Left Anterior Oblique View Research Articles

Angiographic anatomy of the left ventricle

Casts of normal left heart chambers were prepared after the method of Tompsett and were orientated in their normal anatomical positions. They were then photographed from positions equivalent to the projections used in angiocardiography in order to indicate the advantages and shortcomings of the standard projections. Frontal and lateral views produced marked foreshortening of the left ventricle and obscured the mitral valve area. The right anterior oblique demonstrated the ventricular outline and the mitral valve in profile and is advised for the study of ventricular function. The equivalent left posterior oblique is preferred for demonstrating mitral valve disease on purely practical radiographic grounds. The left anterior oblique view projected the ventricular septum in profile and is preferred for the demonstration of ventricular septal defects. This study suggested that slight right anterior oblique views might be more informative in the study of the aortic valve than the lateral or left anterior oblique views normally preferred. Casts of normal left heart chambers were prepared after the method of Tompsett and were orientated in their normal anatomical positions. They were then photographed from positions equivalent to the projections used in angiocardiography in order to indicate the advantages and shortcomings of the standard projections. Frontal and lateral views produced marked foreshortening of the left ventricle and obscured the mitral valve area. The right anterior oblique demonstrated the ventricular outline and the mitral valve in profile and is advised for the study of ventricular function. The equivalent left posterior oblique is preferred for demonstrating mitral valve disease on purely practical radiographic grounds. The left anterior oblique view projected the ventricular septum in profile and is preferred for the demonstration of ventricular septal defects. This study suggested that slight right anterior oblique views might be more informative in the study of the aortic valve than the lateral or left anterior oblique views normally preferred.

Left anterior oblique view for evaluation of left atrial size.

The left anterior oblique film of the chest provides a sensitive and accurate gauge of left atrial enlargement. The posterior wall of the atrium, which distends when the chamber enlarges, is seen in profile in this view. Dilatation of the left atrium is almost always reflected by this segment which assumes a convexly, curved contour. This finding is independent of most of the conditions that can alter the other roentgen signs of left atrial enlargement.

A new apparatus for the investigation of congenital heart disease.

With the move to a new X-ray department, the opportunity was taken to design equipment that was particularly adapted to the problems of investigation of congenital heart disease. Five principles in design were adopted: (1) The apparatus had to allow biplane fiuoroscopy. (2) It had to allow biplane cine-radiography. (3) The two planes should not necessarily be at right angles to each other and the main emphasis was to be on the facility for obtaining oblique projections at varying angles. (4) These projections should be obtainable with the minimum of movement of the subject. (5) There should be good access to the patient. Reasons for deciding on these principles were as follows: Firstly, biplane fiuoroscopy was required to help localisation of the catheter tip in three dimensions; this is invaluable in congenital heart disease, particularly in the more complex anomalies. A simple example of this lies in the constantly recurring question—Was the catheter tip passed from the right atrium to the left? The frontal view will often answer this question but there is more certainty if the tip of the catheter can be seen lying posteriorly in the position of the left atrium in the left anterior oblique view. Secondly, although multiple contrast injections (Astley, Gotsman and Parsons, 1965) still constitute the basis of the investigational method employed in complex lesions, it is obviously advantageous to be able to reduce the number of injections when possible. Hence the requirement of biplane cine-radiography.

Left ventricular cineangiographic observations in muscular subaortic stenosis

Left ventricular cineangiographic studies in 35 patients with muscular subaortic stenosis demonstrated a definite sequence of events in systole in this condition. Early systole was characterized by a rapid, convulsive ejection into the aorta, during which time, in the left anterior oblique view, the anterior ventricular septum began to encroach on the outflow tract and the basal attached portion of the anterior mitral leaflet moved out of the outflow tract in the direction of normal mitral valve closure. By mid-systole, either anterior septal encroachment or a radiolucent area, or both, developed in the outflow tract. This radiolucent area indicated the site of obstruction caused by the mid-systolic apposition of the anterior ventricular septum with the lower (free) half of the anterior mitral valve leaflet. The latter was observed to move actively into the outflow tract in some instances. After the early aortic ejection and the development of the outflow tract obstruction, late systolic mitral regurgitation occurred and appeared to be the principal determinant of the end-systolic size of the left ventricle. Postoperative cineangiograms demonstrated the site of the ventriculomyotomy in the left ventricular outflow tract and lessening or abolition of the outflow tract obstruction and the mitral regurgitation.

Collateral circulation in subclavian stenosis or atresia: Angiographic demonstration of retrograde vertebral-subclavian flow in two cases with right aortic arch

Angiographic evidence of retrograde vertebrosubclavian flow in 2 children is presented. Both have identical congenital anomalies, namely, right aortic arch, aortic diverticulum, left subclavian atresia in one and severe stenosis of the same artery in the other. Although one of these children has what might be the onset of claudication in the arm, symptoms of cerebral ischemia, i.e., “subclavian steal” are absent. Additional blood flow to the affected arm from the cervical collateral vessels and the absence of cerebral atherosclerosis may be factors responsible for the absence of symptoms in these children. It is suggested that in some adults with the “subclavian steal” the arterial stenosis is of congenital origin. The importance of inequality of the radial pulses and blood pressures, a sign found in both adults and children, is emphasized. Clinical differentiation of the sign, also present in coarctation of the aorta with stenosis of the left subclavian artery and the supravalvular aortic stenosis syndrome, is discussed. The anomalies associated with a right aortic arch can be predicted from plain chest roentgenograms with barium swallow by noting the side (right or left) on which the arch and the first part of the aorta descend and the size and shape of the esophageal impressions in the posteroanterior and left anterior oblique views.

The value of the lateral view of the rectosigmoid

Summary Four cases of carcinoma of the rectosigmoid are described in which the growth was shown only on the lateral film. In none was the growth palpable per rectum. In two the growth was not visible at the first sigmoidoscopy, though in one of these it was seen at a second sigmoidoscopy under an˦sthesia. One case is described illustrating an external pressure defect in the sigmoid, seen only on the lateral film. The radiographs of 100 consecutive barium enemas were analysed to determine the relative value of the lateral and oblique views of the rectosigmoid. It was concluded that both lateral and right anterior oblique views of the rectosigmoid should be obtained at every barium enema examination, and that the left anterior oblique view need be obtained only if at fluoroscopy it seems that it might be of value. Our thanks are due to the members of the staff of The Middlesex Hospital for permission to refer to patients under their care, and especially to Mr. O. V. Lloyd-Davies for information and advice in the preparation of this paper. We are grateful, also, to Sir Harold Graham Hodgson, Director of the X-ray Diagnostic Department, for facilities.

The value of the recumbent oesophagram in assessing left auricular enlargement.

1. A measurement of the posterior displacement of the oesophagus was made in the erect and recumbent right anterior oblique views in 50 normal subjects and in 50 cases with mitral valve disease. 2. Standards for this posterior displacement were established for both the erect and recumbent views. 3. The accuracy in the diagnosis of mitral valve disease was no greater in the recumbent view than in the erect view. The actual results favour the erect view in this respect (62 per cent erect, 54 per cent recumbent). 4. The degree of displacement in the erect or recumbent views was not as accurate in the diagnosis of left auricular enlargement as the presence of two or more of the following signs: a left auricular appendage, a double density and evidence of left auricular enlargement in the left and right anterior oblique views. 5. The fallacy of employing backward displacement of the oesophagus with the patient recumbent as an early sign of mitral valve disease was shown by the large percentage (56 per cent) co...

The radiological diagnosis of mitral valve disease.

1. The radiological features of 100 cases of mitral stenosis were contrasted with 100 control cases. 2. Four signs of left auricular enlargement were assessed. When any one of these alone was present there was an almost equal chance of the case in question not being due to mitral valve disease. When two or more were present together the chance of the case being one of mitral disease was approximately 23 : 1. The value of searching for all these four features when attempting to establish the diagnosis of mitral valve disease is stressed. 3. In the mitral series 90 per cent of cases showed at least one of the four signs described for left auricular enlargement. Ten per cent of cases, however, showed no evidence of left auricular enlargement. 4. In the control series 16 per cent of cases showed at least one of the features of left auricular enlargement. 5. The importance of a hitherto recognised, but never emphasised, sign of left auricular enlargement in the left anterior oblique view is stressed. 6. Neither heart size nor the co-existence of other heart disease was found to diminish the frequency with which features of left auricular enlargement could be found in mitral valve disease. 7. Other features of left auricular enlargement were also assessed. It was concluded that they were of little value in establishing the diagnosis in early or doubtful cases. 8. Features other than those due to left auricular enlargement were found to be of little diagnostic value.

Determination of individual enlargement of the ventricles; method based on angiocardiography in the left anterior oblique position.

There are numerous methods of cardiac measurement, but almost all of them are deficient in one respect: they indicate general enlargement of the heart and are therefore useful only for demonstration of cardiomegaly that modifies all the cavities at the time of examination. Since the different diseases that affect the heart frequently produce selective enlargement of a single chamber in the beginning, it is of importance to know how to recognize such a change. Demonstration of enlargement of the left auricle is based on the following well known features: elevation of the left main bronchus as a result of the upward enlargement of the chamber, demonstrable in the postero-anterior and left anterior oblique projections; posterior displacement of the barium-filled esophagus when there is backward bulging of the auricle, seen in the right anterior oblique view; and frequently abnormal prominence at the level of the left middle arch and a double contour of the right inferior arch, to be seen in the postero-anterior film. Lengthening of the right inferior arch in the postero-anterior view is one of the signs of right auricular enlargement. The enlarged auricle will also be visible in the lower portion of the cardiac contour, in a right anterior oblique projection. In some cases it will produce unusual lengthening of the anterosuperior contour demonstrable in the left anterior oblique view. There would seem, therefore, to be sufficient data for radiologic evaluation of the auricular cavities. This is not true of the ventricles. The right ventricle plays no part in the contour of the cardiac shadow as seen in the postero-anterior view except when there is tremendous enlargement. In that event it may appear in the middle or inferior arch on the left side. The convexity of the middle arch, as has been demonstrated by Chavez, Dorbecker, and Celis (1), is normally formed by the main pulmonary artery or its left branch; it may be formed by the left auricle when the latter is unusually enlarged to the left. There may thus be confusion in the interpretation of the postero-anterior film. In both oblique views, the right ventricle forms the anterior contour of the cardiac silhouette, and its enlargement is indicated by changes in its convexity toward the anterior thoracic wall. The left ventricle, as seen in the posteroanterior view, constitutes the left inferior arch in the contour of the heart, and lengthening of this arch indicates left ventricular enlargement. In borderline cases, however, and with the transverse type of heart, this feature is difficult to evaluate. In the right anterior oblique view, when the degree of obliquity is minimal, the left ventricle forms part of the anterior contour; otherwise it lies behind the right ventricle.

Left ascending aorta with right arch and right descending aorta.

Most of the anomalies of the aorta have been carefully described, and the criteria for their diagnosis have been clearly delineated. It is the purpose of this paper to present a rare aortic anomaly which can be detected with ease by routine radiologic examination. The roentgen findings in this condition have not previously been described. Case Report P. G., a five-month-old white boy, was admitted to the hospital because of persistent cyanosis and increasing dyspnea. Intermittent cyanosis had developed one week after birth, and the condition had become sufficiently severe to necessitate continuous oxygen therapy. Physical Examination: The child was small and underweight. Deep generalized cyanosis was present. The heart was normal to percussion, and no murmurs were heard. Coarse rhonchi were audible throughout the lungs. There was marked retraction of the upper abdominal wall. The liver was felt two fingerbreadths below the costal margin and did not pulsate. No clubbing was present. Laboratory Findings: The hemoglobin level was 12 gm., and the red blood cell count was 4,200,000. The electrocardiogram showed marked right axis deviation. Roentgen Examination: The lung fields were abnormally clear. In the postero-anterior projection, the heart appeared normal in size. At the left upper cardiovascular border was a pulsating bulge extending from the region of the pulmonary artery segment up to the point usually occupied by the aortic knob. The descending aorta was clearly delineated on the right (Fig. 1). On the barium esophagram, the esophagus was shown to be displaced to the left at the level of the aortic arch, indicating the presence of a right arch (Fig. 2). In the left anterior oblique view, no obvious chamber enlargement was demonstrated. The barium-filled esophagus was displaced posteriorly at the level of the aortic arch. The descending aorta was more anteriorly placed than is usual in this projection and overlapped the posterior cardiac border (Fig. 3). This constituted further evidence for a right descending aorta. There was some fullness at the usual site of the pulmonary artery in the right anterior oblique view (Fig. 4). In the lateral projection, the trachea was displaced posteriorly, apparently by a smooth vascular structure (Fig. 5). These findings suggested the possibility that the aorta arose on the left, with the transverse portion of the arch crossing anterior to the trachea, and the descending aorta on the right. If this hypothesis were correct, the bulge at the usual site of the pulmonary artery, seen in both the postero-anterior and the right anterior oblique view, represented the ascending aorta. A vascular ring was also a possibility, although there was no evidence of impingement upon the esophagus posteriorly. Because of the relatively avascular lung fields, it was assumed that there was diminished pulmonary arterial flow, and the presence of pulmonic stenosis of a high degree with an atrial septal defect was considered.

The heart in normal infants and children: Incidence of precordial systolic murmurs and fluoroscopic andelectrocardiographic studies

Summary 1. The physical signs, fluoroscopic, and electrocardiographic findings are described in a group of 260 presumably normal infants and children observed during the first fourteen years of life for a total of 1,264 patient years. The average period of observation was about five years. 2. During the first seven years of life, over 50 per cent of the patients presentedprecordial systolic murmurs. The murmur was heard each year in one or more examinations in 78 per cent. During the age span of 8 to 14 years, 66 per cent of the children presented murmurs. The murmur was heard each year in 58 per cent. Eighty-two per cent of the patients presenting murmurs in the first seven years of life retained these murmurs in subsequent years (up to the age of 14 years). 3. The cardiac silhouette was examined in the posterior-anterior and oblique views. The configuration was normal in the posterior-anterior view. In the left anterior oblique view, the angle of clearance of the left ventricle was 50 degrees ± in 90 per cent of the patients. In 10 per cent, sporadic angles of clearance of 55 degrees were observed, especially in obese children with high diaphragms. In the right anterior oblique position, none of the patients showed evidence of left auricular enlargement (absence of retrodisplacement of the esophagus using barium). 4. A total of 927 electrocardiographic tracings were studied. Averagevalues were obtained for the P-R interval (correlated with age and rate), the duration and amplitude of the P waves and QRS complexes, and for the amplitude of the T waves in the three leads. The corrected Q-T interval was obtained. Significant statistical differences were not obtained by comparison of patients with and without murmurs at various age levels. a. The P-R interval was found to be 0.14±0.02 second. During the first year of life it was 0.12±0.02 second. During the age span of 1 to 3 years with rates over 130 per minute, it was 0.13±0.02 second. Six per cent of the patients without murmurs showed sporadic P-R intervals greater than the upper limits. Twelve per cent of the patients with murmurs showed P-R intervals greater than the upper limits. In both groups, one third of the P-R prolongations equaled or exceeded twice the standard deviation. Forty-two per cent of the patients (representing 52 per cent of the tracings) showed fluctuations in consecutive P-R intervals greater than 0.02 second. b. The upper limits of amplitude of the P waves were 1.6, 2.3, and 1.6 mm. in Leads I, II, and III respectively. The lower limits of the P waves were 0.4, 0.3, and −0.4 mm. in the three leads. The upper limits of duration of the P waves were 0.07, 0.08, and 0.07 second in Leads I, II, and III, respectively. c. The upper limits of the amplitude of the T waves were 4-4, 5.7 (5.1 inthe first seven years of life), and 2.6 mm. in Leads I, II, and III, respectively. The lower limits of the T waves were 0.7, 1.7 (0.7 in the first seven years), and −1.8 mm. in the three leads. d. The average amplitude of the QRS complexes was found to be 11, 12.5,and 10.5 in Leads I, II, and III, respectively. The standard deviation was 4 to 5 mm. The upper limits of the duration of QRS2 was 0.08 second. e. The corrected Q-T interval (K in Bazett's formula) was found to range from 0.37 to 0.38±0.20 second. About 18 per cent of the patients presented sporadic electrocardiographicaberrations. These represented 10 per cent of the tracings. One half of the aberrations were P-wave changes. The remainder were divided between QRS and T-wave changes.