A method and apparatus are provided for determining and tracking location of a metallic object in a living body, and then directing a second modality such as ultrasound waves to the determined location The metal detector may be a radar detector adapted to operate on a living body The adaption may include disposing a transfer material having electromagnetic properties similar to the body between the radar detector and the living body, ECG gating the radar detector, and/or employing an optimal estimator with a model of expected stent movement in a living body Applications include determination of extent of in-stent restenosis, performing therapeutic thrombolysis, or determining operational features of a metallic implant

Location tracking of a metallic object in a living body

A system and method to sense heart sounds with one or more implantable medical devices according to one or more parameters. The system alters one or more of the parameters as a function of one or more triggering events. The system then senses heart sounds with the one or more implantable medical devices according to at least the one or more altered parameters.

Adaptive sampling of heart sounds

A system comprising an implantable medical device (IMD) includes an implantable heart sound sensor to produce an electrical signal representative of at least one heart sound. The heart sound is associated with mechanical activity of a patient's heart. Additionally, the IMD includes a heart sound sensor interface circuit coupled to the heart sound sensor to produce a heart sound signal, and a signal analyzer circuit coupled to the heart sound sensor interface circuit. The signal analyzer circuit measures a baseline heart sound signal, and deems that an ischemic event has occurred using, among other things, a measured subsequent change in the heart sound signal from the established baseline heart sound signal.

Ischemia detection using a heart sound sensor

When monitoring a patient, acoustic events (e.g., coughs, snores, impact sounds, verbalizations, etc.) relevant to the patient's status are detected by a microphone array (12) and timestamped. Detected event signals generated by the microphone array (12) are filtered to identify signatures such as zero crossings, corner frequencies, amplitude, pitch, etc., for classification purposes. The filtered signals are digitized and classified into one of a plurality of acoustic event classes (e.g., snore, cough, wheeze, breath, etc.) and/or subclasses. The classified events are displayed to a user (e.g., graphically, textually, etc.) with their timestamps to indicate chronology. A user can review the acoustic events, select one or more events, and listen to a recording of the selected event (s). Additionally, specified acoustic events can trigger an alarm to alert a nurse or the like that the patient requires immediate attention.

Acoustical patient monitoring using a sound classifier and a microphone

A system for ablating tissue includes a catheter having an elongate body, with at least one ablation element (e g, RF electrode) and at least one acoustic transducer located within the body's tip region The transducer receives acoustic signals from proximate the tip region The system also includes a monitoring unit coupled to the transducer to interpret the received acoustic signals as data regarding at least one therapeutic parameter (e g, pre-pop detection, lesion making progress, tissue interface detection, tissue contact force, tissue contact establishment, bubble spatial distribution, bubble depth, bubble size, bubble size distnbution, tissue interface distance, tissue interface position, tissue attenuation, tissue thickness, lesion spectral fingerpπnt) The monitoring unit is operable to provide feedback to a practitioner, such as graphical, audible, and/or haptic output of sensed data, and may also be operable to control operation of the at least one ablation element in response thereto.

Apparatus and methods for acoustic monitoring of ablation procedures

A method and system of cardiac contractility analysis is provided. Cardiac contractility may include indices such as ejection fraction (EF) and rate of change in pressure (dP/dt) in a heart. Heart sounds may be measured and calibrated by attenuation. Likewise, a first acoustic peak in the first heart sound (S1), and a second acoustic peak of the second heart sound (S2) may be identified. The first heart sound (S1) may be calibrated by the second heart sound (S2). Amplitudes of calibrated heart sounds may be correlated to cardiac contractility. Electrical activity and acoustics of the heart are measured. The pre-ejection period of the cardiac cycle may be calculated. The left ventricular ejection time of the cardiac cycle may likewise be calculated. Then a ratio of pre-ejection period over left ventricular ejection time may be calculated and correlated to cardiac contractility. Pressure on the acoustic sensor may be used to calibrate acoustic data.

Systems and methods for cardiac contractility analysis

A tunable auscultation system includes a heart sound acquirer for sensing heart sounds from at least one chest location of the patient. An initial conditioner then conditions the heart sounds through pre-amplification and anti-aliasing. The heart sounds are transduced into electrical signals by a signal processor. The electric heart signals are then tuned by an analysis tool. The analysis tool includes an interaction tuner, a processing tuner and an output tuner. The interaction tuner includes a preset tuning selector and a dynamic range tuning selector. The processing tuner includes a band pass filter and an algorithmic extraction engine which applies extraction algorithms to the electric heart signals, segments them and extracts signals of interest. Signals of interest may be correlated to specific pathologies. The output tuner includes a signal strength indicator, a diagnosis indicator, an overlapping cardiac cycle display and a display configuration engine. A display module provides output.

Systems and methods for tuning, analysis and display of heart sounds

A method and system for determining systolic time intervals, by analysis of radio frequency (RF) scatter patterns in conjunction with Electrocardiogram (ECG) data, is provided. An RF emitter is placed on the cardiac patient. The emitter includes two or more transmitting antennas which emit RF radiation into the cardiac patient, resulting in an RF scatter pattern. An RF sensor receives the scattered RF signals. The RF emitted from the antennas will differ spatially with regard to the RF sensor, causing the RF scatter patterns to differ from one another. A signal processor analyzes these differences to identify inhomogeneous structures, and to identify aortic valve motion, including aortic valve opening and closure. An electrocardiogram identifies the onset of the cardiac cycle. Systolic intervals are determined using the onset of the cardiac cycle and the aortic valve motion. Cardiac contractility also is determined by correlation to systolic intervals. An acoustic sensor is used to verify the aortic valve closure.

Systems and methods for determining systolic time intervals

An auscultation system includes a transducer for generating an acoustic signal at a transducing location of the subject, and a sensor for receiving an attenuated acoustic signal at a sensing location of the subject The attenuated signal received at the sensing location is digitized, and may be analyzed in the frequency and/or time domain The comparison of the digitized attenuated signal against the initial transduced signal allows for the computation of the degree of acoustic attenuation between the transducing and sensing locations Acoustic attenuation may be utilized to generate an intensity ratio The ejection fraction of the heart subject may then be computed by correlation to the intensity ratio Pulse echo methods are also disclosed The echo transducer is oriented on the subject and generates a series of signal pulses.

Systems and methods for calibration of heart sounds

A heart gating system in which the heart sounds are used to generate the acquisition trigger signals This is possible because the various heart sound components have characteristics in the temporal domain to allow for distinguishing the S1's and S2's Hence, the individual heart sound components can be temporally distinguished and gating signals can be generated based on the identified heart sounds such as the S2 heart sound In addition, S1 also has a frequency spectrum different from that of S2 Hence, in another embodiment of the invention, the frequency characteristics of the heart sounds can be used to distinguish S1 from S2 The combined temporal and frequency characteristics of the heart sounds can also be used to distinguish S1 from S2 In addition, detecting carotid pulses and/or changes in thoracic cavity can also used to better distinguish between S1 and S2

Arvind Thiagarajan

Papers

Systems and methods for cardiac contractility analysis

Systems and methods for tuning, analysis and display of heart sounds

Systems and methods for determining systolic time intervals

Systems and methods for calibration of heart sounds

System and methods for gating heart signals