Biomedical subjects

L D Gillam

Publications and source records attributed to L D Gillam.

At least 55 records · Page 3Linked to original sources

PubMed1986

The natural history of regional wall motion in the acutely infarcted canine ventricle.

Two-dimensional echocardiography was employed to define the natural history of regional wall motion abnormalities in a canine model of acute experimental myocardial infarction. Serial short-axis two-dimensional echocardiograms were recorded in 11 closed chest dogs before coronary occlusion and 10, 30, 60, 180 and 360 minutes after permanent coronary ligation. Radiolabeled microsphere-derived blood flows were obtained in each study period and the histochemical (triphenyltetrazolium chloride) extent of infarction was determined at 6 hours. Previously published methods were used to quantitate field by field (every 16.7 ms) excursion of 36 evenly spaced endocardial targets. The circumferential extent of abnormal wall motion was followed sequentially using previously published definitions of abnormality: 1) systolic fractional radial change of less than 20%; 2) dyskinesia (systolic bulging) at the point in time (echocardiographic field) in which there is maximal dyskinesia; and 3) correlation with composite normal ray motion falling outside the 95% confidence limits defined in the control period. On the basis of the triphenyltetrazolium chloride staining pattern, the ventricle was divided into five zones: central infarct zone, zone with greater than 25% transmural infarction, total infarct zone, border zones and normal zone. Mean systolic fractional radial change was calculated for each zone and used as an index of the magnitude of abnormal wall motion. Regardless of the definition of abnormality employed, the circumferential extent of abnormal wall motion manifested at 10 minutes after occlusion did not significantly change, even up to 6 hours later. Similarly, 10 minutes after coronary occlusion the three infarct zones and border zones demonstrated significantly reduced systolic fractional radial change. This remained stable over the remainder of the 6 hour study period. It is concluded that once established at 10 minutes after coronary occlusion, the circumferential extent and magnitude of abnormal wall motion do not significantly change in the immediate postinfarct (6 hour) period.

Animals↗

PubMed1986

A new echocardiographic model for quantifying three-dimensional endocardial surface area.

A new technique for quantitatively mapping the three-dimensional left ventricular endocardial surface was developed, using measurements from standard cross-sectional echocardiographic images. To validate the accuracy of this echocardiographic mapping technique in an animal model, the endocardial areas of 15 excised canine ventricles were calculated using measurements made from echocardiographic studies of the hearts and compared with areas determined with latex casts of the same ventricles. Close correlation (r = 0.87, p less than 0.001) between these two measures of endocardial area provided preliminary confirmation of the accuracy of the maps. To further characterize the mapping algorithm, it was translated into computer format and used to map the surfaces of idealized hemiellipsoids. Areas measured with this mapping technique closely approximated the actual areas of idealized surfaces with a wide spectrum of shapes; maps were particularly accurate for ellipsoids with shapes similar to those of undistorted human ventricles. Also, the accuracies of area calculations were relatively insensitive to deviation from the assumed positions of the echocardiographic short-axis planes. Finally, although the accuracy of the mapping technique improved as data from more transverse planes were added, the procedure proved reliable for estimating surface areas when data from only three planes were used. These studies confirm the accuracy of the echocardiographic mapping technique, and they suggest that the resulting planar plots might be useful as templates for localizing and quantifying the overall extent of abnormal wall motion.

Animals↗

PubMed1986

An echocardiographic technique for quantifying and displaying the extent of regional left ventricular dyssynergy.

A convenient noninvasive method of mapping the left ventricular endocardial surface has been developed that can be used to display regional dysfunction and calculate the total area of abnormal endocardial excursion from data obtained in two orthogonal apical and three or more short-axis cross-sectional echocardiographic images. Visually identified regions of abnormal systolic function are plotted on end-diastolic, planar endocardial surface maps, and the extent of dysfunction can be expressed either as an absolute area or as a fraction of the total endocardial surface area involved. The extent of the left ventricular surface moving abnormally, calculated with this echocardiographic mapping technique, was compared with two histochemical measures of infarct size in a series of 11 closed chest dogs with acute circumflex coronary artery occlusions. Overall extent of abnormally moving left ventricular wall correlated closely with both the fraction of the endocardial area overlying infarct (r = 0.92, p less than or equal to 0.001) and the fraction of the myocardial volume infarcted (r = 0.86, p less than or equal to 0.001). This suggests that the echocardiographic mapping technique can be used to accurately quantify the global extent of abnormal systolic function in the presence of regional wall motion abnormalities.

Animals↗

PubMed1986

Doppler and two-dimensional echocardiographic diagnosis of Björk-Shiley prosthetic valve malfunction: importance of interventricular septal motion and the timing of onset of valve flow.

In a 69 year old woman with a "sticking" Björk-Shiley mitral prosthesis, the diagnosis was suggested by both the two-dimensional and the Doppler ultrasound examinations. In particular, the findings of early diastolic paradoxic septal motion, intermittent delayed opening of the prosthetic disc and variable timing of the onset of mitral valve inflow were believed to be diagnostic of a sticking tilting disc prosthesis.

Aged↗

PubMed1986

Contrast echocardiography in acute myocardial ischemia. III. An in vivo comparison of the extent of abnormal wall motion with the area at risk for necrosis.

To define the in vivo relation between abnormal wall motion and the area at risk for necrosis after acute coronary occlusion, 11 open chest dogs were studied. Five dogs underwent left anterior descending coronary artery occlusion and six underwent left circumflex artery occlusion. Area at risk was defined at five short-axis levels (mitral valve, chordal, high and low papillary muscle and apex) using myocardial contrast echocardiography. Wall motion was measured in the cycles preceding injection of contrast medium. Two observers used two different methods to measure wall motion. In method A, end-diastolic to end-systolic fractional radial change for each of 32 endocardial targets was determined. The extent of abnormal wall motion was then calculated using three definitions of wall motion abnormality: akinesia/dyskinesia, fractional inward endocardial excursion of less than 10%, and fractional inward endocardial excursion of less than 20%. In method B, the information from the entire systolic contraction sequence was analyzed and correlated with a normal contraction pattern. The best linear correlation between area at risk (AR) and abnormal wall motion (AWM) was achieved using method B and expressed by the following linear regression: AWM = 0.92 AR + 3.0 (r = 0.92, p less than 0.0001, SEE = 1.7%). Of the three definitions of abnormality used in method A, the best correlation was achieved between area at risk and less than 10% inward endocardial excursion and was expressed by the following polynomial regression: AWM = -0.01 AR2 + 1.5 AR -0.14 (r = 0.92, p less than 0.001, SEE = 1.7%). These data demonstrate that there is a definite relation between area at risk and abnormal wall motion but that this relation varies depending on the method used to analyze wall motion. However, wall motion during acute ischemia is also influenced by the loading conditions of the heart. Because these may vary in a manner that is independent of the ischemic process, measurement of both risk area and abnormal motion may provide a more comprehensive assessment of cardiac function in myocardial ischemia than is provided by the measurement of either alone.

Animals↗

PubMed1986

Validation of continuous-wave Doppler echocardiographic measurements of mitral and tricuspid prosthetic valve gradients: a simultaneous Doppler-catheter study.

For patients with stenotic native valves, the modified Bernoulli equation (delta P = 4V2) may be applied to Doppler-measured transvalvular velocities to yield an accurate estimate of transvalvular gradients. Although it would be useful if the same approach could be used for those with stenotic prosthetic valves, no previous study has validated the Doppler technique in this setting. We therefore recorded simultaneous continuous-wave Doppler flow profiles and transvalvular manometric gradients in 12 catheterized patients in whom all atrial and ventricular pressures were directly measured (transseptal left atrial catheterization and transthoracic ventricular puncture were performed where necessary). A total of 13 prostheses were studied: 11 mitral (seven porcine, three Starr-Edwards, and one Björk-Shiley) and two tricuspid (one porcine and one Björk-Shiley). The Doppler-determined mean gradient was calculated as the mean of the instantaneous gradients (delta P = 4V2) at 10 msec intervals throughout diastole. The correlation of simultaneous Doppler (DMG) and manometric mean gradients (MG) for the whole group (n = 13) demonstrated a highly significant relationship (MG = 1.07 DMG + 0.28; r = .96, p = .0001). The correlation was equally good for porcine valves alone (n = 8) (MG = 1.06 DMG + 0.55; r = .96, p = .001) and for mechanical valves alone (n = 5) (MG = 1.06 DMG - 0.04; r = .93, p = .02). In a subset of patients without regurgitation (n = 8), prosthetic valve areas were estimated by two Doppler methods originally described by Holen and Hatle, as well as by the invasive Gorlin method. As expected from theoretical considerations, a close correlation was not demonstrated between results of the Gorlin method and those of either Hatle's Doppler method (r = .65, fp = NS) or Holen's method (r = .14, p = NS). Comparison of the results of the two Doppler methods yielded a somewhat closer correlation (r = .73, p less than or equal to .05). These results suggest that in patients with disk-occluder, ball-occluder, and porcine prosthetic valves, Doppler estimates of transvalvular gradients are virtually identical to those obtained invasively.

Aged↗

PubMed1985

Comparison of high pulse repetition frequency and continuous wave Doppler echocardiography in the assessment of high flow velocity in patients with valvular stenosis and regurgitation.

Continuous wave Doppler echocardiography has proved useful in detecting and quantitating the high velocity flow disturbances that characterize many stenotic and regurgitant valvular lesions. Pulsed Doppler echocardiography, in contrast, is limited in its ability to quantitate the high velocities that are detected. Recently, new pulsed Doppler systems have been developed that employ high pulse repetition frequencies and can theoretically measure higher flow velocities than those measured by the standard pulsed Doppler systems. To determine the ability of high pulse repetition frequency Doppler echocardiography to accurately measure high velocity flow signals in comparison with the continuous wave method, 80 patients undergoing routine echocardiographic examination for the assessment of valvular heart disease were studied using both techniques. A total of 113 high velocity flow disturbances were detected in 68 patients. In 41 instances, the maximal velocities by the two methods were within 0.5 m/s of each other. In 68 of the 113 high velocity lesions, however, the high pulse repetition frequency technique underestimated the peak velocity found with continuous wave Doppler echocardiography by more than 0.5 m/s. Comparison of the peak velocities recorded by the two methods for the total group showed no significant correlation (r = 0.04, p = NS). Comparison of the difference in peak velocities obtained by the two techniques with the maximal continuous wave velocity (n = 94, r = 0.70, slope = 0.71) suggested that the underestimation becomes greater as the peak velocity increases. Fifteen of the study patients with aortic stenosis subsequently underwent catheterization.(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗

PubMed1985

Functional and pathologic effects of multiple echocardiographic contrast injections on the myocardium, brain and kidney.

Myocardial contrast echocardiography can define in vivo the area at risk for necrosis after coronary occlusion. However, if this technique is to be used, it cannot be intrinsically toxic to the heart or other critical organs. To determine the functional and pathologic effects of contrast echocardiography, six intracoronary, six intrarenal and six intracarotid artery injections of 2 to 6 cc of a commonly employed contrast agent (agitated Renografin-saline solution) were performed in five dogs. A sixth dog served as a sham to assess any deleterious effects of the model preparation. Two-dimensional echocardiographic images and electrocardiograms were recorded during intracoronary injections, and heart rate, blood pressure, left ventricular end-diastolic pressure and rate of rise of left ventricular pressure (dP/dt) were continuously monitored. At 24 hours, echocardiographic and hemodynamic measurements were repeated, the dogs were killed and the heart, brain and kidneys were removed and prepared for light microscopic examination. Quantitative analysis of left ventricular wall motion was performed on control, peak contrast, post-contrast and 24 hour studies. With each intracoronary injection, there were transient decreases in blood pressure (p = 0.05 versus control) and increases in left ventricular end-diastolic pressure (p = 0.04 versus control). These were associated with depression of wall motion in contrast-enhanced regions (p = 0.01 versus control) and ST-T segment changes on the electrocardiogram. No significant change in heart rate or left ventricular dP/dt was noted. All variables normalized with the clearance of the contrast effect and remained normal to 24 hours. Light microscopic examination revealed no myocardial or cerebral changes attributable to the contrast agent injections.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗

PubMed1985

Osteogenic sarcomas mimicking left atrial myxomas: clinical and two-dimensional echocardiographic features.

Two patients presenting with acute pulmonary edema were found to have a left atrial cardiac osteogenic sarcoma (primary and secondary). The two-dimensional echocardiographic appearance in both cases mimicked that of atrial myxoma. However, two echocardiographic features (that is, tumor extension into pulmonary veins and origin from nonseptal atrial walls) suggested the presence of a nonmyxomatous cardiac tumor.

Adult↗

PubMed1985

Contrast echocardiography in acute myocardial ischemia. II. The effect of site of injection of contrast agent on the estimation of area at risk for necrosis after coronary occlusion.

Myocardial contrast echocardiography has been shown to accurately assess the area at risk for necrosis after acute coronary occlusion in the experimental model. The area at risk as determined by this method, however, has been defined in different ways depending on the model used. Some investigators have injected the contrast agent proximal to the site of coronary occlusion (left main coronary artery or aorta) and defined the area at risk as the segment of myocardium not showing a contrast effect (negative risk area). Others have injected the contrast agent directly into the occluded vessel and have defined the area at risk as that showing contrast enhancement (positive risk area). To evaluate whether the areas at risk determined by these two techniques are identical, six open chest dogs were studied using both methods. The area at risk was slightly but significantly larger when the contrast agent was injected into the occluded vessel than when it was injected proximally into the left main coronary artery (4.98 +/- 1.69 versus 3.97 +/- 1.27 cm2, p less than 0.01). It is concluded that the site of injection of the contrast agent significantly influences the determination of area at risk. Therefore, data obtained by the two techniques should not be used interchangeably, and in a given study the area at risk should be measured consistently using one technique.

Animals↗

PubMed1985

A Doppler-two-dimensional echocardiographic method for quantitation of mitral regurgitation.

A noninvasive method to accurately quantitate the severity of mitral insufficiency would be of major clinical value. In theory, in the absence of confounding variables, regurgitant mitral flow should represent the difference between forward mitral blood flow and aortic blood flow. Since Doppler-two-dimensional echocardiographic (D2DE) methods for measuring transvalvular mitral and aortic flow have been validated, it should be possible to use mitral and aortic flows derived by this method to calculate regurgitant mitral flow. To assess the validity and accuracy of this combined approach for quantitation of regurgitant flow, we developed an open-chest canine preparation in which we could simulate, vary, and accurately measure degrees of mitral regurgitation. Seven animals were anesthetized and prepared to allow controlled right heart output. Mitral regurgitation was than simulated by placing a flexible conduit incorporating a one-way valve and electromagnetic flowmeter between the left ventricular apex and left atrium. Flow through the tube (effective mitral regurgitation) was varied between 0.2 and 1.8 liters/min and forward cardiac output ranged between 0.5 and 4 liters/min. Transmitral and transaortic flows were calculated by previously reported Doppler methods. Doppler-derived estimates of forward flow through the aortic valve correlated well with the flow measured by flowmeter (r = .92), and regurgitant flow and regurgitant fraction calculated by the D2DE approach also compared well with those measured by flowmeter (r = .84 and .83, respectively). This study demonstrates that mitral regurgitant flow and regurgitant fraction calculated by the D2DE method provide an acceptable measure of both absolute regurgitant flow and the regurgitant fraction in the experimental setting.

Animals↗

PubMed1985

Two-dimensional and Doppler echocardiography in the evaluation of penetrating cardiac injury.

Two cases in which Doppler and cross-sectional echocardiography demonstrated intracardiac shunts acquired by stab wounds to the heart are reported. These cases demonstrate the utility of these noninvasive methods in assessing the anatomic residua of penetrating cardiac injuries. In particular, the value of Doppler echocardiography in detecting lesions that are small, irregularly oriented, and situated in locations not well seen in standard two-dimensional echocardiographic imaging views is emphasized.

Adult↗

PubMed1984

Prevalence of aortic valve prolapse with bicuspid aortic valve and its relation to aortic regurgitation: a cross-sectional echocardiographic study.

Although aortic valve prolapse (AVP) has been suggested as a cause of aortic regurgitation (AR) in patients with bicuspid aortic valves, neither the frequency of AVP nor its relation to AR in this setting has been defined. To assess these relations, 64 patients with bicuspid aortic valves diagnosed by 2-dimensional echocardiography and 20 normal subjects, similarly distributed according to age and sex, were studied. The presence and degree of AVP were defined using 3 quantitative terms: aortic valve prolapse distance (AVPD), area (AVPA) and volume (AVPV). Each was corrected (c) for patient size with reference to the diameter of the aorta at the level of insertion of the valve cusps. In normal subjects, the AVPDc averaged 0.09 +/- 0.06 (range 0 to 0.16) and the AVPAc averaged 0.08 +/- 0.06 cm (range 0 to 0.15). In patients with bicuspid aortic valves, the AVPDc averaged 0.26 +/- 0.10 (range 0.11 to 0.59, p = 0.00005 vs normal subjects), whereas the AVPAc averaged 0.35 +/- 0.17 cm (range 0.05 to 0.90, p = 0.00005 vs normal subjects). When the AVPDc criteria were used, 81% of the bicuspid valves were abnormal; when the AVPAc criteria were used, 87% were abnormal. The degree of prolapse defined by the AVPVc, which considers both cusp area and degree of apical displacement, was significantly greater for patients with bicuspid aortic valve with clinical AR than for those without (p = 0.008). However, because of the overlap between groups, there was no point at which this measure uniquely separated patients with and without AR.(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗

PubMed1984

Doppler ultrasound measurement of cardiac output in patients with physiologic pacemakers. Effects of left ventricular function and retrograde ventriculoatrial conduction.

Dual-chamber cardiac pacing (DDD) offers obvious theoretical advantages over traditional ventricular demand (VVI) pacing. Nevertheless, no widely agreed upon criteria exist for the selection of patients for physiologic DDD pacemakers compared with the simpler VVI systems. Accordingly, a non-invasive method for measuring cardiac output (Doppler ultrasound) was used to identify candidates for pacing who would derive the greatest hemodynamic benefit from DDD vs VVI pacing. Among 29 patients studied at rest during VVI-mode pacing, the average cardiac output by Doppler ultrasound was 4.3 +/- 0.3 liters/min (mean +/- standard error of the mean). In the DDD mode, the average cardiac output was 5.0 +/- 0.3 liters/min (p less than 0.001). Baseline left ventricular ejection fraction did not identify a group that improved more with DDD pacing. Patients who showed either retrograde ventriculoatrial conduction or described symptoms consistent with the "pacemaker syndrome" during VVI pacing, however, showed greater increases in cardiac output during DDD pacing. In these patients, the mean improvement in cardiac output was 30.4 +/- 8.6% with DDD vs VVI pacing, as opposed to an average increase of only 14.4 +/- 3.4% in the remaining 20 patients (p = 0.02). Thus, Doppler ultrasound can be used to quantitate the change in cardiac output at rest that occurs with DDD vs VVI pacing. The change is independent of the level of left ventricular function but is substantially higher when there is evidence of ventriculoatrial conduction or the pacemaker syndrome.

Adult↗

PubMed1984

Comparison of the echocardiographic and hemodynamic diagnosis of rheumatic tricuspid stenosis.

Two-dimensional echocardiography has proved to be reliable in the diagnosis of mitral, aortic and pulmonary stenosis. Its role in the diagnosis of rheumatic tricuspid stenosis is still being defined; therefore, the tricuspid valve echograms of 147 patients with rheumatic heart disease were examined. Thirty-eight of these patients also underwent hemodynamic evaluation. Tricuspid stenosis was defined echocardiographically as diastolic anterior leaflet doming, thickening and restricted excursion of the other two tricuspid leaflets and decreased separation of the leaflet tips. Using these criteria, the sensitivity and specificity of the echocardiogram in detecting tricuspid stenosis were 69 and 96%, respectively, in the group of 38 patients who had both echocardiographic and hemodynamic evaluations. However, when the smaller group of 17 patients who had simultaneous right atrial and right ventricular pressure recordings were considered separately, there was complete agreement between the echocardiographic and hemodynamic data. Thus, the two-dimensional echocardiogram is a sensitive and specific test for diagnosing rheumatic tricuspid stenosis. In addition, these data provided an opportunity to determine the prevalence of tricuspid stenosis in this group of patients with chronic rheumatic valvular disease. Tricuspid stenosis was present in 14 (9.5%) of the total group of 147 patients who had two-dimensional echocardiograms, and in 10 (26.3%) of the 38 who had both echocardiographic and hemodynamic studies. In patients with rheumatic heart disease about to undergo cardiac catheterization, an echocardiographic study should prove useful in making the diagnosis of tricuspid stenosis.

Adult↗

PubMed1984

Echocardiographic measurement of right ventricular volume.

The volume of the right ventricle can be determined angiographically from its projections in two mutually perpendicular planes. Echocardiographic techniques for measuring right ventricular volume, however, have been more difficult and less successful. In this study, a method was developed for calculating right ventricular volume from two intersecting cross-sectional echocardiographic views: the apical four-chamber and subcostal right ventricular outflow tract views. First, the areas and lengths of casts of 12 human right ventricles obtained at autopsy were directly measured in the chosen views. Actual cast volumes correlated best with a formula giving volume as 2/3 times the area in one view times the long axis in the other view. The degree of correlation was similarly high for calculations involving the area derived from either view and the length of the roughly orthogonal section. This relationship for right ventricular volume was then confirmed with two-dimensional echocardiographic images of hollow latex molds made from the casts (r = .95, p less than .0001). The significance of these findings is discussed in relation to angiographic results and models of the right ventricle.

Adult↗

PubMed1984

Importance of temporal heterogeneity in assessing the contraction abnormalities associated with acute myocardial ischemia.

A number of recent two-dimensional echocardiographic studies have attempted to relate quantitative changes in short-axis left ventricular radial wall motion to underlying myocardial ischemia/infarction. The significance of temporal variation in the contraction sequence within these ischemic regions in the overall evaluation of segmental left ventricular dysfunction, however, remains undefined. To assess this, we examined the motion of 192 individual radii that intersected known ischemic segments at 16.7 msec intervals from end-diastole to end-systole. The studies were performed in 13 dogs 1 hr after acute coronary ligation (six of the left anterior descending and seven of the circumflex coronary artery). Zones of infarction were confirmed by triphenyltetrazolium chloride staining at the termination of the experiment and by a corresponding decrease of more than 75% in myocardial perfusion at the 1 hr sampling period. Dyskinesis (defined for each radius as negative or outward excursion relative to the end-diastolic reference on two consecutive fields) was noted along 168 of 192 radii (88%) at some point in the contraction sequence. The maximal outward or dyskinetic motion occurred most commonly in the fourth decile of the normalized contraction sequence. In 147 of the 168 dyskinetic radii (88%) the maximal outward motion occurred during the first half of systole while in only two radii in one animal was the maximal outward motion noted at end-systole. The total number of radii showing dyskinetic motion at any given point in the contraction sequence likewise varied with time. Although again the greatest number of radii showed abnormal motion during the fourth decile of the normalized contraction sequence, only 66 of 168 or 39% remained dyskinetic to end-systole. No relationship was observed between the point of maximal dyskinesis (time-weighted average of all dyskinetic radii for a given animal) and (1) the total number of radii showing dyskinesis, (2) the total number of radii within the infarct zone, or (3) the infarct area expressed as a percent of the slice area. The major factor determining persistence of dyskinesis to end-systole for any radius was the maximal outward motion of the endocardial segment at the point of maximal dyskinesis. Therefore, simple measurement of endocardial excursion from end-diastole to end-systole may fail to detect important wall motion abnormalities and, in some cases, may miss dyskinetic segments completely.

Acute Disease↗

PubMed1984

A comparison of quantitative echocardiographic methods for delineating infarct-induced abnormal wall motion.

Current echocardiographic methods for quantitating abnormal regional left ventricular wall motion rely primarily on changes in endocardial excusion from end-diastole to end-systole. Recent studies demonstrating important spatial and temporal heterogeneity in wall motion within ischemic regions, however, raise questions about the validity of this approach. To determine the optimal method for defining abnormal left ventricular wall motion, we used a canine preparation of acute experimental infarction to examine four quantitative methods of wall motion analysis. The circumferential extent of abnormal wall motion assessed by each method was compared with the circumferential extent of infarction (defined by triphenyltetrazolium chloride staining) and the circumferential extent of reduced transmural blood flow (determined by radiolabeled microsphere techniques) 6 hr after acute coronary occlusion. The following methods of quantitating abnormal wall motion were examined: (1) determination of end-diastolic to end-systolic endocardial excursion (less than 0.20 end-diastolic radius), (2) determination of the extent of maximal dyskinesis (systolic bulging), and (3) and (4) two derived correlation methods that consider the entire course of systolic radial motion by correlating the observed echocardiographic field-by-field (every 16.7 msec) motion of each of 36 evenly spaced endocardial targets with the course of normal motion established from pooled normal data. Results obtained with the correlation methods showed a better correlation with the triphenyltetrazolium chloride-defined circumferential extent of infarction (r = .87 and r = .78) than did determinations of reduced end-diastolic to end-systolic endocardial excursion (r = .35) or the extent of maximal dyskinesis (r = .37). Similarly, the best correlation with the extent of reduced flow was obtained with one of the correlation methods (r = .80). We conclude that correlation methods that "integrate" endocardial motion over the entire systolic contraction sequence provide better definition of ischemic left ventricular dysfunction than do methods that consider motion at only single points in time.

Acute Disease↗