Devices, systems, and methods for treating cardiac arrhythmia are disclosed herein. In some embodiments, devices, systems, and methods disclosed herein deliver interrogating energy to tissue at a position on a wall of an anatomical structure of a patient. If the devices, systems, and methods disclosed herein detect a change in electrical activity of the anatomical structure in response to the interrogating energy, the devices, systems, and methods disclosed herein can apply irreversible therapy to the tissue. In some embodiments, the change in electrical activity corresponds to slowing or termination of a detected arrhythmia

A laser can be controlled based on different tissue compositions, such as in real time. After a first time period, a first composition of a in vivo target site can be identified. Based on the first composition, a plurality of lasers can be controlled to emit light at a first wavelength where controlling includes activating a first combination of the plurality of lasers. After a second time period, a second composition of the in vivo target site different from the first composition can be identified. Based on the second composition, a plurality of lasers can be controlled to emit light at a second wavelength, such as can include activating a second combination of the plurality of lasers. The first combination of the plurality of lasers can be different from the second combination of the plurality of lasers.

A method for determining a characteristic of material at a target is provided. A target is illuminated with a pulsed light source. A fluorescence signal from the target when the pulsed light source is an “off” state is then sensed. Based on analysis of the fluorescence signal, a characteristic of material at the target is identified. A device can then be controlled based on the identified characteristic of the material at the target.

Disclosed herein is a system for ablating and characterizing tissue. The system comprises an ablation element configured to emit ablative energy toward a tissue of interest, an imaging apparatus configured to emit energy and collect imaging data including reflected signals from the tissue of interest, and a characterization application. The characterization application comprises a signal analyzer for analyzing the imaging data and determining one or more signal properties from the reflected signals, and a correlation processor configured to associate the one or more signal properties to pre-determined tissue signal properties of different tissue components through a pattern recognition technique. The pre-determined tissue signal properties are embodied in a database, and the correlation processor is configured to identify a tissue component and an ablation level of the tissue of interest based on the pattern recognition technique.

A surgical system is disclosed including an end effector, a control circuit, a closure member, and a firing member. The end effector includes a first jaw, a second jaw, and an electrode. The first jaw is rotatable relative to the second jaw between an open position and a close position to capture tissue therebetween. The electrode is configured to conduct a sub-therapeutic RF current to the tissue. The control circuit is operably coupled to the electrode. The control circuit is configured to measure impedance of the tissue over time based on the sub-therapeutic RF current. The closure member is configured to move the first jaw towards the second jaw at a closure rate based on the impedance of the tissue. The firing member is configured to move within the end effectors towards a fired position at a firing rate based on the impedance of the tissue.

Devices, systems, and methods for treating cardiac arrhythmia are disclosed herein. In some embodiments, devices, systems, and methods disclosed herein deliver interrogating energy to tissue at a position on a wall of an anatomical structure of a patient. If the devices, systems, and methods disclosed herein detect a change in electrical activity of the anatomical structure in response to the interrogating energy, the devices, systems, and methods disclosed herein can apply irreversible therapy to the tissue. In some embodiments, the change in electrical activity corresponds to slowing or termination of a detected arrhythmia.

An ablation catheter system includes: a catheter shaft; a balloon attached to the catheter shaft; a lumen extending through the catheter shaft in a longitudinal direction thereof and communicating with the interior of the balloon; a heating electrode and a temperature sensor provided in the interior of the balloon; a heater that applies electrical energy to the heating electrode; a pressure sensor; a balloon volume sensor; and a processor that calculates the estimated depth of ablation, using as variables, heating temperature of a generator, ablation time of the generator, a value of balloon pressure obtained from the pressure sensor and a value of balloon volume obtained from the balloon volume sensor.

A surgical instrument is disclosed. The surgical instrument comprises an end effector comprising an ultrasonic blade and a clamp arm. The clamp arm is movable relative to the ultrasonic blade to transition the end effector between an open configuration and a closed configuration to clamp tissue between the ultrasonic blade and the clamp arm. The surgical instrument further comprises an ultrasonic transducer configured to generate an ultrasonic energy output and a waveguide configured to transmit the ultrasonic energy output to the ultrasonic blade. The surgical instrument further comprises a control circuit, configured to detect an immersion of the end effector in a liquid and compensate for heat flux lost due to the immersion of the end effector in the liquid.

A method of controlling the temperature of an ultrasonic blade includes applying a power level to an ultrasonic transducer to achieve a desired temperature at an ultrasonic blade coupled to the transducer via an ultrasonic waveguide, inferring a temperature of the blade based on a voltage V.sub.g(t) signal and a current I.sub.g(t) signal applied to the transducer, comparing the inferred temperature of the blade to a predetermined temperature; and adjusting the power level to the transducer based on the comparison. In some aspects, the method includes measuring a phase angle φ between the voltage V.sub.g(t) and the current I.sub.g(t) and inferring the temperature of the blade from the phase angle φ. In some aspects, the method includes measuring an impedance Z.sub.g(t) equal to a ratio of the voltage V.sub.g(t) to the current I.sub.g(t) and inferring the temperature of the blade from the impedance Z.sub.g(t).

A system includes a laser catheter and a rotating optical member to receive a laser beam along an optical path and rotate to a selected position to redirect the laser beam from the optical path onto one or more selected optical fibers of a laser catheter, wherein a distal end of the laser catheter irradiates an endovascular structure.