bluuebunny/crossref_metadata_2025_split huggingface dataset:
Cardiac Tamponade Following Open-Heart Surgery
Authors: ENGELMAN RICHARD M. , SPENCER FRANK C. , REED GEORGE E. , TICE DAVID A. 
Published: June 2012

A review of 310 consecutive cardiac operations with cardiopulmonary bypass for acquired valvular and congenital heart disease found eight cases of late tamponade, 8 to 30 days after operation, and four cases of early tamponade, within 36 hours after operation. Early tamponade, associated with postoperative bleeding, was easily recognized and treated, but late tamponade was often misdiagnosed as cardiac failure or pulmonary embolism. In the eight late cases, six were associated with anticoagulation and hemorrhage, while two developed a bloody effusion with a pericardiotomy syndrome.
Tamponade produced an elevated right atrial pressure, low central or mixed venous oxygen tension, oliguria, hypotension, and tachycardia. A severe metabolic acidosis was a late finding.
Treatment in the presence of bleeding was uniformly effective if thoracotomy and drainage were promptly instituted. Pericardiocentesis sufficed only in the patients with a pericardiotomy syndrome. Three deaths occurred in the late group from a delay in diagnosis (37.5% mortality).
Circulatory Effects of Carotid Sinus Nerve Stimulation in Dogs with Reference to Coronary Flow and Resistance
Authors: FALICOV RAUL E. , RESNEKOV LEON , KOCANDRLE VLADIMIR , KING SHEILA , KITTLE C. FREDERICK 
Published: June 2012

The effects of electrical stimulation of the carotid sinus nerves upon heart rate, myocardial function, circulatory dynamics, and coronary flow were studied in the anesthetized, open-chest dog. Carotid sinus nerve stimulation produced a transient profound bradycardia, which was abolished by vagotomy, and a more sustained, less marked, slowing of the heart, which became less marked after propranolol. The effects on cardiac output were variable. Significant drops in aortic pressure and systemic resistance were observed. Anterior descending coronary arterial flow also decreased significantly, but the changes in calculated coronary vascular resistance were variable. A disproportionate reduction in coronary blood flow was observed relative to the decrease in myocardial oxygen consumption.
Under the conditions of our experiment, carotid sinus nerve stimulation significantly decreased cardiac work, arterial pressure, and myocardial contractility, and probably produced some coronary vasoconstriction secondary to the reduction in myocardial oxygen demand.
Fatal Malfunction of Edwards Low-Profile Mitral Valves
Authors: HORSLEY HOWARD T. , RAPPOPORT WILLIAM J. , VIGODA PHILIP S. , VOGEL JOHN H. K. 
Published: June 2012

Three of nine patients in whom the Edwards low-profile valve was placed in the mitral position have shown serious valve malfunction. Two of these expired despite emergency valve replacement. The third valve was replaced semielectively, with a good outcome.
The valve malfunction has resulted from pannus formation on the uncovered metal struts, with severe limitation of motion and cocking of the valve disc. It is felt that careful serial evaluation of signs, symptoms, and valve cinefluorography is mandatory in patients with this valve. Should one or more of these parameters indicate valve malfunction, especially if serial observations indicate progressive worsening, valve replacement with another type of prosthesis should be very seriously considered. Serial cinefluorographic observation of the disc motion is indicated even in a setting of clinical well being.
Immediate Revascularization of the Heart
Authors: ADAM MAURICE , MITCHEL BEN F. , LAMBERT CARY J. 
Published: June 2012

The surgical treatment of myocardial ischemia demands immediate revascularization. In 70 patients this demand was met by the use of 114 aorta-to-coronary artery saphenous vein bypass grafts. Thirty-four single, 28 double, and 8 triple bypass grafts were used. They were taken to the right coronary artery (38 times), to the left anterior descending coronary artery (60 times), and to the circumflex coronary artery (16 times). There were 28 patients with three-vessel coronary disease (stenosis greater than 75%) and 15 with two-vessel disease. In spite of this, the operative mortality was only 10% (7 of 70), and four patients died of their disease while awaiting surgery. Relief of symptoms, which occurs without delay, has continued in 81% of the patients (57 of 70).
The use of aorta-to-coronary artery saphenous vein bypass grafts "jump grafts" is proposed as being widely applicable, very effective, and the safest procedure available for the surgical treatment of coronary artery occlusive disease. More observations on longterm results are still needed.
Distribution of Pulmonary Blood Flow after Myocardial Ischemia and Infarction
Authors: KAZEMI HOMAYOUN , PARSONS EDWARD F. , VALENCA LAERCIO M. , STRIEDER DENISE J. 
Published: June 2012

Regional distribution of pulmonary blood flow and ventilation was determined with the
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xenon technic in the erect position at the bedside in 15 patients an average of 6 days after uncomplicated myocardial infarction (MI) and in five patients with severe angina in the same coronary care unit. Follow-up studies were repeated within 3 to 25 weeks on six of the patients with MI.

There was marked reduction in perfusion to the lung base after myocardial infarction. Patients with severe angina showed some underperfusion of the lower lung zones, but to a much less degree than those with acute MI. The pattern of pulmonary perfusion reverted toward that seen in angina in the follow-up studies of patients with MI. Distribution of ventilation was normal in all patients.
The results of the study suggest that there are probably chronic changes in the pulmonary vasculature of patients with arteriosclerotic heart disease which lead to redistribution of pulmonary blood flow toward the apex, and that the marked under-perfusion of the lung base demonstrated following acute myocardial infarction reflects an acute increase in the pulmonary venous and interstitial pressures most likely due to occult left ventricular failure.
The Role of Left Atrial Transport in Aortic and Mitral Stenosis
Authors: STOTT DONALD K. , MARPOLE DEREK G. F. , BRISTOW J. DAVID , KLOSTER FRANK E. , GRISWOLD HERBERT E. 
Published: June 2012

The relationship of left atrial contraction to ventricular filling was studied in 24 patients. Eight patients had aortic stenosis, eight had mitral stenosis, and eight others served as a control group. All had normal sinus rhythm. Cineangiocardiographic volumetric determinations of the left ventricle were done throughout the cardiac cycle, and the rate of left ventricular filling before and during left atrial contraction was calculated.
In the group with aortic stenosis 39% of the left ventricular stroke volume entered the ventricle during left atrial contraction; in the group with mitral stenosis 24% was contributed during left atrial contraction, and in the control patients, 26%.
The rate of left ventricular filling more than doubled during left atrial contraction in aortic stenosis, while no consistent change in the rate of filling occurred during left atrial contraction in mitral stenosis and in the control group.
The character of the resistance to left ventricular filling in aortic stenosis and mitral stenosis is discussed. An important contribution by left atrial contraction to left ventricular performance in aortic stenosis is suggested.
Anomalous Left Coronary Artery from Pulmonary Artery
Authors: PERRY LOWELL W. , SCOTT LEWIS P. 
Published: June 2012

Anomalous origin of the left coronary artery from the pulmonary artery has been noted in 11 patients at Children's Hospital of the District of Columbia from 1946 to 1969. Four of our cases plus 40 in the literature have been reported with complete catheterization data. These 44 infants and children can be divided into three groups (A, B, and C) according to the magnitude of the shunt at pulmonary artery level.
The type of treatment in infants and children with anomalous left coronary artery and increased oxygen saturation in the pulmonary artery at the time of catheterization (group A) appears to be immaterial, as all have survived. Mortality rates in patients with left-to-right shunts not large enough to be detected by oxygen studies (group B) indicate no significant difference in those treated medically or surgically; hence, if possible, surgery should be delayed in this group until after 1 to 2 years of age when surgical mortality is negligible. In patients with filling of the left coronary artery from the pulmonary artery (group C), direct anastomosis of the anomalous left coronary artery to the aorta seems to be the only therapeutic recourse.
To date, there are insufficient data to indicate the efficacy of direct anastomosis of the anomalous left coronary artery to the aorta in the sick infant.
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.
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.
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.
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.
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.
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.