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The accuracy of M-mode and 2D echocardiographic measurements of LV mass is limited. We hypothesized that real-time three-dimensional (RT3D) imaging may allow more accurate measurements. LV mass was calculated from 2D and RT3D images obtained in 21 consecutive patients. The RT3D data resulted in LV mass that correlated with cardiac magnetic resonance measurements better (r=0.90) than 2D (r=0.79). The 2D technique underestimated LV mass (bias 39%). RT3D showed only minimal bias (3%), and reduced the interobserver (37% to 7%) and intraobserver (19% to 8%) variability. RT3D imaging provides the basis for accurate and reliable measurement of LV mass.

Background Regional myocardial geometry, function, and perfusion status are critical variables for understanding infarction-induced left ventricle (LV) remodeling. Three-dimensional contrast echocardiography (3DCE) is uniquely suited to measure these parameters. We evaluate the ability of 3DCE to assess geometric changes in the normally perfused but hypocontractile borderzone myocardium (BZM) immediately after a myocardial infarction (MI) in an ovine model, and we compare 3DCE with two-dimensional contrast echocardiography (2DCE) in the long and short axis. Methods Four sheep were studied with 3DCE and 4 were studied using 2DCE, before and 30 minutes after an anteroapical MI. Each 3DCE data set was acquired over 18 consecutive cardiac cycles. The LV geometry was reconstructed and perfusion data spatially correlated, thereby constituting a 3D model of ventricular geometry and perfusion. The borderzone was defined as the contrast-perfused myocardium adjacent to the infarct. Results The 2DCE short-axis analysis demonstrated decreased curvature and decreased wall thickness in the borderzone after MI. These findings are consistent with increased BZM wall stress. However, the long-axis 2DCE analysis demonstrated increased BZM wall thickness and a surprising change in BZM concavity acutely after infarction. The 3DCE analysis confirmed these findings and added additional information regarding regional variability in BZM geometry that was not evident in the two orthogonal 2D views. Conclusions This study provides evidence that regional changes in BZM geometry are more complex than previously believed and are not necessarily indicative of increased regional stress. The superiority of 3DCE over 2DCE for assessing these changes is strongly supported.

Determination of ejection fraction (EF) in clinical practice typically involves manual tracing of endocardial borders. This method is time-intensive and highly dependent on image quality. Mitral annular displacement (MAD) has been shown to correlate well with EF. Previously, this method involved tedious analysis of M-mode tracings. We developed and studied a new technique that is ultrasound beam angle-independent for automated detection of MAD, based on a tissue tracking algorithm. A regression formula was derived in a study group to predict EF from MAD measurements and tested prospectively in a separate group of patients. We found that our technique provides accurate, ultra-fast estimation of EF with lower inter- and intraobserver variability when compared with manually traced biplane EF.

Background — Leaflet curvature is known to reduce mechanical stress. There are 2 major components that contribute to this curvature. Leaflet billowing introduces the most obvious form of leaflet curvature. The saddle shape of the mitral annulus imparts a more subtle form of leaflet curvature. This study explores the relative contributions of leaflet billowing and annular shape on leaflet curvature and stress distribution. Methods and Results — Both numerical simulation and experimental data were used. The simulation consisted of an array of numerically generated mitral annular phantoms encompassing flat to markedly saddle-shaped annular heights. Highest peak leaflet stresses occurred for the flat annulus. As saddle height increased, peak stresses decreased. The minimum peak leaflet stress occurred at an annular height to commissural width ratio of 15% to 25%. The second phase involved data acquisition for the annulus from 3 humans by 3D echocardiography, 3 sheep by sonomicrometry array localization, 2 sheep by 3D echocardiography, and 2 baboons by 3D echocardiography. All 3 species imaged had annuli of a similar shape, with an annular height to commissural width ratio of 10% to 15%. Conclusion — The saddle shape of the mitral annulus confers a mechanical advantage to the leaflets by adding curvature. This may be valuable when leaflet curvature becomes reduced due to diminished leaflet billowing caused by annular dilatation. The fact that the saddle shape is conserved across mammalian species provides indirect evidence of the advantages it confers. This analysis of mitral annular contour may prove applicable in developing the next generation of mitral annular prostheses.

Background. In this study we tested the hypothesis that delayed reperfusion of ischemic myocardium—too late to save myocytes—attenuates infarct expansion and improves collagen synthesis. Methods. The hypothesis was tested in a sheep model of anteroapical infarction that has no collateral blood flow to the area at risk. After coronary ligation or arterial occlusion for 1 or 6 hours, sheep had serial hemodynamic and quantitative echocardiographic studies before and after infarction and 2, 5, 8, and 12 weeks later. Hearts were examined by light and electron microscopy at 2 and 12 weeks; hydroxyproline and ratios of type I/III collagen were measured at 12 weeks. Results. After coronary occlusion, left ventricular (LV) function progressively decreased and size increased to form an anteroapical aneurysm. After 1 hour of ischemia, neither resting LV size nor function changed; the infarct contained a midmyocardial scar between epicardial and endocardial muscle. After 6 hours of ischemia, LV function was significantly better than that in nonperfused sheep. Two weeks after 6 hours of ischemia, no viable myocytes were visible by light microscopy, but electron micrographs showed rare intact nucleated myocytes with scarce cytoplasmic myofibrils. At the 12th week epicardial and endocardial myocytes reappeared in the infarct. Infarct collagen type I/III ratios were 1.2 in reperfused groups and 0.7 in nonperfused sheep. Conclusions. Delayed reperfusion causes loss and subsequent reappearance of ovine epicardial myocytes, improves collagen type I/III ratios, and attenuates LV dilatation and loss of function. One hypothesis to explain the reappearance of myocytes is that reperfusion partially reverses an incomplete apoptotic process.

An ultrasonic diagnostic imaging method and system are described for detecting abnormalities in the synchronicity of heart wall stimulation. Points on opposite sides of a chamber of the heart are identified in a starting ultrasound image, then tracked through at least a portion of the heart cycle. The changing positions of lines extending between pairs of the points are accumulated and displayed in a color kinesis display in which each color depicts the location of a line at a particular point in the cardiac cycle. In an illustrated example the points are tracked through the cardiac cycle by speckle tracking of the speckle pattern of the adjacent myocardial tissue, tracking specific anatomy, or tracking tissue texture.

A three dimensional ultrasonic diagnostic imaging system is operated to guide or observe the operation of an invasive medical device (30) in three dimensions. An interventional system (20) is used to operate the invasive medical device (30) and produces spatially-based information relating to the activity of the invasive medical device (30). The spatially-based information from the interventional system (20) is merged into the three dimensional ultrasonic image data to produce a live three dimensional image of the invasive medical device (30) or its activity. In one embodiment the locations where the activity of the invasive medical device (30) is performed is recorded and displayed in the three dimensional ultrasonic image. The three dimensional ultrasonic image may be shown as an anatomical volume rendered image or as a wire frame model (130) of the anatomy. In another embodiment an integrated three dimensional ultrasonic imaging and invasive device system is described.

Quantified measures of a volumetric object in the body can be made ultrasonically by acquiring concurrent biplane images of two different image planes of the object. Corresponding borders of the volumetric object are traced using automatic border detection. The border tracings are used in their planar spatial relationship to compute a graphical model of the volumetric object. The volume of the graphical model may be computed by the rule of disks, and a graphical or numerical display of the changing volume with time displayed. A user interface comprises both real time biplane images, the real time graphical model, and the quantified measures.

A three dimensional ultrasonic diagnostic imaging system is operated to guide or observe the operation of an invasive medical device (30) in three dimensions. The invasive medical device (30) is shown in a detailed ultrasonic image and the balance of the volumetric region (120) in which the device is located is shown in a wide field of view. The detailed and wide fields of view may be displayed separately or overlapping in spatial alignment on an image display (18). The wide field of view may be shown in two or three dimensions. A quantified display may be shown together with the wide and detailed anatomical displays. The detailed view may also be shown in an enlarged or zoomed format.

A system and method of ultrasound quantification acquires acoustic image data from anatomic locations distributed in more than 2 dimensions, and uses a segmentation algorithm to provide real-time volume measurements. A 2D array is used to acquire two orthogonal (bi-plane) 2D images simultaneously. The images are segmented individually to determine the volume borders using any number of acoustic algorithms. The borders from the two bi-plane images are mathematically combined to give a volume measurement. A control processor controls the system to thereby obtain instant feedback of the segmented image data and enhance the volume measurements of the image. The system and method is extended to a number of simultaneous 2D images and to a full 3D volume acquisition.

An ultrasonic apparatus and method are described in which a volumetric region of the body is imaged by biplane images. One biplane image has a fixed planar orientation to the transducer, and the plane of the other biplane image can be varied in relation to the fixed reference image. In a preferred embodiment one image can be rotated relative to the other, and can be tilted relative to the other. An image orientation icon is shown on the display screen together with the two biplane images depicting the relative orientation of the two planar images.

A system and method for controlling the heat of an ultrasonic transducer is disclosed. In the presently preferred embodiments, the operator selects one or more mutable system parameters of the ultrasound system which will be changed if either the temperature becomes too great, or at the operator's command, or both.

The objective of this study was to evaluate the efficacy of nicardipine, a dihydropyridine calcium channel antagonist, administered as an IV bolus dose to acutely decrease arterial pressure in anesthetized cardiac surgical patients. We performed a double-blind, randomized, self-controlled, dose-ranging study in 40 adult cardiac surgical patients to determine the pharmacokinetics and pharmacodynamics of nicardipine 0.25 mg, 0.50 mg, 1.00 mg, and 2.00 mg administered as an IV bolus. Transesophageal echocardiography was used to assess left ventricular preload, afterload, and global systolic function. Plasma nicardipine concentration was measured using high-performance liquid chromatography. Nicardipine selectively decreased arterial pressure in a dose-dependent manner with a maximum response within 100 s and recovery to half the maximum response within 3‐7 min without associated changes in heart rate. The decreases in arterial pressure were associated with only small decreases in left ventricular end-systolic wall stress and small increases in global left ventricular systolic function without changes in left ventricular end-diastolic cavity area or cardiac output. The time course for nicardipine bolus was consistent with a two-compartment pharmacokinetic model with rapid redistribution from a small central compartment. Implications: Nicardipine was effective for selectively decreasing arterial blood pressure acutely, but had no effects on ventricular preload or cardiac output. The absence of dose-dependent changes in cardiac output, left ventricular systolic performance, and left ventricular afterload despite significant decreases in arterial pressure suggested that nicardipine had a small negative inotropic action. (Anesth Analg 1999;89:1116 ‐23)

Objectives Safe and effective device closure of ventricular septal defects remains a challenge. We have developed a transcardiac approach to close ventricular septal defects using a patch delivery and fixation system that can be secured under real-time three-dimensional echocardiographic guidance. Methods In Yorkshire pigs (n = 8) a coring device was introduced into the left ventricle through a purse-string suture placed on the left ventricular apex, and a muscular ventricular septal defect was created. The patch deployment device containing a 20-mm polyester patch was advanced toward the ventricular septal defect through another purse-string suture on the left ventricular apex, and the patch was deployed under real-time three-dimensional echocardiographic guidance. The anchor delivery device was then introduced into the left ventricle through the first purse-string suture. Nitinol anchors to attach the patch around the ventricular septal defect were deployed under real-time three-dimensional echocardiographic guidance. After patch attachment, residual shunts were sought by means of two-dimensional and three-dimensional color Doppler echocardiography. The heart was then excised, and the septum with the patch was inspected. Results A ventricular septal defect was created in the midventricular (n = 4), anterior (n = 2), and apical (n = 2) septum. The mean size was 9.8 mm (8.2–12.0 mm), as determined by means of two-dimensional color Doppler scanning. The ventricular septal defects were completely closed in 7 animals. In one a 2.4-mm residual shunt was identified. No anatomic structures were compromised. Conclusions Beating-heart perventricular muscular ventricular septal defect closure without cardiopulmonary bypass can be successfully achieved by using a catheter-based patch delivery and fixation system under real-time three-dimensional echocardiographic guidance. This approach might be a better alternative to cardiac surgery or transcatheter device closure.

ObjectiveStereoscopic vision display technology has been shown to be a useful tool in image-guided surgical interventions. However, the concept has not been applied to 3-dimensional echocardiography-guided cardiac procedures. We evaluated stereoscopic vision display as an aid for intracardiac navigation during 3-dimensional echocardiography-guided beating-heart surgery in a model of atrial septal defect closure.MethodsAn atrial septal defect (6 mm) was created in 6 pigs using 3-dimensional echocardiography guidance. The defect was then closed using a catheter-based patch delivery system, and the patch was attached with tissue mini-anchors. Stereoscopic vision was generated with a high-performance volume renderer with stereoscopic glasses. Three-dimensional echocardiography with stereoscopic vision display was compared with 3-dimensional echocardiography with standard display for guidance of surgical repair. Task performance measures for each anchor placement (N = 32 per group) were completion time, trajectory of the tip of the anchor deployment device, and accuracy of the anchor placement.ResultsThe mean time of the anchor deployment for stereoscopic vision display group was shorter by 44% compared with the standard display group: 9.7 ± 0.9 seconds versus 17.2 ± 0.9 seconds (P < .001). Trajectory tracking of the anchor deployment device tip demonstrated greater navigational accuracy measured by trajectory deviation: 3.8 ± 0.7 mm versus 6.1 ± 0.3 mm, 38% improvement (P < .01). Accuracy of anchor placement was not significantly different: 2.3 ± 0.3 mm for the stereoscopic vision display group versus 2.3 ± 0.3 mm for the standard display group.ConclusionStereoscopic vision display combined with 3-dimensional echocardiography improved the visualization of 3-dimensional echocardiography ultrasound images, decreased the time required for surgical task completion, and increased the precision of instrument navigation, potentially improving the safety of beating-heart intracardiac surgical interventions.