Dynamic three-dimensional echocardiographic reconstruction of the intact human left ventricle: technique and initial observations in patients.
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Adult↗
Biomedical subjects
D A Conetta
Publications and source records attributed to D A Conetta.
Echocardiographic analysis of systolic and diastolic left ventricular wall motion during transient myocardial ischemia.
Left ventricular (LV) wall motion (anterior and posterior) and simultaneous LV pressure were recorded during 30-second left anterior descending (LAD) or circumflex (CX) coronary artery occlusions in open-chest dogs to provide an echocardiographic model of the evolution of wall motion changes during myocardial ischemia. Prominent diastolic echocardiographic motion changes of progressive decrease in LV wall rapid-filling velocities (RFS), slow-filling velocities (SFS), and increased end-diastolic diameter were accompanied by a marked increase in initial and end-diastolic pressures (150% and 70%, respectively; all p less than 0.05). Early (within ten seconds) and progressive decrease in rat (SES), amplitude (E), and duration (TTR) of systolic motion were noted with an increased systolic diameter (p less than 0.05). Ischemic regions developed a characteristic pattern with early relaxation followed by a diastolic inward motion (DIM). These observations confirm and extend other investigators' findings on the motion of the ischemic myocardium and may be applicable to responses to transient myocardial ischemia noted in humans.
Animals↗
Effects of transient regional ischemia on left ventricular diastolic function.
Simultaneous left ventricular echograms and high-gain pressure recordings were made during 30 s of regional myocardial ischemia induced by snare occlusions of the proximal left anterior descending (LAD) or left circumflex (LCx) coronary arteries in open-chest dogs. Left ventricular diastolic diameter (d) and pressure (p) were measured during slow filling. A normalized (for diameter D) distensibility estimate (DE = delta d/delta p/D) was calculated, as were slow filling slopes (SFSs) of the septum and posterior wall. After occlusion, significant (p less than 0.05) decreases of DE and anterior and posterior left-ventricular-wall mid-diastolic normalized slow-filling slopes (ASFS/D and PSFS/D) were observed. Correlations were noted between percentage decreases of DE and ASFS/D (r = 0.69, p less than 0.0001) and PSFS/D (r = 0.62, p less than 0.0001). No significant differences between decreases of DE and SFS were noted between ischemic and non-ischemic regions. Transient regional myocardial ischemia was associated with a generalized alteration in left ventricular filling patterns in mid-diastole.
Animals↗
A framework for three-dimensional time-varying reconstruction of the human left ventricle: sources of error and estimation of their magnitude.
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Cardiac Volume↗
Effect of graded narrowing of left main coronary artery on left ventricular function.
The relationship between left ventricular function and coronary blood flow was studied in 16 chloralose-anesthetized dogs with an intact coronary circulation and left ventricle. Left ventricular dimensions, hemodynamic function indices, and coronary blood flow were measured simultaneously as the origin of the left coronary artery was narrowed by a calibrated snare. With a left coronary blood flow reduction of 17% (average), left ventricular minor axis diameter increased and maximum aortic blood flow acceleration and maximum rate of rise of left ventricular pressure decreased. Other measured indices of ventricular function did not change significantly. Larger coronary flow decrements caused a decrease in aortic systolic and diastolic pressures, stroke volume and cardiac output and an increase in heart rate and left ventricular end-diastolic pressure. These results confirm a close relationship between left ventricular function and blood supply.
Animals↗
Intracardiac M-mode echocardiography for continuous left ventricular monitoring: method and potential application.
Because no accurate and readily applied method exists for continuous recording of left ventricular cavity dimensions and wall motion in man, we designed a catheter-mounted echocardiographic probe. The purpose of this report is to describe the instrumentation, technique, limitations, complications and preliminary observations employing the probe in humans. The echo transducer built into a cardiac allowed positioning in the right heart under fluoroscopy. The echo signals permitted continuous left ventricular cavity measurements at rest and during maneuvers. Our results suggest that intracardiac echo may be able to provide clear definition of motion patterns of the mitral valve and left ventricular walls. The ultrasonic catheter is an instrument that potentially offers a new technique for continuous monitoring of left ventricular size and motion.
Cardiac Catheterization↗
Echocardiographic analysis of systolic and diastolic left ventricular wall motion in normal man.
Although the motion of the left ventricular wall has been examined by angiographic and by echocardiographic studies in both experimental animals and in man, there are no complete studies of the motion of the left ventricular posterior wall throughout the entire cardiac cycle. Because the posterior wall can be demonstrated echocardiographically in essentially all patients, it offers a potential of wide clinical application in the evaluation of left ventricular function. This study was undertaken to provide a detailed inclusive analysis of the motion of the left ventricular posterior wall. In 64 human volunteers the echocardiographic movements of the left ventricular posterior wall were identified. Using the R wave of the electrocardiogram as a reference and to identify phases of the cardiac cycle, each movement of the left ventricular posterior wall was temporally related to aortic or mitral valvular movements (or both). In a subset of 14 subjects, dual M-mode echocardiograms confirmed the validity of these temporal relationships. In three subjects, high-fidelity recordings from catheter tip micromanometers were made simultaneously with the echocardiogram to permit description of the temporal relationships between pressure and motion. Results of this study provide a base of normal data for comparison with the motion of the left ventricular posterior wall in a variety of diseases and in response to therapy.
Adolescent↗
The coronary hemodynamics of left main and branch coronary stenoses. The effects of reduction in stenosis diameter, stenosis length, and number of stenoses.
Although considerable investigation has been devoted to the concept of "critical" coronary stenosis, there is general lack of agreement on which coronary stenoses consistently decrease coronary blood flow (CBF). In 32 open-chest dogs we studied CBF and the aorta-distal coronary pressure gradient at rest and with reactive hyperemia (RH) as stenoses were created in the left coronary artery (LCA) or its major branches--anterior descending (LAD) or circumflex (LCx) arteries. The effects of stenosis location, reduction in stenosis diameter, stenosis length, and the number of stenoses were studied. Resting CBF and resting distal coronary pressure were decreased by short snare stenoses, which reduced the diameter of the LCA or either major branch more than 80%. Lengthening 50 to 60% LAD or LCx stenoses decreased CBF and increased the pressure gradient. There were small increases in pressure gradients but no change in CBF with multiple stenoses in either the LAD or LCx branch. During peak RH, CBF was decreased by a 60% LCA or branch snare stenosis. Peak RH CBF responses decreased further as length of an LAD or LCx stenosis increased. Multiple stenoses affected peak RH CBF responses significantly more than a single stenosis of the same total length. These data indicate that several anatomic variables of coronary stenosis affect the physiological responses of the coronary circulation. The variables are (1) reduction in lumen diameter, (2) length of stenosis, and (3) number of stenoses in one vessel.
Animals↗
A method for evaluation of enhancement operations in two-dimensional echocardiographic images.
A means of estimating the degree of enhancement of structure and suppression of background noise in filtered two-dimensional echocardiographic images is described. The method is termed the peak-to-background ratio. To test the method, two-dimensional short-axis echocardiographic images were enhanced with Laplacian operations of increasing mask size. There was excellent correlation between the calculated peak-to-background ratio and the subjective opinion of trained echocardiographers. Furthermore, radial length measurements made from images that were thought to be optimally enhanced by the peak-to-background ratio calculation showed the lowest interobserver mean differences. We conclude that the peak-to-background ratio does reflect improvement in characteristics of the image that favor more precise measurement (amplification of peaks and suppression of background) and can be used to help guide a dynamic approach to image processing.
Analog-Digital Conversion↗
Comparison of velocity and volumetric indexes of left ventricular filling during increased heart rate with exercise and amyl nitrite.
Physiologic variables, such as heart rate, affect the noninvasive indexes of left ventricular filling, complicating the interpretation of these indexes for clinical assessment of diastolic function. We compared the effect in normal subjects of increased heart rate provoked by both exercise and amyl nitrite on noninvasive velocity and volumetric indexes of left ventricular filling. Velocity indexes were affected in a different pattern with exercise compared with amyl nitrite because peak E wave velocity and relative atrial contribution to filling increased with exercise. In contrast, the volumetric index of rapid left ventricular filling increased similarly with both mechanisms. These findings demonstrate the importance of recognizing the different effects on indexes of left ventricular filling when heart rate is increased by different methods.
Adult↗
Cardiac assessment in Turner's syndrome: a case for the inclusion of coronary angiography.
This case reveals a 25-year-old woman presenting with a supraventricular tachycardia who was found to have Turner's syndrome. Color flow Doppler echocardiography revealed diastolic jets, which cardiac arteriography confirmed as coronary artery-pulmonary artery fistulas.
Adult↗
A second-generation computer-based edge detection algorithm for short-axis, two-dimensional echocardiographic images: accuracy and improvement in interobserver variability.
The present study tested the hypothesis that a second-generation endocardial edge detection algorithm that used a priori endocardial and epicardial information would improve accuracy and reduce the variability of border definition. Five nonexpert observers utilized the version 2 algorithm on 20 cycles of two-dimensional short-axis images (five excellent, seven good, and eight poor quality studies stored digitally from a previously reported project). Manually defined areas by five recognized experts on these 20 cardiac cycles were considered to be "true areas." Areas defined by the experts with version 1 of the algorithm were also used for comparison. Regression of the version 2 areas with mean, manually defined excellent quality areas yielded a similar correlation (r = 0.985) to that reported between the manual and the version 1 areas (r = 0.986). For all 20 cycles in the series, however, the correlation between version 2 and the manually defined areas was lower (r = 0.952) than that of the same correlation with version 1 areas (r = 0.980). For all studies the interobserver variability (percent area difference) was +/- 14.4% for manually defined borders, +/- 11.1% for version 1-defined borders, and +/- 7.7% for version 2-defined borders. No difference in variability was observed for excellent quality studies (+/- 5.3% versus 5.2%) between version 1 and version 2 areas. However, the version 2 algorithm significantly reduced interobserver variability for good and poor quality studies (+/- 8.4% to 7.6%, p less than 0.025, and 16.3% to 9.1%, p less than 0.05, respectively). We concluded that: the version 2 algorithm provided accuracy and significantly reduced the variability of area measurement in good and poor quality studies and that epicardial information was important to the improvement by providing wall thickness information to assist in filling areas of dropout and avoidance of intracavitary structures.
Algorithms↗