Mitral and aortic valve orifice area in normal subjects and in patients with congestive cardiomyopathy: Determination by two dimensional echocardiography

Previous determinations of normal valve orifice areas have been mainly from postmortem studies. In this study mitral and aortic valve orifice area were determined from two dimensional echocardiograms in 20 normal subjects and 20 patients with congestive cardiomyopathy. Mitral valve orifice area was larger than quoted in standard textbooks. Both mitral and aortic valve orifice area were reduced in patients with cardiomyopathy. Valve opening was assessed relative to left ventricular and aortic root size. The ratio of mitral valve orifice area to left ventricular cross-sectional area was markedly reduced in patients with cardiomyopathy compared with normal subjects. The ratio of aortic valve orifice area to aortic root size also was reduced in patients with cardiomyopathy.Anterior mitral leaflet E point-septal separation was similar to that in previous reports contrasting normal subjects with patients with myopathy. Among patients with cardiomyopathy, mitral E point-septal separation was primarily a function of left ventricular size and was not significantly correlated with fractional shortening or ejection fraction within this group having uniformly poor systolic function.     

Two dimensional echocardiographic quantification of infarct size alteration by pharmacologic agents.

In 27 closed chest dogs left ventricular wall motion abnormalities assessed quantitatively with two dimensional echocardiography were used as a measure of myocardial infarct size, and the change in extent of segmental wall motion abnormalities due to drug intervention early after infarction was evaluated. The extent of wall motion abnormalities was measured with echocardiography before and at 20 and 40 minutes and 5 1/2 hours after coronary occlusion. Three subgroups of dogs received, respectively, an infusion of nitroglycerin, phenylephrine or saline solution. Infarct size was measured with technetium pyrophosphate scintigraphy of the excised left ventricle. The infarct size correlated well with the extent of wall motion abnormalities before death. Wall motion was initially similar among the three groups but was significantly improved after treatment with nitroglycerin (P less than 0.025), remained stable with continued saline infusion and worsened significantly (P less than 0.05) after treatment with phenylephrine. Two dimensional echocardiography can be used to quantify experimental canine myocardial infarction and assess the effect of nitroglycerin.     

Clinical utility of two dimensional echocardiography in infective endocarditis

The relative value of M mode and two dimensional echocardiography for detecting masses associated with endocarditis was assessed in 58 patients with clinically suspected intracardiac infection. Original M mode and two dimensional reports were retrospectively classified as showing (1) a mass lesion, (2) an abnormality not specifically a mass, (3) no mass, or (4) a technically inadequate study. None of the 15 patients without endocarditis had an intracardiac mass recorded on echocardiography. In 36 of the 43 patients with confirmed endocarditis technically adequate M mode studies and reports were available. Five (14 percent) of the 36 M mode studies showed a mass, 12 showed a more nonspecific abnormality and 19 showed no mass. Adequate two dimensional studies were available in 42 of the 43 cases. Thirty-four (81 percent) of these studies showed a mass, seven showed a more nonspecific abnormality and one showed no mass. Two dimensional studies were specially helpful in patients with a mass on a prosthetic valve or the tricuspid valve.Clinical follow-up examination showed that 17 of the 34 patients with a mass seen on two dimensional echocardiography underwent urgent surgery for clinical indications; 4 more underwent surgery later after full medical treatment. Thirteen of the original 34 patients with a recordable mass were treated with antibiotic drugs alone. The conservative use and interpretation of the M mode echocardiograms in this study made them inferior to two dimensional studies as aids in the confident recognition of intracardiac masses associated with infective endocarditis. The presence of such masses does not in itself require surgical intervention nor does it predict the ultimate course of the patient.     

Limitations of comparing left ventricular volumes by two dimensional echocardiography,myocardial markers and cineangiography

Measurement of left ventricular volume at end-diastole or end-systole with both two dimensional echocardiography and either Cineangiography or radionuclide scans, not recorded simultaneously, has shown large echocardiographic underestimation of volumes even in normal ventricles. In this study fluoroscopic and two dimensional echocardiographic recordings were obtained in 18 patients with abnormal wall motion and previously implanted myocardial markers. The echocardiographic values for volume and those derived from myocardial markers correlated well (r = 0.87), and there were no statistically significant differences in values obtained with the two methods at end-diastole or end-systole. The ejection fractions obtained with two dimensional echocardiography (mean ± standard deviation 46 ± 7 percent) and with fluoroscopic recording of the markers (41 ± 9 npercent) did not differ statistically.These results were compared with those in another 18 patients (nine with abnormal wall motion) having two dimensional echocardiography within 24 hours of a 30 ° right anterior oblique contrast left ventriculogram. Again, two dimensional echocardiographic ventricular volume correlated well with the angiographic volume (r = 0.85), although echocardiographic end-diastolic volume was consistently 20 percent less than angiographic end-diastolic volume (p < 0.01). Ejection fraction obtained with echocardiography (47 ± 8 percent) was less than that obtained with angiography (60 ± 7 percent) (p < 0.001). Interobserver variability in calculating volume with echocardiography was 4 percent.Probable reasons for the lack of severe underestimation of volume with echocardiography even in very abnormal ventricles, relative to that demonstrated in prior reports, include improvements in ultrasonic beam width, tracing method, transducer position and scan plane orientation within the ventricle. In addition, the possible effects of angiographic dye in the ventricular trabeculae are discussed and the effect of simultaneous studies by two different methods are compared.     

Conduction disturbances related to the site and severity of mitral anular calcification: A 2-dimensional echocardiographic and electrocardiographs correlative study

To investigate an apparent association of mitral anular calcium (MAC) and electrocardiographic abnormalities, the relation between location of 2-dimensional (2-D) echo-quantified MAC and conduction disturbances was studied in 140 patients with MAC (MAC group) and in 135 age- and sex-matched patients without MAC (control group). The MAC group was subclassified regarding site and severity of calcium in the mitral anulus. The site of MAC was defined as Type I, near the primary conduction system—MAC located in the medial segment and/or extending to the anterior mitral leaflet; and Type II—MAC located at the central and/or lateral segments away from the primary conduction system. The severity of MAC was graded on 2-D echocardiography as mild (localized within 1 segment) and moderate to severe (> 1 segment).

Seven patients with MAC, and only 1 control subject, had pacemakers in place. Conduction disturbances were present in 44 (31%) of 140 patients with MAC, and in 37 (27%) of 135 control patients (difference not significant). But there were more conduction disturbances in patients with Type I MAC (53%) than in those with Type II MAC (26%) (p < 0.01). Specifically, complete left bundle branch block and intraventricular conduction delay were more prevalent when MAC was near the conduction system. Conduction disturbances also were more prevalent in patients with Type I MAC than in the control group: intraventricular conduction delay (Type I, 12% versus control, 4%; p < 0.05) and total conduction disturbances (53 versus 28%; p < 0.01). These data suggest that moderate to severe degrees of MAC located near the conduction system are associated with conduction disturbances, especially intraventricular conduction delay.     

Two-dimensional echocardiographic assessment of bioprosthetic valve dysfunction and infective endocarditis

Two-dimensional echocardiography of Hancock porcine heterograft valves was evaluated by correlation with clinical, hemodynamic, angiographic and pathologic findings in 80 patients. Ninety-five aortic and mitral bioprostheses were categorized by the type of valvular abnormality: group I, dysfunction due to primary tissue failure (41 valves); group II, dysfunction due to paravalvular leakage without infection (5 valves); group III, infective endocarditis with or without hemodynamic dysfunction (28 valves); and group IV, control cases without dysfunction or infection (21 valves). Increased size of a bioprosthetic leaflet image (minimal dimensions 3 x 5 mm) was observed in 46% (19 of 41) of cases with primary tissue failure and in 62% (10 of 16) of cases with leaflet vegetations due to endocarditis. Prolapse of leaflet echoes to below the level of the bioprosthetic sewing ring occurred in 76% (28 of 37) of cases with torn leaflets and also in 46% (6 of 13) of valves with vegetations on intact leaflets. Antegrade extension of leaflet echoes to beyond the level of the stents, observed in 4 of 16 cases with leaflet vegetations, was the only echocardiographic sign distinguishing leaflet infection from leaflet degeneration. Aortic bioprostheses with ring dehiscence affecting 40 to 90% of the anular circumference showed motion discordant with the motion of the adjacent aortic root and native anulus. Although echocardiographic abnormalities are frequently observed with bioprosthetic leaflet degeneration or infection, the echocardiographic appearance often does not distinguish between these two major complications and is best interpreted concurrently with other clinical and laboratory assessment.     

Effect of transducer placement on echocardiographic measurement of left ventricular dimensions

An echocardiogram from the left ventricle may be used to estimate left ventricular volume and rate of circumferential fiber shortening, to measure posterior wall and interventricular septal thickness and to evaluate the normality of septal motion. Extended application of this technique in this laboratory has emphasized the need for a more standardized means of transducer location and direction. The effect of placing the ultrasonic transducer in several intercostal spaces along the left sternal border was tested in 14 patients. Variability in the left ventricular dimension and the difference in this dimension from end-diastole to end-systole were greater than for duplicate measurements from the same interspace. A system has been developed for more consistent placement of the transducer in each patient, using intracardiac landmarks and observation of transducer orientation to record specific cardiac structures.     

Cardiovascular physiology in a case of heterotopic cardiac transplantation

Successful heterotopic cardiac transplantation in a 24 year old man with end stage cardiomyopathy provided an opportunity to study cardiovascular physiology. The donor and native hearts, functioning independently in parallel, were studied by serial physical examination, electrocardiography, echocardiography, nuclear angiography and cardiac catheterization. Results indicated that the donor left heart assumed the predominant role in supplying systemic output, possibly contributing to decreasing function of the patient's own (native) heart. Analysis of serial nuclear angiograms revealed an initial postoperative ejection fraction of 52 and 21 percent in the donor and the native left ventricle, respectively; repeat studies 3 months postoperatively showed values of 50 and 9 percent, respectively, indicating significant deterioration in native left ventricular cardiac function. Observation of valve motion of the native heart showed major irregularities of the aortic valve in contrast to seemingly normal, regular mitral valve motion. These data raise interesting questions regarding interpretation of valve motion as an indicator of ventricular function.     

Echocardiographic recognition of paraseptal structures

Improved echocardiographic equipment provides detailed images of the heart and shows anatomic paraseptal structures previously not well defined. Echocardiograms were analyzed from 33 patients who later underwent cardiac transplantation, and the paraseptal structures noted were correlated with the pathologic specimens. Patterns associated with right ventricular chordae tendineae, the moderator band and the posterior papillary muscle are illustrated. Hypertrophic and fibrotic right ventricular trabeculae and left ventricular paraseptal bands are noted. These structures can be specifically sought and identified using the current generation of echocardiographs, thereby avoiding potential problems of septal definition and measurement.     

In vivo ultrasonic tissue characterization of human intracardiac masses

Interactions between an ultrasonic signal and cardiac tissue have been used to characterize the histologic state of myocardium in vitro. To assess the utility of in vivo ultrasonic tissue characterization, stochastic analysis was applied to the digitized echocardiographic signals from 15 patients with 2-dimensional echocardiograms suggesting intracardiac masses. Ten subjects with echocardiograms suggesting mural thrombi underwent subsequent surgery or necropsy, which confirmed thrombi in 6 and revealed no thrombi (designated artifact) in 4. Five other patients had intracardiac tumors. The amplitudes within the digitized ultrasonic signals were displayed as histograms, which were described by a parameter k that represented the degree to which each histogram departed from a totally random probability density function. In 5 of 6 thrombi, k = 0, but in all 4 artifacts, k greater than 0. The sixth thrombus had k = 0.5 due to the specular effect of the interface between the thrombus' 2 lobes. All 5 tumors had k greater than 0. Ultrasonic tissue characterization using a stochastic analysis of backscatter can be performed in vivo and helps differentiate thrombus from artifact and tumor in the heart.     

Standardized intracardiac measurements of two-dimensional echocardiography

Thirty-five healthy adults were studied by two-dimensional echocardiography to attempt to standardize a simple method for measurement of intracardiac dimensions. Both ventricles and the atria and aorta were measured in five different views: parasternal long-axis, parasternal short-axis at the level of the aortic valve, the chordae tendineae and the papillary muscles and an apical four chamber view. The minor axis of each chamber was measured in all five views; the major axis in the apical four chamber view also was measured. All measurements are presented as a range of values (mean and 2 standard deviations about the mean); the mean value is given as well as the absolute range of values measured. Normalization according to body surface area is also presented. Data from these multiple views allow assessment of asymmetry of cardiac chambers in normal subjects. The mean minor axis dimension at end-diastole of the right ventricle in the parasternal long-axis view (1.9 to 3.8 cm) was 13.6% smaller than in the four chamber view (2.2 to 4.4 cm), whereas the minor axis dimension of the left ventricle in the parasternal long-axis view (3.5 to 6.0 cm) was only 1.1% larger than in the four chamber view (3.3 to 6.0 cm). Therefore, the right ventricular minor axis dimensions are not interchangeable. Reproducibility in 10 subjects for all dimensions showed a maximal variability of 4.8%. These values permit a standardized and expeditious method for measuring intracardiac dimensions by two-dimensional echocardiography.     

Echocardiographic features of primary pulmonary hypertension

Echocardiograms were recorded in nine patients with primary pulmonary hypertension proved at cardiac catheterization. A reduced diastolic slope of the anterior mitral valve leaflet, simulating mitral stenosis but with normal motion of the posterior leaflet, was observed in all patients. Other features found included a large right ventricular dimension (nine patients), a small left ventricular dimension (three patients), a thick interventricular septum (six patients), systolic mitral leaflet prolapse (four patients) and abnormal septal motion (four patients). The last feature was most probably due to secondary tricuspid or pulmonic insufficiency, or both. The finding of a decreased mitral valve slope, often used as a criterion for mitral stenosis, should not be accepted alone as proof of mitral stenosis; the posterior mitral valve leaflet echo must be carefully searched for and identified. This echo is often difficult to identify, but the normal motion of this structure found in all patients excludes the diagnosis of mitral stenosis as a cause for the pulmonary hypertension.     

Echocardiography: Pericardial thickening and constrictive pericarditis

A total of 167 patients with pericardial thickening noted on M mode echocardiography were studied retrospectively. After the echocardiogram, 72 patients underwent cardiac surgery, cardiac catheterization or autopsy for various heart diseases; 96 patients had none of these procedures. In 49 patients the pericardium was directly visualized at surgery or autopsy; 76 percent of these had pericardial thickening or adhesions. In another 8 percent, pericardial adhesions were absent, but no comment had been made about the appearance of the pericardium itself. In the remaining 16 percent, no comment had been made about the pericardium or pericardial space. Cardiac catheterization in 64 patients revealed 24 with hemodynamic findings of constrictive pericarditis or effusive constrictive disease.Seven echocardiographic patterns consistent with pericardial adhesions or pericardial thickening are described and related when possible to the subsequent findings at heart surgery or autopsy. The clinical diagnoses of 167 patients with pericardial thickening are presented. The hemodynamic diagnosis of constrictive pericardial disease was associated with the echocardiographic finding of pericardial thickening, but there were no consistent echocardiographic patterns of pericardial thickening diagnostic of constriction. However, certain other echocardiographic abnormalities of left ventricular posterior wall motion and interventricular septal motion and a high E-F_o slope were suggestive of constriction.     

Aortitis in ankylosing spondylitis: Early detection of aortic root abnormalities with two dimensional echocardiography

Mild aortic root dilatation, cusp thickening and subvalvular fibrous ridges have been reported as characteristic in patients with ankylosing spondylitis and aortic regurgitation. Thirty-five patients with ankylosing Spondylitis (10 also had Reiter's syndrome) without clinically apparent cardiac involvement were studied using phased array two dimensional and sector-directed M mode echocardiography to determine the prevalence of aortic abnormalities. Aortic root dimensions were measured at the aortic anulus, at the tip of the cusps and 0.5 to 1.5 cm above the cusps. The two dimensional echocardiographic study was also analyzed for qualitative abnormalities. The dimensions were compared with those in 20 normal men and among patient subgroups separated according to age, duration and severity of ankylosing spondylitis and presence of qualitative abnormalities. With one exception, no abnormally increased aortic dimensions suggestive of aortic dilatation were found in any group. However, two patients had aortic dimensions greater than 4.2 cm at the valve (normal 4.0 cm or less). Also, six patients had discrete areas of increased bright echoes below the left or noncoronary cusps suggestive of a subaortic “bump” and two of the six patients had increased aortic cusp echoes suggestive of thickening or fibrosis, or both. These changes tended to occur more commonly in older patients and those with more severe disease. It is concluded that aortic root changes suggestive of inflammation or fibrosis, or both, occur in asymptomatic patients with ankylosing spondylitis and are detectable on two dimensional echocardiography. Dilatation usually does not occur without aortic regurgitation.     

Small vessel disease of the heart resulting in myocardial necrosis and death despite angiographically normal coronary arteries.

A 46 year old man who had undergone cardiac transplantation 1 year previously had progressive congestive heart failure without evidence of cardiac rejection. Cardiac catheterization and angiography revealed a reduced ejection fraction and cardiac output caused by diffuse left ventricular hypokinesia, but the epicardial coronary arteries were widely patent. The transit time of injected contrast material across the coronary arterial tree was greatly slowed. Within a few days cardiogenic shock and death occurred. The large epicardial coronary vessels were grossly patent at autopsy, although nonstenosing arteriosclerotic plaques were identifiable histologically. However, intramyocardial vessels showed severe arteriosclerotic narrowing, resulting in multiple, diffuse microinfarcts.     

Exercise response of the denervated heart in long-term cardiac transplant recipients

The left ventricular response to volume loading and graded supine bicycle exercise (3 minutes at 15, 45 and 90 watts) was assessed in nine long-term (more than 1 year) cardiac transplant recipients. Computer-aided fluoroscopy of radiopaque myocardial markers implanted in the left ventricle at the time of surgery was used to measure left ventricular dynamics. Pulmonary arterial and left ventricular pressures were monitored. Plasma norepinephrine was measured by radio-enzymatic assay at each level of exercise.Early in exercise mean end-diastolic volume (six patients) increased from a resting value of 125 to 138 ml (p < 0.02) at the 45 watt level, then decreased to 121 ml at the 90 watt level. End-systolic volume decreased from 68 to 63 ml and then to 49 ml (p < 0.01) at corresponding exercise levels. Stroke volume increased from 57 to 76 ml (p < 0.01) then declined slightly to 71 ml (p < 0.02 for increase relative to resting value). Heart rate increased gradually from 102 to 116 beats/min (p < 0.05) and then rapidly to 140 beats/min (p < 0.01). Thus cardiac output increased significantly at all levels of exercise from 5.7 liters/min at rest, to 6.5 at 15 watts (p < 0.02), to 8.7 at 45 watts (p < 0.01) and to 10.0 liters/min at 90 watts (p < 0.01). Plasma norepinephrine increased slowly from 233 pcg/ml at rest to 460 at 45 watts, then rapidly to 1,970 pcg/ml at 90 watts. Increases in velocity of circumferential fiber shortening (Vcf) and heart rate were correlated with increasing norepinephrine concentrations (r = 0.92 for Vcf; r = 0.79 for heart rate). A functioning Frank-Starling mechanism was demonstrated in seven patients with volume loading by leg elevation resulting in significant increases in end-diastolic volume, stroke volume and cardiac output in the absence of any increase in heart rate. Thus, cardiac output increases in the transplanted heart were brought about early in exercise by augmented preload and the Frank-Starling mechanism, and later in exercise by chronotropic and inotropic influences of increased circulating catecholamines.     

Apparent asymmetric septal hypertrophy due to angled interventricular septum

A distinct geometric pattern is described in patients whose M mode echocardiogram falsely indicates asymmetric septal hypertrophy. Sixty-four patients were referred because of clinically suspected idiopathic hypertropic subaortic stenosis. Thirty-six of these patients had M mode echocardiograms showing asymmetric septal hypertrophy (septal/free wall ratio 1.3 or greater). On two dimensional study, only 16 of the 36 had this finding; each of the remaining 20 had a normal interventricular septum. The apparent asymmetric septal hypertrophy on M mode echocardiography was due to anterior angulation of the septum: The thickness of the septum was exaggerated because of its oblique orientation with respect to the path of the single dimensional echocardiographic beam. This anterior direction of the septum was indicated by measuring the angle between the mid line axis of the aortic root and that of the septum. In patients with apparent asymmetric septal hypertrophy this angle was lower (97 ° ± 2.6 ° [mean ± standard error of the mean]than in patients with true asymmetric septal hypertrophy (124 ° ± 2.9 °, p <0.001) or in normal subjects (128 ° ± 1.9 °, p <0.001).M mode echocardiograms were similar in the groups with apparent and true asymmetric septal hypertrophy with respect to septal velocity and percent thickening. The two groups were likewise similar with respect to clinical features (chest pain, palpitation, systolic murmur). The group with true asymmetric septal hypertrophy had a larger proportion of electrocardiographic abnormalities. Because of limitations in technique, M mode echocardiography may allow overdiagnosis of asymmetric septal hypertrophy in certain patients. When a more secure diagnosis of this abnormality is necessary, two dimensional echocardiography is helpful.     

Preoperative invasive testing in mitral stenosis: Indications based on assessment of diagnostic yield

The role of preoperative invasive testing in mitral stenosis was assessed in 82 patients undergoing cardiac catheterization for isolated mitral stenosis. The patients were diagnosed by physical examination and echocardiography and were considered for surgical treatment primarily to relieve dyspnea. They had no precordial murmur attributable to an aortic valvular lesion and had no history of chest pain. The presence of mitral stenosis was confirmed at catheterization in all patients. All 38 patients in New York Heart Association functional class III and 8 of 9 patients in class IV had hemodynamic confirmation of mitral disease warranting operation. Although a mitral gradient was present in all 35 patients in class II, operation was not recommended in 9 (26%) of 35 with normal or mildly elevated pulmonary arterial wedge pressure. Invasive testing did not increase preoperative knowledge of aortic, tricuspid, or pulmonary valvular lesions which required surgical treatment. Coronary arteriography was performed in 44 patients (54%) and identified 4 patients with luminal narrowing (> 70% diameter reduction) affecting 1 or 2 arteries. These results suggest that preoperative invasive testing in patients with mitral stenosis is unnecessary when symptoms are moderate to severe and clinical evidence of aortic valvular or coronary artery disease is absent. However, preoperative cardiac catheterization is indicated in patients with mild symptoms to avoid unnecessary or premature mitral valve operations.