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Data dealing with cholesterol, phospholipid, their ratios, and total lipids in a group of 40 "normal" and 40 individuals with manifest coronary artery disease have been evaluated and have been found to have a low order of significance in determining the atherosclerotic status for both individuals and for groups. Serum lipoproteins separated by paper electrophoresis and visualized with Fat Red 7B have been shown to occur in 5 fractions. Of these, lipalbumin and beta lipoproteins as well as beta/alpha and beta/lipalbumin ratios reveal a high level of significance for distinguishing normal from abnormal individuals and groups.

Rabbits were injected with saline suspensions of fibers of filter paper and of mixtures of filter paper and human fibrin or filter paper and rabbit whole blood. The emboli became impacted in the pulmonary arteries or adhered to the intima. In one rabbit an embolus adhered to the endocardium of the right ventricle. An acute arteritis resulted which was finally organized leaving a diffuse or eccentric scar on the intima. The filter paper fibers were surrounded by a foreign body granuloma and localized in either the intima or adventitia. Frequently they passed entirely through the wall clausing varying amounts of injury and were found in the adventitia or perivascular lung tissue. This is interpreted as indicating the existence of a mechanism for ridding the circulation of foreign material in the blood.

We describe a simple method of recording the direct body ballistocardiogram by means of a microscope and a powerful light source. The beam passes through a slit attached to the body, and the image of this moving slit is magnified by the microscope and focused on moving photographic paper. When a static force is applied to the body, the base line of the record is permanently displaced and so the amplitude of the ballistocardiogram can be calibrated. By superimposing a ballistocardiogram obtained by means of the electrocardiogram on the same film, accurate comparisons of the two records and a calibration of the electrical instrument can be obtained.

The cause of atherosclerosis and reason for its high incidence in diabetes are not known. In this study proteins and lipoids of serums of patients with diabetes or atherosclerosis are examined by paper electrophoresis to determine whether such changes may be a common factor for both of these conditions.

This article describes the case of a 10-year-old girl with generalized tortuosity and lengthening of all her major arteries-the carotid arteries, the aorta from the arcus to the bifurcation, and the iliac, femoral, splenic, hepatic, renal, and intercostal arteries. The condition appears to be a new entity. Pertinent abnormalities were as follows: gross pulsation of the arteries in the neck, telangiectasis of both cheeks, high palate, tortuosity of all the arteries, aortic valvular insufficiency, 1+ to 2+ capillary fragility on tourniquet test (lacet), 1+ Wassermann reaction, 4+ cephalin flocculation, and histological fragmentation of the internal elastic membrane of the arteries. Syphilis, arteriosclerosis, hypertension, mucopolysaccharidosis, and defects of amino acid metabolism were ruled out and the author concludes that the condition was most probably caused by a congenital defect of the elastic tissues of the arterial system.

Three patients with idiopathic orthostatic (postural) hypotension were infused over a 4-hr period with 104.6 µc of 3-hydroxytyramine-2- 14 C, the immediate precursor in the synthesis of the sympathetic neurohormone, that is, noradrenaline (norepinephrine). Urine was collected during the infusion period and at various intervals thereafter for a total of 5 days. By means of column fractionation, the various metabolic products of hydroxytyramine, including endogenous noradrenaline and its metabolic products, were separated, identified, and their radioactivity measured. From the comparison of the hydroxytyramine metabolic pattern of normal subjects to that of idiopathic orthostatic hypotensive patients, it was apparent that the greatest changes occurred in the formation of noradrenaline and 3-methoxy-4-hydroxymandelic acid (MOMA, VMA). The synthesis of noradrenaline was significantly reduced in the hypotensive patients, and there was also a marked reduction in the formation of MOMA, the principal metabolic product of noradrenaline. The implication of these findings is that the pathogenesis of idiopathic orthostatic hypotension is related to a defect in the neurogenic structures involved in the biosynthesis of noradrenaline. This conclusion is further supported by the fact that one of the subjects (M.Q.) at autopsy showed only degenerative changes in the sympathetic ganglia and neurons.

3 H-digitoxin and polyethylene glycol (nonabsorbable marker) were given orally to five subjects provided with a gastrointestinal tube. Of the radioactivity administered, approximately 15, 30, and 70% had been absorbed when the test solution was passing the stomach, the duodenum, and the upper jejunum, respectively. The absorption was rapid, and the plasma contained detectable amounts of radioactivity after 5 minutes. There was no evidence of a disposition of 3 H-digitoxin in intestinal aspirates. On a sixth subject labeled digitoxin was instilled in the mid-jejunum. The concentration of label in the plasma and the pattern of elimination of radioactivity in the urine and the feces in this subject indicated that the absorption of digitoxin was effective also in the more distal part of the gut. The combined results from the present study indicate that the absorption of orally administered digitoxin is complete. The biliary excretion of label 4 to 24 hours after the start of the experiments was calculated from the bilirubin turnover and the mean radioactivity per mg bilirubin in duodenal aspirates obtained after intravenous injections of cholecystokinin. Less than 10% of the administered dose appeared to be excreted with the bile. The radioactivity recovered in plasma showed less decomposition than that found in duodenal bile and urine.

This paper is the first of a series of three which will deal with the relationship between the voltages in electrocardiographic leads and the electromotive forces of the heart. The general purpose of this series is to discuss various experimental and theoretic technics which can be used in the analysis of a given lead, and in the building up, or "synthesis," of leads having desired characteristics. The procedures used are based on a fundamental theorem which takes into account not only the irregular shape and conductivity of the body but also the spatial dispersion of the electromotive forces within the heart. It is closely related to the "lead vector" concept of Burger and van Milaan. In this first paper the basic definitions and theorems are developed. The second paper discusses various methods of analysing leads. The third and last presents a number of systematic procedures for designing leads, both vectorcardiographic and unipolar. Such leads can have substantially higher accuracies than those now in use, because their design takes into account the shape and conductivity of the body and its tissues, and the eccentric and extended location of the heart.

This paper describes a method of analyzing electrocardiograms that detects and identifies nonfibrillatory atrial, A-V junctional, and ventricular pacemakers in atrial fibrillation, measures the ventricular beat intervals produced by the detected pacemaker, and estimates the block between pacemaker and ventricle. The identification and measurements are made with a known degree of assurance which may be increased or diminished since it depends entirely upon the number of heart beats analyzed. By applying the method to 61 recordings of 31 patients, we detected 18 instances of A-V junctional tachycardia and escape rhythm of which only three had been identified by ordinary electrocardiographic interpretation. The procedure consists of recording the electrocardiogram on magnetic tape, reducing the contained information to certain displays, and testing statistically the hypotheses suggested by them. The displays employed are: (1) A plot of the duration or the reciprocal of the duration of successive electrocardiographic R-R intervals against elapsed time (tachogram); (2) a plot of the number of R-R intervals in the recording within each duration class against the duration of the class (interval histogram); (3) a plot of the number of beat-to-beat interval sequences formed by intervals with equal durations, successively diminishing durations, and durations representing multiples of a common time segment against the duration of the identifying interval of each sequence (sequence histogram); and (4) a graphic presentation of the averaged electrocardiographic presystolic potential. The paper also presents evidence that A-V junctional escape rhythm in atrial fibrillation is due to pathological A-V block and should be considered to be the result of digitalis excess when this drug is exhibited.

Recent advances in the diagnosis and treatment of segmental lesions of large blood vessels have created a need for storage of arterial and venous grafts and plastic prostheses. It has been the purpose of this paper to describe in some detail the problems and technics of procurement, sterilization, preservation and utilization of arterial and venous grafts. Emphasis has been placed on the need for bacteriologic and histologic safeguards in the maintenance of a blood vessel bank. A brief section was devoted to the current status of plastic prostheses. Finally, it is of considerable importance to recognize the fact that this is a new field which is being subjected to intensive study and that advances and modifications will be forthcoming. Therefore, this paper represents an interim rather than a final report.

Rabbits were injected with saline suspensions of fibers of filter paper and of mixtures of filter paper and human fibrin or filter paper and rabbit whole blood. The emboli became impacted in the pulmonary arteries or adhered to the intima. In one rabbit an embolus adhered to the endocardium of the right ventricle. An acute arteritis resulted which was finally organized leaving a diffuse or eccentric scar on the intima. The filter paper fibers were surrounded by a foreign body granuloma and localized in either the intima or adventitia. Frequently they passed entirely through the wall clausing varying amounts of injury and were found in the adventitia or perivascular lung tissue. This is interpreted as indicating the existence of a mechanism for ridding the circulation of foreign material in the blood.

The background of basic conceptions underlying this paper is familiar to everyone by experience. The powerful automobile, when the light turns from red to green, can make a "jack-rabbit start" which leaves the less powerful cars far behind. If the engine of the big car is weakened, as by a cylinder gone dead, it can still do 50 miles per hour on the parkway and get you to your destination, but the jack-rabbit start is no longer possible. The first sign of weakness manifests itself more conspicuously in differences in acceleration than in differences in speed or in the distance that can be traveled; indeed the effect on acceleration may be the only manifestation of weakness. There is every reason to expect that this analogy would hold for the cardiac performance also and that the first sign of a weakening myocardium might well manifest itself by a change in acceleration of the ejected blood. This paper is chiefly concerned with the development of a simple method, available to clinicians, which would aid in the detection of changes in the acceleration of the aortic blood. This opportunity has also been used to answer certain criticisms of our previously published work, some, we believe, due to misunderstanding of the mathematical background of statistical procedures, and others due to a frank difference of opinion concerning the accuracy of the Fick method used to test the results secured by one of our formulas published previously.

Effective capillary blood flow (ECF) through the myocardium was studied after experimentally produced myocardial infarction in 33 dogs, and after clinical acute myocardial infarction in nine human subjects. In dogs, ECF as measured by Rubidium-86, was compared to terminal vascular capacity (TVC) as measured by I-131 albumin in infarcted and noninfarcted portions of the myocardium. In man, ECF was determined from the myocardial uptake of Rubidium-84 by the double coincidence counting system. A discrepancy between ECF and TVC in animals became apparent by the tenth day after infarction, at which time TVC had attained control levels, whereas ECF had not; 2 months later, ECF was still 24% less than control. Studies in man demonstrated a significant decrease in ECF within 4 days of infarction; the low flow persisted in one patient 6 weeks after the initial injury. Low ECF in patients was present despite the insignificant changes in cardiac and stroke indices, and in mean aortic pressure. It is thought that the low values for ECF after acute myocardial infarction might reflect alterations in cellular metabolism leading to interference with tissue uptake of rubidium. The discussion that followed this paper appears after the paper by Dr. Richard Gorlin.

When this paper was submitted to the editors of CIRCULATION it called to their attention the desirability of enlarging the work that Dr. Braunstein has begun in the following paper. Accordingly, Dr. Howard Sprague, President of the American Heart Association appointed a committee to study the field and to make recommendations leading toward both a uniform terminology and uniform methods of presenting data secured by ballistocardiographs, and Dr. Braunstein kindly consented to withhold the publication of his paper until the committee was ready to report. This committee has now approved the terminology suggested by Dr. Braunstein and, in a first report, which immediately follows Dr. Braunstein's paper, makes other recommendations pertaining to terminology and conventions for parts of the field not covered by Dr. Braunstein's paper.

In this second paper of a series of three on electrocardiographic leads, presented primarily from the standpoint of an electrical engineer or physicist, the concept of the lead field introduced in the first paper is considered in detail and several necessarily indirect methods for the estimation of these fields are presented.

Safe and permanent closure of patent ductus arteriosus (PDA) can be accomplished with an ivalon plug introduced by catheterization from the femoral artery. The authors' experience thus far obtained from treating more than a hundred patients suggests that the technique described in this paper is a feasible alternative to the surgical approach. A prerequisite has been the size and shape of the PDA, the lumen of which had to be conical in shape and smaller than the lumen of the femoral artery. Now safe closure of oversized PDA complicated by pulmonary hypertension has become possible, using a plug designed with a special mechanism for anchorage to the PDA. The technique of this closure is described in detail in this report of its successful use in a 50-year-old woman patient with an oversized, calcified PDA complicated by pulmonary and systemic hypertension and cystic lung disease. Treating such high-risk cases with transfemoral closure means real improvement in therapy over surgical treatment.

An intra-His bundle lesion developed in 26 out of 38 dogs (68%) that survived the initial period of arrhythmias that followed ligation of the anterior septal artery. The lesion was isolated in the His bundle in ten experiments and was associated with bundle branch block in 16. The evolution of intra-His bundle block (IHBB) was evaluated utilizing standard ECG leads, catheter electrode, and plunge wire recordings from the His bundle and bundle branches. In all experiments the His bundle potential recorded by the catheter electrode was split into at least two distinct deflections (H 1 and H 2 ). This was always associated with a progressive increase of the H 1 -V interval and represented "first degree IHBB." A "second degree IHBB," characterized by intermittent block of the atrial impulse between the two His deflections, consistently developed either spontaneously or in response to atrial pacing. The first "stage" of second degree IHBB had a Mobitz type II pattern with a constant P-R, H 1 -V, and H 1 -H 2 intervals of the beats preceding and following the block. In 20 of 26 observations, this stage merged into the second stage of second degree IHBB characterized by a progressive increment of the H 1 -H 2 intervals prior to failure of a ventricular response. The increment of conduction time, which was at first in the range of a few msec, would not be recognized in standard ECG recordings. This increment could increase up to 180 msec, giving rise to an obvious Wenckebach periodicity that would be recognized at the usual 25 mm/sec paper speed. Complete (third degree) IHBB was observed either in the form of paroxysmal or persistent block. Paroxysmal block occurred spontaneously or could be induced by a critical rate of rapid atrial pacing during early stages of second degree IHBB. Complete IHBB that developed later was persistent and usually associated with a slow idioventricular rhythm. The study suggests that Mobitz type II and the Wenckebach patterns of conduction disturbance in the His bundle are different stages of the same electrophysiological disturbance, with Mobitz type II block representing the initial stages of failure of impulse propagation.

Significant correlation has been shown between the severity of coronary disease and level of coronary blood flow as measured by the rubidium coincidence technique. Contrary to the commonly expressed view, however, the rubidium coincidence method does not evaluate nutritional flow, but estimates total coronary blood flow (CBF T ). An equation is derived that does evaluate nutritional flow (CBF N ), allowing simultaneous measurement of total and nutritional flow. The extraction ratio of the total body (ER TB ) relative to the extraction ratio of the heart (ER C ) was measured in a total of 21 dogs by employing the relative uptake of labeled microspheres and diffusible ions, 86 Rb and 131 Cs. CBF T , measured with a bolus injection of 86 Rb or 131 Cs, was compared with total flow measured by the microsphere technique in dogs, with and without drug administration (norepinephrine, isoproterenol, nitroglycerin). These studies showed that while rubidium gives accurate mean values of total flow (4% mean difference, r = 0.92) individual estimates may be in error by as much as ± 42%. It was found, however, that isotopes of cesium are not suitable for measuring either total or nutritional coronary blood flow by the methods described in this paper. Comparison of CBF N with CBF T showed that not only was CBF N significantly less than CBF T , but the percentage increase in CBF N was significantly less than that of CBF T after norepinephrine or isoproterenol administration.

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.

Nine surface electrocardiograms recorded on the thoracic surface at fixed and identical locations in 412 individuals were found to account for the maximal useful waveform information available in each individual. In other words, nine waveforms were capable of resynthesizing any waveform recorded on their thoracic surface. These nine waveforms were then submitted to multivariate statistical procedures and their diagnostic performance compared to the Frank leads on which the same procedures were applied. Before the data were fed into the computer, all waveforms were time-normalized and divided into eight equal parts, yielding 72 variables and 24 variables for the nine lead system and the Frank leads, respectively, for each individual. In this paper we attempted to discriminate between normal subjects and patients with documented angina pectoris (typical history and positive coronary angiography); myocardial infarction was excluded in these patients. Only the resting QRS complex was considered. With the 9-lead system, keeping the specificity (true negatives) at 90%, the sensitivity (true positives) is 76%; with the Frank leads, the same specificity yielded a sensitivity of 49%. The repeatability of the results on new independent controls was also found very satisfactory. The discrimination between patients with angina pectoris on one hand and left ventricular hypertrophy and myocardial infarction on the other hand resulted in a performance level of 89% and 87%, respectively, for the 9-lead system. A good correlation was also found between the extent of the coronary lesions (number of coronary vessels involved) and the fraction of correctly diagnosed patients. The present study concluded that the retrieval of more complete surface information results in an evident improvement of the diagnostic performance of electrocardiography.

This paper is based on a study of specimens of the heart that were obtained in 60 cases of complete transposition of the great vessels. The external relationship of the aorta and pulmonary trunk usually differed from the classic description of the aorta lying directly anterior to the pulmonary trunk (type III). This relationship was present in only two of the 60 cases. In 39 cases, the relationship of the great vessels was oblique (type I). In 19 of the 60 cases, the relationship of the great vessels was side-to-side (type II). There were two main patterns of origin of the coronary arteries. One had a tendency to be associated with the oblique (type I) relationship of the great vessels, which was most common; the other had a tendency to be associated with the side-to-side (type II) relationship of the great vessels, which was the second most common type. A ventricular septal defect was present in 22 (37 per cent) of the 60 cases. The anatomic characteristics of these defects were the same as occur in cases of an isolated defect in the ventricular septum. It was of particular interest that a left ventricular-right atrial communication was observed in three cases. Miscellaneous conditions observed include congenital obstruction of the aortic arch (eight cases), a right aortic arch in association with a ventricular septal defect and pulmonary stenosis (two cases), and juxtaposition of the atrial appendages (two cases). The atrioventricular valves resembled the homolateral valves of normal hearts. An Ebstein-like malformation of the mitral valve was present in one case.

The successful treatment of essential hypertension remains one of the most difficult problems in medicine. Approximately 18 years have elapsed since extensive sympathectomy was first performed for essential hypertension. Extensive sympathectomy occasionally produces striking decrease in blood pressure of patients with essential hypertension; in many instances it fails to decrease blood pressure or modify the course of the disease. That which is most desired are some standards for preoperative selection of patients so that only patients who will be benefited by sympathectomy will be operated on. Unfortunately this apparently cannot be accomplished. The indications for sympathectomy remain at least partially uncertain and there is no agreement among those most experienced in the field of hypertension relative to the results of operation. There also are differences of opinion about the extensiveness of sympathectomy which is advisable. This paper indicates clearly differences of opinion among those most experienced in this field and emphasizes some of the points of agreement. It seems clear that additional technics of sympathectomy cannot be devised for the treatment of essential hypertension. There seems little doubt that sympathectomy would not be performed were adequate medical treatment available. This presentation gives the opinion of internists and surgeons who are particularly interested in hypertension and its treatment.

The paper presents clinical and pathological data on 33 cases of ruptured papillary muscle of the heart as revealed by review of the literature. All of the known causes of this event are listed and the characteristic clinical features are emphasized by including two additional typical case reports.

This paper reports a case of atrial rupture of the heart and reviews 79 other cases collected from the literature proven by autopsy. Incidence, etiology, pathologic physiology, diagnosis and possible treatment are discussed. Infarction of the atrial wall due to an obliterative endarteritis or thrombotic occlusion is the most common cause of spontaneous rupture of the atrium. With a high index of suspicion of atrial rupture in a patient with atrial infarction or cardiac tamponade, earlier diagnosis and surgical treatment may become possible.

Although abundant evidence of concomitant cardiovascular disease is scattered throughout the literature on osteitis deformans, appreciation of the etiologic relationship between the two diseases has been lacking. This paper shows that cardiovascular disease accompanying extensive osteitis deformans may result from: (1) excessive demand on the heart from increased vascularity of affected bones; (2) the influence of concomitant arteriosclerosis apparently exceeding the normal for the age concerned; (3) characteristic thoracic spine deformities which compromise cardiorespiratory function, and (4) hypertension. Fifty-four cases are presented. The incidence of cardiovascular disease exceeds that in the general population of the same age and corresponds with the extent of skeletal involvement.

In the ordinary evolution of an acute myocardial infarct the electrocardiogram shows T wave (ischemia), RS-T segment ("current of injury") and QRS (death of muscle) changes. This paper presents a special group of cases of infarction in which only T wave and RS-T segment changes developed even when patients were observed over a considerable period. Therefore, the curves as such could not be considered diagnostic of myocardial infarction. The authors here describe a unique and intriguing group of cases of fatal myocardial infarction with electrocardiograms resembling those seen in stress tests for coronary insufficiency and showing rimlike subendocardial infarcts at postmortem.

This paper presents a method for bioassay of vasotropic substances. Data on the accuracy of the method are presented in terms of the response to repeated injections of methacholine. Some of the factors affecting the response to methacholine are analyzed. The peripheral vasodilator effect of a nondialyzable substance present in human urine is demonstrated and the effectiveness of this substance is related to that of methacholine.

This paper outlines the electrocardiographic course of a 46-year-old recipient of a cardiac transplant in whom direct myocardial leads were implanted. There was one episode of decreased QRS voltage with an intraventricular conduction delay, suggestive of an acute immunologic rejection. On one occasion bradycardia occurred, and this was treated by ventricular pacing. There was also an episode of supraventricular tachycardia. Vagotonic maneuvers or agents would not have been appropriate treatment for this arrhythmia. In the presence of both donor and recipient P waves, the interpretation of some of the arrhythmias was difficult. Since the QRS voltage is important in diagnosing early rejection, great care was taken in accurately standardizing the electrocardiogram and in reproducibly placing electrocardiographic leads. The myocardial leads were found to reflect voltage changes more clearly than surface leads. The presence of myocardial wires also proved convenient for pacing. The use of a right atrial recording electrode is recommended for the diagnosis of complex arrhythmias. This will permit more accurate identification of donor and recipient P waves.

It has been difficult for the clinician to evaluate quantitatively and qualitatively the degree of damage to the liver in the presence of congestive heart failure. This paper gives a statistical analysis of the results of various liver function tests on a group of patients with congestive heart failure. The analysis includes comparisons based on etiology, type of rhythm, duration of heart failure, and nutrition.

The clinical diagnosis of the presence and severity of tricuspid insufficiency is difficult and is complicated by the transient nature of this abnormality as well as its usual occurrence in subjects with other valve disease. This paper presents correlative hemodynamic data from 100 consecutive catheterized patients with valvular heart disease in 90 of whom the presence of tricuspid insufficiency was sought by the indicator-dilution technic. Tricuspid regurgitation was present in 28 of the 90 patients. Subjects were grouped into 20 controls without tricuspid insufficiency and those with mild, moderate, and severe tricuspid insufficiency. The hemodynamics of these groups were compared by the analysis of variance to determine which parameters relate most closely to tricuspid insufficiency. The results are interpreted to confirm that tricuspid insufficiency results from those factors which overdistend the right side of the heart, and by permitting blood to escape retrograde from the right ventricle serves as a safety valve preventing progressive overload of the pulmonary circulation.

This paper describes a fully calibrated and standardized acoustical test method for evaluating the transmission patterns and the filtration patterns of intact stethoscopes. An essential component of the test system is the artificial ear which duplicates the acoustical contribution of the average human ear to the stethoscope's acoustics. The transmission patterns of bell-type stethoscopes fall into four distinct groups which correspond to their basic design features. Shallow bells and single tubing design both result in attenuation at higher frequencies. A deep, trumpet-shaped bell with double tubing design may provide amplification at higher frequencies. Diaphragms attenuate the transmission acoustics of stethoscopes. When the low frequencies are selectively attenuated, high frequencies are heard more distinctly. Some diaphragms were found to attenuate at all frequencies. The acoustical performance of any stethoscope is critical. Any attenuation of clinically significant sounds of low intensity may render them totally inaudible. The majority of stethoscopes tested (bell and diaphragm chestpieces) attenuate high frequency sounds. The adoption of stethoscopic performance criteria is urged. Few modern stethoscopes show any significant acoustical improvement since the time of Laennec.

The use of the artificial kidney at the Peter Bent Brigham Hospital in the treatment of acute renal shutdown has afforded a unique and extensive opportunity to study the disturbances of rhythm and conduction occurring in potassium intoxication. In this theoretic, and at times frankly speculative, paper the authors present evidence which suggests the applicability to man of Wiggers' views based upon animal experimentation, namely that the ectopic rhythms developing in this condition arise "by default" (escape mechanisms) rather than "by usurpation" (increased excitability) and that potassium exerts its early and preponderant effect upon the subendocardial layers of the human ventricle.

An anatomicopathologic entity of the tetralogy of Fallot with an additional finding of an accessory flap of tricuspid valvular tissue is described. In the 3 cases reported in this paper, the outstanding hemodynamic finding was a right ventricular systolic pressure that was significantly greater than the systemic systolic pressure. The hemodynamic findings were explained by the fact that the accessory tricuspid flap partially closed the large ventricular septal defect. The clinical picture was similar to that of either severe pulmonary stenosis with an intact ventricular septum or severe pulmonary stenosis with a small ventricular septal defect and a right-to-left shunt at the ventricular level.

Sympathectomy and thrombo-endarterectomy have been largely unsatisfactory in the treatment of patients with arterial insufficiency of the lower extremities. In this paper the results are analyzed of a large experience with the use of lyophilized arterial homografts to bridge occlusive lesions below the aortic bifurcation. The criteria for selection of patients for operation, the simplified procedure of end-to-side by-pass of the obstruction, and the excellent results in 145 operations are presented.

This paper reports six cases (age range 8 months to 69 years) of iatrogenic foreign bodies lodged within the heart or great vessels. Four cases were produced during left heart catheterization by breakage of a metal stylet, and two after the insertion of a Pudenz valve (for hydrocephalus) which embolized into the right ventricle and pulmonary artery. In five of these patients, the foreign body was intracardiac (three in the left ventricle and two in the right ventricle and pulmonary artery) and the open-heart surgery was utilized for successful removal. In the sixth patient, the stylet was removed from the innominate artery via a closed procedure. Five of the six patients survived (including the youngest and oldest) and their postoperative course was uneventful. The one death followed removal of the right-left atrial foreign body and total aortic valve replacement for calcific stenosis, and failure appeared related to the basic disease rather than to the foreign body. Such complications have rarely been reported in the literature. The high ratio of success, if treatment is prompt before the formation of clots (which is rapid), needs full appreciation, and emphasis is given to the benefits of prompt surgery for removal.

This paper presents a theory for the cause of congenital malformations of the heart and other structures associated with absence of the spleen. A colmplete review of the literature and the data of the authors' 5 cases lead to this proposal: a lethal factor, possibly the product of a faulty ovulation, specifically affects the germinal bed of the mesoblastic surface of the coelom at an ovulatory age of 24 to 28 days.

Making a diagnosis of a patency of a ductus arteriosus is often difficult in the first few months or first year of life. When the diagnosis is in doubt, one may profitably turn to angiocardiography for help. In this paper a method of demonstrating the patent ductus by the injection of contrast medium is described. The practical importance of the correct diagnosis is presented with reference to 4 cases treated surgically in the early months of life. Demonstration of coarctation of the aorta by this method is also discussed.

The present use of anticoagulants is hampered by the necessity of giving a number of injections of heparin each day, or of using an oral anticoagulant which acts by throttling prothrombin delivery from the liver and does not seem to be a safe anticoagulant, since its laboratory control is not standardized. Because of this an attempt is made in this paper to show the effectiveness of administering heparin subcutaneously and of giving only enough to restore the clotting mechanism to its normal level but not necessarily prolonging the clotting time. With this principle a single injection of heparin a day or every second day seems sufficient, and the danger of hemorrhage is greatly minized.

Very little information is available about the incidence of coronary heart disease in India, or of factors considered responsible for it. In a previous paper, the incidence of atherosclerosis as judged by electrocardiogram, the fat intake, and serum cholesterol levels in 2 low-income groups (industrial and rural) in Delhi were investigated. These data in high-income groups in Delhi have now been studied and the results compared. There were considerable differences in the findings in the 2 groups.

This paper reports a case of complete heart block whose Stokes-Adams attacks were induced by straining at stool and invariably by digital stimulation of the rectum. Electrocardiograms during attacks exhibited high ventricular tachycardia or fibrillation and chaotic heart action.

This paper traces the development of our present concept of the structural organization of the sarcoplasmic reticulum in striated muscle and reviews the physiologic evidence for its participation in intracellular impulse conduction. Comparative observations are presented showing that this system of membrane-limited tubules is particularly well developed in exceptionally fast-acting skeletal muscles. These findings are interpreted as evidence supporting the hypothesis that the reticulum is involved in the coupling of excitation to contraction, but it is considered likely that it also has other important functions in muscle metabolism. The sarcoplasmic reticulum of cardiac muscle is found to be much less extensive and less precisely arranged in relation to the cross-banded pattern of the myofibrils, than it is in skeletal muscle. It is believed, nevertheless, that it may prove to have a significant role in the physiology of the myocardium.

This paper is designed to provide a contemporary overview of primary myocardial disease. The cardiomyopathies are dealt with in the light of both pathophysiologic and etiologic classifications. A relatively simple diagnostic approach is based upon these classifications together with the clinical manifestations of the cardiomyopathies. The essential principles of the natural history are summarized, and treatment is dealt with in terms of specific curatives, general pharmacologic measures, and management of factors that modify, aggravate, or contribute to the development of primary myocardial disease.

This paper describes records of the transmembrane action potential of fibers from different parts of the specialized conducting system and electrograms recorded directly from these fibers in situ. On the basis of these records it is possible to describe certain physiologic mechanisms for conduction delay, block, and supernormal conduction. In general, impaired conduction is associated with a reduced level of membrane potential. This may be caused by incomplete repolarization or partial depolarization. In the normal conducting system, local differences in, action-potential duration and local pacemaker activity most frequently are the cause of a low membrane potential. In disease states, on the other hand, many other factors may be operative. At the atrial margin of the atrioventricular (A-V) node, local anatomic and electrophysiologic properties of the fibers normally cause a very low conduction velocity. The safety factors for conduction here appear to be quite low, and delayed transmission or block often does not result from refractoriness or partial depolarization of nodal fibers. Supernormal conduction, at least in Purkinje fibers, seems to result from the high level of membrane potential reached at the end of repolarization. Whether other factors are responsible for supernormality within the A-V node remains to be seen.