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Echocardiography has proven to be a useful technique in the diagnosis and assessment of therapy in idiopathic hypertrophic subaortic stenosis (IHSS). Asymmetric septal hypertrophy has been described as the pathognomonic anatomic marker of the disease. A characteristic systolic anterior motion of the anterior mitral valve leaflet has been detected in the presence of hemodynamically significant subaortic left ventricular outflow obstruction. An echocardiographic quantification of the outflow gradient (the obstruction index) has been derived previously. Four patients were studied by ultrasound at the time of cardiac catheterization. All four demonstrated systolic anterior motion of the anterior mitral leaflet in the absence of a resting gradient. In three of the four, the calculated obstruction index predicted hemodynamically significant resting gradients. All four patients were shown to have labile gradients with provocative maneuvers. A fifth patient with abnormal systolic anterior motion demonstrated a close correlation between the obstruction index and resting gradient; however, symmetric hypertrophy of the septum and left ventricular posterior wall was detected by ultrasound. Therefore, the abnormal mitral valve pattern may be seen in the absence of a resting gradient and symmetric left ventricular hypertrophy may exist in the presence of IHSS.

The interventricular septal wall thickness and motion was studied by echocardiography in 25 normal subjects and 43 patients with various cardiovascular disease proved at cardiac catheterization. The mean septal thickness was 7.2 mm. ± 0.7 S.D. in the normal subjects, 10,1 mm. ± 1.0 S.D. in 11 patients with left ventricular volume overload (P It is concluded that study of the interventricular septum by echocardiography provides a non-invasive technique with a high specificity but a lower sensitivity for identifying patients with left ventricular dysfunction.

We present our experience with 12 patients with operation for ventricular septal rupture following acute myocardial infarction. Clinically, two sets of symptoms are described. In the first, shock and severe failure occur shortly after the infarction. In the second, signs of moderate failure and a pansystolic murmur appear several days following the acute infarction. The two patients with shock shortly after infarction died during operation. The other ten patients survived the operation, although three died 11 days, 45 days, and 18 months afterward. The seven survivors are doing well after an average of 31 months. The surgical techniques used are discussed. These results compare favorably with the ominous natural course of this complication of acute infarction.

To determine a possibility of success in construction of an akinetic septum as a radical correction for single ventricle, seven normal canine hearts were spatially analyzed to obtain ratios which would enable to reconstruct the heart by awaring only the maximum external circumference of the ventricles (the left and right free walls on cross section). Then, those data obtained were employed to construct single ventricle to analyze the possibility of the septal construction in it in Part 11 of this study. On determining the volumes of the right and left ventricles, which was madantory, in Part 11 of this study, in discussion of cardiac function required in the single ventricle corrected with an akinetic septum, two methods were employed, one, being with planimetry on photographs of the hearts cross-sectioned, the other being with planimetry on drawings that were obtained from equations. The equations employed were based on a postulation that both the ventricles were round on cross-section and that they overlapped partly each other. Thereby, one circle was complete and was assumed the left ventricle. The volumes determined by the equations were very close to the volumes measured on the photographed heart. A long axis employed in the analysis of the normal heart was from the apex to the center of the mitral orifice with a reason that this axis would be more beneficial to a surgeon because of easier accessibility to the atrioventricular groove as a landmark on operation. The cross-section in this study was perpendicular to the long axis.

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.

Seventeen patients with left bundle branch block were studied using standard echocardiographic techniques employing a strip chart recorder. All 17 patients were found to have specific echocardiographic findings of abnormal septal motion uniquely different from previously described forms found in volume overload states of the right ventricle as well as coronary artery disease. The specific echocardiographic abnormality demonstrated in left bundle branch block is a very dynamic posterior motion of the interventricular septum occurring within 0.04 seconds of the onset of the QRS and preceding the anterior motion of the posterior left ventricular wall during ventricular ejection. This type of septal motion is not seen in the other forms of abnormal septal motion and appears to be specific for left bundle branch block.

Following the attempt to arrange a clear description of the physical characteristics of blunt thoracic trauma, the morphological findings of a case of traumatic ventricular septum defect with interventricular and atrioventricular communications is presented in detail. Accepting the principle that the occurance of a traumatic defect in the ventricular septum without a previous lesion of the myocardial texture is highly improbable, a embryologic based theory of the formal genesis of traumatic ventricular septum defects, in sense of a “Pathoklise”, is reviewed. The formal relationships between (1) “high-seated” traumatic ventricular septum defects (type I) and congenital heart anomalies following alteration of the vectorial bulbus turn and, (2) between the purely muscular, apical traumatic ventricular septum defects (type II) and connatal interventricular communications at “atypical location” are demonstrated.

Echocardiographic study was done on four pediatric patients with coexisting hypertrophic subaortic stenosis (HSS) and fixed left ventricular outflow (LVO) obstruction. One had valvar aortic stenosis, two had discrete subaortic stenosis and one had coarctation of the aorta. Preoperatively, HSS was not suspected in any of these patients because of the classical findings of fixed LVO obstruction. The echocardiographic examination revealed an abnormal systolic anterior movement (SAM) of the anterior mitral leaflet with ventricular septal hypertrophy in all, but these findings were overlooked or thought to be related to a subvalvar diaphragm. One or two years after the surgical removal of their fixed obstruction, all showed clinical pictures of HSS. Postoperative echocardiographic examination showed an abnormal SAM with asymmetrical septal hypertrophy, and cardiac catheterization revealed mild to severe degrees of resting pressure gradients across LVO tracts. Amyl nitrite inhalation produced a more prominent SAM with increasing pressure gradient, and angiotensin infusion abolished the SAM and reduced the pressure gradient. From our present study, echocardiography has the potential for identification of HSS coexisting with a fixed LVO obstruction. We recommend that all patients with LVO obstruction have an echocardiographic examination along with pharmacological testing. The demonstration of an unusually thickened ventricular septum and especially, abnormal SAM of the mitral valve would require careful evaluation of left heart hemodynamics and the determination of the level of the major obstruction during cardiac catheterization for pre and postoperative management.

Thirteen rabbit atrioventricular nodes were studied both morphologically and electrophysiologically. Two of these nodes were subsequently reconstructed in three-dimensional fashion. From the morphological standpoint, it was shown that the atrioventricular node was divided into a smaller enclosed portion and a larger open portion by a fibrous collar derived from the central fibrous body. Three distinct nodal cell types were identified within these nodal segments. The open node was mostly occupied by transitional cells which merged proximally with the atrial myocardium. As they entered the enclosed node, some of these transitional cells merged into a knot of midnodal cells. Others passed circumferentially round this knot and together with the midnodal cells, joined with a tract of lower nodal cells. The latter cells were continuous with the His bundle anteriorly, but they also extended into the open node posteriorly. It was possible to correlate the activation sequence of the node accurately with the disposition of these cells. Using both reconstructions and techniques to mark cells from which action potentials had been recorded, it was shown that the transitional cells correlated with the AN zone of the node. Cells with N potentials were located in the environs of the midnodal cell knot. The anterior portion of the lower nodal cells correlated with the NH nodal zone. The posterior extension of the lower nodal cells and the overlay fibers of the anterior transitional cells both functioned as dead-end pathways. Histologically distinct tracts were not identified within the internodal atrial myocardium.

Idiopathic left ventricular hypertrophy is diagnosed when hypertrophy without dilatation appears to be present without apparent cause. Since asymmetric septal hypertrophy occurs commonly, and since it may present nonspecifically as left ventricular hypertrophy, we hypothesized that many patients with idiopathic left ventricular hypertrophy might in fact have asymmetric septal hypertrophy. We therefore evaluated echocardiographically 39 patients with idiopathic left ventricular hypertrophy diagnosed by physical findings or electrocardiographic criteria or both. All family members of patients with known asymmetric septal hypertrophy were excluded. Of the 39, 33 had asymmetric septal hypertrophy, six were normal, and none had evidence of idiopathic left ventricular hypertrophy. All six of those with normal echocardiograms had left ventricular hypertrophy solely by electrocardiographic criteria and were without cardiac symptoms, suggesting a false-positive diagnosis. If idiopathic left ventricular hy...

The anatomic and clinical findings are reported in five cases of complete dextrotransposition of the great arteries with an uncommon and varied conal pathology, different from the usual conal architecture of classic complete dextrotransposition of the great arteries. The following points summarize the most important findings: (1) The ventricular septal defect was due to a positional anomaly or a deficiency of the conal septum in all of these cases. (2) The conal free wall distribution was different from that designated as characteristic of classic complete dextrotransposition of the great arteries, ie, in three cases, a persistence of the subpulmonary conal free wall preventing the pulmonary-mitral fibrous continuity. (3) A positional deviation of the conal septum inside the conus resulted in obstructive anomalies of the subpulmonary outflow tract in two cases and of the subaortic in another. (4) There was overriding of the conal septum of the ventricular septum in two cases. (5) In keeping with item 4, the observation of the pulmonary outflow tract of three additional cases of classic complete dextrotransposition of the great arteries with intact ventricular septum suggests a possible origin of the fibromuscular subpulmonary stenosis in these patients: the abnormal fusion line between the ventricular septum and a malorientated conal septum. Some important angiocardiographic characteristics of these cases are also shown. The surgical Implications of these particular anatomic characteristics are discussed.

Isolated dextrocardia or isolated levocardia almost invariably indicates the presence of a complex cardiac anomaly. An accurate anatomic diagnosis in patients with these malformations requires knowledge of the atrial position, the relative position of the ventricles (atrioventricular concordancy or discordancy) and the presence or absence of a ventricular septum. Fifteen patients were studied to demonstrate that diagnostic ultrasound, in conjunction with the plain chest roentgenogram, provides a noninvasive method for accurately assessing atrioventricular relations and arrangement of the great vessels, in the presence of isolated discordancy of the cardiac apex. The patients studied were aged 10 months to 17 years; seven had isolated dextrocardia, five had situs inversus totalis, two had isolated levocardia and one had levocardia with abdominal heterotaxy. Thirteen of the 15 patients evaluated by echocardiography underwent cardiac catheterization and angiography. The correct diagnosis was made from the echograms and plain chest roentgenograms alone in 11 of the 13 patients. We conclude that with echocardiography and the knowledge of atrial situs, it is possible to define accurately important anatomic relations before cardiac catheterization in patients with cardiac malposition.

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.

Echocardiograms were obtained from 200 normal newborn infants ranging from 6 to 10 pounds in weight and from 10 to 72 hours in age. A continuous recording technique is described employing a 5 MHz transducer. Criteria have been established for a normal echocardiographic profile in the full-term neonate. This profile consists of obtaining quantitative measurements of mitral valve excursion and velocity, tricuspid valve excursion and velocity, pulmonary artery diameter, aortic root diameter, left atrial diameter, and interventricular septal thicknesses. In addition, qualitative assessment is made of the septal contour, position of the aortic root to pulmonary artery, continuity of mitral valve with posterior aortic root, and continuity of tricuspid valve with anterior aortic root. No correlation was found between the magnitude of any one parameter and either body surface area or weight. The establishment of normal echocardiographic criteria for the newborn may be expected to significantly facilitate application of this noninvasive technique to infants born with congenital heart disease.

A study of heart specimens without ventricular septal defect from patients with down's syndrome showed a significant enlargement of the membranous ventricular septum as compared to the normal heart. This increase in area of the ventricular septum occupied by membranous tissue from 2 to 9% may not only predispose patients with Down's syndrome to congenital heart disease, but may be one end of a spectrum of cardiac anomalies related to malalignment or maldevelopment of the ventricular septum in Down's syndrome.

By employing electrographic electrodes, suction electrodes and microelectrodes, 2 conduction pathways were discovered in the anteromedial portion and in the posteromedial portion along the AV ring at the lower margin of the left atrium in the isolated rabbit heart. They were found to conduct the left atrial impulses to the right atrium and separately through the AV node to the ventricle. The one in the posteromedial portion was found to be different from the inferior interatrial pathway reported recently by Scherlag et al. Histological examination after functional studies revealed that each pathway was embedded in the fibrofatty tissues at the site of the attachment of the mitral valve to the left atrium. The anterior pathway encircled the anterior portion of the mitral ring and entered the anterosuperior portion of the AV node. The posterior pathway encircled the posterior portion of the mitral ring and entered the posteroinferior portion of the AV node. They can be regarded as interatrial pathways and in a sense as accessory AV conduction pathways from the left atrium.

Equations are presented for simultaneous determination of right and left ventricular outputs and ductus arteriosus, foramen ovale, and upper and lower body flows in the mammalian fetus. The method is a modification of indicator dilution theory as applied to the radioactive microsphere method of blood flow measurement, and can be used repeatedly in any fetus.

Sixteen patients were studied subsequent to the development of acute ventricular septal rupture in 7 and severe mitral regurgitation in 9. These lesions occurred within two weeks of acute myocardial infarctions. Intraaortic balloon assistance was initiated when cardiovascular deterioration occurred, and hemodynamic improvement was obtained in all patients. Shunting through a ventricular septal perforation was reduced during balloon assistance, and mitral regurgitation, when present, was decreased. These effects were short-lived, and the patients were subsequently studied with coronary angiography and ventriculography. Two of 3 patients with anterior ventricular septal defect underwent successful surgical correction. Three patients had attempted closure of inferior ventricular septal defect without success. The fourth patient with an inferior ventricular septal defect died of his lesion without any attempt at surgical repair. Four patients with rupture of the papillary muscle were long-term surgical survivors. Coronary artery bypass grafting was carried out when indicated in these patients. Two of 5 patients with papillary muscle dysfunction who underwent operation during the acute period of their infarction were long-term survivors. The findings suggest that the mechanical lesions of mitral regurgitation and ventricular septal perforation are amenable to surgical intervention if a sufficient amount of residual functional muscle can be preserved in the left ventricle. Intraaortic balloon assistance allows a period of time to stabilize the condition of patients with these lesions, to reduce myocardial ischemia, and to carry out studies to determine the degree of associated coronary artery disease and the extent of irreversible myocardial damage. Based on the findings from these studies, surgical procedures may be selected.

Echocardiography provides a reliable, sensitive and practical noninvasive means for the accurate diagnosis of idiopathic hypertrophic subaortic stenosis (IHSS) and the sequential assessment of severity of left ventricular outflow obstruction in the management of this condition. The principal echocardiographic features of IHSS have been demonstrated to include: (1) anterior displacement of the anterior mitral valve in midejection; (2) asymmetric ventricular septal hypertrophy; (3) anterior position of the mitral valve at the onset of systole; (4) forward systolic movement of the posterior mitral leaflet; (5) reduced rate of anterior mitral valve closure in diastole; and (6) partial closure of the aortic leaflets in midejection. The characteristic abnormalities of anterior systolic leaflet motion observed on mitral valve echogram and the response of the leaflet to provocative maneuvers and surgical treatment strongly support the importance of the role of obstruction in IHSS and the apposition of the anterior mitral leaflet, with the hypertrophied ventricular septum as the site of subaortic stenosis.

Echocardiography is being used increasingly in cardiac diagnosis because it permits rapidly moving cardiac structures to be visualized with ease and safety. Echocardiographic studies previously have been limited to qualitative observations because detailed quantitative measurements of cardiac structural motion have required time-consuming manual information processing. A video scanner-analog computer system has been developed that greatly simplifies the analysis of routine echocardiograms. Up to eight nonoverlapping cardiac structures are first traced manually on transparent paper from selected portions of echocardiographic records, and then Converted by a television camera into a picture consisting of 525 video lines. These lines are processed sequentially by eight signal detectors, each generating a digital value proportional to the distance of the traced signals from the beginning of the video line. The data are converted to analog form by analog computer techniques and recorded on a strip chart. Evaluation of the system has demonstrated that signals of up to 12 Hz can be accurately processed without attenuation. In addition, a comparison of the scanner-derived instantaneous left ventricular transverse dimension with that measured directly from the original echocardiograms revealed excellent correlation ( r = 0.98). The use of this system to analyze cardiac structures may have wide applicability in cardiac research and diagnosis because it allows complex quantitative data to be obtained easily from routine echocardiograms.

Construction of the interventricular septum has been thought to be a radical correction for single ventricle and a possibility of its success was analyzed by reconstructing single ventricle with the data obtained in the normal canine hearts (Part I). The possibility was discussed in term of physical efficiency of cardiac performance required in the post-correction single ventricle, namely by 1) myocardial fiber shortening. 2) diastolic and systolic volume ratio of the ventricles. 3) stroke volume and 4) radial and tangential forces. The circumferential fiber shortening was within normal limits (18%), when the septum was constructed with an akinetic prosthesis where the circumference perpendicular to the long axis was equally divided into 2 in length. However, ventricular volumes and stroke volumes were larger in the systemic (left) ventricle than in the venous (right). When the septum was constructed at the rising points of the septum, the ventricular volume ratio became normal. However the circumferential fiber shortening was beyond normal limit (35%) and the right ventricular stroke volume was much larger than those of the left. Thereby, it was concluded that the septum should be constructed somewhere between the midpoint and the rising points of the septum in the circumference, namely 8 per cent of the circumference in length from the midpoint toward the left.

Accurate definition of the site and length of the atretic segment in the patient with pulmonary atresia and intact ventricular septum is of prognostic and surgical significance. A double catheter technique was developed to allow precise localization of the site of atresia, whether valvular, infundibular, or both. Simultaneous opacification of the pulmonary artery by way of the ductus arteriosus or systemic to pulmonary arterial anastomosis by one catheter and the right ventricle by the second catheter was accomplished in five patients with pulmonary atresia, severe hypoplasia of the right ventricle and intact ventricular septum. The patients were 2 days to 17 months of age and weighed 3,200 to 9,200 g at the time the technique was applied. In these patients, the site of atresia proved to be valvular in one, and both valvular and infundibular in four. The double catheter technique is also applicable to patients with ventricular septal defect and acquired or congenital pulmonary atresia who have had palliative shunts, and to patients with complex transpositions and pulmonary atresia.

This is a serial-section study of the conduction system in a 2-year-old boxer with electrocardiographic evidence of complete A-V block. The following findings were present: a lack of communication between the atria and the A-V node, atrophy of the A-V node, and tenuous connections between the A-V node and the A-V bundle. These were accompanied by acute degenerative changes in the conduction system. These changes are considered to be the result of arteriolosclerotic heart disease.

Twenty healthy term newborn infants born at St. Anthony Hospital in Denver, Colorado were examined by echocardiography during the first 72 hours of life. All infants were without cardiac or pulmonary disease and were appropriate for gestational age within the classification of Battalion and Lubchenco. Measurements of intracardiac dimensions, including right ventricular cavity, left ventricular cavity, left atrium and aortic root, as well as thickness of the intraventricular septum and posterior wall of the left ventricle, were determined by three independent observers. The data correlated with other studies performed at centers located at lower elevations.

Clusters of small cells in the interatrial septum of the heart fluoresce yellow-green when prepared according to the Falck-Hillarp method for biogenic amines. An attempt was made to locate these cells in electron microscopic preparations. Cells were found that contained many typical amine-storage granules. There were two types of granule; each cell contained one variety or the other, but none contained both. The granule-containing cells were in highly vascular, glomus-like clusters, most of which were in the vicinity of the AV node. Nerve terminals containing 550 A transclucent vesicles made synaptic contact with granule-containing cells. These were typical efferent synapses. It is possible therefore that the granule-containing cells, under neural control, secrete catecholamines into the capillaries of the interatrial septum. However, in view of the several similarities between the glomus-like bodies of heart and the carotid and aortic bodies, the possibility of chemoreceptor function also must be considered.

In this malformation the difficulty in sending blood through the stenosed pulmonary valve leads to right heart enlargement and to functional patency of the foramen ovale, through which a venousarterial shunt occurs. The onset of symptoms and their severity depend on the size of the opening in the pulmonary valve. Characteristic physical findings and results of fluoroscopy, electrocardiogram, circulation time, arterial blood studies, exercise test, angiocardiogram, and cardiac catheterization are presented. Diagnosis is important because these patients develop cardiac failure following at Blalock-Taussig operation, but may be greatly helped by pulmonic valvulotomy.

We have described a case of multiple and complex malformations of the coronary arterial system, i.e., single coronary artery which gave off several branches, one of which connected abnormally with the right ventricular cavity so as to produce a shunt. In addition, there was severe pulmonary stenosis with a high right ventricular pressure. This, in turn, maintained a right-to-left shunt through the abnormal coronary vessel. Another, similar shunt was present at the atrial level through an atrial septal defect. These malformations were suspected clinically. Specialized studies (catheterization and angiocardiography) confirmed the diagnosis. The patient was operated upon for ligation of the abnormal coronary vessel and correction of the pulmonary stenosis. He died as a result of cardiac arrest. The hemodynamic pattern of this unusual case is discussed.

Five patients with an ostium primum type of atrial septal defect were studied by clinical and laboratory methods and the diagnosis was verified either at the time of open-heart surgery and/or at autopsy. The atrioventricular valves formed the floor of the defect and were deformed in 4 of the 5 patients. Mitral insufficiency was present as a result of this valvular deformity in these four patients. This valvular deformity resulted in a high pitched blowing systolic murmur, audible over the apical and lower left sternal areas, and left axis deviation and indications of left ventricular hypertrophy, determined by electrocardiography. The deformity of the mitral valve is considered to be the basis for these variations from the typical findings found in the patient with an ostium secundum type of atrial septal defect and make the differential diagnosis of the persistent ostium primum possible under these circumstances.

Discussions of the various presenting forms of transposition and initial management of the infant in terms of relief of cyanosis and control of congestive heart failure precede a description of the author’s technique of palliation by balloon atrioseptostomy, which provides for adequate intracardiac mixing until total surgical correction can be performed.

A PATIENT withcardiomyopathy often presents with evidence ofheart failure intheabsence ofapparent underlying cause. Thisclinical picture usually results fromdisease oftheheart muscle itself, butthepossibility exists thatitmight alsobeduetoimpairment oftheaction ofstructurally andfunctionally normal myocardium byinco-ordinated ventricular contraction. Thedevelopment ofechocardiography has provided a non-invasive methodofstudying left ventricular contraction, allowing frequent records to bemaderapidly andpainlessly without hazard tothe patient. Thepattern ofcontraction ischaracterized fromrecords showing echoes fromtheinterventricular septum andposterior wallinaregion just belowthemitral valve. Thenormalposition and movement ofthese twostructures areshowninFig. 1. During ventricular systole thedominant movement oftheinterventricular septum isina posterior direction, while theposterior wall movesforwards as thetransverse diameter ofthecavity isreduced. During diastole, thetwoechoes moveinthereverse direction, rapidly atfirst andthenmoreslowly inthe period ofdiastasis. Thispattern ofmovementhas beentaken torepresent aco-ordinated ventricular contraction andisthatcommonly seen, eveninthe presence ofconsiderable cavity dilatation orventricularhypertrophy. Abnormalities ofseptal movement havepreviously beendescribed inassociation withatrial septal defect andareprobably related totheincrease inright ventricular stroke volumethatoccurs inthis condition (Diamond etal., 1971). Inthemajority of thesepatients septal movementisthereverse of normal, being inananterior direction during systole whileintheremainder itundergoes a series of movements oflowamplitude, withno dominant displacement ineither direction. Similar abnormalities ofseptal movementmayoccurinassociation withacquired pulmonary hypertension ortricuspid regurgitation due, forexample, torheumatic mitral valvedisease, whentherelative loads ontheright andleft ventricles arealtered. Inthepresent study, echocardiography wasused todefine theeffects ofabnormalities ofventricular activation on thepattern ofcontraction. Eight patients withclassical left bundle branch block were studied, inwhomtheduration oftheQRScomplex -w'-~

The pathologic features of anomalies of the tricuspid valve superficially resembling congenital aneurysms of the membranous septum are described in 5 cases. In each of 3 cases a ventricular septal defect was associated with a pouch in a leaflet of the tricuspid valve. In the fourth and fifth cases, anomalous attachment of the septal leaflet of the tricuspid valve to the edge of a ventricular septal defect yielded a pouch-like structure. Left ventricular-right atrial communication was a common finding, a feature that may also be seen in cases of true aneurysms of the membranous septum. In 1 case a pouch of the anterior tricuspid leaflet had caused obstruction of the right ventricular infundibulum.

1. 1. Synchronous external and internal phonocardiographic tracings were recorded in 8 patients who had small ventricular septal defect (less than 45 per cent left-to-right shunt) and normal pulmonary arterial pressure, and were without pulmonary stenosis. The external phonocardiograms showed a widely radiating pansystolic murmur, either plateau shaped or with a late crescendo. The internal phonocardiogram showed a similar murmur in the right ventricle. In 3 patients the murmur due to the ventricular septal defect radiated widely into both pulmonary arteries but was not equally loud at all sites in the right ventricle, suggesting jet flow of shunted blood down the pulmonary arteries. In 3 patients the septal-defect murmur was confined to the ventricle, and a separate pulmonary ejection murmur was recorded beyond the pulmonary valve. 2. 2. Amyl nitrite softened the pansystolic regurgitant murmur recorded in the right ventricle. In the pulmonary artery, however, the short ejection murmur was intensified, but this had no influence on the externally recorded murmur, which also softened. 3. 3. Phenylephrine produced marked intensification and prolongation of the murmur in the right ventricle and of the externally recorded murmur, and in one subject the intrapulmonary ejection murmur intensified. 4. 4. Since changes in the chest-wall murmur closely parallel changes in the right ventricular murmur, variation in intensity of the chest-wall murmur alone provides information of the change in volume rate of shunt flow. 5. 5. In the case of minute ventricular septal defect the tracings recorded at the fourth left intercostal space and in the right ventricle both showed the characteristic crescendo-decrescendo murmur which softened after amyl nitrite and intensified and lengthened after phenylephrine. The intrapulmonary ejection murmur increased with amyl nitrite. Since the septal-defect murmur is softer and more localized in the case of minute septal defect, a separate pulmonary ejection murmur may be heard in the pulmonary area. Unless auscultation is made at the correct site, the diagnostic effect of amyl nitrite may not be detected. 6. 6. This study has thrown some light on the different behavior of the regurgitant systolic murmur of ventricular septal defect and the pulmonary ejection murmur under the influence of vasoactive drugs. It has clarified the interpretation of these murmurs when they are heard at the chest wall.

An acquired interventricular septal defect of the heart resulted from a nonpenetrating traumatic cardiac injury sustained by the driver in an automobile accident. The defect developed 10 days after the accident, when intractable cardiac failure began and continued until death, 28 days later. Clinical and pathologic observations are reported and correlated.

His (H), right bundle branch (RB), and left bundle branch (LB) potentials were recorded by electrode catheters passed into the left and right ventricles in seven patients without conduction defects. In another three patients, H and LB were recorded. Initial ventricular activation was considered to coincide with the onset of the QRS (Q). The following intervals were measured in milliseconds: H-Q, LB-Q, RB-Q, H-LB, H-RB, and LB-RB. The average and range of these was as follows: H-Q 46 (39-54), LB-Q 27 (24-30), RB-Q 25 (20-27), H-LB 20 (14-28), H-RB 21 (15-29), and LB-RB 2 (1-10). LB-RB was 3 msec or less in six of seven patients. Coupled atrial pacing produced delays in H-RB without effect on H-LB and LB-Q. The production of incomplete and complete right bundle branch block was related to increase in the LB-RB interval. One patient developed left bundle branch block (LBBB) during coupled pacing with delay of LB while RB-Q remained unchanged. H-Q intervals were measured in three additional patients with rate related LBBB during both control and block. Prolongation of H-Q was less than 3 msec during LBBB. It is concluded that the proximal left and right bundle branches are usually activated simultaneously in man, and that block of either bundle without contralateral bundle delay does not significantly delay the onset of ventricular activation.

Analysis of accumulated experience with the repair of atrial septal defect in 119 adults has revealed several factors determinable preoperatively that appear to have a strong influence on the operative risk. These factors are related to the presence of pulmonary vascular disease or heart failure and contribute importantly to the selection of patients for operation.

Through utilization of a technique developed in this laboratory it has been possible to study the sequence of activation of the Purkinje fibers and muscle fibers beneath the endocardium of the left interventricular septal surface at the same 21 specific points before and after left bundle branch block (LBBB). It has been demonstrated that activation of the Purkinje system (P) at a specific point on the septum precedes that of the adjacent muscle fibers both before and after LBBB. It is concluded, therefore, that activation of the muscle fibers of the left septal surface is a direct result of excitation spreading to these fibers from the subendocardial Purkinje network both before and after LBBB. After LBBB the time required for complete activation of the left septal surface is considerably less than the control value; this finding is consistent with the concept that, after LBBB, activity spreads within the homolateral subendocardial Purkinje system, which has been activated simultaneously at multiple points, and then spreads to the adjacent muscle fibers of the left septal surface. Representative recordings from all points on the specialized conducting system (SCS) have been presented, including bipolar electrograms from the bundle of His (BH), right bundle branch (RBB), right Purkinje-papillary junction (RPPJ), free-running Purkinje fibers which extend from the base of the right anterior papillary muscle to the endocardium of the wall of the right ventricle (FRP), left bundle branch (LBB), anterior false tendon of the left ventricle (AFT), left anterior Purkinje-papillary junction (LAPPJ), and peripheral Purkinje fibers of the left septal surface at multiple sites (P). In order to facilitate the orderly presentation of data, a system of nomenclature based on the abbreviation for each of the anatomic points from which electrical potentials are recorded has been suggested for use in studying the specialized conducting system (SCS) of the heart.