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Objectives. The goal of this study was to develop an accurate, simplified proximal isovelocity surface area (PISA) method for calculating volume flow rate using lower blue-red interface velocity produced by a color Doppler zero baseline shift technique. Background. The Doppler color proximal isovelocity surface area method has been shown to be accurate for calculating the volume flow rate (Q) across a narrowed orifice by the formula Q = PISA × Blue-red interface velocity. A hemispheric model is generally used to calculate proximal isovelocity surface area (PISA = 2πa2, where a = the radius corresponding to the blue-red interface velocity). Although a hemispheric model is simple, requiring measurement of one radius, it may underestimate the actual volume flow rate because, in the general case, the shape of a proximal isovelocity surface area is hemielliptic. Although a hemielliptic model is generally more accurate for calculating proximal isovelocity surface area, it is more complex, requiring measurement of two orthogonal radii. Methods. Sixteen in vitro constant flow model studies were performed using planar circular orifices (diameter range 6 to 16 mm). The blue-red interface velocity was changed from 3 to 54 cm/s using color Doppler zero baseline shift. Results. 1) With decreasing blue-red interface velocity, the size of the proximal isovelocity surface area was increased, and its shape changed from hemielliptic to hemispheric. 2) With the blue-red interface velocity in the range 11 to 15 cm/s, the proximal isovelocity surface area became nearly hemispheric; however, it was difficult to determine the blue-red interface radius at a blue-red interface velocity

To determine which factors may affect the image quality when an intravascular ultrasound catheter is used in vivo, the influence of blood, temperature change, and contrast media were evaluated. In addition, to confirm the reproducibility of intravascular ultrasound imaging to measure cross-sectional lumen area, intraobserver and interobserver variability were determined. The findings indicated that ultrasound images in blood are mildly attenuated, that changes from room temperature to body temperature do not have a significant impact on the image quality, that contrast media attenuates the image intensity in a dose-dependent manner, and that the intravascular ultrasound imaging catheter provides a reproducible method for measuring arterial lumen area with excellent intraobserver and interobserver correlation. © 1990, American Society of Echocardiography. All rights reserved.

A method to assess the degree to which an atheroma plaque has been disrupted by percutaneous interventional methods could be of considerable benefit. An intravascular ultrasound catheter could provide quantitative information about the distribution and quality of the atheroma prior to and following a balloon dilatation, laser, or atherectomy procedure. Additionally, the ultrasound transducer could be configured within an angioplasty balloon to visualize the arterial wall in cross section during the dilatation. Visualization of the atheroma and arterial wall also might be of benefit to help characterize the type of tissue within the plaque, which may potentially help suggest which of several alternative therapies may be most effective. The intravascular imaging catheter would provide a feasible method of identifying normal and diseased arterial wall structures during diagnostic and interventional angiographic procedures. This distinction is critical during laser therapy of eccentric plaques to prevent exposure of the uninvolved wall (Fig. 7). These high quality ultrasound images may allow quantitative assessment of the extent of atheromatous involvement of artery walls as well as the character of the atheroma tissue. Such an approach, performed percutaneously in the catheterization lab, could represent a fundamental departure from traditional angiographic methods for assessing the severity of coronary, carotid, or peripheral arterial disease.

A prototype intravascular ultrasound imaging catheter with a 20 MHz transducer was used to obtain 59 cross-sectional images in 14 segments of human atherosclerotic arteries. Three distinct components of the arterial wall were visualized on the ultrasound images: a highly reflective intima, an echolucent media, and a moderately reflective adventitia. Images were obtained at 1 mm increments in vitro and were compared with histologic sections at the same levels. Measurements of the arterial layers showed a close correlation between ultrasound images and histologic sections for the thickness of the intimal plaque (r = 0.91), the media (r = 0.83), and the total wall thickness (r = 0.85). The ultrasound images overestimated the mean intimal and total wall thickness by 0.3 mm and 0.7 mm compared to measurements in histologic sections (p less than 0.001). Intravascular imaging with high-frequency ultrasound is an accurate method for measuring microanatomic arterial dimensions and the extent of atheromatous involvement of the arterial wall. This method could represent an important adjunct to traditional angiographic techniques for assessing the severity of atherosclerosis.

To evaluate the mechanism of excimer laser recanalization and compare the results with those of laser-assisted thermal probe recanalization and mechanical recanalization, a total of 42 human atherosclerotic totally occluded arterial segments (2–15 cm long) were recanalized by excimer laser with a 400–800 micron quartz fiber pulsed at 20 Hz with 50 mJ/mm2of energy (n = 21), an Argon heated thermal probe at 10–12 watts (n = 11), a guidewire directed through a 6 Fr multipurpose catheter, or an angioplasty balloon catheter (n = 10). On histologic examination, the excimer laster created a single round lumen or multiple lumens (“Swiss-cheese” like appearance) with no evidence of thermal injury at the perimeter of the lumen. The incidence of perforation in vitro was less with an excimer laser catherter (8/21 or 38%) than with the thermal prove (10/11 or 91%) (p

Downloaded from www.ajronline.org by Univ of California Irvine on 10/07/15 from IP address 128.200.102.37. Copyright ARRS. For personal use only; all rights reserved Case The Mechanism Assisted of Peripheral Thermal Intravascular Recanalization Angioplasty: Cres P. Miranda,1 Larry Deutsch,2 The mechanism of recanalization during laser-assisted an- gioplasty in the treatment of obstructive atherosclerotic vas- cular disease has been controversial. Initial reports claimed that the laser-heated metal-tipped probe ablated atheroma as the hot tip “sought the lumen” and progressed down the artery as it created a new lumen in the central portion of the plaque [1 -3]. In distinction to the initial animal and clinical studies, an in vitro study of the mechanism of recanalization with laser-assisted thermal angioplasty found it to be a pre- dominantly mechanical process in which the laser probe was deflected by the hard, fibrocalcific plaque away from the true lumen and followed a dissection plane between the intimal plaque and the arterial media [4]. However, in human clinical trials, it is difficult to prove the exact pathway of the laser probe by using angiography or angioscopy. Recent work has documented the feasibility of imaging arteries in cross-section with a miniaturized catheter-mounted transducer that generates arterial images from inside the artery lumen [5, 6]. This report documents that the information obtained from the intravascular sonographic de- vice in vivo is consistent with the hypothesis derived from our in vitro study for the mechanism of recanalization by the laser probe. Received 1 Division 2 Division Confirmation Jim Griffith,3 Case 4 The Beckman AJR 155:1100-1102, Inc., Santa Laser by Jim Gessert,3 (SFA) man with claudication occlusions Institute, Irvine, the 100 © American Berns,4 at the had bilateral superficial bifurcation with the common femoral femoral right SFA was 20 cm, and the left SFA was occluded 23 cm. The right femoral artery was recanalized in a retrograde fashion from a puncture in the popliteal fossa. A 1 .5-mm-diameter laser probe (Model PLA-plus, advanced under and an 8-French Trimedyne fluoroscopic angioplasty Inc., Santa Ana, CA) was inserted control guiding through catheter. and an introducing sheath The laser probe was used as a cold mechanical device without turning on the argon laser. The laser probe was advanced by using intermittent forward pressure to puncture the occlusive atheroma. The course of the laser probe was followed under fluoroscopic control until it advanced to the proximal end of the SFA and reentered the lumen of the common femoral artery. The laser probe was then removed, and a guidewire was inserted through a 7-French diagnostic catheter, which was used in a rotary maneuver to enlarge the communication between the SFA and the common femoral artery. The 20-MHz sonographic catheter (Interlherapy, Inc. , Costa Mesa, CA) was advanced in the new channel to the level of the common Figure 1 A shows the level of the distal Roentgen the intravascular SFA before femoral artery. sonogram the sonographic that was obtained catheter , Orange, CA 92668. Address reprint requests to J. M. Tobis. CA 92668. CA 92717. 1990 0361-803X/90/1 Michael artery. Both popliteal arteries were reconstituted, and distal runoff was good. The patient refused surgical intervention but was willing to undergo percutaneous angioplasty. The length of the occlusion of Ana, CA 92705. November Avi Bergman,3 Report A 73-year-old artery February 1 2, 1 990; accepted after revision April 27, 1990. of Cardiology, University of Califomia, Irvine, Medical Center, P.O. Box 14091 of Radiologic Sciences, University of Califomia, Irvine, Medical Center, Orange, InterTherapy by Laser- Sonography Jonathan M. Tobis,1 and Walter Henry1 sonographic Report Ray Society entered at

An array of miniature ultrasound crystals mounted on preassembled subassembly which is, in turn, mounted on a small lumen catheter provides dimensional and other quantitative information relating to arterial wall geometry and character at disease or obstruction sites. Balloons also mounted to the catheter make it possible to use the catheter for the angioplasty (PCTA) procedure while actually imaging, in real time, the artery being dilatated and unblocked by the procedure. Efficient, highly miniature transducers are presented along with several different configurations for catheter structure containing fluid lumen, through-lumen, and electrical microcable assemblies for conducting electrical signals to and from the transducers.

Using a mechanical sector-scanner, two-dimensional echocardiograms were obtained from 28 normal subjects, 15 patients with tetralogy of Fallot, 11 patients with complete transposition of the great arteries and six patients with double outlet right ventricle. The image obtained perpendicular to the long axis of the left ventricle at the base of the venticular septum was superimposed on the image obtained perpendicular to the long axis at the origin of the great arteries. In normal subjects, these superimposed images demonstrated that the aorta originated posterior and to the left of the ventricular septum. In patients with tetralogy of Fallot, the aorta was displaced anterior and to the right resulting in the aorta over-riding the ventricular septum. In patients with double outlet right ventricle both great arteries originated anterior to the ventricular septum (i.e., from the right ventricle). In patients with complete transposition, the aorta originated anterior and the pulmonary artery posterior to the ventricular septum. Thus, cross-sectional echocardiography permits noninvasive identification of the relation of the ventricles and great arteries and, therefore, provides important information for the diagnosis of patients with congenital heart disease.

Clinical and pathologic observations were made in four infants who died with asymmetric septal hypertrophy in the first five months of life. One of these infants was stillborn and the other three were aged 1½ months, 4½ months, and 5 months at the time of their deaths. The three live-born infants demonstrated severe congestive heart failure and cardiac enlargement. The clinical features present in these three infants during life suggested a variety of other congenital cardiac malformations, including congenital mitral regurgitation, pulmonary stenosis, and endocardial fibroelastosis. In each of the four infants the ventricular septum was markedly hypertrophied and was thicker than the postero-basal left ventricular wall; septal to postero-basal free wall thickness ratios ranged from 1.8 to 2.6. Moreover, the septum of each infant contained a disordered arrangement of hypertrophied cardiac muscle cells. In three of the infants the myocardial cellular abnormalities were less marked in the left ventricular free walls than in the ventricular septum. In the fourth infant disorganized cardiac muscle cells were distributed widely in both the ventricular septum and left ventricular free wall; the clinical findings suggested the absence of left ventricular outflow obstruction in this infant. Asymmetric septal hypertrophy was documented in one first degree relative of each infant. It is concluded that asymmetric septal hypertrophy is a genetically transmitted disease that may present clinically in infancy and lead to infant death. Furthermore, the characteristic pathologic feature of asymmetric septal hypertrophy in adults, a disproportionately thickened ventricular septum containing numerous hypertrophied and disorganized cardiac muscle cells, can be present at birth.

Attempts to measure left ventricular stroke volume utilizing the Doppler aortic flow method have found varying correlations between invasive thermodilution and noninvasive Doppler methods. Because stroke volume is the product of the Doppler flow velocity integral (that is, the area under the flow velocity curve) and the cross-sectional area of the vessel through which blood flows, both variables are potential sources of error. Previous studies have shown that the Doppler flow velocity integral can be measured with acceptable reproducibility in the ascending aorta. Consequently, in this study an attempt was made to determine empirically the optimal method for measuring aortic diameter and area. The diameter of the ascending aorta was measured utilizing four Mmode and seven two-dimensional echocardiographic conventions. Doppler aortic flow velocity patterns were recorded with a 2.25 MHz M-mode echocardiographic transducer from the suprasternal notch by mapping the ascending aorta until aortic peak flow velocity was recorded. In 19 adult patients undergoing cardiac catheterization for clinical indications, Doppler stroke volume estimates utilizing the various echocardiographic conventions for measuring aortic root diameter and area were compared with simultaneous measurements of stroke volume by the thermodilution technique. The best correlation (r = 0.87) with thermodilution stroke volume was obtained by estimating aortic area from the two-dimensional parasternal long-axis images with the aortic dimension measured distal to the aortic sinuses from the inner to inner wall. The data were related by the equation: Thermodilution stroke volume=(0.73)×(two-dimensional Doppler stroke volume)+17cc. M-mode echographic measurements of aortic diameter resulted in Doppler estimates of left ventricular stroke volume that correlated poorly (r < 0.3) with thermodilution estimates. © 1985, American College of Cardiology Foundation. All rights reserved.

Cardiovascular complications are a major source of morbidity and mortality in hypertensive patients. To assess the prevalence of anatomic and functional abnormalities of the heart in such patients, we studied 234 asymptomatic subjects with mild-to-moderate systemic hypertension by echocardiography. After adjusting the echocardiographic values for age and body surface area, we found abnormally increased ventricular septal and/or posterobasal free-wall thickness in 61% of the hypertensive subjects. We found increased left atrial, aortic root, and left ventricular internal dimension (at end-diastole) in 5-7%, and decreased mitral valve closing velocity (E-F slope) and left ventricular ejection fraction were noted in six and 15% of the subjects, respectively. Four percent of the patients had disproportionate septal thickening (i.e., ventricular septal-to-left ventricular free-wall thickness ratio greater than or equal to 1.3). In contrast to the high prevalence of cardiac abnormalities detected by echocardiography, less than 10% of the hypertensive subjects had abnormal 12-lead ECGs or abnormal chest x-rays. These findings demonstrate a high prevalence of cardiac abnormalities in a population of asymptomatic hypertensive subjects. These abnormalities can be detected by echocardiography before they are otherwise apparent.

Fifty consecutive patients undergoing aortic valve replacement for isolated aortic regurgitation were studied prospectively by echocardiography, electrocardiography and cardiac catheterization. Good quality echocardiograms were obtained in 49 of the 50 patients. Left ventricular (LV) dilatation was present in all 49 patients. LV systolic function, as assessed by echocardiographic percent fractional shortening, was normal in many patients but was moderately to severely reduced (less than 25%) in 14 patients (29%). Echocardiographic studies 6 months postoperatively revealed significant reductions in LV end-diastolic dimension (73.8 mm vs 58.7 mm; p less than 0.01), and serial echocardiographic studies early and late after operation revealed that the decrease in LV size had occurred by the time of the early study (8-22 days postoperatively), with little additional change thereafter. Operative deaths occurred in three of the 49 patients (6%). Eight of the 49 patients (16%) died of congestive heart failure (CHF) after hospital discharge at times ranging from 5-43 months after operation. Preoperative echocardiographic measurements of the LV end-systolic dimension and percent fractional shortening were strongly associated (p less than 0.01) with these late CHF deaths. Preoperative LV end-systolic dimension greater than 55 mm and fractional shortening less than 25% identified the high-risk group: nine of 13 patients (69%) in this group died either at operation or subsequently from CHF. In contrast, of 32 patients with LV end-systolic dimension less than 55 mm, only one died at operation and one died late from CHF. Thus, the population at high risk of late death from CHF was identified before operation by echocardiography.

Left ventricular ejection fraction (LVEF) was calculated from 25 first-pass digital subtraction angiograms using a densitometric analysis. Digital subtraction angiograms are obtained in a computerized format; therefore, they can be readily analyzed with computer software to measure the density of the iodine signal within the image. The video signals from the image intensifier were logarithmically amplified so that there was a linear correlation between the video signal intensity and the depth of the iodine contrast material represented by that video signal. LVEF was also calculated by the area-length method from the same digital subtraction angiograms. There was close correlation between these two techniques (r = 0.94, standard error of the estimate = 5.04%). The videodensitometric EF technique is simple to perform, it correlates well with the standard area-length method, and is not dependent on geometric assumptions of LV geometry. © 1983.

In an attempt to define quantitatively the relation between left atrial size and atrial fibrillation, echocardiography was used to study 85 patients with isolated mitral valve disease, 50 patients with isolated aortic valve disease, and 130 patients with asymmetric septal hypertrophy. In all three groups of patients, atrial fibrillation was rare when left atrial dimension was below 44 mm (3 of 117 or 3%) but common when this dimension exceeded 40 mm (80 of 148 or 54%). In addition, when left atrial dimension exceeds 45 mm, cardioversion, while initially successful, is unlikely to produce sinus rhythm that can be maintained at least six months. These data suggest that left atrial size is an important factor in the development of atrial fibrillation and in determining the long term result of cardioversion. The pathophysiologic mechansim most consistent with this is that a chronic hemodynamic burden initially produces left atrial enlargement which in turn predisposes to atrial fibrillation. Only prospective studies will determine definitively whether these observations will be useful in decisions concerning prophylactic anticoagulation and elective cardioversion.

The results of operative treatment in 83 patients with idiopathic hypertrophic subaortic stenosis (IHSS) are described. Most patients with the disease are asymptomatic, or derive satisfactory symptomatic improvement from nonoperative therapy: administration of propranolol, exerice limitation, control of arrhythmia, etc. Operation is required, however, in 10-15% of patients, those who remain severely symptomatic after nonoperative treatment or who become refractory to it. Operation relieves symptoms in IHSS by relieving obstruction to left ventricular outflow, and for a patient to be considered an operative candidate severe obstruction must be documented at left heart catheterization either under resting conditions or after provocative interventions. All 83 patients were severely incapacitated--58 in Class III and 24 in Class IV. Seventy had obstruction at rest (average gradient 96 mm Hg), and 13 had only provocable obstruction. At operation the hypertrophic interventricular septum was exposed via an aortotomy, and a vertical bar of muscle was resected between parallel myotomy incisions. There were six operative deaths (7%); no patient has died since 1970. Seven patients have died late after operation, five of them from causes unrelated to their heart disease or the operation. All surviving patients describe symptomatic improvement. Fifty-two patients with obstruction at rest preoperatively (average gradient 95 mm Hg) have been studied postoperatively: no resting gradient was evident in 47, while in the remaining five the gradient was less than 25 mm Hg. Recurrence of obstruction has never been observed at late catheterization (21 pts) or late echocardiographic examination (37 pts). Obstruction could not be provoked postoperatively in ten of the 11 patients who had large gradients only with the Valsalva maneuver or isoproterenol administration preoperatively. Obstructed and provocable obstructed patients had similar symptomatic improvement after operation. A variety of rhythm and conduction abnormalities were observed both pre and postoperatively, and these are described in detail. The results of operation in these 83 patients with IHSS demonstrate that gratifying symptomatic and hemodynamic improvement uniformly follows left ventriculomyotomy and myectomy. Relief of obstruction and amelioration of symptoms have proved to be long-lasting during postoperative observation periods extending to 14 years. Continued application of the operative procedure in properly selected patients appears to be indicated.

One hundred and thiry-four patients with hypertrophic cardiomyopathy were evaluated by standard 12-lead electrocardiography. Normal electrocardiograms were extremely uncommon, occurring in less than 7% of each subgroup of patients (i.e., those with or without either symptoms or obstruction to left ventricular outflow), with the exception of those who were both asymptomatic and had no left ventricular outflow obstruction. Even in this subgroup, however, normal electrocardiograms occurred in only 27% of patients. Repolarization abnormalities and left ventricular hypertrophy were the most common abnormalities, occurring in 81% and 62%, respectively, of the total population. A broad spectrum of other electrocardiographic abnormalities was found, but none was unique to hypertrophic cardiomyopathy. Patients with vs those without electrocardiographic left ventricular hypertrophy or left atrial abnormality had significantly (P less than 0.005) greater mean ventricular septal thickness (22 +/- 0.6 vs 19 +/- 0.6 mm) and left atrial dimension (48 +/- 1 vs 40 +/- 1 mm) measured by echocardiography, and signficantly (P less than 0.01) higher mean pulmonary capillary wedge pressure (16 +/- 1 vs 10 +/- 1 mm Hg) and left ventricular end-diastolic pressure (20 +/- 1 vs 15 +/- 1 mm Hg). The high prevalence and diverse nature of electrocardiographic abnormalities suggest that any patient with an unusual and unexplained electrocardiogram should be suspected of having hypertrophic cardiomyopathy even if the physical examination is normal, as is often the case in patients without obstruction.

In an attempt to improve visualization of the position of the guidewire and dilatation balloon during coronary angioplasty, a method was developed called digital coronary roadmapping. With this method a digitally acquired coronary angiogram is interlaced with the live fluoroscopic image of the guidewire and balloon catheter. The digital coronary angiogram is superimposed at the same magnification and radiologic projection as the live fluoroscopic image onto the video monitor above the catheterization table. The digital roadmap image thus provides immediate feedback to the angiographer to assist in directing the guidewire into the appropriate coronary artery branch and to help in placement of the balloon so that it straddles the site of stenosis. © 1985.

Patients with typical idiopathic hypertrophic subaortic stenosis (IHSS) represent only one subgroup of a cardiac disease in which the characteristic anatomic abnormality is asymmetric septal hypertrophy (ASH). In most patients with ASH, left ventricular outflow obstruction is absent and cardiac dysfunction presumably is due to widespread involvement of the left ventricle by an underlying myocardial abnormality. In other patients with ASH, left ventricular outflow obstruction is present (typical IHSS) and constitutes a major feature of the hemodynamic and physical findings. To determine whether patients with outflow obstruction also have the underlying myocardial abnormality diffusely involving the left ventricle, the gross morphology of hearts from patients with and without outflow obstruction were studied both by necropsy and by echocardiography. Echocardiographic studies revealed that the ventricular septum was thicker in obstructive ASH, a finding confirmed by the postmortem studies. The necropsy studies also indicated that although the left ventricular free wall was thickened in both obstructive and nonobstructive ASH, the configuration of the left ventricular free wall was distinctly different in the two groups. In obstructive ASH, the free wall was hypertrophied and identical in appearance to that seen in valvular aortic stenosis. Moreover, echocardiographic studies indicated that the thickening of the free wall behind posterior mitral leaflet appeared to regress after operative relief of the outflow obstruction. In contrast, the left ventricular free wall of severely symptomatic patients without outflow obstruction had a markedly different and unique appearance; the free wall of left ventricle directly behind the posterior mitral leaflet was of normal or less than normal thickness, whereas the remaining free wall was nonuniformly thickened. On the basis of these findings and the microscopic data presented in the companion paper, we conclude that the myocardial abnormality in obstructive ASH (typical IHSS) is localized largely to the ventricular septum, with left ventricular free wall thickening occurring as a consequence of outflow obstruction. In symptomatic patients with nonobstructive ASH, however, the data suggest that the left ventricle, including free wall, is extensively involved with a primary myocardial abnormality.

In several patients with asymmetric septal hypertrophy (ASH) diagnosed by echocardiography (septal-free wall thickness ratios greater than or equal to 1.3), we have discovered marked discrepancies between the echocardiographic and necropsy measurements of wall thicknesses that led to uncertainty regarding the actual cardiac diagnosis. To resolve these apparent incongruities, the echocardiograms and hearts of 17 patients with cardiac disease were studied. Six of nine patients with abnormal septal-free wall ratios greater than or equal to 1.3 during life had septal-free wall ratios that were not diagnostic of disproportionate septal thickening at necropsy. Such discrepancies may be explained as follows: 1) echocardiographic measurements during life were made in diastole (as per convention), but measurements at necropsy were made in hearts that appeared to have been in the systolic phase of the cardiac cycle; 2) the left ventricular free wall thickens considerably more than the ventricular septum in systole, as determined by echocardiography. This latter phenomenon resulted in septal-free wall ratios in systole that were consistently smaller than those in diastole. Furthermore, septal-free wall ratios obtained at necropsy corresponded most closely to those obtained by echocardiography in systole.

Pericardial tamponade occurring late in the hospitalization of a patient who has undergone a heart operation can be life threatening. Recognition of this insidious, but treatable, complication is difficult. Three patients experienced delayed tamponade while receiving warfarin prophylactically following coronary artery bypass. Two-dimensional echocardiography was useful in recognizing the effusion (and thus aided the diagnosis of tamponade) in each patient. The question of whether prophylactic anticoagulation should be employed for patients undergoing coronary artery bypass procedures is also considered in light of both the present experience and collected reports from the literature.

Echocardiographic and necropsy studies were performed in 304 patients with various cardiac diseases. The overall prevalence of disproportionate ventricular septal thickening (septal to free wall ratio greater than or equal to 1.3) was 10%. However, it was related to the type of cardiac lesion. Prevalence was high (greater than 20%) in pulmonary stenosis or primary pulmonary hypertension, lower (less than 15%) in Eisenmenger syndrome or aortic or mitral valvular disease and was not present in atrial or ventricular septal defect. In right ventricular overload, prevalence of disproportionate septal thickening correlated with increasing ventricular systolic pressure. None of 16 patients with disproportionate septal thickening studied at necropsy showed marked disorientation of cardiac muscle cells in the ventricular septum, characteristic of genetically transmitted asymmetric septal hypertrophy (ASH). Furthermore, disproportionate septal thickening was demonstrated by echocardiography in only one of 59 first degree relatives of patients with disproportionate septal thickening and associated cardiac diseases. Thus, disproportionate ventricular septal thickening associated with other cardiac diseases usually is due to secondary hypertrophy and is not a manifestation of genetically transmitted ASH.

To determine the optimal time for recording left ventricular angiograms during atrial pacing stress tests, digital subtraction left ventriculograms were obtained using 12 ml of contrast material in 40 patients at rest and at peak pacing. Nineteen of the 40 patients had a third digital left ventriculogram performed between 5 and 10 seconds and 21 patients had a third digital left ventriculogram performed 30 seconds after pacing was stopped. Coronary angiography showed significant coronary artery disease (CAD) in 29 patients and no evidence of significant CAD in 11 patients. Ejection fraction (EF) increased or did not change at peak pacing in 10 of 11 patients without CAD. In the 29 patients with CAD, mean EF decreased an average of 10 percentage points (p < 0.001) and fell 2 or more percentage points in 25 patients (86%) at peak pacing. These changes in EF were accompanied by the development of wall motion abnormalities, which occurred in segments of myocardium that were supplied by coronary arteries with angiographic CAD (more than 50% diameter narrowing). In contrast, the mean EF during the postpacing studies decreased only 2.2 percentage points (difference not significant) over rest values. Moreover, 15 to 29 patients (52%) with CAD had a decrease in EF of 2 or more percentage points. Therefore, the sensitivity of the atrial pacing stress test was diminished when the analysis was performed at 10 or 30 seconds after pacing. It is concluded that EF changes and wall motion abnormalities induced by atrial pacing are of short duration. As a result, the optimal time for performing left ventricular analysis of EF and wall motion during atrial pacing is apparently at the peak heart rate and not 10 to 30 seconds after pacing is stopped. © 1985.

Real-time, two dimensional echocardiography was used to identify great artery relations in 23 infants and small children, including 16 patients with angiography documented transposition of the great arteries, tetralogy of Fallot, or pulmonary aresia. Using this technique, the heart was scanned perpendicular to its long axis at the origin of the great arteries. Great arteries cross-sectioned perpendicular to their long axes appear as circles; when sectioned longitudinally these arteries appeared as elongated sausage-shaped structures. I- patients with normally related great arteries, a curcular structure (aorta) always was positioned posterior to an elongated, sausage-shaped structure (distal right ventricular outflow tract and proximal main pulmonary artery). In transposition of the great arteries, two adjacent circular structures were observed; the anterior circle (aorta) was located to the right, left or directly anterior to the posterior circle (pulmonary artery). In pulmonary atresia or hypoplasis, a large posterior circle (aorta) was associated with an anteriorly positioned structure that was either short and small (atretic right ventricular outflow tract) or elongated with an area of severe narrowing (hypoplastic right ventricular outflow tract). Thus, real-time two-dimensional echocardiography provides a rapid, noninvasive means of accurately identifying congenital malformations of the great arteries in infants and small children and may be a useful adjunct to cardiac catheterization in the diagnosis of cyanotic congenital heart disease.

An ultrasound transducer which is sutured to the heart at operation and removal percutaneously has been developed and tested in 20 animals. The potential of this device to monitor cardiac function was measured by simultaneously recording 67 left ventricular angiograms and echograms over a wide range of hemodynamic function. In addition, the reproducibility of the data obtained from the transducer and the safety of application and withdrawal were examined. We found highly significant (p less than 0.005) linear correlation between echocardiographic and angiographic measurements of left ventricular end-diastolic volume, end-systolic volume, and ejection fraction. This transducer may provide the means to assess left ventricular size and ejection fraction continuously after cardiac operations in man.

Digital Angiography: Technology Jonathan The Implementation of Computer for Cardiovascular Imaging Tobis, Orhan Nalcioglu, T HERE HAVE BEEN significant improve- ments in computer technology over the past five years that have resulted in dramatic clinical applications of digital angiography.lm3 Although digital angiography was initially developed as a means for obtaining intravenous first-pass angio- grams, it has proven to be most beneficial as an adjunct to invasive cardiac catheterization. One reason for this rapid development is the com- puter’s unique capacities to manipulate images and obtain functional information about blood flow, iodine contrast density, and ventricular performance.4” In the area of cardiovascular diagnosis, digital angiography has been used to obtain left ventriculograms with a lower dose ( I2 mL) of iodinated contrast media than is used during standard film-based angiography. This permits multiple left ventriculograms to be per- formed, which, in turn, facilitates the perfor- mance of interventional studies such as atria1 pacing to assess the functional significance of coronary artery stenosis. During selective coro- nary angiography, digital acquisition of the images has been shown to yield diagnostic infor- mation equal to cineangiography using 35 mm film.’ In addition, the digital format provides immediate access to enhance the coronary images through computer processing techniques such as edge sharpening, contrast amplification, and fourfold image magnification. Computer software programs are also readily applied to facilitate quantitation of coronary lesions either by edge detection or videodensitometric analysis. Computer processing of selective coronary angio- grams has also been used to study the relative appearance time of iodinated contrast as a mea- sure of coronary flow reserve across stenotic vessels.* An exciting application of digital angi- ography has been the development of digital roadmapping, which uses computer processing to provide a continual image of the coronary anat- omy to act as a guide during angioplasty.’ As advances in computer technology improve and the speed of acquisition and storage of data increases, the medical applications of this science will continue to have profound effects. This Progress in Cardiovascular Diseases, Vol XXVIII, No 3 (November/December), and Walter Henry review will describe these recent innovations in the application of computers to cardiovascular imaging. CAPABILITIES Digitization OF DIGITAL PROCESSING Process Computers are typically used to process radio- logic images by transforming the continuous black and white gradations of an x-ray picture into a matrix in which the shade of gray in each small segment of the image is assigned a number that corresponds to the intensity of x-ray absorp- tion in that small image segment.” Instead of recording the x-ray image on radiographic film, the x-rays that penetrate the body and strike the image intensifier are transformed by a television camera into a television image as is commonly performed during fluoroscopy.” Each television frame is created by a rapidly moving electron beam that traces out 512 horizontal lines from the top to the bottom of the image. This television or video image is described as an analog image because there is a continuous change in electric voltage along each horizontal line corresponding to the varying light intensity across the image. Digital image-processing computers take this analog video image and convert it or digitize it into a series of binary numbers that can be utilized by the computer for manipulating the image. Each television frame is digitized by breaking up each of the 512 horizontal lines in the image into 5 12 bins. This process establishes the x--v coordinates of each bin (also referred to as a picture element or pixel) in the new com- puter image. In a 512 x 512 matrix, there are From the Division of Cardiology, University of California, Irvine, Medical Center, IO1 City Dr South, Orange. Calif Supported in part by grants from the American Heart Association, California A@iliate. and by grant No. RO I-HL31440-01 from the National Institutes of Health. Address reprint requests to Jonathan Tobis. MD, Division of Cardiology, University of California. Irvine, Medical Center, 101 City Dr South. Orange CA 92468. d I985 by Grune & Stratton, Inc. pp 195-212

Abnormal left ventricular diastolic properties have been described in patients with hypertrophic cardiomyopathy. To evaluate the diastolic filling characteristics of the left ventricle in patients with this disease, pulsed Doppler echocardiography was used to study mitral flow velocity in 17 patients with hypertrophic cardiomyopathy (11 with and 6 without systolic anterior motion of the mitral valve) and 16 age-matched normal subjects. There were no statistically significant differences between patients with hypertrophic cardiomyopathy with and without systolic anterior motion with regard to ventricular septal thickness, left ventricular posterior wall thickness, left ventricular internal dimensions or the extent of hypertrophy evaluated by two-dimensional echocardiography. Mitral regurgitation was detected by Doppler echocardiography in all 11 patients with and in 2 (33 %) of the 6 patients without systolic anterior motion of the mitral valve. Early and late diastolic peak flow velocity, the ratio of late to early diastolic peak flow velocity and deceleration of early diastolic flow were measured from Doppler mitral flow velocity recordings. There were no statistically significant differences in these four indexes between the patients with systolic anterior motion and normal subjects. In contrast, the patients with hypertrophic cardiomyopathy without systolic anterior motion showed lower early diastolic peak flow velocity, higher ratio of late to early diastolic peak flow velocity and lower deceleration of early diastolic How compared with the patients with systolic anterior motion and normal subjects, suggesting impaired left ventricular diastolic filling. These observed differences in mitral flow velocity between patients with hypertrophic cardiomyopathy with and without systolic anterior motion of the mitral valve may be explained by the more frequent occurrence of mitral regurgitation, which augments early diastolic left ventricular filling, or the less extensive myopathic process reported previously in patients with systolic anterior motion, rather than by differences in the extent of hypertrophy.

The clinical and morphologic features of tunnel subaortic stenosis, an unusual form of obstruction to left ventricular outflow, are described in 11 patients. Although patients with tunnel subaortic stenosis demonstrate a variety of cardiovascular malformations, the most characteristic anatomic feature is fibromuscular tubular narrowing of the outflow tract that remains relatively unchanged during the cardiac cycle. The aortic anulus was abnormally small in six of the 11 patients, including one who also had a hypoplastic ascending aorta. Evidence of a small mitral orifice was present in two patients, and two other patients had asymmetric septal hypertrophy. Although operation was successful in significantly reducing the outflow gradient in two of the seven operated patients, all seven patients had gradients of 50 mm Hg or more at the most recent postoperative evaluation. Three patients (two with previous operation) died suddenly; each of these patients had mild or no symptoms. Because of the apparent ineffectiveness of current operative methods in patients with tunnel subaortic stenosis, it is important to differentiate this condition from obstructions to left ventricular outflow.

Pulsed Doppler pulmonary artery velocity measurements are useful in evaluating a number of cardiac conditions including pulmonary hypertension, pulmonary stenosis and insufficiency, intracardiac shunts and other congenital abnormalities. However, variations in sample location relative to the arterial wall and valve have been thought to affect pulmonary artery velocity and acceleration measurements clinically. Therefore, pulsed Doppler and color flow mapping were performed in a pulsatile flow apparatus connected to a glass or Plexiglas model of the main pulmonary artery and its bifurcation, which contained a Hancock 29 mm pericardial tissue valve (5.35 cm2 orifice). Doppler sample volumes were placed at four sites: 1) at the pulmonary valve leaflet tips, centrally; 2) 2 cm distal to the leaflet tips, centrally; 3) 2 cm distal but laterally near the pulmonary artery wall; and 4) at the pulmonary artery bifurcation, centrally. Doppler peak flow velocity and acceleration time were measured. There was no difference between sites 1 and 2 in peak flow velocity or acceleration time. At site 3, peak flow velocity and acceleration time were both less than at site 1 (mean +/- SD, 85 +/- 44 versus 105 +/- 39 cm/s, p less than 0.005, and 162 +/- 65 versus 188 +/- 46 ms, p less than 0.03, respectively). Moreover, the pulmonary artery velocity contour at site 3 exhibited increased spectral dispersion and notching and increased variance on the color spectrum. At site 4, peak flow velocity was less than at site 1 (85 +/- 31 versus 105 +/- 39 cm/s, p less than 0.005), whereas pulmonary artery acceleration time was not significantly different. In this model, Doppler pulmonary artery flow velocity was best recorded within 2 cm of the valve and in the center of the vessel. Similar studies should be performed in the human pulmonary artery to standardize the recording technique and sample sites for Doppler measurements of velocity and acceleration.

Echocardiographic and hemodynamic studies were obtained in 42 consecutive patients undergoing aortic valve replacement for isolated aortic stenosis. Concentric left ventricular (LV) wall thickening, the most common preoperative abnormality, occurred in 95% of patients. LV dilation with reduced fractional shortening was noted in approximately 25% of patients but was severe in only one patient. Six months after operation, LV wall thickness had decreased on average but had not returned to normal and fractional shortening was unchanged. Repeat measurements in 13 patients an average of 37 months after operation were unchanged compared with measurements made 6 months after operation. When patients were subdivided into those with LV dilatation and those without, we found that patients with dilated ventricles preoperatively had a greater decrease in LV internal dimension and mass than those without preoperative dilatation. The patient data also were examined for possible association with mortality. One operative (2%) and five late cardiac (13%) deaths occurred. No preoperative or 6-month postoperative echocardiographic or hemodynamic measurement was strongly associated with these deaths, nor were any late deaths due to congestive heart failure. Compared with preoperative measurements in symptomatic patients who were operated for isolated aortic regurgitation, patients with aortic stenosis had smaller left ventricles with less depression of systolic function, as well as less aortic root and left atrial dilatation. Our data do not support the concept that the aortic valve should be replaced before the onset of symptoms to prevent irreversible LV damage in patients with isolated aortic stenosis.

Asymmetric septal hypertrophy, or ASH, is a genetically determined myocardial disorder that is transmitted as an autosomal dominant trait. ASH is characterized by a disproportionately thickened ventricular septum that contains numerous hypertrophied, bizarrely-shaped and disorganized cardiac muscle cells. Disproportionate hypertrophy of the ventricular septum has also been observed in association with certain congenital cardiac malformations. To determine whether such congenital cardiac malformations are part of the disease spectrum of genetically determined ASH, cardiac pathologic observations were made in eight patients with disproportionate septal thickening (ventricular septal to posterobasal left ventricular free wall thickness ratios of 1.5 to 2.5) and the following three categories of associated lesions: 1) parachute deformity of the mitral valve (occurring either as an isolated lesion or with ventricular septal defect, coarctation of the aorta, supravalvular ring of the left atrium, or double outlet right ventricle); 2) complete interruption of the aortic arch; and 3) ventricular septal defect. The arrangement of cardiac muscle cells in the disproportionately thickened ventricular septum was normal in six of the eight patients; in the other two patients (one with parachute deformity of the mitral valve and one with ventricular septal defect) numerous bundles of hypertrophied cardiac muscle cells were interlaced in a disorganized fashion among more normally arranged bundles of cells. First degree relatives of six of the eight patients were studied by echocardiography and found to have normal ventricular wall thicknesses and septal-free wall ratios. It is concluded that disproportionate ventricular septal thickening may occur in patients with a variety of congenital heart malformations, but that such a finding is not necessarily a manifestation of the disease spectrum of genetically determined ASH.

During the past several years one-dimensional pulse-echo ultrasound techniques have proven extremely useful in cardiac diagnosis. A one-dimensional system, however, only visualizes structures lying along a single straight line. The spatial relationships of the various cardiac structures are therefore not so easily defined as with two-dimensional systems which display the heart by constructing a plane image composed of many straight lines. We have developed a sector scanning system for obtaining two-dimensional echocardiograms in real time using ultrasonic pulse-echo techniques. Images are produced by angling rapidly a single transducer through a 30-degree sector from a fixed spot (between ribs) on the patient's chest. Thirty complete sectors (or frames) are produced per second. The use of a large diameter transducer ensures that signal strength is good and cardiac structures, including endocardium, can be visualized. Other advantages include high transducer sensitivity, real time imaging and easy visualization of various regions of the heart. Experience with more than 100 patients indicates that diagnostic quality two-dimensional echocardiograms can be readily obtained in essentially the same patients from whom one-dimensional echocardiograms are recorded and can usually be performed in less time.

Previously described Doppler color How mapping methods for estimating the severity of valvular regurgitation have focused on the distal jet. In this study, a newer Doppler color flow technique, focusing on the flow proximal to an orifice, was used. This method identifies a proximal isovelocity surface area (PISA) by displaying an aliasing interface. Volume flow rate (cm3/s) can be calculated as PISA (cm2) × aliasing velocity (cm/s). For planar circular orifices, a hemi-elliptic model accurately approximated the shape of PISA.Clinically, however, orifice shapes may be noncircular. In vitro flow experiments (n = 226) using orifices of various shapes (ellipse, square, triangle, star, rectangle) were performed. Volume flow rate calculated using a hemi-elliptic model for PISA was accurate, with average percent differences from actual flow rate = +4.3% for a square, −4.2% for a triangle, −4.7% for a star, −4.5% for an ellipse and −2.8% for a rectangle. However, average percent differences for calculated volume flow rates using a hemispheric model for PISA shape ranged from −11.6% (square) to −34.8% (rectangle).In addition, to evaluate whether PISA is influenced by machine factors, in vitro studies (n = 83) were performed. For a volume flow rate of 13 liters/min, the color aliasing radius was not affected by: 1) system gain(radius = 9.9 mm at −20 dB versus 10.4 mm at +20 dB); 2) wall filter(10.8 mm at high versus 11.2 mm at tow); 3) frame rate(11.2 mm at 6/s versus 10.6 mm at 22/s); 4) transmit power(10.3 mm at high versus 10.1 mm at low); and 5) packet size(10.6 mm at 4 samples/line versus 10.5 mm at 8 samples/line). The aliasing radius was lower at higher aliasing velocities. However, the calculated volume flow rate was not affected by changes in aliasing velocity.It is concluded that differences in planar orifice shape do not affect volume flow rate calculated using a hemi-elliptic model. Furthermore, changes in machine factors do not alter volume flow rate calculated using the PISA method. The PISA method may have advantages over previous Doppler color flow methods in calculating volume flow rate and may be useful clinically in estimating valvular regurgitant or shunt volume.

To assess the ability to detect coronary artery narrowings from computer-acquired angiograms, a panel of 4 observers independently identified and measured focal coronary narrowings from digital subtraction angiograms and compared the results to those obtained from standard 35-mm cine film angiograms. Both cine and digital angiograms were obtained sequentially using selective intracoronary artery injection of standard amounts of iodinated contrast media. Digital images were obtained at 8 frames/s with a 512 × 512 × 8-bit pixel matrix. Modifications in the imaging chain for computer acquisition included a slower pulsed radiographic mode, a progressive scan camera, and initial storage of the images on an 80-megabyte digital hard disk. Postprocessing computer algorithms were used to enhance the unsubtracted digital images; these included single-frame, mask-mode subtraction, vessel boundary edge enhancement, and 4-fold pixel magnification. In 19 patient studies, 32 arteries were reduced more than 25 % in diameter according to at least 1 of 4 observers on either the digital or cine film angiograms. There was no significant difference in the mean percent diameter narrowing for all the narrowings between the digital angiograms (53 ± 31 %) and the cineangiograms (52 ± 31 %). In addition, a 2-way analysis of variance yielded no significant difference between the amount of variability in the measurements between the cine film and the digital technique. This similar variability persisted when subsets of patients based on the degrees of stenosis were considered (e.g., only narrowings from 50 to 90% diameter reduction). Because digital acquisition permits immediate playback with image enhancement and greater ease of coronary artery quantification, digital angiography may have widespread clinical use for the detection and quantitation of coronary artery disease. © 1984.

Echocardiographic data from 92 younger normal subjects (1 month to 23 years of age) and 136 older normal subjects (20-97 years of age) were pooled and analyzed to obtain prediction equations for normal echocardiographic values. Using a bivariate regression model with the assumption that variability is constant as a percentage of the expected value, we developed regression equation and graphs that allow calculation of a 95% prediction interval for several echocardiographic measurements as a function of the subject's age and either body weight or body surface area. Body weight could be substituted for body surface area with no loss of precision. Further, examination of residuals showed that the linear prediction model fit well for all ages and all echocardiographic measurements studied. The measurements were obtained using the recently published standards recommended by the American Society of Echocardiography.

The Future of Computerized Cardiac Angiography WALTER L. HENRY, MD, and JONATHAN TOBIS, During the past 2 decades, digital computers have had an enormous impact in many areas, including medicine. Initially, the benefits to be derived from computers for the medical care system were obscured by high equip- ment costs and difficulty in interacting with the devices. During the past 5 years, however, the cost of computer hardware has decreased dramatically and improve- ments in software have allowed more effective human- computer interaction. These recent developments have produced equipment in which the advantages of com- puter technology are obvious to the physician-user. For example, most, if not all, present-day medical imaging devices are basically specialized computers programmed to process images coming from a variety of sources, such as x-ray machines, gamma cameras or ultrasound transducers. Computer processing of x-ray images is a clinical application that has occurred only recently. This is particularly true in the field of cardiac angiography, in which many frames of angiographic images must be processed each second. In addition, each cardiac angi- ographic frame must be converted into a computer format in such a way that very small detail in the image is preserved. This requirement for fine detail and high frame rates made computer processing of cardiac an- giograms possible only during the past few years, as large and relatively inexpensive computers and so- phisticated digital storage devices were developed. Advances in computer technology are still occurring very rapidly, and computer processing of ventricular and coronary angiograms is now feasible in a routine clinical environment. Computer processing of cardiac angiograms has many advantages. One of the major advantages is that images can be manipulated using various algorithms to enhance the visibility of iodinated contrast material. For ex- ample, the mask subtraction algorithm allows studies to be done with a smaller amount of contrast medium, which, in turn, may result in less risk and less discomfort to the patient. This algorithm has been used by several groups, who have shown that digital subtraction left ventriculograms can be obtained with direct intracar- diac injection of one-fourth the standard amount of contrast material. The lower amount of contrast pro- duces fewer ectopic beats and fewer hemodynamic changes during and after the injection. A second major advantage of computer processing of ventricular and MD coronary angiograms is the ability to quantify disease in a way that has been cumbersome, if not impossible, using film-based tine methods. Although methods for performing quantitative analysis of coronary angio- grams are being developed, preliminary studies indicate that it should be possible in a routine clinical environ- ment to quickly and accurately quantify the reduction of a coronary artery lumen produced by atherosclerotic lesions. The ability to estimate the minimal luminal diameter of coronary lesions should provide signifi- cantly improved information upon which clinical deci- sion making can be based. This information may prove especially useful before and during coronary angioplasty procedures. In addition, these methods will facilitate an analysis of the impact of various interventions, in- cluding angioplasty, on coronary artery disease. Computer processing of cardiac angiograms is not without problems and cost. Financially, present digital angiographic systems are expensive-$200,000 to $300,000. This cost is partially offset by savings in film and film processing equipment. These film savings do not nearly offset the cost of image processing computers. Some indirect costs, however, may be significantly re- duced by computer processing of cardiac images, such as the technician and physician time required to analyze quantitatively ventricular and coronary angiographic studies. When the cost of physician and technician time is factored in, present devices are somewhat more cost competitive. Another problem with computer image processing relates to the use of mask subtraction for enhancing ventricular and coronary images. With this method, a mask image of the heart must be obtained before the injection of contrast material into the ventricle or cor- onary arteries. Therefore, the patient must not move between the time the mask is obtained and the subse- quent images are processed. Otherwise, misregistration artifacts appear in the images. This problem can be minimized by having the patient hold his breath just before and during the injection of contrast material. Also, various algorithms built into the image processing computer can be used to move the mask relative to the contrast-filled images in order to reduce misregistration artifact. Thus, even when patients move during the study, the digitized and subtracted ventricular and coronary images can be processed and misregistration artifact minimized. Alternatively, other image pro- cessing methods that do not require the use of a mask, such as recursive filtering, can be used to enhance im- ages. Coronary stenosis can also be quantified using the unsubtracted images. In our experience, the unsub- tracted coronary images that are stored digitally, edge enhanced and magnified are as good for analysis as standard film-based images. Although the spatial res- From the Department of Medicine, University of California, Irvine, California College of Medicine, Orange, California. Manuscript received February 13, 1984, accepted February 25, 1984. Address for reprints: Walter L. Henry, MD, University of California, Irvine, California College of Medicine, 101 City Drive South, Orange, California 92668.

During the past decade, closed-circuit television has become an important means of displaying images in medicine. Important concurrent physiological signals in analog form are not readily displayed simultaneously with images using standard television systems. This communication describes a moving-trace design which superimposes analog traces on video images. Investigators can thereby directly visualize and evaluate relationships between images and dynamic physiologic variables.

Pulse-echo ultrasound, a valuable tool for noninvasive cardiac examination, has been used extensively to determine left ventricular volume and wall thickness. It is often difficult, however, to visualize simultaneously the endocardial and epicardial surfaces of the left ventricular posterior wall because of dynamic range and grey scale limitations. Although the signal reflected at the epicardial-lung interface is much stronger than the signal from surrounding myocardium and lung, it is often obliterated when the receiver gain is increased sufficiently to record the endocardial echo. We have developed a switched gain technique which allows both wall surfaces to be visualized in real time. An oscillator rapidly switches the receiver gain between two levels that are independently set to display the two wall surfaces; thus, echograms are generated with high and low gain portions closely mixed. The endocardial surface is seen best at high gain; the epicardial surface at lower amplification.

Using digital subtraction angiography, left ventriculograms were obtained with 10 ml of iodinated contrast material in 21 patients both at rest and during atrial pacing. In 15 patients with significant coronary artery lesions (CAD) (greater than 50% diameter narrowing in at least 1 major artery), ejection fraction decreased during atrial pacing from a mean of 62 +/- 14% to 51 +/- 15% (p less than 0.001). In 14 (93%) of 15 patients, ejection fraction decreased or was unchanged during pacing. In 6 patients with chest pain but normal coronary arteries, ejection fraction increased from a mean of 66 +/- 9% at rest to 72 +/- 6% during atrial pacing (p less than 0.01). Ejection fraction increased by greater than or equal to 5% during pacing in 5 of 6 patients with normal coronary arteries. Patients with CAD also had an abnormal response in end-systolic volume during atrial pacing (50 +/- 31 ml at rest versus 47 +/- 24 ml during pacing) compared with patients with normal coronary arteries (46 +/- 16 ml at rest versus 26 +/- 9 ml during pacing; p less than 0.01). The digital ventriculograms demonstrated new or increased wall motion abnormalities during atrial pacing in 4 of 5 patients with CAD who had wall motion abnormalities at rest and in 8 of 10 patients with CAD who had normal wall motion at rest. Moreover, these wall motion abnormalities occurred in myocardial wall segments that were supplied by coronary arteries with significant lesions. Thus, because digital subtraction angiography allows multiple left ventriculograms to be obtained during routine cardiac catheterization, intervention studies such as atrial pacing can be used to obtain a functional assessment of the severity of coronary arterial lesions.

Cardiac size, function and rhythm were examined in 11 patients with anorexia nervosa. Mean left ventricular, left atrial and aortic dimensions on echocardiogram were below normal adult values at baseline. In addition to decreased cardiac dimensions--ventricular ectopy, relative hypotension, bradycardia and blunted heart rate--response to exercise were noted. Left ventricular systolic function, however, was unimpaired as indicated by normal echocardiographic fractional shortening, and by normal exercise augmentation of ejection fraction determined by radionuclide cineangiography. Eight of the patients responded to treatment with a mean weight gain of 32%. In these eight, cardiac dimensions increased toward normal: left ventricular dimension increased by 13%; left atrial dimension by 20%; aortic dimension by 15% and estimated left ventricular mass by 20%. We conclude that abnormalities of heart size and rhythm occur in patients with anorexia nervosa. However, cardiac dimensions, including left ventricular mass, may increase following nutritional rehabilitation, accompanied by an increase in heart rate and blood pressure.

Left ventriculograms were obtained with the use of 10 ml of contrast media by passing fluoroscopic video images through a video image processor. The low concentration of dye in the left ventricle was enhanced by the technique of mask mode subtraction, and the images were postprocessed to increase visibility by manipulation of the gray scale and contrast levels. These digital subtraction angiograms were compared to standard cineangiograms by means of 40 ml of contrast media. Of 30 patients studied, six (20%) had runs of ventricular tachycardia during the cineangiogram and had to be excluded. In the remaining 24 patients, there was a good correlation between the two techniques for left ventricular end-diastolic volume (r = 0.77, end-systolic volume (r = 0.95), and ejection fraction (r = 0.97). Spatial resolution in the digital studies was adequate to appreciate wall motion abnormalities that were visualized on the cineangiograms. Left ventricular end-diastolic pressure (LVEDP) did not change after the 10 ml injection, but the mean LVEDP rose 6.0 mm Hg after the 40 ml cineangiograms (p less than 0.01). Digital subtraction angiography can be used to obtain left ventriculograms with one-fourth the amount of contrast media and one-fourth the x-ray exposure compared to standard cineangiograms. This technology will permit multiple left ventriculograms to be obtained which, in turn, will allow intervention studies to be performed in the catheterization laboratory.

Although considerable information is available concerning the clinical features and natural history of asymmetric septal hypertrophy (ASH) in adults, little is known of this disease in children. The clinical characteristics and course of 46 children with ASH, who were evaluated at the National Heart and Lung Institute, have been analyzed. Twenty-four children had obstruction to ventricular outflow; 22 children had no obstruction to ventricular outflow, including 11 patients without overt manifestations of cardiac disease other than echocardiographic evidence of ASH. Thirty-five of the 46 children have been followed for one to 16 years (average 7.4 years). These latter children represent that subgroup of patients with ASH referred to the National Heart and Lung Institute and diagnosed prior to the general availability of echocardiography. The clinical course of these patients was variable. Fourteen (40%) of the 35 patients improved or remained stable, including four patients who received propranolol. Ten (29%) of the 35 patients deteriorated clinically and 11 (31%) of the 35 patients died suddenly (4% mortality per year). Two of the patients who died suddenly had previously undergone operation (six and 13 years previously) with resultant abolition of the outflow gradient; four others were taking propranolol. Neither symptomatology, electrocardiographic abnormalities, heart size, left ventricular ejection or upstroke time, magnitude of outflow gradient, or left ventricular end-diastolic pressure proved predictive of sudden death. Excluding patients who had previous operation, eight (40%) of 20 patients with obstruction who were followed long term and one (9%) of 11 patients without outflow obstruction died suddenly. Thus, the clinical and hemodynamic spectrum of ASH in childhood is broad. However, deterioration in clinical condition or sudden death has been relatively common in children with overt signs of cardiac disease.

To test the hypothesis that the ventricular septum moves during systole toward the center of the ventricular mass (so that the end-diastolic position of the septum within the heart should determine both the direction and the magnitude of septal motion during systole), echocardiograms from patients with several different hemodynamic burdens were analyzed. A linear relation was noted between the end-diastolic intracardiac position of the ventricular septum and the direction and magnitude of systolic septal motion in 1) forty three patients with an atrial septal defect )regression coefficient r = 0.80), 2) fourteen patients with other causes of right ventricular volume overload (r = 0.82), 3) nineteen patients with left ventricular volume overload (r = 0.74), 4) ten patients with right ventricular pressure overload (r = 0.93), 5) ten patients with left ventricular pressure overload (r = 0.80), 6) twenty-eight normal subjects (r = 0.82). We conclude that, in the presence of normal ventricular activation and contraction, the direction and magnitude of sepatal motion during systole is determined by the intracardiac position of the septum at enddiastole.

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Patients with hypertrophic cardiomyopathy (i.e., asymmetric septal hypertrophy) may show obstruction to left ventricular outflow under basal conditions or with provocative maneuvers. The presence of dynamic left ventricular outflow tract obstruction in patients with concentric ventricular wall thickening (but without abnormalities of the aortic valve) has been less well appreciated. Clinical and morphologic features of five patients with nondilated left ventricles and with left ventricular outflow obstruction are presented. In each patient peak systolic pressure gradients between left ventricle and systematic artery were measured at cardiac catheterization and ranged from 60-140 mm Hg under basal conditions or with provocation. Each patient had echocardiographically documented systolic anterior motion of the anterior mitral leaflet, which was apparently responsible for the outflow obstruction, and concentric left ventricular wall thickening (septal-free wall thickness ratio of less than 1.3). Two of the five patients had evidence of genetically transmitted hypertrophic cardiomyopathy, as evidenced by disorganized muscle cells in the ventricular septum or asymmetric septal hypertrophy in first degree relatives. Hence, left ventricular outflow tract obstruction associated with systolic anterior motion of the anterior mitral leaflet may occur in some patients with concentric left ventricular hypertrophy who do not have typical hypertrophic cardiomyopathy.

Forty-five symptomatic patients with aortic regurgitation underwent graded treadmill exercise testing before operation. Twenty-seven patients (group A) could not complete stage I of the National Institutes of Health exercise protocol because of limiting symptoms (exercise duration less than or equal to 22.5 minutes); 18 patients (group B) completed this stage without limiting symptoms (exercise duration > 22.5 minutes). Patients in group A had higher resting pulmonary capillary wedge pressures (mean 19 vs 13 mm Hg, p < 0.05) and left ventricular (LV) end-diastolic pressures (mean 24 vs 16 mm Hg, p < 0.05) than those in group B, but did not differ with respect to LV systolic dimension or fractional shortening by echocardiography or LV ejection fraction at rest or during exercise by radionuclide cineangiography. Among 32 patients with subnormal preoperative LV fractional shortening on echo, nine of 17 in group A and 0 of 15 in group B have died (p < 0.01); seven of the nine deaths were from late congestive heart failure. Group A patients also had less decrease postoperatively in LV diastolic size by echocardiography (mean decrease 8 vs 23 mm, p < 0.001) and less increase postoperatively in LV ejection fraction during exercise by radionuclide cineangiography (mean increase 11% vs 23%, p 0.05) than group B patients. No group A patient and 60% of group B patients had normal exercise ejection fractions postoperatively (p < 0.01). The differences in postoperative mortality and function were not predicted by the differences in preoperative hemodynamics between the two groups. Thus, exercise capacity is imprecise in assessing preoperative LV function in symptomatic patients with aortic regurgitation, but is useful in predicting long-term survival after operation and reversibility of LV dilatation and systolic dysfunction.

To determine if the hemodynamic response to vasodilator therapy can be assessed noninvasively by pulsed Doppler velocimetry, we compared the hemodynamic changes after treatment to changes in Doppler aortic blood flow measurements. The relationship between the absolute values and percent changes of invasively measured systemic vascular resistance (SVR) and stroke volume (SV) and Doppler-measured peak flow velocity (PFV), left ventricular ejection time (ET) and flow velocity integral (FVI) were evaluated. Measurements were made during 18 drug interventions in 13 patients treated with vasodilator agents for congestive heart failure (CHF). A poor correlation was found between the absolute values of either SVR or SV and the absolute values of each of the three Doppler aortic blood flow indexes studied. In contrast, a good correlation was found between percent changes in aortic PFV and in SVR (r = -0.89), and between percent changes in Doppler aortic FVI and in SV (r = 0.88). The correlation between percent changes in SVR and FVI revealed an r value of -0.65, while the correlation between percent changes in SVR and in ET showed an r value of -0.15. Percent changes in SV and either PFV or ET correlated with r values of 0.75 and 0.70, respectively. We conclude that Doppler aortic blood flow measurement can be used to assess quantitative changes in SVR and SV after vasodilator therapy. These findings suggest that it may be useful for evaluating vasodilator drug therapy in patients with CHF.