external to the sensor. The use of the connected sensor is allowed when the examining indicates that the said two identifiers of the connected sensor are consistent, and rejected when the identifiers are inconsistent. The two identifiers are further updated in response to the use of the connected sensor in the patient monitor, thereby to keep the said identifiers consistent and updated for a subsequent use attempt of the sensor.

Abstract: A control console is disclosed for controlling one or more medical devices. The control console communicates to at least one medical device, and at least one peripheral module associated with the medical device if needed. The control console has a microprocessor for processing data to direct an operation of the medical device.

Abstract: An electrosurgical generator is disclosed. The generator includes an output stage configured to generate a waveform, a first input configured to adjust a cut setting representative of a cutting effect of the waveform, and a second input configured to adjust a hemostasis setting representative of a hemostasis effect of the waveform. The generator also includes a controller configured to receive cut and hemostasis settings and to adjust one of a duty cycle, a crest factor and a power level of the waveform to achieve a combined cutting and hemostasis effect based on the cut and hemostasis settings.

Abstract: An electronic apparatus includes a circuit portion that is configured to control an operation of the electronic apparatus and a heat-activated mechanical switch including, for example, a shape-memory material. The shape-memory material has a property such that the shape-memory material assumes a predetermined shape when the electronic apparatus is heated to a transition temperature. The shape-memory material disables the apparatus by acting on the circuit portion when the shape-memory material assumes the predetermined shape.

Abstract: A thermocouple measuring circuit for sensing a temperature at a measuring point is provided. The thermocouple measurement circuit (12) includes a thermocouple input for sensing a temperature at a measuring point, a compensation circuit (14) for compensating thermocouple effects of junctions of the thermocouple, and an instrumentation amplifier (16) for summing an output of the thermocouple and an output of the compensation circuit and outputting a voltage indicative of the temperature sensed, wherein the output of the compensation circuit is a reference voltage for the output of the instrumentation amplifier. Various embodiments of the thermocouple measurement circuit may be employed in electrosurgical generators for controlling output power dependent on temperature conditions.

Abstract: A method is provided for ablating brain tissue of a living mammal comprising: placing first and second electrodes in a brain of the living mammal; applying a plurality of electrical pulses through the first and second placed electrodes which are predetermined to: cause irreversible electroporation (IRE) of brain tissue of the mammal within a target ablation zone; and cause a temporary disruption of a blood brain barrier (BBB) within a surrounding zone that surrounds the target ablation zone to allow material in a blood vessel to be transferred to the surrounding zone through the temporarily disrupted BBB. Such methods are useful for delivering large molecule material within a blood vessel of the brain across the BBB, where the large molecule is otherwise blocked by the BBB from passing through the blood vessel into the brain.

Abstract: A system and method for performing electrosurgical procedures are disclosed. The system includes an electrosurgical generator adapted to supply electrosurgical energy to tissue in form of one or more electrosurgical waveforms having a crest factor and a duty cycle. The system also includes sensor circuitry adapted to measure impedance and to obtain one or more measured impedance signals. The sensor circuitry is further adapted to generate one or more arc detection signals upon detecting an arcing condition§. The system further includes a controller adapted to generate one or more target control signals as a function of the measured impedance signals and to adjust output of the electrosurgical generator based on the arc detection signal. An electrosurgical instrument is also included having one or more active electrodes adapted to apply electrosurgical energy to tissue.

Abstract: Devices and methods provide for ablation of cardiac tissue for treating cardiac arrhythmias such as atrial fibrillation. Although the devices and methods are often be used to ablate epicardial tissue in the vicinity of at least one pulmonary vein, various embodiments may be used to ablate other cardiac tissues in other locations on a heart. Devices generally include at least one tissue contacting member for contacting epicardial tissue and securing the ablation device to the epicardial tissue, and at least one ablation member for ablating the tissue. Various embodiments include features, such as suction apertures, which enable the device to attach to the epicardial surface with sufficient strength to allow the tissue to be stabilized via the device. For example, some embodiments may be used to stabilize a beating heart to enable a beating heart ablation procedure. Many of the devices may be introduced into a patient via minimally invasive introducer devices and the like.

Abstract: A system for measuring real-time tissue reflection spectral characteristics during ablation includes a catheter for collecting light reflected from tissue undergoing ablation, a detection component for separating constituent wavelengths of the collected light, a quantification apparatus for generating measured light intensity data of the collected light, and a processor for analyzing the data in relation to time. A method for monitoring formation of steam pop during ablation includes delivering light to tissue, delivering ablative energy to the tissue, measuring the reflectance spectral intensity of the tissue, and observing whether the measured reflectance spectral intensity (MRSI) initially increases in a specified time period followed by a decrease at a specified rate. If the MRSI does not decrease, delivery of ablation energy continues.