Betty C. Corya

Prognostic value of a normal exercise echocardiogram

Follow-up information was obtained from 148 patients who had normal resting and post-treadmill exercise echocardiograms to determine the prognostic value of a normal exercise echocardiogram in patients evaluated for suspected coronary artery disease. There were 77 men and 71 women with a mean age of 52.5 years and a pretest likelihood of coronary artery disease of 39%. Patients were followed for a mean duration of 28.4 +/- 8.5 months. The exercise ECG was abnormal in 69 patients (47%) including 28 who had ischemic responses. Cardiac events occurred in six patients, three with normal and three with abnormal exercise ECGs. Events occurred only in those patients (6 of 68) who exercised to work loads less than 6 METs or who achieved less than 85% of the age-predicted maximal heart rate. Three patients had coronary artery bypass grafting for angina from 10.5 to 22.5 months after echocardiography. A fourth patient had bypass grafting for mild single-vessel disease at the time of mitral valve replacement. Two patients had myocardial infarctions (0.85% per year) at 7.5 and 41 months after echocardiography. There were no deaths. Coronary revascularization is infrequently required in the 28 months after a normal exercise echocardiogram. A normal exercise echocardiogram in a patient with good exercise capacity was predictive of an excellent prognosis, even in those who had abnormal exercise ECGs. Myocardial infarction and death were rare events, even in patients with decreased exercise capacity.

Detection of Left Ventricular Asynergy by Echocardiography

The purpose of this study was to determnie if echocardiography could detect left ventricular asynergy. Forty-eight patients underwent selective coronary arteriography and cineventriculography for the evaluation of chest pain. Four patients were studied twice: three before and after myocardial revascularization and one before and after an intervening myocardial infarction. Echocardiographic M-mode scans were registered on a strip chart as the left ventricle was scanned with an ultrasonic beam from the aortic root to the region of the posterior papillary muscle approximately 18 hrs prior to the catheterization studies.Ten of the forty-eight patients had no evidence of coronary artery disease. All ten patients had normal ventriculograms in right anterior oblique projection and their echocardiographic scans showed all areas of the left ventricular posterior wall endocardium to move anteriorly 0.9-1.4 cm (mean 1.2 cm) and all parts of the left side of the interventricular septum to move posteriorly 0.3-0.8 cm (mean 0.5 cm) during systole. The 38 patients with significant obstructive coronary artery disease had a total of 42 studies; 25 of these studies showed left ventricular asynergy on the ventriculogram taken in right anterior oblique. The echocardiograms associated with all but one of these studies demonstrating left ventricular asynergy had abnormal motion of some part of the interventricular septum and/or left ventricular posterior wall. Seventeen studies in patients with significant coronary artery disease did not exhibit left ventricular asynergy on the ventriculogram but eight of these studies were associated with distinctly abnormal echocardiograms.None of the ten patients with significant coronary artery disease and normal echocardiograms had evidence of transmural infarction on their electrocardiograms. Echocardiographic abnormalities correlated with the anatomic area predicted by the myocardial infarction pattern on the electrocardiogram in 18 of 20 patients.All patients demonstrating abnormal echographic interventricular septal motion had a significant obstructive lesion in the left anterior descending coronary artery. In the absence of significant involvement of the left anterior descending coronary artery, echographically recorded interventricular septal motion was invariably normal. On the other hand, eight patients had significant obstruction in their left anterior descending coronary artery and their echographic interventricular septal motion was normal.The results of this correlative study indicate that M-mode echocardiographic scans can detect left ventricular asynergy and may possibly predict regional myocardial involvement in coronary artery disease.

Detection of myocardial scar tissue by M-mode echocardiography.

Wall thicknesses were measured and echo densities were evaluated from the left ventricular echograms of 182 patients. The echogram was considered to reflect scar tissue when 1) either the interventricular septum, the posterior left ventricular wall or the anterior left ventricular wall was less than 7 mm thick in mid-diastole and was more echo-producing than its opposing wall or another area of the same wall in a sector scan, or 2) an area of myocardium was 30% less thick than an adjacent area within a sector scan. Myocardial scarring was diagnosed by echocardiography in 52 of the 182 patients. The echocardiographic presence or absence of scarring was confirmed in 95% (173 of 182) of cases, 34 cases by microscopic examination and 139 by surgical appearance. This study shows that M-mode echocardiography is both a sensitive and specific method for detecting myocardial scar tissue.

Echocardiography in acute myocardial infarction.

Sixty-four patient with acute transmural myocardial infarction had daily echocardiograms while in the coronary care unit. Patients with previous infarction were excluded. The electrocardiographic site of infarction was anterior wall in 28, inferior wall in 33 and both anterior and inferior wall in 3 patients. Echocardiograms satisfactory for interpretation were obtained in 92 percent of cases. Abnormal left ventricular wall motion corresponding to the electrocardiographic site of infarction was seen in the echocardiogram in 84 percent of cases. Exaggerated normal motion in noninfarcted areas was seen in 30 percent. The left ventricular internal dimension correlated with clinical heart failure (P less than 0.005) and was increased in 50 percent. Abnormal mitral valve closure, which reflects increased left ventricular end-diastolic pressure, was present in 33 percent. This finding did not correlate significantly with clinical heart failure. By combining the measurements of left ventricular internal dimension and mitral valve closure, it was possible to predict hospital mortality from the echocardiograms. The results indicate that echocardiography is a useful technique in the study and management of patients with acute myocardial infarction.

Abnormal Mitral Valve Motion in Patients with Elevated Left Ventricular Diastolic Pressures

In order to see whether or not the echocardiographically recorded mitral valve could reflect alterations in left ventricular pressure, simultaneous mitral valve echograms and left ventricular pressures were obtained on patients undergoing diagnostic cardiac catheterization. Attention was given to the left ventricular initial diastolic pressure (LVIDP), left ventricular end-diastolic pressure (LVEDP), and the atrial component of the left ventricular pressure (LVa). The echocardiographic measurements included the opening velocity of the mitral valve in early diastole (D-E slope) and the interval between the A point, which is the onset of closure of the mitral valve following atrial systole, and the C point, which represents closure of the mitral valve as indicated by the meeting of the anterior and posterior mitral leaflets. In order to compensate for variations in atrioventricular conduction, the A-C interval was subtracted from the electrocardiographic P-R interval. In 19 patients, the LVIDP was less than 14 mm Hg, the LVEDP was less than 20 mm Hg, and the LVa was less than 8 mm Hg. In these patients, the D-E slope was greater than 25 cm/sec and the PR-AC interval was greater than 0.06 sec. Six patients who had an LVIDP of 14 mm Hg or greater had a D-E slope of less than 25 cm/sec. There were 14 patients with an LVEDP greater than 20 mm Hg and an LVa of 8 mm Hg or greater. All of these patients had a PR-AC interval of less than 0.06 sec. There were an additional three patients who had an LVEDP above 20 mm Hg, but whose LVa was less than 8 mm Hg. In these three patients, the PR-AC interval was greater than 0.06 sec. Thus, the shortened PR-AC interval correlated primarily with an elevated LVa. This study indicates that the echocardiographic pattern of mitral valve motion is altered in patients who have markedly elevated left ventricular diastolic pressures.

Echocardiographic Features of Congestive Cardiomyopathy Compared with Normal Subjects and Patients with Coronary Artery Disease

Echocardiograms of ten patients with congestive cardiomyopathy were compared to those of three groups of patients: (1) 17 with no catheterization or angiographic evidence of cardiac disease; (2) 19 with 75% or greater obstruction of one or more coronary arteries (CAD); and (3) 8 with previous myocardial infarction and congestive heart failure (CAD-CHF). Echocardiographic values of interest included the left ventricular internal dimension at end-diastole/body surface area (LVIDd index), the amplitudes of the left septal echo (LSa) and posterior endocardial echo (ENa), LSa + ENa, and the maximum rate of rise of the posterior endocardial echo ([See Equation in PDF File]). Septal and posterior wall thicknesses were measured and the presence or absence of pericardial effusion and abnormal mitral valve closure were observed. All of the left ventricular measurements were significantly different when comparing the cardiomyopathy group with the normal and CAD groups. Differentiating cardiomyopathy from the CAD-CHF group was far more difficult with the only highly significant difference being the LSa + ENa (P < 0.001). Only one cardiomyopathy patient and one CAD-CHF patient had a sum of LSa + ENa overlapping the other group.These results are consistent with the diffuse disease usually seen in congestive cardiomyopathy and the segmental nature of coronary artery disease in which some area of the left ventricle moves well even in the presence of congestive heart failure.

Systolic thickening and thinning of the septum and posterior wall in patients with coronary artery disease, congestive cardiomyopathy, and atrial septal defect.

SUMMARYEchocardiographic septal and posterior wall thicknesses and the percent change with systole were measured in 146 patients with the following diagnoses: acute myocardial infarction (40), chronic coronary artery disease (49), congestive cardiomyopathy (8), atrial septal defect (20), and no cardiac disease (29). Mean diastolic thicknesses for the groups of patients with coronary artery disease and congestive cardiomyopathy were not significantly different from normal although there were abnormal values for individual patients within each group. Mean diastolic thickness of the septum was greater than normal for the group with atrial septal defect (P < 0.02). Wall thinning with systole was associated with acute infarction or ischemia (P < 0.0001); decreased thickening (less than normal) commonly occurred in patients acute myocardial infarction, chronic coronary artery disease, congestive cardiomyopathy. Patients with atrial septal defect normal thickening with abnormal motion.Results of this study show that 1) systolic thinning is indicative an acute event; 2) abnormal changes in systolic wall thickening occur commonly in patients with coronary artery disease or congestive cardiomyopathy; and 3) abnormal wall motion may occur without abnormal wall thickening, as the echoes of patients with atrial septal defect indicate.

Echocardiographic detection of ischemic and infarcted myocardium

The purpose of this study was to determine the potential of a clinically adaptable two-dimensional echocardiographic system using computer enhancement and a mathematically defined integrated backscatter ratio for the early detection of ischemic and infarcted myocardium. Fifteen dogs had two-dimensional echocardiograms recorded during either open chest coronary occlusion (n = 5), closed chest occlusion (n = 5), occlusion followed by reperfusion (n = 3) or sham coronary occlusion (n = 2). A serial increase in integrated backscatter ratio, representing differences in returned ultrasound intensities between a reference point and specific myocardial regions, was detected between 7 and 12 minutes of complete occlusion in 9 of 12 animals (p less than 0.05), and at minutes 18, 43 and 67 in the remaining 3 animals. Reperfusion after 20 minutes of occlusion in two studies resulted in normalization of the backscatter ratio. An increase in backscatter ratio was not detected when 5 minute occlusion periods were used or during the 5 hour sham occlusion studies. The computer enhancement techniques utilized in this study provided increased visual detail of intracardiac structures over that provided by routine two-dimensional echocardiograms; myocardial tissue was identifiable in what appeared to be echo-free segments; and boundaries that appeared as noncontiguous horizontal lines on the routine echocardiograms were identifiable as trabeculae. The results indicate that: 1) significant increases in backscatter from nonperfused myocardium are detectable echocardiographically within 12 minutes of coronary occlusion and temporal changes can be assessed in the canine model, and 2) the echocardiographic data acquisition and computer analysis system utilized provide a clinically adaptable approach to identify and map myocardial characteristics in human beings.

Role of echocardiography in patients with coronary artery disease

Impaired left ventricular performance, one of the hallmarks of coronary artery disease, can be detected by echocardiography in various ways. One of these approaches is the recording of abnormal wall motion. Because of the way in which the left ventricle can be examined echocardiographically, this technique has the capability of detecting regional wall abnormalities. In fact echocardiography is probably the most sensitive technique available, including even contrast ventriculography, for the detection of akinetic, hypokinetic or dyskinetic wall segments. With increasing experience it is apparent that more areas of the left ventricle can be examined echocardiographically than had previously been thought possible. Newer techniques include directing the ultrasonic beam not only through the body of the left ventricle but also toward the apical portion of the ventricle near the vicinity of the papillary muscles. In addition the true anterior left ventricular wall can be examined by moving the transducer laterally away from the left sternal border. Yet another approach utilizes a subxiphoid position for the transducer while the ultrasonic beam is directed through the medial portion of the septum and posterolateral wall of the left ventricle. M-mode scanning techniques together with recently developed cross-sectional echocardiographic instruments give great promise of improved detection of abnormalities of ventricular shape, especially the presence of aneurysms. The cross-sectional approach makes it possible to examine the left ventricular apex, an area virtually impossible to record with M-mode echocardiography. Recording of left ventricular dimensions and abnormal mitral valve motion may help in assessing overall left ventricular performance. A dilated left ventricular dimension in the vicinity of the mitral valve seems to be an ominous finding both in patients with acute myocardial infarction and in patients with chronic coronary disease being considered for possible surgery. Another echocardiographic sign of abnormal ventricular performance is altered closure of the mitral valve, which reflects a significantly elevated left ventricular diastolic pressure. These echocardiographic techniques are still in the investigational stages and are more technically difficult than the usual echocardiographic applications. However, the preliminary data are encouraging and make us hopeful that echocardiography will prove to be an important tool in the overall evaluation of the left ventricle in patients with coronary artery disease.

Anterior left ventricular wall echoes in coronary artery disease. Linear scanning with a single element transducer.

Abstract The feasibility and usefulness of obtaining anterior left ventricular wall echoes were studied using a linear cardiac scan with a single element tranducer and M mode recordings. One hundred four patients were examined: 50 with acute myocardial infarction and 54 who underwent left ventricular angiography and coronary cineangiography for evaluation of chest pain. Of the 54 patients with cardiac catheterization studies, 11 had no evidence of cardiac disease, 42 had 50 percent or greater obstruction in one or more of the three major coronary arteries and one had aortic insufficiency. Anterior left ventricular wall echo motion toward the transducer or absence of motion during ejection was called abnormal, and motion away from the transducer during ejection was interpreted as normal. Abnormal motion was seen in four of four patients with an isolated lesion of the anterior descending coronary artery, in one of three with an isolated lesion of the right coronary artery and in neither of two with an isolated lesion of the left circumflex artery. Of the 20 patients with obstructive coronary artery disease by arteriography and abnormal left ventricular wall echo motion, 18 had obstruction of the left anterior descending artery with or without other disease. Correlation of the anterior left ventricular echograms with the left ventricular angiograms was poor, with agreement in only 66 percent (33 of 50) of cases. Twenty-five of 26 patients with acute infarction and abnormal anterior left ventricular wall echo motion had electrocardiographic changes indicative of anterior or lateral wall infarction, or both. Twenty-five of 34 patients with electrocardiographic changes indicative of anterior wall infarction had an abnormal anterior wall motion echo. This study shows that obtaining the anterior left ventricular wall echo is feasible and useful in patients with coronary artery disease since abnormal anterior left ventricular wall motion is closely associated with anterior wall ischemia or infarction in these patients.