bluuebunny/crossref_metadata_2025_split huggingface dataset:
Incidence of Bacterial Endocarditis in Ventricular Septal Defects
Authors: SHAH PRAVIN , SINGH WALTER S. A. , ROSE VERA , KEITH JOHN D. 
Published: June 2012

In summary, the population figures presented place the risk of bacterial endocarditis for cases of ventricular septal defect in the 5 to 14-year age group as 1 in 470 patient years, or 2.1 per 100 cases in 10 years. The estimated risks for the 5-year-old and 15-year-old patient up to the age of 70 years would be 13.6% and 11.5% respectively. In the city of Toronto, only four cases were seen in 10 years in the general population of over half a million, while in metropolitan Toronto with the population of 1.3 million, eight cases were seen in a similar period. If the clinical experiences of the various authors reported in the literature are pooled with that at The Hospital for Sick Children in Toronto, one would have 21 cases of bacterial endocarditis in 11,328 patient years. This would place the incidence as approximately 1 in 500 patient years.
It is suggested that the surgery for ventricular septal defect may itself initiate bacterial endocarditis as noted in three of our cases.
On the basis of the available data, there is insufficient evidence to designate the risk of future bacterial endocarditis as an adequate reason for surgical closure of the defect.
The Electrocardiogram in Tricuspid Atresia and Pulmonary Atresia with Intact Ventricular Septum
Authors: GAMBOA RAUL , GERSONY WELTON M. , NADAS ALEXANDER S. 
Published: June 2012

Electrocardiograms were studied in 37 patients with tricuspid atresia and in 20 with pulmonary atresia and intact ventricular septum. The results were correlated with angiocardiographic findings and postmortem examinations. Differential features were as follows:
1. Biatrial hypertrophy with characteristic P "tricuspidale" was noted in 81% of the electrocardiograms in patients with tricuspid atresia, whereas this pattern was seen in only two infants with pulmonary atresia and intact ventricular septum.
2. In tricuspid atresia, left axis deviation was usually directed posteriorly; however, anmal or right axis deviation was present in seven cases, six of whom were type 2C and the seventh, type 1A. In every case the horizontal QRS axis was oriented posteriorly. By contrast, in patients with pulmonary atresia there were no instances of left axis deviation in the frontal plane. Normal frontal plane axis was present in 12 patients, all of whom were type I; right axis deviation was evident in eight patients including the three infants with type II deformity. The horizontal QRS axis was usually directed posteriorly; however, anterior orientation occurred in several patients.
3. A typical feature of the vectorcardiogram in patients with tricuspid atresia was the increased anterior magnitude of the initial forces followed by a sharp posterior shift. The initial forces in patients with pulmonary atresia were not characteristic.
4. The electrocardiographic features in patients with tricuspid atresia and normal position of the great vessels showed decreased right ventricular potentials consistent with true hypoplasia of the right ventricle, but in patients with pulmonary atresia similar lack of right ventricular potentials could be correlated with decreased right ventricular cavity, whereas the ventricular wall was actually hypertrophied.
Ventricular Pressure-Flow Dynamics in Tetralogy of Fallot
Authors: LEVIN AARON R. , BOINEAU JOHN P. , SPACH MADISON S. , CANENT RAMON V. , CAPP M. PAUL , ANDERSON PAGE A. W. 
Published: June 2012

The present study was conducted to determine the instantaneous pressure-flow relationships across the ventricular septal defect in tetralogy of Fallot. Simultaneous right and left ventricular pressures and the pressure gradient were recorded with matched catheter systems. Biplane cineangiocardiography was used to evaluate the timing of the bi-directional shunts during various phases of the cardiac cycle. The instantaneous pressure differences between the two ventricles and the direction of the pressure gradient correlated well with the timing of the shunt across the defect.
In 27 patients with moderate tetralogy of Fallot, a consistent pattern of bidirectional shunting was shown. The right-to-left shunt occurred at two places and two sites during the cardiac cycle; namely, during early ventricular ejection into the aorta, and during isovolumic ventricular relaxation directly across the ventricular defect into the left ventricle. Left-to-right gradients and shunting across the defect were found to occur during isovolumic ventricular contraction and during diastole. The results of this study suggest that further investigation of various cardiac defects may yield important information concerning shunting mechanisms.
Kinetocardiogram, Phonocardiogram, and Arterial Pulse Waves During Acute Hemodynamic Changes
Authors: DADDARIO ROBERT C. , FREIS EDWARD D. 
Published: June 2012

The effects of drugs that produce known hemodynamic alterations were assessed on externally recorded pulse waves, heart sounds, and the relationship of these to each other and to the electrocardiogram.
The shape of the carotid pulse and the carotid-femoral pulse-wave transmission time difference showed changes that could be related to alterations in central arterial distensibility. The ratio of the second to the first positive inflection, and of the incisura to the first positive inflection of the carotid pulse wave, increased following use of drugs which raised mean arterial pressure and decreased after those which lowered blood pressure. The carotid-femoral transmission time difference decreased with vasopressor agents, increased with amyl nitrite and hexamethonium, and showed no consistent change after isoproterenol.
Left ventricular ejection time, measured from the carotid pulse, changed in relation to heart rate, increasing with cardiac slowing and decreasing when the rate accelerated. The ejection time index remained unchanged except for a slight increase following amyl nitrite and a decrease after hexamethonium.
Alterations in isovolumic contraction time approximately paralleled changes in diastolic pressure. The ratio of diastolic pressure to isovolumic contraction time provides an index of the rate of rise of left ventricular pressure. The quotient of diastolic pressure divided by isovolumic contraction time increased with adrenergic stimulation (isoproterenol) and decreased after ganglion blockade. It was not significantly changed by angiotensin II, methoxamine, or amyl nitrite.

The interval between the onset of QRS and the beginning of the first heart sound (Q-S
1
), shortened considerably after isoproterenol and moderately following amyl nitrite. It increased after hexamethonium and remained essentially unchanged following angiotensin II or methoxamine. These results suggest that the Q-S
1
interval may reflect ventricular contractility in the absence of mitral valvular disease.

The amplitude of the first heart sound appeared to be a sensitive indicator of ventricular contractility increasing with isoproterenol and amyl nitrite, decreasing with hexamethonium and remaining unchanged following use of angiotensin II or methoxamine.
Hemodynamic State Early after Prosthetic Replacement of Mitral Valve
Authors: RASTELLI G. C. , KIRKLIN JOHN W. 
Published: June 2012

Cardiac output, stroke volume, and atrial, pulmonary arterial, left ventricular, and systemic arterial pressures were measured preoperatively, during operation, and for 48 hours thereafter in 14 patients undergoing prosthetic replacement of the mitral valve. Cardiac output was usually abnormally low after repair, being lowest 3 to 6 hours after operation. This pattern was different from that in a patient undergoing plication of the posterior leaflet and very different from that in a patient undergoing removal of a left atrial myxoma, who served as controls.
Ventricular filling pressure was high, there was no significant diastolic pressure difference across the Starr-Edwards prosthesis, and there was no pressure difference across the left ventricular outflow tract. Blood gas levels and pH were within satisfactory range.
The data are interpreted as indicating that impairment of ventricular performance, particularly left, usually contributes significantly to the low cardiac output in these patients. This is probably related in part to preoperative ventricular function. Possible additional contributing factors are discussed.
Cardiac Motion in Patients with Pericardial Effusion
Authors: FEIGENBAUM HARVEY , ZAKY ADIB , GRABHORN LARRY L. 
Published: June 2012

Diagnostic ultrasound was used to record the movement of the anterior and posterior heart walls in 23 patients with proven pericardial effusion. Fifteen of these patients demonstrated heart-wall motion that could not be distinguished from the normal pattern. Two patients with acute cardiac tamponade exhibited markedly reduced cardiac motion. The ultrasoundcardiograms obtained from the remaining six patients indicated posterior displacement of the entire heart during systole. The extent of this cardiac displacement varied. Five of the six patients with excessive cardiac motion had malignant pericardial effusion, and four of the six had clinical evidence of cardiac tamponade. The two patients with the most marked excursions exhibited electrical alternation.
The results of this study substantiate the theory that excessive cardiac motion may occur in some patients with pericardial effusion. Objective evidence is also provided in support of the positional etiology of electrical alternation associated with pericardial effusion. An attempt is made to identify some of the factors responsible for the observed abnormal cardiac motion, and some speculation is offered as to what role rotation might play in the cardiac displacement.
This study also serves as an example of the type of cardiovascular investigation that can be performed with diagnostic ultrasound.
Anatomic Findings in a Case of Ventricular Pre-Excitation (WPW) Terminating in Complete Atrioventricular Block
Authors: LEV MAURICE , LEFFLER WILLIAM B. , LANGENDORF RICHARD , PICK ALFRED 
Published: June 2012

1. Electrocardiographic and detailed histological studies are presented of a case of ventricular pre-excitation with progressive A-V and intraventricular block terminating in complete A-V dissociation.
2. Whereas the demonstration of a tract which leads from the atrial septal musculature to the A-V bundle bypassing the A-V node explains the short P-R interval, the delta wave is accounted for by the demonstration of unusually copious Mahaim fibers from the A-V bundle to the posterior portion of the muscular ventricular septum.
3. Thus, this appears to be the first demonstration of Mahaim fibers responsible for A-V transmission in the pre-excitation syndrome.
4. The correlation of the data permitted reconstruction of anatomic changes preceding, and responsible for, the gradual progression of the atrioventricular and intraventricular conduction disorder.
5. On the basis of this correlation it would appear that the two characteristic criteria of ventricular pre-excitation, shortened P-R and the delta wave, may in some cases have a different anatomic background. A separation of these parameters permits an explanation of certain atypical and puzzling aspects encountered in the syndrome of ventricular pre-excitation and related conditions.
Studies in Clinical Shock and Hypotension
Authors: COHN JAY N. , LURIA MYRON H. , Eustace Ann 
Published: June 2012

Hemodynamic studies were performed on 44 patients with nonhemorrhagic shock or hypotension in order to assess the degree of vasoconstriction and cardiac stimulation.
In 19 patients, reflex adrenergic discharge was characterized by elevated total peripheral vascular resistance, a high ratio of central blood volume to total blood volume, tachycardia, and clinical signs of skin vasoconstriction. Reduced total blood volume in most of these patients at the time of study could be explained as the result of fever, administration of vasopressor drugs, or prolonged reflex vasoconstriction.
Eight patients were hypotensive with low peripheral resistance usually associated with tachycardia and hypovolemia. The fact that all died within several hours suggests that this "irreversible" syndrome was related to local accumulation of acid metabolites with terminal failure of vasoconstriction.
In 17 patients, absence of reflex vasoconstriction despite hypotension was manifested by low or normal peripheral resistance, low ratios of central blood volume to total blood volume, warm skin, and normal total blood volume. While tachycardia often was absent in this group, heart rate was more closely related to body temperature than to vasoconstriction. Lack of intense adrenergic discharge in these hypotensive patients could be attributed either to the absence of a hypovolemic stimulus or to impairment of normal sympathetic nervous system pathways. The high incidence of alcoholism, cirrhosis, malignancy, pulmonary emphysema, and diabetes in these patients suggests the possibility that adrenergic insufficiency was a factor in the failure of vasoconstriction in at least some of them.
The frequency of hypovolemia in the patients with vasoconstriction stresses the need for recognition and correction of occult depletion of blood volume in shock of diverse etiologies.
Epidemiological Study of Sudden and Unexpected Deaths due to Arteriosclerotic Heart Disease
Authors: KULLER LEWIS , LILIENFELD ABRAHAM , FISHER RUSSELL 
Published: June 2012

A study of sudden unexpected nontraumatic deaths was begun on June 1, 1964. A sample of all nontraumatic deaths in Baltimore residents between the ages of 20 and 64 from June 15, 1964, to June 14, 1965, was obtained. The deaths were then studied by reviewing all available medical information in order to determine: (1) whether the death was possibly sudden or not and (2) the accuracy of the diagnosis reported on the death certificate. The next of kin or other relative or friend of each deceased person who died suddenly was then interviewed.
For comparison, information was obtained on (1) a probability sample of the Baltimore population, and (2) deaths due to arteriosclerotic heart disease (ASHD deaths) that were found to be "not-sudden."
There were 1,857 deaths in the original sample, of which 589 were sudden according to the definition of sudden death. After adjustment for sampling, it was estimated that 1,178 (32%) of the total 3,648 deaths in Baltimore were sudden. Arteriosclerotic heart disease (ASHD) accounted for 58% and the cardiovascular group together for 69% of the sudden deaths.
Sixty per cent of all ASHD deaths were sudden. Of the 1,030 ASHD deaths in Baltimore City between the ages of 40 and 64, 20.6% occurred outside of a hospital and 46.2% represented deaths on arrival at a hospital. Only 18.9% of all ASHD deaths occurred after the first 24 hours of hospitalization.
By use of data provided in several crosssectional and prospective studies, it was estimated that 22% of new coronary events were sudden deaths and that the case-fatality rate was 31%.
In approximately half of the ASHD sudden deaths the deceased had a history of heart disease prior to death and in 24% the deceased had seen a physician within the week prior to death. Unfortunately we were not able to determine the reasons for these visits.
In considering the implications of these findings with regard to the prevention of ASHD deaths, it would appear that prevention of only a comparatively small percentage (8.2%) of ASHD deaths is completely dependent on primary prevention. For the remaining ASHD deaths a combination of both primary and secondary prevention may be effective. Because of the rapidity of death and the high frequency of these deaths either occurring outside of a hospital or being called deaths on arrival, hospital treatment may well have little effect on reducing the ASHD mortality, while, on the other hand, the combination of better and earlier diagnosis and intensive treatment in a hospital could conceivably re- duce the mortality.
The Dominant Pacemaker of the Human Heart
Authors: LISTER JOHN W. , DELMAN ABNER J. , STEIN EMANUEL , GRUNWALD RONALD , ROBINSON GEORGE 
Published: June 2012

In 25 cases at open heart surgery, atrial and ventricular close bipolar electrograms, an atrial unipolar electrogram, and a lead-II electrocardiogram were simultaneously monitored throughout each procedure. In six cases the ventricles or atria, or both, were paced by electrical stimulation. Although atrial activity could frequently not be clearly delineated on the lead II electrocardiogram, the time relationship between atrial and ventricular depolarization could at all times be determined from the electrograms.
During ventricular premature beats and ventricular rhythms, retrograde A-V conduction and retrograde activation of the atria were common, and unidirectional retrograde A-V block was infrequent. In spontaneous and induced cardiac arrhythmias the fastest pacemaker of the heart, atrial, His bundle, or ventricular, usually activated the entire heart.
Studies in Clinical Shock and Hypotension
Authors: COHN JAY N. , LURIA MYRON H. , DADDARIO ROBERT C. , TRISTANI FELIX E. 
Published: June 2012

Thirty-one patients with nonhemorrhagic shock or hypotension of diverse etiologies accompanied by low cardiac output and normal or low right atrial pressure were given a rapid infusion of dextran. Cardiac output returned to normal in 20 patients and shock or hypotension was corrected in 16.
In 10 patients with evidence of vasoconstriction and normal cardiac function, dextran reversed the circulatory abnormality, returning blood pressure, cardiac output, and peripheral vascular resistance to normal. Twelve patients with hypotension without evidence of reflex vasoconstriction were improved by dextran but the hypotension persisted occasionally. In nine patients, dextran revealed heart failure as manifested by a precipitous rise in right atrial pressure without much increase in cardiac output. Control hemodynamic observations and the response to dextran could not necessarily be predicted from the nature of the disease which precipitated the shock.
The efficacy of a rapid infusion of low molecular weight or clinical dextran associated with its freedom from significant toxicity should make it the treatment of choice in non-hemorrhagic shock of any cause associated with normal central venous pressure.
Quantitation of Precordial Movement
Authors: SUTTON GEORGE C. , CRAIGE ERNEST , GRIZZLE JAMES E. 
Published: June 2012

Precordial displacement records of 39 patients with mitral regurgitation have been analyzed using a new method of quantitation. Three groups of patients were studied, and the data from each group have been compared in a number of different ways to those obtained from a control group. The optimal method of discrimination is a graphic representation involving the two variables of the height of the outward movement in systole and the height of the rapid-filling wave. This method allows discrimination between normal persons and patients with mitral regurgitation in a high proportion of cases.
It is postulated that the increase of systolic outward movement in patients with mitral regurgitation is related to an increase in stroke volume of the left ventricle, and the increase in the height or the slope of the rapid-filling wave represents increase in flow and rate of flow into the ventricle in early diastole. The importance of consideration of the functional status of the ventricle in the assessment of precordial movement is stressed.
Cardioversion Following Prosthetic Mitral Valve Replacement
Authors: SEMER HOWARD , HULTGREN HERBERT , KLEIGER ROBERT , BRANIFF BLAINE 
Published: June 2012

Direct current conversion of atrial fibrillation has been attempted in 60 consecutive patients following prosthetic mitral valve replacement (Starr-Edwards prosthesis). Sinus rhythm was attained and persisted for at least 24 hours after the procedure in 68% (41 patients) and 40% of the entire group (24 patients) were still in normal sinus rhythm an average of 10 months later. Successful initial conversion and persistence of sinus rhythm occurred most frequently in patients whose duration of atrial fibrillation was less than 5 years and who had a small left atrium.
Results differed little whether conversion was attempted 7 to 21 days or 1 to 15 months after open valve replacement. Atrial disease associated with a long period of antecedent atrial fibrillation and marked left atrial enlargement appeared to be the most important factors responsible for persistence of atrial fibrillation or early relapse. Attempts at cardioversion are recommended for all patients with persistent atrial fibrillation following mitral valve replacement in view of the high success rate and the safety of the procedure.
Basal Lamina of Abdominal Skeletal Muscle Capillaries in Diabetics and Nondiabetics
Authors: VRACKO RUDOLF , STRANDNESS DONALD E. 
Published: June 2012

In a "blind" study, skeletal muscle biopsies were obtained from the trunk of 13 nondiabetics, eight chemical diabetics, and four overt diabetics of comparable age. On electron micrographs of 20 capillaries from each case, the areas of various components of the capillary structure were measured with a planimeter. The area of the basal lamina was expressed as a percentage of the total vessel area. This method for measuring objectively the relative thickness of capillary basal lamina considered the vessel size, plane of sectioning, and the function state of the vessel. The theoretical validity of the method is discussed.
The widths of the basal lamina of the capillaries of the trunk skeletal muscles of both diabetics and nondiabetics were identical. Morphological differences between the two groups were not present. The discrepancies in results of investigations concerned with the quantity of basal lamina in capillaries of skeletal muscle may be due to naturally occurring regional differences, or because capillary beds of different organs or tissues may be affected differently in diabetes mellitus.
Effect of Aminophylline on Urinary Excretion of Epinephrine and Norepinephrine in Man
Authors: ATUK NUZHET O. , BLAYDES M. CARY , WESTERVELT FREDERIC B. , WOOD J. EDWIN 
Published: June 2012

The excretion of catecholamines and the changes in plasma concentration of free fatty acids during aminophylline administration were explored. The relationships between cardiac arrhythmia, cardiac rate, and change in blood pressure under the conditions of these experiments were defined. Eighteen experiments were performed on eight volunteers. Blood pressures and heart rates before and during aminophylline infusion were recorded at frequent intervals, and urine and blood were collected during the control and infusion periods and in some subjects after the infusion. Loading with ethanol, glucose, or placebo before administration of aminophylline was used.
These studies demonstrated that intravenous infusion of aminophylline increases the urinary excretion of epinephrine and norepinephrine in man, the rate of excretion of epinephrine being greater than that of norepinephrine. This increase was accompanied by an increase in the concentration of free fatty acids in the plasma.