bluuebunny/crossref_metadata_2025_split huggingface dataset:
Familial Aggregation of Factors Associated with Coronary Heart Disease
Authors: DEUTSCHER SIGISMOND , EPSTEIN FREDERICK H. , KJELSBERG MARCUS O. 
Published: June 2012

In the course of an epidemiological study covering an entire community, Tecumseh, Michigan, the familial aggregation of various levels of four variables associated with coronary heart disease-serum cholesterol, systolic blood pressure, relative weight, and blood glucose after a standard load-was assessed quantitatively by determining the relative frequencies of high, intermediate, and low levels of the variables for several familial combinations. High, intermediate, and low levels for each variable were defined in terms of quintiles (highest, middle three, lowest, respectively) of the distribution of the variable specific for age and sex.
Parents and their children and siblings were compared. There was a striking resemblance between children and their fathers and mothers for all the four variables under study, as well as for height which was used as a frame of reference. The degree of resemblance between parents and children was approximately the same at the three levels-"low," "intermediate," and "high"-of the variables, pointing to a multifactorial mode of determination.
In an attempt to assess the relative role of environmental and genetic factors with respect to the determination of the variables under study, degrees of aggregation by age were compared. An appreciable degree of resemblance was found among siblings below the age of 16 who may be presumed to share the same environment to a great extent. Aggregation was less marked for siblings between the ages of 16 and 40, a time when less of the same environment is shared, but it rose again after age 40. It is postulated that the observed rise after age 40 is due to an increase in the penetrance of the genes involved, at middle age and beyond. In addition, this pattern of aggregation suggests that environmental factors may play a stronger role prior to middle age. A similar subdivision by age, was used to study relationships between parents and children; although no corresponding differences between age groups were found, this apparent inconsistency with the sibship data could be explained, in part, by differences in age composition of the groups involved.
The practical implication of the foregoing pattern of familial aggregation lies in the possibility of specifying for an individual the risk of developing high values of a variable predisposing to coronary heart disease in the future on the basis of the values shown by his parents and siblings.
Effects of Heart Rate on the Dynamics of Force Development in the Intact Human Ventricle
Authors: SONNENBLICK EDMUND H. , MORROW ANDREW G. , WILLIAMS JOHN F. 
Published: June 2012

The effects of heart rate on the dynamics of force development in the ventricle were studied in the intact human heart. In the course of corrective cardiac operations, Walton-Brodie strain-gauge arches were sutured to the right ventricles of 11 patients. The peak contractile force, the time to peak force, and the maximum rate of change of force (df/dt) were determined at various heart rates, produced by electrical stimulation of the right atrium or right ventricle. As the rate was increased, from an average of 72 to 145 per minute, no significant change in peak contractile force was observed. The peak df/dt, however, increased with each increment in heart rate, and the time to peak force decreased. This inverse relationship between peak df/dt and time to peak force accounts for the constancy of the peak force observed within several contractions after heart rate was changed. Also, since df/dt and the time to peak force reflect the intensity and duration of the active state, respectively, an inverse relationship between these factors is implied. Sudden changes in heart rate were associated with transient changes in peak contractile force, attributable to differences in the rates with which peak df/dt and time to peak force reached new constant values.
In man, therefore, a "velocity staircase," rather than a "force staircase," occurs with changes in heart rate. The possession of this mechanism apparently permits the human ventricle to maintain its force of contraction and preserve the duration of diastolic filling with increases in rate.
The Hemodynamics of Common (or Single) Ventricle
Authors: RAHIMTOOLA SHAHBUDIN H. , ONGLEY PATRICK A. , SWAN H. J. C. 
Published: June 2012

Data from 43 patients with common ventricle for whom satisfactory hemodynamic data are available are presented; these form 3.2% of the patients with congenital heart disease studied by means of catheterization at the Mayo Clinic. Selective biplane angiocardiography is essential for diagnosis of common ventricle. Associated cardiovascular anomalies are common, with transposition of the great vessels occurring in 84% of the patients.
The right-to-left shunt present in all 43 patients results in desaturation of systemic arterial blood. The common ventricle receives all the systemic and pulmonary venous blood [see table in the PDF file] flows; yet complete mixing is uncommon in this chamber, for it occurred in only 16% of the patients who did not have severe pulmonary stenosis. Fifty-eight per cent had oxygenated blood directed preferentially to the systemic circuit ("favorable streaming"). This occurred most commonly with L-transposition and resulted in a higher oxygen saturation of systemic arterial blood. Obstruction to pulmonary flow (from pulmonary stenosis or pulmonary vascular disease) results in a larger right-to-left shunt and lower oxygen saturation of systemic arterial blood.
Anatomic Evidence for Spontaneous Closure of Ventricular Septal Defect
Authors: SIMMONS ROBERT L. , MOLLER JAMES H. , EDWARDS JESSE E. 
Published: June 2012

Pathological evidence for spontaneous closure of ventricular septal defect in seven adults has been presented. These cases were observed among 1,605 necropsies (an incidence of about 1 per 225 necropsies).
In two of the cases, the ventricular septal defect was closed by an adherent tricuspid valve, possibly the result of bacterial endocarditis.
In the remaining five cases a muscular ventricular septal defect was closed by a fibrous membrane.
The Gradient in Pressure Across the Pulmonary Vascular Bed During Diastole
Authors: KALTMAN ALFRED J. , HERBERT WALTER H. , CONROY RICHARD J. , KOSSMANN CHARLES E. 
Published: June 2012

By means of right and left heart catheterization 70 patients with congenital or acquired heart disease were examined to determine whether or not a gradient in pressure existed between the pulmonary artery and the left ventricle at the end of diastole. In the absence of mitral valvular obstruction in 56 patients there was a statistically significant correlation of pulmonary artery diastolic, left ventricular end-diastolic, and left atrial mean pressures less than 15 mm Hg which was independent of heart rate. Diastolic pressures at identical levels as high as 40 mm Hg were demonstrated in the presence of aortic insufficiency without left ventricular failure, and as high as 47 mm Hg during pulmonary edema in one patient with aortic stenosis and insufficiency. A diastolic gradient in pressure between the pulmonary artery and the left ventricle existed in 14 patients with pulmonary hypertension. These patients all had congenital intracardiac shunts and it may be assumed that they had some obstruction in the pulmonary vascular bed.
These findings suggest that within defined limits friction across the pulmonary vascular bed is so small that a state of pressure equilibrium exists at the end of diastole. When the limits are met clinically, the pressures in the pulmonary artery and in the left ventricle at the end of diastole are identical.
Coupled Pacing and Coupled Pacing with Concealed Conduction
Authors: SHEINER LEWIS B. , STOCK RICHARD J. 
Published: June 2012

In the case reported coupled pacing via an intracardiac catheter electrode was undertaken and continued for 28 days in order to slow the rapid ventricular response in atrial fibrillation, refractory to drug management and cardioversion.
A new phenomenon was observed in which the coupled stimulus caused cardiac cycle prolongation but elicited neither a mechanical nor a propagated electrical ventricular response. Possible mechanisms of this phenomenon are discussed. Stimulation of the bundle of His or a bundle branch with retrograde, concealed conduction in the A-V node and simultaneous antegrade concealed conduction and block are suggested as the most likely.
When this phenomenon was produced after each consecutive spontaneous depolarization, a reduction in ventricular rate resulted without the production of coupled extrasystolic ventricular depolarizations. This constituted a new coupled pacing technique, termed "coupled concealed pacing."
The long-term effects of this technique and of conventional coupled pacing and paired stimulation in this patient are also reported.
Acute and Chronic Effects of an Adrenergic Beta-Receptor Blocking Agent (Propranolol) in Treatment of Cardiac Arrhythmias
Authors: LURIA MYRON H. , ADELSON EDWARD I. , MILLER ALBERT J. 
Published: June 2012

The effects of intravenous and oral administration of propranolol, an adrenergic beta-receptor blocking agent, have been studied in 29 patients with various cardiac arrhythmias. The ventricular responses in chronic or paroxysmal ectopic supraventricular arrhythmias were decreased at rest or during exercise. Sinus tachycardias were regularly slowed. Two supraventricular tachycardias and one ventricular tachycardia, all consistently precipitated by exogenous stimuli, were prevented. Six instances of digitalis-induced arrhythmias were responsive to treatment.
Propranolol, especially when given orally, is of definite value in selected disturbances of cardiac rhythm. Reasonable caution should be exercised, however, because of the risk of precipitation of congestive heart failure or hypotension in patients with limited cardiac reserves.
Anticoagulant Therapy in Coronary Artery Disease
Authors: WESSLER STANFORD , GASTON LAMONT W. 
Published: June 2012

Information available at the present time allows the following conclusions to be drawn:
1. Anticoagulant therapy is clearly effective in treating and preventing venous thrombosis and pulmonary emboli.
2. If used in the treatment of acute myocardial infarction, anticoagulant drugs may salvage 3 to 4% of the treated population. This small gain is probably achieved by the prevention of thromboembolic episodes. While only a small percentage of patients are benefited, the actual number of persons salvaged is relatively great because of the large size of the population at risk. In the considerable majority of treated patients who do not benefit from coumarin drugs, the therapy need do no harm, if proper safeguards are employed in the selection of patients and the administration and laboratory control of the drug.
3. In long-term therapy of patients who have recovered from acute myocardial infarction, it appears that men, especially below age 60, may be helped for the first 1 or 2 years after infarction.
4. More data are required to evaluate the role of anticoagulant treatment in patients with angina pectoris or coronary insufficiency. For the present, the physician may reasonably be influenced in the use of anticoagulant therapy by the recent onset of symptoms, the patient's age, and the family history.
5. Although appropriately controlled studies are lacking, it appears as though patients with peripheral emboli secondary to coronary artery disease may be benefited by anticoagulant therapy.
Severe Pulsus Alternans Associated with Primary Myocardial Disease in Children
Authors: HARRIS LEONARD C. , NGHIEM QUANG X. , SCHREIBER MELVYN H. , WALLACE JOHN M. 
Published: June 2012

Five children, including two siblings, with clinically similar primary myocardial disease, were studied. One of the siblings expired 3 years after the onset of symptoms, and autopsy showed features of "cardiovascular collagenosis (endocardiomyopathy)." Moderate-to-severe pulsus alternans was present in all cases and persisted even after control of cardiac failure and return to moderate physical activity. No electrical alternans or bigeminy was observed.
Cardiac catheterizations were performed on all patients. Left ventricular volume was radiographically determined in the siblings. Left ventricular end-diastolic volume was calculated as greater, and end-systolic volume smaller, for large beats as compared with small beats. Though alternating, end-diastolic volume was abnormally large, preceding both small and large beats. End-diastolic pressure alternated in the same way. Beat to beat (R-R) interval, alternating by as much as 0.09 second, was equalized by pacing in the right atrium and right ventricle, with persistence of pulsus alternans to a lesser degree. Isovolumetric contraction time was prolonged preceding small beats in spite of the large preceding end-diastolic volumes.
The data appear to be consistent with Starling's law but suggest that impaired contractility, possibly due to alternate deletion of contractile elements, is an additional etiological factor.
Parasystole with Fixed Coupling
Authors: LANGENDORF RICHARD , PICK ALFRED 
Published: June 2012

Four examples of spontaneous and six of artificial ventricular parasystole exhibiting fixed coupling of the premature beats were presented. In five cases, one of the pacemakers was located in the S-A node, in four in the A-V junction, and in one at first in the A-V junction and later in the ventricles. The material was divided according to the presence either of mutual protection of the two pacemakers (group I, four cases) or of unilateral protection of the parasystolic pacemaker (group II, five cases).
When the rates of both pacemakers are regular and the conditions for impulse propagation remain stable, fixed (forced) coupling of parasystolic beats develops under the following conditions: in group I (with mutual protection) (a) if there is-by chance or by experimental adjustment-a simple numerical relation between the two pacemaker rates, or (b) if subthreshold stimuli become effective only during a short super-normal period of excitability in the early portion of the ventricular cycle; and in group II (with unilateral protection) as a result of a fixed relationship that develops secondarily to the discharge of the dominant pacemaker by the parasystolic pacemaker, a mechanism referred to as "reversed coupling." This mechanism may be combined with that of group Ib.
Persistence of Reflex Sympathetic Nervous System Activity in Man on Guanethidine or Reserpine
Authors: COFFMAN JAY D. 
Published: June 2012

The effect of guanethidine and reserpine on the reflex sympathetic nervous system vasoconstriction in the calf and foot induced by a prolonged, generalized stimulus (body cooling for 1 hour) was studied in 12 normal subjects. Large daily clinical-doses of guanethidine (40 to 60 mg) or reserpine (1 mg) were given orally for 2 and 3 weeks, respectively. Foot and calf blood flows were measured by venous-occlusion, water plethysmography. Two control studies were performed on each subject, one before and another long after administration of the drug; body cooling produced significant decrease in calf and foot blood flow and increases in vascular resistance in both control studies. Subjects evidenced drug effects by a significant decrease in pulse rate, postural hypotension, hypotension following exercise, and blockade or attenuation of the Valsalva maneuver "overshoot." The attenuation of the sympathetic nervous-system vasoconstrictor reflex to general body cooling was not statistically significant.
Since large clinical doses of reserpine or guanethidine administered for 3 or 2 weeks, respectively, did not inhibit the reflex sympathetic vasoconstrictor effect of total body cooling, functional sympathetic neurotransmitter substance cannot be said to be absent.
Intracardiac Pressure-Flow Dynamics in Isolated Ventricular Septal Defects
Authors: LEVIN AARON R. , SPACH MADISON S. , CANENT RAMON V. , BOINEAU JOHN P. , CAPP M. PAUL , JAIN VISHNU , BARR ROGER C. 
Published: June 2012

This study was conducted to determine the nature of intracardiac shunting in 50 patients between the ages of 3 and 15 years with isolated ventricular septal defects. Simultaneous right and left ventricular pressures and biplane cineangiocardiography were utilized to study the timing and the direction of flow across the defect. Patients with low to moderately elevated right ventricular pressures demonstrated left-to-right shunting across the defect throughout the cardiac cycle. When pressure in the right ventricle approximated that of the left, right-to-left shunting occurred across the defect into the left ventricle during isovolumic relaxation. All patients shared in common the following: (1) a predominant left-to-right gradient and shunt across the defect into the body of the right ventricle during diastole; and, (2) augmentation of the left-to-right gradient with resultant increase of the shunt into the right ventricle during isovolumic contraction immediately preceding opening of the aortic valve.
In comparing patients with and without pulmonary hypertension, the major variations in the cardiac cycle occurred during the periods of ventricular ejection and isovolumic relaxation. These two periods are primarily affected by the changing relationships of the size of the defect, ratio of pulmonary to systemic resistance, and magnitude of net shunts.
Surgical Treatment of Cardiac Defects Associated with Corrected Transposition of the Great Vessels
Authors: HALLMAN GRADY L. , GILL SARJIT S. , BLOODWELL ROBERT D. , MCNAMARA DAN G. , LATSON JOSEPH R. , LEACHMAN ROBERT D. , COOLEY DENTON A. 
Published: June 2012

Corrected transposition of the great vessels is characterized by transposition of the aorta in front and to the left of the pulmonary artery and inversion of the ventricles and atrioventricular valves. Unless it is associated with an intracardiac defect, the circulation of blood inside the heart is normal, and the anomaly may not be recognized clinically. The altered anatomy requires important modifications in the technical features of operative correction of associated cardiac defects.
Among 53 patients with corrected transposition of the great vessels, 31 underwent operation for associated intracardiac defects. These were ventricular septal defects (11 patients), tetralogy of Fallot (seven), common ventricle (five), single ventricle (three), tetralogy of Fallot with pulmonary atresia (two), pulmonary stenosis (one), pulmonary atresia (one), and tetralogy of Fallot with common ventricle (one).
Postoperative complete heart block, which usually leads to a fatal outcome, may follow closure of ventricular septal defect when conventional techniques are used. Although only one death from heart block occurred in seven patients operated on through a right ventriculotomy, we have employed left ventriculotomy in the last two patients to reduce the risk of heart block and to afford better exposure of the ventricular septal defect. The presence of preoperative complete heart block does not contraindicate correction of associated defects, but consideration should be given to insertion of a pacemaker at the time the lesion is corrected since these patients are likely to have Stokes-Adams attacks later.
The anatomical features of associated common ventricle, single ventricle, and tetralogy of Fallot present such severe technical problems that complete correction of these anomalies is accompanied by a high risk. Total correction of tetralogy of Fallot was successfully carried out in only one of seven patients. Others were treated by some form of systemic-pulmonary shunt with good results. Two patients with tetralogy of Fallot and pulmonary atresia and one patient with pulmonary atresia were also treated by systemic-pulmonary shunts and obtained satisfactory palliation. One patient with pulmonary stenosis underwent successful transventricular pulmonary valvulotomy. A ventricular septum was created in five patients with common ventricle. There were only two survivors; the other three died of complete heart block.
Recognition of corrected transposition of the great vessels associated with an intracardiac defect that requires operative repair is important because of technical problems that the morphological alterations of ventricular inversion impose.
Pulmonary Compliance Following Open-Heart Surgery and Its Relationship to Ventilation and Gas Exchange
Authors: ELLISON LOIS T. , DUKE JOHN F. , ELLISON ROBERT G. 
Published: June 2012

Pulmonary function was studied preoperatively and postoperatively in 71 patients undergoing 41 open-heart operations, ten thoracic operations not requiring cardiopulmonary bypass, ten intra-abdominal, and ten peripheral procedures. After operation total respiratory compliance was significantly reduced below the preoperative value for ten days in the open-heart group. Decreases of lesser degree and of shorter duration were noted in the thoracic and intra-abdominal patients with no significant reduction in the peripheral cases. Tidal volume decreased proportionately to the decrease in compliance, and respiratory rate increased, while total ventilation usually remained the same or was slightly increased. Oxygen uptake was significantly increased after open-heart operations, and there was a significant negative correlation between oxygen uptake and compliance. Abnormal venous admixture, not corrected by oxygen inhalation, was observed after cardiopulmonary bypass with a return to preoperative level coinciding with that of compliance. Cardiac output did not correlate with any other measurement.
The data suggest that the postoperative breathing pattern after open-heart surgery is a compensatory adjustment to decreased compliance and that reduced compliance is one of the causes of the increased work of breathing and oxygen demands after open-heart surgery.
Electrocardiographic Changes in Clinically Normal Older Men Following Near Maximal and Maximal Exercise
Authors: LESTER F. MARTIN , SHEFFIELD L. T. , REEVES T. JOSEPH 
Published: June 2012

This study was undertaken to compare the incidence of electrocardiographic abnormalities associated with a near maximal and a maximal exercise test, because of previous reports of high incidence of such abnormalities among older men.
One hundred fourteen male volunteers ranging in age from 40 to 75 years were studied by both near maximal and maximal exercise testing. All subjects were considered normal by history and physical examination. Electrocardiographic responses to exercise testing were monitored by telemetered bipolar leads during and immediately after exercise and by standard electrocardiographic leads made during the recovery period between 30 seconds and 5 minutes after the termination of exercise. Both near maximal and maximal exercise testing were accomplished without significant complication. The incidence of segmental ST depression following the near-maximal test was less than 1%. The incidence of segmental ST depression following the maximal exercise test was 5.2% (6-114). Only one of the five abnormalities detected during or after maximal exercise persisted for more than 30 seconds after the conclusion of exercise. Since such changes occur in a high percentage of patients with heart disease, such changes appear to have a high degree of specificity for some form of cardiac abnormality.