Abstract: A compact, portable ultrasound imaging system includes a combination of an isolation circuit, an ultrasound signal generator, and a beam former within a single unit. The isolation circuit may limit unintended, leakage current from the ultrasound system through the transducer array of the ultrasound system. The signal generator and beam-former may be implemented using large scale integration semiconductor chips. Connections are provided for connecting an ultrasound transducer array, for outputting ultrasound data and for receiving user input and commands.

Abstract: A medical imaging system is provided which includes a signal generator configured to obtain a trigger signal corresponding to a timing of interest, imaging equipment configured to obtain a plurality of images of a feature of interest, and a processor programmed to correlate the plurality of images with the trigger signal. Also provided is a method of correlating a plurality of medical images by obtaining a trigger signal of a timing of interest, obtaining a plurality of images of a feature of interest, and correlating the plurality of images with the trigger signal.

Abstract: A method for diagnosing and mapping atrial fibrillation correlates recordings of electrical activity from intracardiac multielectrode catheters with the locations of electrodes within the heart to obtain a global mapping of cardiac electrical activity. Time delay and/or amplitude information in the recorded electrical activities is fused with electrode location information to generate a display on a 3-D anatomical template of the heart. Time delay and/or amplitude information is displayed using color code and/or lines of equal value, to aid diagnosis and localization of electrical activity irregularities. Mapping of atrial fibrillation enables physicians to treat arrhythmia by ablation, pacing, shock therapy and/or drugs at initiation or during an episode based on therapy delivery at critical mapped locations for arrhythmia onset or maintenance. Locations for placement of pacing leads and pacemaker timing parameters may also be obtained from the display.

Abstract: A method and system for enhancing Doppler spectrum displays is described. Two or more colors are utilized to represent the power scale in the spectral Doppler display. Doppler signals from stronger reflectors of ultrasound, such as cardiac muscle or vessel walls, can then be assigned a different color than Doppler signals from weaker reflectors, such as blood, allowing for better understanding and interpretation of the Doppler spectra.

Abstract: A method and apparatus for enhancing evaluation of valvular function in terms of regurgitation is described. The techniques include a method and apparatus for monitoring flow across a valve and evaluating regurgitation through the valve. An ultrasound scanner with Doppler capabilities processes and represents Doppler signal data in a color scale. The Doppler signal data is processed such that different colors are assigned to signals that have different power levels. An ECG signal may be correlated to the Doppler signals to determine systole and diastole periods, then the regurgitation is determined by estimating a peak reverse blood flow based on Doppler signals from blood at systole. The Doppler signals may also be processed so as to determine a cardiac cycle, then regurgitation is determined as the ratio of a reverse blood flow as a percentage of a forward blood flow.

Abstract: A method and system for estimating the volume of blood ejected from the left ventricle of the heart to a succeeding chamber/conduit, or vice-versa, while imaging the intersection of such structures is described. The process utilizes either the M-mode to estimate volume differences in a view of the ventricle over time or Doppler processing techniques to obtain flow profiles across intersections (e.g., valves), or blood vessels, which are then utilized to calculate output. This process can be combined with ECG guidance/triggering to measure/track changes in output from beat to beat, or during the course of an evaluation or therapeutic procedure. This process can be specifically used for the placement of permanent pacemaker electrodes.

Abstract: A method and apparatus for processing ultrasound images is provided, including extracting an M-mode data set from the ultrasound images, discerning, from the M-mode data set, a first velocity for a first moving structure and a second velocity for a second moving structure, the second velocity being different from the first velocity, and differentiating between the first moving structure and the second moving structure based on the discerned velocities.

Abstract: An imaging system is provided with an ultrasound catheter and a controller coupled to the ultrasound catheter. The catheter includes a localizer sensor configured to generate positional information for the ultrasound catheter, and an imaging ultrasound sensor having a restricted field of view. The controller co-registers images from the imaging ultrasound sensor with positional information from the localizer sensor.

Abstract: An intra-cardiac imaging system that includes an ultrasound catheter that can image the left heart from within the right heart. The catheter has a proximal end, a distal end, and a lumen extending therebetween. The distal end includes an acoustic window longitudinally oriented and having a length of at least ten millimeters. A linear ultrasound transducer having an active surface is longitudinally mounted inside the lumen of the catheter at the distal end of the catheter adjacent the acoustic window. The active surface of the ultrasound transducer is directed toward the acoustic window, is approximately the same length as the acoustic window, and is capable of transmitting an ultrasound signal at a frequency of about 1.5 MHz to about 9 MHz.

Abstract: An ultrasound imaging system is provided with an interface for receiving user input, and a controller coupled to the interface, the controller being adapted and configured to adjust parameters for a catheter-based ultrasound probe in response to received user input. Preferably, the controller is programmed to receive a user request for a desired imaging depth, determine an imaging frequency that corresponds to the desired imaging depth, and adjust the imaging frequency of the system to the determined imaging frequency that corresponds to the desired imaging depth.

Abstract: Steerable catheters are provided including an elongated flexible member having a proximal end, a distal end and a lumen extending therebetween (i.e., between the proximal end and the distal end). A plurality of electrical cables is bundled together and positioned within the lumen of the flexible member. The cross-section of the bundle of electrical cables is substantially ovular or rectangular so as to be bendable in two approximately opposite directions. Methods of steering such a catheter within a body include advancing the catheter within a body while a first force is applied to the bundle of electrical cables to cause the distal end of the elongate flexible member to form a bend. The catheter is farther advanced within the body while a second, opposite force is applied to the bundle of electrical cables to remove the bend in the distal end.

Abstract: A peritoneal ultrasound imager includes an elongated body less than about 20 inches in length that is adapted to be inserted through a cannula into or near the pericardium space, and an ultrasound transducer array at one end of the body that is suitable for ultrasound echocardiography. The cannula and ultrasound imager may be of a single piece construction. A method for imaging the heart includes introducing a cannula into the wall of a patient's chest, inserting the elongated body into the cannula, moving the inserted elongated body to a position near the heart, and imaging the heart with ultrasound echo.

Abstract: An ultrasonic imaging catheter is disclosed that includes a thermistor mounted on the catheter in the vicinity of the ultrasound transducer for monitoring the temperature in the vicinity thereof. The electrical signal from the thermistor can be used to control the output of the ultrasound transducer to thereby control the temperature of the same. In a further aspect of the invention, an isolation box is provided that is external to the ultrasound machine itself and is connected to the same by a cable. Ideally, the isolation box which houses a sufficient number of isolation transformers, is small, so it can be placed easily on or near the patient's bed.

Abstract: A method and system for initializing a pacemaker includes receiving electrophysiology (EP) data from an intra-body EP catheter or catheters positioned relative to a patient's heart, calculating a patient specific pacemaker operating parameter or parameters from the received EP data and programming the pacemaker to operate based on the calculated patient specific pacemaker operating parameter or parameters. Stimulation of the patient's heart using the EP catheter or catheters based on the calculated pacemaker operating parameter or parameters may then be accomplished to determine whether the patient's heart achieves an acceptable physiological response when stimulated based on the calculated pacemaker operating parameter or parameters, and recalculation of the pacemaker operating parameter or parameters may be accomplished if the stimulation fails to achieve the acceptable physiological response.

Abstract: A system and method for limiting a temperature induced in a body by an ultrasound imaging catheter are provided. The method includes receiving, at an isolation box, an imaging signal from an imaging catheter, receiving, at an isolation box, a signal indicative of a temperature of tissue adjacent to the imaging catheter, removing power to the imaging catheter at the isolation box if the signal indicates the temperature of tissue adjacent to the imaging catheter exceeds a known value, and sending the imaging signal from the catheter to a processor if the signal indicates the temperature of tissue adjacent to the imaging catheter is less than the limit.

Abstract: An interface for limiting an amount of current passing to an intra-body medical device is provided, the interface including a first catheter port configured for coupling with a first catheter, a first processor port configured for coupling with a first cable linkable to a first processor, and a current isolator coupled to the first catheter port and to the first processor port, the current isolator limiting an amount of current passing to the first catheter port.

Abstract: A medical imaging system is provided which includes a signal generator configured to obtain a trigger signal corresponding to a timing of interest, imaging equipment configured to obtain a plurality of images of a feature of interest, and a processor programmed to correlate the plurality of images with the trigger signal. Also provided is a method of correlating a plurality of medical images by obtaining a trigger signal of a timing of interest, obtaining a plurality of images of a feature of interest, and correlating the plurality of images with the trigger signal.

Abstract: A catheter for facilitating intracardiac atrial defibrillation that includes an elongated flexible member that has a proximal end and a distal end is disclosed. Three spaced apart electrode arrays are secured around the periphery of the flexible member in a predetermined pattern so that a first electrode array is positioned within the superior vena cava, a second electrode array is positioned within the right atrium, and a third electrode array is positioned within the coronary sinus. Alternatively, the third electrode array may be positioned in the right ventricle rather than the coronary sinus. Electrical leads extend through the proximal end of the flexible member to supply electrical current to the electrode arrays, thereby defibrillating or cardioverting the heart. In other embodiments, a balloon envelope is also secured to the periphery of the flexible member adjacent the distal end.

Abstract: A method and system for estimating the volume of blood ejected from the left ventricle of the heart to a succeeding chamber/conduit, or vice-versa, while imaging the intersection of such structures is described. The process utilizes either the M-mode to estimate volume differences in a view of the ventricle over time or Doppler processing techniques to obtain flow profiles across intersections (e.g., valves), or blood vessels, which are then utilized to calculate output. This process can be combined with ECG guidance/triggering to measure/track changes in output from beat to beat, or during the course of an evaluation or therapeutic procedure. This process can be specifically used for the placement of permanent pacemaker electrodes.

Abstract: A catheter for facilitating intracardiac atrial defibrillation that includes an elongated flexible member that has a proximal end and a distal end is disclosed. Three spaced apart electrode arrays are secured around the periphery of the flexible member in a predetermined pattern so that a first electrode array is positioned within the superior vena cava, a second electrode array is positioned within the right atrium, and a third electrode array is positioned within the coronary sinus. Alternatively, the third electrode array may be positioned in the right ventricle rather than the coronary sinus. Electrical leads extend through the proximal end of the flexible member to supply electrical current to the electrode arrays, thereby defibrillating or cardioverting the heart.