bluuebunny/crossref_metadata_2025 huggingface dataset:
Serial Cardiac Catheterizations and Exercise Hemodynamics after Correction of Tetralogy of Fallot
Authors: BRISTOW J. DAVID , KLOSTER FRANK E. , LEES MARTIN H. , MENASHE VICTOR D. , GRISWOLD HERBERT E. , STARR ALBERT
Published: June 2012

Eleven patients had right heart catheterization an average of 13 mo after total correction of tetralogy of Fallot, and the procedures were then repeated an average of 7 years postoperatively. In the intervening time there was generally no important change in the pressure gradient between the right ventricle and pulmonary artery or in right ventricular systolic pressure. Mean right atrial pressure tended to fall with time. Arteriovenous oxygen difference at rest was lower at the second study, and the resting cardiac output was generally normal. One patient with a persistent ventricular septal defect had progressive hemodynamic deterioration between the two studies. Exercise performance up to 10 years postoperatively was also assessed. The relationship between oxygen consumption and cardiac output was usually normal, but exercise magnified the right heart's filling pressure abnormalities. In the absence of an easily demonstrable ventricular septal defect, right heart hemodynamics were either stable or improved up to 10 years postoperatively. The exercise response of cardiac output was usually normal at moderate work loads.
Anomalies Associated with Coarctation of Aorta Particular Reference to Infancy
Authors: BECKER ANTON E. , BECKER MIES J. , EDWARDS JESSE E.
Published: June 2012

One hundred specimens from subjects with coarctation of the aorta were studied with regard to the nature and occurrence of additional cardiovascular anomalies. Seventy-seven were less than 6 months of age at the time of death (group I) and 23 were 6 months of age or older (group II).

Exclusive of cases of bicuspid aortic valve, there were one or more associated anomalies in 87 cases, that is 91% of the patients under 6 months of age and in 74% of those in the older group. The various types of additional anomalies in order of decreasing frequency were as follows: (1) tubular hypoplasia of the aortic arch (49 cases); (2) abnormal communications (mainly ventricular septal defect and patent ductus arteriosus) (49 cases); (3) left ventricular outflow obstruction (mainly subaortic stenosis) (37 cases); (4) left ventricular inflow obstruction (26 cases); and (5) positional anomalies of the great vessels (mainly transpositions) (13 cases).

More than one anomaly in addition to the coarctation was commonly present. The overall incidence of congenital bicuspid aortic valve was 46%. Among 71 cases in which the relationship to the ductus could be determined, the coarctation was proximal or opposite the ductus in 62 cases and distal to the ductus in nine cases.
Experimental and Clinical Studies on Lactate and Pyruvate as Indicators of the Severity of Acute Circulatory Failure (Shock)
Authors: WEIL MAX HARRY , AFIFI ABDELMONEN A.
Published: June 2012

The increase in lactate (L) and pyruvate (P) content of arterial blood during experimental and clinical shock states and the extent to which such increases serve as measures of oxygen deficit and irreversible injury were investigated on an empirical basis.

A standardized method for production of hemorrhagic shock in the Wistar rat was employed. During a 4-hour bleeding period, oxygen consumption of the rat was reduced to approximately 40% of control value, pH was reduced from 7.39 to 7.08, and a concurrent increase in L from 0.80 to 6.06 m
m
and in P from 0.07 to 0.18 m
m
were observed. Cumulative oxygen debt correlated with log L (r = 0.50;
P
< 0.0005) and both were significantly related to survival. Correlation of cumulative oxygen debt and survival, both with P and with computed values of the lactate pyruvate ratio (L/P) and excess lactate (XL), were of no higher magnitude. Partial correlation analysis demonstrated that neither the measurement of P nor the computation of L/P or XL improved predictability.

In 142 patients who presented with clinical manifestation of circulatory shock and of whom 62 survived and 80 died, the best empirical discrimination between survivors and those who died was provided by measurement of L, which failed only 11% of the time. This was confirmed by discriminant function analysis in which the percentage probability of misclassification based on L was 12% whereas this probability increased to 21% with L/P and 19% with XL. The combination of XL and L/P with L failed to improve discrimination. In this series of patients, L served as a sensitive predictor; as L increased from 2.1 to 8.0 m
m
, the estimated probability of survival decreased from 90 to 10%.

These studies corroborate that L alone serves as a reliable indicator, but neither the measurement of P nor the computation of L/P or XL was shown to improve either the reliability of L as a measure of cumulative oxygen debt or its value as a prognosticator of survival during shock states.
Juxtaposition of the Atrial Appendages
Authors: WAGNER HENRY R. , ALDAY LUIS E. , VLAD PETER
Published: June 2012

Six cases of juxtaposition of the atrial appendages are documented by necropsied specimens and analyzed. A high incidence of conotruncal anomalies, especially transposition of the great arteries, further A-V valve abnormalities, and pulmonary valve atresia, is found. The recognition of juxtaposition of the atrial appendages during cardiac catheterization should alert the investigator to the presence of a complex cardiac anomaly. A case with a rare type of right juxtaposition of the atrial appendages and bizarre spatial orientation of the atria, ventricles, and great arteries is presented.
Effect of Torso Resistivity Variation on the Electrocardiograms of Children, Using a Grid Lead System
Authors: FISCHMANN EUGENE J. , BARBER MARK R. , LEHNER HERBERT H.
Published: June 2012

Most clinical ECG leads determine cardiac currents from a few surface potential samples, without quantitating torso geometry and structure, by empirical-intuitive methods. The present report is part of a broader study asking whether the known limitations of ECG can be reduced by multi-electrode grid leads which sample extensively, measure torso geometry and structure, and use clearly defined biomathematics.

One torso characteristic not measured in clinical ECG is torso resistivity ρ, while past studies of the cardiac dipole moment replaced measurement of ρ by assuming that it is 480 ohms-cm. In essence this amounts to using Ohm's law: Current = voltage/resistance without consideration of the resistance term.

The present work attempts to measure each patient's ρ as part of the ECG recording procedure, by one of two methods: Dipole moment and ρ are separately determined and the measured dipole moment (Mm) is later corrected by computer, or the ECG recorder is calibrated for the patient's ρ, resulting in an ECG directly read as corrected dipole moment, ma-cm.

The effect of ρ variation on the ECG was assessed in 51 children by comparing instantaneous and maximal Mm and its components when ρ was an arbitrary 480 ohms-cm (Mm 480) or individually measured (Mmi). Measured ρ was less than 480 ohms-cm in all subjects and decreased with age. The differences between Mm 480 and Mmi were typically half to a third of the mean Mm 480 and about half of the Mm 96 percentile. Correction of the ECG for individual ρ should result in revaluation of estimates of the heart's total force, as did area correction in previous reports of this series.
Mechanism of Elevated Innominate Artery Pressures in Supravalvular Aortic Stenosis
Authors: GOLDSTEIN ROBERT E. , EPSTEIN STEPHEN E.
Published: June 2012

Patients with supravalvular aortic stenosis frequently have higher phasic and mean blood pressures in the innominate artery than in the aorta distal to the stenosis, a finding never fully explained. Theoretically, this phenomenon could result from the impact of a jet upon blood within the innominate artery. Slowing of the jet would convert kinetic into potential energy, thus increasing pressure within the innominate artery. The aorta distal to the innominate artery would receive blood whose kinetic energy had been dissipated and would consequently remain at the same pressure as the aorta proximal to the origin of the innominate artery. This hypothesis was tested in a model simulating supravalvular aortic stenosis. Cinematography showed a jet directed into the innominate artery. Only after this jet was dispersed, did fluid turn backward to flow into the distal portion of the aorta. Observed pressure rises in the innominate artery corresponded closely with values predicted from the estimated kinetic energy of the jet. Dispersion of the jet by replacement of the stenotic orifice with an equally obstructive screen or proximal displacement of the stenosis (simulating valvular aortic stenosis) abolished the pressure difference. The results obtained were thus entirely consistent with the mechanism proposed to explain the elevated innominate artery pressures seen in supravalvular aortic stenosis.
An Explanation of Asymmetric Upper Extremity Blood Pressures in Supravalvular Aortic Stenosis
Authors: FRENCH JAMES W. , GUNTHEROTH WARREN G.
Published: June 2012

The Coanda effect, the tendency of a jet stream to adhere to a wall, was investigated as an explanation of the unequal pressures in the upper extremities in patients with supravalvular aortic stenosis (SVAS). Of 56 patients with SVAS reviewed, 48 had unequal blood pressures in the upper extremities. The average difference was 18 mm Hg systolic. Although 11 of the 20 patients in the control group (valvular aortic stenosis) had some blood pressure asymmetry, the average difference was 3.5 mm Hg systolic. In valvular aortic stenosis, the velocity of the jet is quickly dissipated beyond the stenotic orifice, preventing any sustained high-velocity stream. However, the smooth, annular narrowing of SVAS creates a "step" between the orifice and the ascending aortic wall which enhances the natural affinity of a jet for a boundary wall and conserves the kinetic energy of the jet stream. In most patients with SVAS, the high-velocity stream is along the right aortic wall, causing disproportionately high pressure in the right arm.
Submaximal Exercise Testing in a Random Sample of an Elderly Population
Authors: RILEY C. P. , OBERMAN A. , LAMPTON T. D. , HURST D. C.
Published: June 2012

To examine the electrocardiographic response to exercise in an older population, 280 participants in a longitudinal study of cerebrovascular disease were tested. Subjects were randomly selected from the total 50 to 69-year-old population of Birmingham, Alabama. Approximately 60% of the participants reached a heart rate more than 80% of their predicted maximal heart rate.

Subjects were divided into three groups on clinical grounds: (I) vascular disease, (II) risk factor(s) only, and (III) normal. Positive tests (at least 0.10 mv of ischemic ST-segment depression) were most frequent in group I (24%), though not significantly different from group II (19%) and group III (12%).

Hypercholesterolemia was significantly associated with a positive exercise test only in those subjects with vascular disease. Nonspecific ST-T wave changes on the resting electrocardiogram were associated with a positive test in all subjects, but with only a borderline test in those subjects without vascular disease. No significant associations were noted between abnormal exercise test and either cigarette smoking or hypertension.
Thermographic Patterns of Angina Pectoris
Authors: POTANIN CONSTANTINE , HUNT DAVID , SHEFFIELD L. THOMAS
Published: June 2012

Liquid crystals, encapsulated onto black Mylar tapes, were used as cutaneous temperature sensors in 50 male patients, who had thermographic examinations while they were being exercised on the treadmill, in an attempt to induce angina pectoris. Twenty-eight of the group remained free of pain and the exercise thoracic thermogram was essentially unchanged from the control or resting state. Twenty-two patients developed angina pectoris during exercise, of whom 21 had associated ST depression in the electrocardiogram, and 17 thermographic abnormalities. When the pain was unilateral (nine patients), skin coolness was invariable and was within the distribution of the pain. When the pain was central (13 patients), skin coolness was present in some of the patients (eight of 13) and was not always within the area of pain. When present, the skin coolness was transient and settled within minutes of relief of pain.
Systolic and Diastolic Abnormalities of the Left Ventricle in Coronary Artery Disease
Authors: BRISTOW J. D. , VAN ZEE BRUCE E. , JUDKINS MELVIN P.
Published: June 2012

Left ventricular volume and circumference were calculated from cineangiocardiograms at 60 frames/sec in 15 patients with arteriographically proven coronary artery disease (CAD) and five control subjects. The patients with CAD had no mitral regurgitation and had an average end-diastolic volume equivalent to that reported by others in normal subjects and to that of the control group. The average end-diastolic pressure was higher in CAD and was often abnormal, despite lack of increase in enddiastolic volume. The ejection was lower in the CAD group as was the extent of circumferential fiber shortening. Maximal and mean rates of fiber shortening correlated positively with ejection fraction and were low in some individuals with CAD.

We conclude that our patients without significant increase in left ventricular enddiastolic volume had abnormalities of diastolic compliance and contractile performance.
Delay of ST Depression after Maximal Exercise by Walking for 2 Minutes
Authors: GUTMAN ROBERT A. , ALEXANDER E. RUSSELL , LI YEOU-BING , CHIANG BI-NIN , WATTEN RAYMOND H. , TING NONG , BRUCE ROBERT A.
Published: June 2012

Maximal exercise testing of 241 healthy, highly selected, middle-aged American men in Taiwan and Hong Kong revealed a lower prevalence of ST-segment depression than among American men in Seattle. This difference was attributed to circumstances restricting availability of American men in Taiwan and Hong Kong with risk factors ordinarily associated with this response.

ST depression, when present, was usually manifested after a delay of 4 to 5 min in the American men studied in the Orient, as previously noted, in healthy Chinese men. This delay is attributed to the circulatory effects of walking slowly for 2 min after maximal exercise which prevents venous pooling and a rapid decrease in cardiac output and coronary perfusion.

Occurrence of ST depression in these selected American men in the Orient was more frequently associated with higher systolic pressure and minor ST-T abnormalities in the resting electrocardiogram than in American men in Seattle.
Clinical and Laboratory Findings in Patients with Nonobstructive Intraventricular Pressure Differences
Authors: GAULT JAMES H. , SIMON ALLAN L.
Published: June 2012

Clinical and laboratory findings were examined in eight patients with nonobstructive intraventricular pressure differences resulting from catheter entrapment in obliterated apical portions of the left ventricular cavity. Cardiorespiratory symptoms were reported by six of the eight patients; three had angina pectoris, and two had experienced syncope. A soft systolic ejection murmur was noted at the cardiac apex or left sternal edge, or at both sites, in each patient at rest or following exercise; no patient had a bifid systolic arterial pulse contour. Paradoxical splitting of the second heart sound with respiration did not occur. In five patients the cardiac index was substantially elevated. In four, an intraventricular pressure difference was present in the basal state, while in the remaining four a pressure difference was elicited by the Valsalva maneuver and isoproterenol. In each patient the arterial pulse pressure consistently increased in the beat following a ventricular extrasystole, and angiographic evidence of left ventricular outflow obstruction was not observed. In all patients, obliteration of the apical portion of the left ventricular cavity during systole was demonstrated angiographically to result from an extreme degree of systolic emptying. Left ventricular hypertrophy was demonstrated angiographically in six patients, four of whom exhibited asymmetric hypertrophy, predominantly involving the interventricular septum. In two patients no abnormality of the left ventricular cavity contour was apparent. These clinical, hemodynamic, and angiographic findings allow differentiation of patients with nonobstructive pressure differences from those with hypertrophic subaortic stenosis.
His Bundle Recordings in Patients with Reciprocating Tachycardias and Wolff-Parkinson-White Syndrome
Authors: CASTILLO CESAR A. , CASTELLANOS AGUSTIN
Published: June 2012

The mechanisms of reciprocating tachycardias were studied in three patients with WPW syndrome using the catheter technic of His bundle recordings. In the first case it could not be determined with certainty whether the tachycardias involved two anatomically independent fascicles or a single longitudinally dissociated pathway. They were terminated by carotid sinus pressure, which caused A-V nodal block, or by properly timed atrial stimuli, which interrupted the circuit. Short-lived paroxysms of atrial fibrillation in cases 1 and 2 were most probably related to atrial vulnerability. In case 3 there were three types of QRS complexes in lead II representing (a) exclusive His bundle conduction, (b) simultaneous His and Kent bundle conduction, and (c) coexisting His and infra-nodal preferential (Mahaim fiber[?]) conduction. This patient also had three types of reciprocating tachycardias-two of ventricular, and one of atrial origin. The reciprocating circuit probably involved the three pathways.
His Bundle Recordings in Bilateral Bundle-Branch Block Combined with Wolff-Parkinson-White Syndrome
Authors: MASSUMI R. A.
Published: June 2012

An example of bilateral bundle-branch block (RBBB) in the presence of WPW syndrome in which diagnosis was established with the aid of His bundle recordings is presented. Complete RBBB and intermittent block of the superior and inferior divisions of the left bundle branch were coexistent for at least 2 years before complete heart block (trifascicular block) occurred. It was demonstrated that the preexcitation pathway conducted and blocked together with the normal pathways. It is suggested that the anomalous bundle in this case traveled with the normal pathways and that this close relationship is more common than has been suspected.

Retrograde V-A conduction at 1:1 ratio was present during electrical stimulation of the right ventricle and the anomalous bundle was used for retrograde spread of activation from the ventricles to the atria. The retrograde P waves, thus produced, conducted antegrade through the His bundle (reciprocation) but reached the ventricles only when they appeared near the end of the T waves of the preceding beats. The mechanism of supramaximal conductivity or excitability, therefore, appears to be a plausible explanation.
Pseudo A-V Block Secondary to Premature Nonpropagated His Bundle Depolarizations
Authors: ROSEN KENNETH M. , RAHIMTOOLA SHAHBUDIN H. , GUNNAR ROLF M.
Published: June 2012

His and right bundle electrograms were recorded in a patient with unexplained P-R prolongations and periods suggestive of both type I and II second degree A-V block. The mechanism of these conduction disturbances was shown to be due to multiple nonpropagated premature His bundle depolarizations (H') which produced their effects on the subsequent cycle by virtue of concealed conduction into the A-V junction. The effects on A-V conduction were related to the time of occurrence of H' in relation to the subsequent P wave: If H'-P was short, a more profound conduction defect occurred. H' was generally undetectable on the ECG because of both antegrade and retrograde block, but a few propagated H' produced typical junctional premature contractions. Propagation of H' depended on a short preceding cycle length and a late occurrence of H'. The site of origin of H' appeared to be in the bundle of His. The mechanism of production of H' did not appear to be either reentry or parasystole.

The term pseudo A-V block is used to describe the arrhythmia because there was no evidence of an intrinsic abnormality of A-V conduction. It is expected that other unusual electrocardiographic phenomena may be explainable with intracardiac recordings of specialized conduction tissue potentials.
Significance of His and Left Bundle Recordings from the Left Heart in Man
Authors: NARULA ONKAR S. , JAVIER ROGER P. , SAMET PHILIP , MARAMBA LAMBERTO C.
Published: June 2012

Eight patients were studied by simultaneous intracardiac recordings of the specialized conduction system from left and right heart. Five patients had normal A-V conduction, one had left axis deviation (LAD), and two had bundle-branch block. Bundle of His (BH) and right bundle (RB) recordings from the right heart were obtained and validated as previously described. In addition a bipolar electrode catheter was introduced into the root of the aorta and left ventricle via the right brachial artery. BH and left bundle (LB) electrograms were recorded at the level of the aortic cusps and just below the aortic valve, respectively. BH recordings from both sides could be temporally superimposed and were similar in onset and duration. In patients with normal A-V conduction the duration of these deflections was BH 15 to 20, LB 15, and RB 10 msec. The conduction time from the proximal LB to ventricular (V) activation (LB-V) ranged from 20 to 25 msec. The LB-V and RB-V conduction times from comparable points were similar and support the previous observations that interventricular septal activation occurs almost simultaneously on both sides. In the patient with right bundle-branch block (RBBB) and LAD with a slightly prolonged H-V time (50 msec), the delay was localized distal to the main LB (LB-V = 30 msec). During ectopic "ventricular," probably left bundle rhythm, retrograde activation of the BH was demonstrated. Aberration (RBBB) of the supraventricular impulse resulting from invasion of the RB by the preceding interpolated premature "ventricular" beat is suggested.
Left Ventricular Hemodynamics Before and 1 Year After Internal Mammary Artery Implantation in Patients with Coronary Artery Disease and Angina Pectoris
Authors: MCCALLISTER BEN D. , RICHMOND DAVID R. , SALTUPS ANDRIS , HALLERMANN FRANZ J. , WALLACE ROBERT B. , FRYE ROBERT L.
Published: June 2012

Left ventricular hemodynamics at rest and during supine exercise were studied before and 1 year after internal mammary artery implantation in 24 patients with severe coronary artery disease and angina pectoris and in five similar patients before and after 1 year of medical treatment. In the surgical group, 14 had evidence of one or more implants providing collaterals to coronary arteries, and 10 had no evidence of collaterals from the implant. Only two patients, both with functioning implants, showed a return to normal of left ventricular end-diastolic pressure at rest and during exercise. There was no correlation between clinical improvement and hemodynamics at the time of the postoperative study. It is concluded that left ventricular hemodynamics may return to normal after internal mammary artery implantation but this was uncommon in the present study.
Erythrocyte Destruction in Different Types of Starr-Edwards Aortic Ball Valves
Authors: MYHRE ERIK , DALE JON , RASMUSSEN KNUT
Published: June 2012

Increased destruction of red blood cells follows the insertion of ball valves into the heart in most cases. Usually, hemolysis is slight, but in some patients uncompensated hemolytic anemia develops. To study the influence on hemolysis of the mechanical properties of the prostheses, the degree of erythrocyte destruction was evaluated in patients with Starr-Edwards aortic prostheses of different types and size.

Fifty-six patients with Starr-Edwards aortic ball valves were examined; 13 had prostheses of the 1200 series with silastic rubber balls, and 43 had valves of the 2300 series with hollow Stellite (metallic) balls. Thirty-one patients had valves with an orifice area of 1.8 cm
2
or less; the others had larger-sized valves.

The degree of hemolysis was predicted from the serum lactic dehydrogenase activity, which has previously been shown to correlate well with the red blood cell survival. The half-life of
51
Cr-labelled red cells was also determined in 16 cases.

Hemolysis was significantly higher in patients with Stellite ball valves than in those with silastic rubber ball valves, and red blood cell destruction was more pronounced in patients with small prostheses than in patients with larger valves. Hemolysis was not higher in three patients with paravalvular leakage than in patients with competent prostheses. Valve type and size seem to be the most important factors in producing hemolysis.
Hemodynamic Determinants of Exercise ST-Segment Depression in Coronary Patients
Authors: DETRY JEAN-MARIE R. , PIETTE FRANZ , BRASSEUR LUCIEN A.
Published: June 2012

Eight patients with coronary heart disease were studied during two periods of exercise separated by 30 min of rest; workload was increased in a stepwise fashion every minute of exercise up to a level that produced limiting symptoms of angina, fatigue, or dyspnea. The magnitude of ST-segment depression and the central aortic pressure were measured during exercise and recovery periods, and myocardial oxygen requirements were estimated by the pressure-time index (systolic aortic pressure x heart rate x ejection time).

Seven of the eight patients exhibited a close relationship (r ranged from 0.74 to 0.98) between magnitude of exercise ST-segment depression and indices expressing myocardial oxygen requirements; heart rate, blood pressure, and ejection time were also related to magnitude of exercise ST-segment depression. These relationships were reproducible during two consecutive exercises. Like onset of angina, magnitude of exercise ST-segment depression is usually related to hemodynamic factors influencing myocardial oxygen needs. Consequently, comparisons of exercise-induced ST depression before and after therapy (drugs, physical training, and surgery) are valid only if ECG findings are compared at the same level of myocardial oxygen requirements.

In contrast, absence of such a relationship during recovery suggests an important difference in mechanisms of the post-exercise electrocardiogram.
Cinecoronary Arteriography in Young Men
Authors: WELCH C. CHARLES , PROUDFIT WILLIAM L. , SONES F. MASON , SHIREY EARL K. , SHELDON WILLIAM C. , RAZAVI MEHDI
Published: June 2012

Of a group of 723 men less than 40 years old who underwent cinecoronary arteriography primarily for evaluation of chest pain, 357 (49%) were found to have at least 50% narrowing of one or more coronary arteries. The youngest person was 17 years old.

The distribution of lesions in the young men was similar to that found earlier in a study of persons not selected by age. The anterior descending coronary artery was most frequently affected; the right coronary artery was most often totally occluded. No total occlusions of the left main coronary artery were seen.

Electrocardiographic evidence of myocardial infarction, found in 109 patients, was less common with disease of the circumflex or right coronary arteries than with disease of the anterior descending coronary artery. This observation was confirmed by examination of left ventriculograms for areas of decreased contractility. Six patients had no significant arterial narrowing.

The extent of arterial involvement seemed to be related to the duration of symptoms in patients who had angina pectoris or myocardial infarctions.

Clinical diagnoses correlated well with the angiographic findings, particularly in those men considered to be normal and those with typical angina pectoris. Addition of atypical features or prolonged pain decreased the degree of correlation.

Only 20% of those with cholesterol levels less than 200 mg/100 ml had significant lesions, whereas 81% with levels more than 275 mg/100 ml had such findings.
Autologous Pulmonary Valve Replacement of the Diseased Aortic Valve
Authors: GONZALEZ-LAVIN L. , GEENS M. , SOMERVILLE J. , ROSS D. N.
Published: June 2012

Living tissue has the potential to replace and reestablish its structure and, therefore, offers the best hope for permanent replacement of diseased cardiac valves. The autologous pulmonary valve has been used to replace the aortic valve in 97 patients since June 1967. An aortic homograft valve, and more recently an autologous conduit of fascia lata, containing a valvular structure, has been used to reconstruct the right ventricular outflow tract. Only four deaths have occurred among the last 50 patients, an 8% operative mortality. Histologic examination of valves, 1 and 13 mo after implantation, revealed normal architecture of cells and collagen fibers with normal living structures.

This initial experience has encouraged the authors to pursue this method of aortic valve replacement in selected cases.
Studies in Clinical Shock and Hypotension
Authors: TRISTANI FELIX E. , COHN JAY N.
Published: June 2012

Renal blood flow was measured by the indicator-dilution technic in 17 patients with shock related to sepsis, myocardial infarction, pulmonary embolism, or pancreatitis. Renal blood flow averaged 225 ml/min/kidney, the renal plasma transit time was prolonged to an average of nearly three times normal, and the renal fraction of cardiac output was reduced to an average of 10.6%. A direct relationship between renal vascular resistance and systematic nonrenal vascular resistance suggested that renal vasocontriction was a manifestation of a more generalized vasoconstrictor process. Since rapid infusion of dextran in patients with normal central venous pressure relaxed renal vasoconstriction and tended to increase the renal fraction, inadequate venous return apparently is an important factor in the reduced renal blood flow in shock.

None of the vasoactive drugs used were effective in restoring normal renal perfusion. The vasoconstrictor drugs (norepinephrine, metaraminol, and angiotensin) increased arterial pressure and renal vascular resistance without significantly altering renal blood flow. Isoproterenol and dopamine increased renal blood flow by an average of 26%, but the renal fraction of cardiac output often decreased further. Renal blood flow was increased by an average of 67% during renal arterial infusion of acetylcholine or hydralazine.

It is concluded that shock is associated with preferential diversion of blood flow away from the renal bed. Although plasma volume expansion and vasoactive drug therapy may improve perfusion, renal hypoperfusion often persists.
Effects of a Phenolic Ether, Su-13437, on Serum Cholesterol, Triglyceride, and Transaminase Levels of Human Subjects
Authors: DUNCAN CHARLES H. , BEST MAURICE M.
Published: June 2012

The hypolipidemic activity of the phenolic ether, 2-methyl-2-[p-(1,2,3,4-tetrahydro-1-naphthyl)-phenoxy]-propionic acid (Su-13437, Ciba) has been studied in 10 hypercholesterolemic patients. The patients were studied at 3-week intervals during 30 weeks of placebo administration and a 30-week period of treatment with Su-13437, 400 mg daily.

Individual mean serum total cholesterol during administration of placebo ranged from 255 to 609 mg/100 ml and during treatment from 187 to 493, the mean reduction being 22%. Five of the subjects were also hypertriglyceridemic, with individual mean levels of triglycerides during placebo periods ranging from 159 to 1247 mg/100 ml. During treatment with Su-13437 mean triglyceride levels of these five patients ranged from 81 to 314 mg/100 ml, a mean reduction of 51%.

The drug was well tolerated and its only effect on the hematologic and biochemical tests for possible toxicity was an increase in SGOT and SGPT levels in two patients, the levels being maximal between the sixth and ninth weeks of drug administration and returning later toward pretreatment values despite continuation of Su-13437.
Vectorcardiographic Differentiation Between Right Ventricular Hypertrophy and Posterobasal Myocardial Infarction
Authors: MATHUR VIRENDRA S. , LEVINE HAROLD D.
Published: June 2012

Vectorcardiograms were recorded by the Frank lead system in 203 cases of right ventricular hypertrophy (RVH) and 85 cases of posterobasal myocardial infarction (PBMI). Of the RVH cases, 33 were confirmed by autopsy and 135 by cardiac catheterization or surgery. Of the cases of PBMI, 12 were confirmed by autopsy and 48 had definite clinical episodes associated with enzymatic or serial electrocardiographic changes or both.

Of several measurements made, the following proved most helpful: (1) location of mean frontal plane QRS axis between 75° and 220° in 64% of the cases of RVH and between 350° and 74° in 78% of the cases of PBMI; (2) location of mean horizontal plane QRS axis between 350° and 90° in 85% of the cases of PBMI but in only 11% of the cases of RVH; (3) location of the 0.04-sec instantaneous vector in the horizontal plane between 350° and 60° in 76% of the cases of PBMI but in only 22% of the cases of RVH; (4) magnitude of terminal rightward voltage of less than 1.0 mv in 88% of the cases of PBMI and equal to or greater than 1.0 mv in 80% of the cases of RVH; and (5) clockwise inscription of the horizontal plane loop favored RVH, but counterclockwise rotation in the horizontal plane was not helpful. Synthesis of criteria 2 and 4 provided the best combination for the separation of RVH from PBMI. If both these criteria were fulfilled, a correct diagnosis could be made with 95% certainty.
Right Bundle-Branch Block and Left Anterior Fascicular Block (Left Anterior Hemiblock) Following Tricuspid Valve Replacement
Authors: ARAVINDAKSHAN V. , ELIZARI MARCELO V. , ROSENBAUM MAURICIO B.
Published: June 2012

Right bundle-branch block occurred in 42.8% and left anterior hemiblock in 35% of 14 patients after surgical replacement of the tricuspid valve. The combination of RBBB with left anterior hemiblock is caused by injury to the branching portion of the bundle of His or more likely, by a lesion involving the pseudobifurcation. This study provides further proof that left anterior hemiblock may be produced by a "central" lesion of the conduction system. An attempt was made to re-define the relationships of the bundle of His and bundle branches to the membranous septum and septal leaflet of the tricuspid valve and to correlate the site of surgical injury with the type of conduction disturbances produced.
A Dynamic Electrocardiographic Concept Useful in the Diagnosis of Cor Pulmonale
Authors: KILCOYNE MARGARET M. , DAVIS ANNE L. , FERRER M. IRENÉ
Published: June 2012

The results of a survey of 200 patients with chronic obstructive pulmonary disease (COPD) revealed that the electrocardiographic criteria used in the past are relatively poor delineators of cor pulmonale in COPD, either in its early or late stages. The study offers a dynamic concept designed to aid in discovering right ventricular (RV) complications in COPD-the coupling of arterial blood gas analysis and four electrocardiographic fluctuations which signal RV abnormality. Where arterial O
2
saturation fell below 85% and pulmonary artery mean pressure (PA
m
) was 25 mm Hg or greater, one or more of these four fluctuations were seen in patients with cor pulmonale: (1) a rightward shift of the mean QRS axis of 30° or more; (2) T-wave abnormalities in right V leads; (3) ST depressions in leads II, III, and aV
F
; and (4) transitory right bundle-branch block. With recovery of better arterial saturation and decrease in PA
m
they subsided. Thus, a clinical appraisal of patients with COPD should include serial analyses of arterial blood gas plus serial electrocardiograms if early (and hence reversible) RV abnormality and cor pulmonale are to be uncovered.
Interruption of the Aortic Arch Without a Patent Ductus Arteriosus
Authors: MORGAN JACOB R. , FORKER ALAN D. , FOSBURG RICHARD G. , NEUGEBAUER M. KEN , ROGERS ALBERT K. , BEMILLER CARL R.
Published: June 2012

Complete interruption of the aortic arch without a patent ductus arteriosus is compatible with survival for many years. This is demonstrated by the case reported herein and two others reported in the literature. With no connection between the ascending and the descending aorta and with both subclavian arteries coming off the descending aorta, blood supply to the entire body, except for the head, was by retrograde flow through the vertebral arteries and left cervical collaterals. Bounding carotid pulsations with diminished arm and leg pulses are apparent in this anomaly. Surgical restoration of the continuity between the ascending and the descending aorta was successful in this case and the two previously reported cases. The surgical results of all cases of interruption or atresia of the aortic arch, including those with a patent ductus arteriosus, are reviewed, and the appearance of the ascending aorta on angiography is suggested as a possible differential point between interruption and atresia of the aortic arch.
Taussig-Bing Malformation, Coarctation of the Aorta, and Reversed Patent Ductus Arteriosus
Authors: WEDEMEYER ANNE LITTLE , LUCAS RUSSELL V. , CASTANEDA ALDO R.
Published: June 2012

Operative correction of a Taussig-Bing malformation was successfully accomplished in a 23-mo-old boy, weighing 6.8 kg. Associated coarctation of the aorta and reversed patent ductus arteriosus were corrected in a preliminary operation. The patient's management was complicated by severe preoperative thrombocytopenia which responded to multiple phlebotomies. Surgical repair of the Taussig-Bing malformation consisted in patching the ventricular septal defect to create physiologically complete transposition of great vessels. Then a Mustard procedure was done.
Hemodynamic Responses to Tilt and Beta-Adrenergic Blockade in Young Patients with Borderline Hypertension
Authors: SANNERSTEDT RUNE , JULIUS STEVO , CONWAY JAMES
Published: June 2012

Seventeen young patients with borderline hypertension (one female) and 18 normotensive paid volunteers (two females) were studied at rest and in the tilted position after 10 min of 45° head-up tilt. Cardiac output, heart rate, and intra-arterial pressure were recorded. The measurements at rest and during the tilt were repeated after betaadrenergic blockade with propranolol.

By comparison with the normotensives, cardiac output and heart rate in those with borderline hypertension were elevated initially, after 50 min of rest, and during tilt. The change of the cardiac output and heart rate to tilt was of the same magnitude in patients and control subjects. Consequently, regulation of the rate and flow in borderline hypertensives appears to be normal but starts from a higher base line level.

After blockade with propranolol, cardiac output in patients with borderline hypertension was still slightly elevated, but the difference from controls was not significant. The heart rate, however, remained significantly elevated at rest and during tilt. Elevation of the heart rate in borderline hypertensives is not mediated through the beta-adrenergic system and may result from decreased parasympathetic inhibition or from different intrinsic myocardial pacing.
Retrograde Activation of the His Bundle During Intermittent Paired Ventricular Stimulation in the Human Heart
Authors: CASTILLO CESAR A. , CASTELLANOS AGUSTIN
Published: June 2012

Intermittent paired ventricular pacing was performed in five patients, one of them with Wolff-Parkinson-White (WPW) syndrome. Retrograde activation of the His bundle and of the atria was observed in all patients. Bipolar leads with interelectrode distances of 1 mm seemed to be slightly better than the conventional ones (10 mm apart) for the identification of His (H) deflections buried inside the QRS complexes. Diagnosis of retrograde atrial activation was enhanced by the use of a high bipolar right atrial lead. In cases 1 and 2, V
2
-A
2
and V
2
-H
2
intervals consistently lengthened as the V
1
-V
2
interval was reduced. In two other patients, previously present retrograde P waves disappeared as the V
1
-V
2
interval was reduced. Yet at even shorter intervals, retrograde conduction to the His bundle and to the atria was seen. Ventricular echoes occurred in two cases, and reciprocating tachycardia in one. In these instances the His bundle was engaged in both retrograde and forward conduction. Finally in the patient with WPW syndrome A
2
preceded H
2
at a given coupling interval, suggesting retrograde atrial pre-excitation through an extra-Hisian pathway.
Right Bundle-Branch Block Associated with Left Superior or Inferior Intraventricular Block
Authors: SCANLON PATRICK J. , PRYOR RAY , BLOUNT S. GILBERT
Published: June 2012

In an 11-year period 209 cases of partial bilateral bundle-branch block were seen. These included patients with right bundle-branch block and either left superior or left inferior intraventricular block. The majority of patients had evidence of coronary artery disease or hypertension, though a significant number had no clinical evidence of heart disease. The majority of patients had follow-up ECG tracings, with an average follow-up for the whole group of about 2 years. The incidence of complete heart block was 14.4% (30 of 209). Complete heart block developed more than 10 years after the discovery of bilateral bundle-branch block in several patients. It is anticipated that with more complete and longer follow-up the incidence of complete heart block will be even higher.
Echocardiographic Features of Atrial Septal Defect
Authors: DIAMOND MORTON A. , DILLON JAMES C. , HAINE CHARLES L. , CHANG SONIA , FEIGENBAUM HARVEY
Published: June 2012

Echocardiographic studies were performed on 39 adult patients with atrial septal defects. Findings were compared with those from normal subjects, patients with other congenital left-to-right shunts (ventricular septal defect and patent ductus arteriosus), patients with uncomplicated right ventricular pressure overload (pulmonic stenosis and pulmonary hypertension), and patients with pulmonary hypertension complicated by tricuspid regurgitation. Two echocardiographic features were assessed: 1) a right ventricular dimension, or RVD Index, representing the distance between the right ventricular epicardial echoes and echoes from the right side of the interventricular septum divided by the patient's body surface area, and 2) motion of the interventricular septum.

The increased RVD Index and abnormal septal motion observed in the patients with atrial septal defects provided an ultrasound complex that could clearly separate these patients from normal individuals, those with ventricular septal defect and patent ductus arteriosus, and those with uncomplicated right ventricular pressure overload. However, patients with tricuspid regurgitation could not be differentiated from the group with atrial septal defects, indicating that this echocardiographic complex reflected a volume overload of the right ventricle.
Spontaneous Closure of Physiologically Advantageous Ventricular Septal Defects
Authors: RAO P. SYAMASUNDAR , SISSMAN NORMAN J.
Published: June 2012

The clinical and pathological features of two cases in which physiologically advantageous ventricular septal defects closed spontaneously are presented. The first patient, with tricuspid atresia, Type I(c), developed symptoms and signs of increasing systemic hypoxemia, decreasing pulmonary blood flow, and a systolic murmur of decreasing intensity. His ventricular septal defect, previously demonstrated angiocardiographically, could not be found at autopsy; it is presumed to have closed by fusion of its muscular rims with subsequent covering by endocardial proliferation. The second patient, with a double-outlet right ventricle, demonstrated progressive left ventricular enlargement and congestive failure despite increasing pulmonary vascular resistance. Postmortem examination showed that this defect was sealed by adherence of the septal leaflet of the tricuspid valve to the edges of the defect. Appreciation of the true nature of the changing anatomical situation would have resulted in more rational effective therapeutic approaches.

The cases presented and review of pertinent literature contribute to more complete understanding of circumstances surrounding the spontaneous closure of ventricular septal defects.
Serial Hemodynamic Observations in Asymptomatic Children with Valvar Aortic Stenosis
Authors: FRIEDMAN WILLIAM F. , MODLINGER JAMES , MORGAN JACOB R.
Published: June 2012

The natural history of valvar aortic stenosis in children is uncertain. This report analyzes serial clinical and catheterization data of nine initially asymptomatic children. The first hemodynamic study was performed at an average age of 6.8 years, and the follow-up study at an average age of 13.1 years. Cardiac indices and left ventricular enddiastolic pressures were consistently normal in all patients. The peak transvalvar pressure difference increased between the initial and final studies in seven out of nine patients. The gradient ranged from 15 to 40 mm Hg (mean 28.2) at the first study, and from 20 to 100 mm Hg (mean 61.6) at the most recent evaluation. Severe stenosis (gradient> 50 mm Hg, normal cardiac output; or calculated orifice <0.7 cm
2
/m
2
) developed in five of nine patients during a 6.8 year average follow-up. The obstruction advanced from mild to moderate in two patients; mild obstruction was unchanged in the remaining two. While the onset of symptoms and changes in the electrocardiogram suggested the possibility of severe obstruction in two patients, there was a poor correlation between the presence of symptoms, the results of the electrocardiogram, the results of the chest X-ray, and the transvalvar pressure gradient in any individual patient. The results of this study suggest that a progressive increase in the severity of obstruction may occur commonly, even in young children, and support the application of serial hemodynamic study to routine patient management.
Electrical Stimulation of the Heart in Patients with Wolff-Parkinson-White Syndrome, Type A
Authors: WELLENS HEIN J. J. , SCHUILENBERG REINIER M. , DURRER DIRK
Published: June 2012

The initiation and termination of tachycardias were studied in five patients with Wolff-Parkinson-White syndrome, type A. In all patients, electrical stimulation was performed from the right side of the heart. In three patients the effect of induced left-sided premature beats was studied as well. In contrast to patients with Wolff-Parkinson-White syndrome, type B, there was difficulty in initiation and termination of tachycardias with premature beats applied to the right atrium or ventricle. This could easily be accomplished with left-sided premature stimuli. In two patients the simultaneous recording of right and left atrial activation during a tachycardia, showing atrioventricular conduction by way of the A-V nodal-His pathway and ventriculoatrial conduction via the anomalous connection, revealed that left atrial activation occurred far in advance of right atrial activation. During regular driving of the right and the left atrium at identical rates the most pronounced pre-excitation pattern was seen after left atrial stimulation.

Our results are in agreement with a circus movement or reciprocal mechanism by way of the A-V nodal-His pathway and the anomalous A-V connection as a causal mechanism for tachycardias in Wolff-Parkinson-White syndrome, type A. In contrast to the usual finding of atrioventricular conduction during the tachycardia via the A-V nodal—His pathway and ventriculoatrial conduction by way of the anomalous connection, one patient showed tachyeardias running in the opposite direction. A location of the anomalous pathway on the left side of the heart is supported by our findings.