173 results about "Endocardium" patented technology

A leadless cardiac pacemaker having a radial fixation mechanism is provided. The cardiac pacemaker can include fixation mechanism separate from a pacing electrode and having a diameter equal to or less than the outer diameter of the pacemaker. The fixation mechanism can allow the pacemaker to be inserted into tissue with less than 2 rotations of the pacemaker to place the pacing electrode in contact with the tissue. In some embodiments, the fixation mechanism can comprise a plurality of hooks or protrusions positioned near a distal portion of the pacemaker. The fixation mechanism(s) can be configured to penetrate the endocardium of the patient and reside mostly within the myocardium. Methods of delivering the leadless cardiac pacemaker into the heart are also provided.

A system (10) for determining electrical potentials on an endocardial surface of a heart is provided. The system includes a non-contact, non-expandable, miniature, multi-electrode catheter probe (12), a plurality of electrodes (32) disposed on an end portion (30) thereof, means for determining endocardial potentials (14) based on electrical potentials measured by the catheter probe, a matrix of coefficients that is generated based on a geometric relationship between the probe surface, and the endocardial surface. A method is also provided.

A method and system for generating a patient specific anatomical heart model is disclosed. Volumetric image data, such as computed tomography (CT) or echocardiography image data, of a patient's cardiac region is received. Individual models for multiple heart components, such as the left ventricle (LV) endocardium, LV epicardium, right ventricle (RV), left atrium (LA), right atrium (RA), mitral valve, aortic valve, aorta, and pulmonary trunk, are estimated in said volumetric cardiac image data. A patient specific anatomical heart model is generated by integrating the individual models for each of the heart components.

A method for automatic left ventricle segmentation of cine short-axis magnetic resonance (MR) images that does not require manually drawn initial contours, trained statistical shape models, or gray-level appearance models is provided. More specifically, the method employs a roundness metric to automatically locate the left ventricle. Epicardial contour segmentation is simplified by mapping the pixels from Cartesian to approximately polar coordinates. Furthermore, region growing is utilized by distributing seed points around the endocardial contour to find the LV myocardium and, thus, the epicardial contour. This is a robust technique for images where the epicardial edge has poor contrast. A fast Fourier transform (FFT) is utilized to smooth both the determined endocardial and epicardial contours. In addition to determining endocardial and epicardial contours, the method also determines the contours of papillary muscles and trabeculations.

The present invention discloses an endocardial three-dimensional guide system and guide method. Said system includes excitation device, three pairs of excitation electrodes, catheter position signal obtaining device, respiratory impedance regulating device and cardiac chambers mechanical external form synchronization device. Said excitation device contains digital control logic and constant-current generation module. The above-mentioned catheter position signal obtaining device includes catheter, positioning amplifier, A/D converter, digital demodulator and coordinate converter. Said respiratory impedance regulating device includes body surface electric field signal collecting circuit, positioning amplifier, A/D converter, respiratory data extraction module and respiratory correction module.

An injector apparatus and associated methods for safely and repeatedly delivering an injectate at a predefined depth into the myocardium of the heart may be catheter-based or implemented in a handheld unit for use in open chest procedures. The injector includes a body, a stabilizer secured to a distal end of the body for stabilizing the distal end of the body relative to the myocardium, and a needle that may be controllably advanced from the distal end of the body into the myocardium. The stabilizer employs any suitable technique for stabilizing the distal end of the catheter body relative to the myocardium while the heart is beating. An enlarged region disposed along the needle functions as a stop to prevent the needle from being advanced into the myocardium beyond a desired penetration depth. To make an injection, the physician brings the distal end of the body in proximity to the endocardium or the epicardium using any suitable technique, actuates the stabilizer to stabilize the distal end relative to the myocardium; and advances the needle into the myocardium. Advancement of the needle into the myocardium is impeded by the enlarged region, thereby placing the needle tip at the desired penetration depth and avoiding puncturing of the heart. The injection is then made, and the needle and catheter are removed.

A method and apparatus for improving blood flow to an ischemic region (e.g., myocardial ischemia) a patient is provided. An ultrasonic transducer is positioned proximate to the ischemic region. Ultrasonic energy is applied at a frequency at or above 1 MHz to create one or more thermal lesions in the ischemic region of the myocardium. The thermal lesions can have a gradient of sizes. The ultrasound transducer can have a curved shape so that ultrasound energy emitted by the transducer converges to a site within the myocardium, to create a thermal lesion without injuring the epicardium or endocardium.

A method is provided for segmenting an image of interest of a left ventricle. The method includes determining a myocardium contour according to a graph cut of candidate endocardium contours, and a spline fitting to candidate epicardium contours in the absence of shape propagation. The method further includes applying a plurality of shape constraints to candidate endocardium contours and candidate epicardium contours to determine the myocardium contour, wherein a template is determined by shape propagation of a plurality of images in a sequence including the image of interest in the presence of shape propagation.

A method for assessing cardiac function using an ultrasound imaging catheter system includes positioning an ultrasound catheter so the ultrasound transducer can image a ventricle, obtaining images of the ventricle at two or more times within the cardiac cycle, recognizing an edge of the endocardium, measuring dimensions of the ventricle, calculating a volume or area of the ventricle at the two or more points in the cardiac cycle, and calculating the ejection fraction based upon the difference in volume or area at the two or more times in the cardiac cycle. The method can be used to determine a location for an intervention, such as placement of a pacemaker pacing lead, and may be performed before and after an intervention to assess the impact of the treatment on cardiac function.

Methods and process for detection of myocardial ischemia involve detection and analysis of changes in electrical conduction velocity within the heart to monitor changes in the condition of the cardiac muscle and indicate possible ischemia. Conduction velocity slows considerably when oxygen supply to the heart is reduced. Analysis of electrical conduction velocity can be used to verify the occurrence of myocardial ischemia in a more reliable manner. Changes in conduction velocity may be monitored based on conduction time between electrodes positioned in the left and right ventricles of the heart. The electrodes may be endocardial or epicardial electrodes. In general, the techniques may involve launching a stimulation waveform at one electrode and sensing a local cardiac depolarization at another electrode to assess conduction time.

A method for cardiac segmentation in magnetic resonance (MR) cine data, includes providing a time series of 3D cardiac MR images acquired at a plurality of phases over at least one cardiac cycle, in which each 3D image includes a plurality of 2D slices, and a heart and blood pool has been detected in each image. Gray scales of each image are analyzed to compute histograms of the blood pool and myocardium. Non-rigid registration deformation fields are calculated to register a selected image slice with corresponding slices in each phase. Endocardium and epicardium gradients are calculated for one phase of the selected image slice. Contours for the endocardium and epicardium are computed from the gradients in the one phase, and the endocardium and epicardium contours are recovered in all phases of the selected image slice. The recovered endocardium and epicardium contours segment the heart in the selected image slice.

A method and system for measuring the volume of the left ventricle (LV) in a 3D medical image, such as a CT, volume is disclosed. Heart chambers are segmented in the CT volume, including at least the LV endocardium and the LV epicardium. An optimal threshold value is automatically determined based on voxel intensities within the LV endocardium and voxel intensities between the LV endocardium and the LV epicardium. Voxels within the LV endocardium are labeled as blood pool voxels or papillary muscle voxels based on the optimal threshold value. The LV volume can be measured excluding the papillary muscles based on the number of blood pool voxels, and the LV volume can be measured including the papillary muscles based on the total number of voxels within the LV endocardium.

A method for cardiac segmentation includes providing a plurality of digitized medical images, each image comprising a plurality of intensities corresponding to a domain of points on an 2-dimensional grid, the plurality of images forming a sequence of cardiac images acquired at different time points, filtering noise from the sequence of images, approximating the endocardium with a first circle, approximating the epicardium with a second circle, finding candidate points for the endocardium, finding candidate points for the epicardium, and interpolating gaps between points of the endocardium and between points of the epicardium wherein the myocardium is segmented.