bluuebunny/crossref_metadata_2025 huggingface dataset:
Hemodynamic Effects of Nitroglycerin in Patients with Angina Pectoris Studied by an Atrial Pacing Method
Authors: FRICK M. H. , BALCON R. , CROSS D. , SOWTON E.
Published: June 2012

The hemodynamic effects of nitroglycerin on 20 patients with coronary arterial disease were assessed by using atrial pacing to invoke angina pectoris. This new technique also permitted study of the hemodynamics during pain without the interference of the effects of muscular exercise on the heart affected by coronary artery disease.

The pain threshold of each patient was determined by successive pacing runs and the effects of nitroglycerin were evaluated both before and during the pacing up to the level of pain. With regard to the circulatory status at pain an abnormally elevated pulmonary capillary venous "wedge" pressure was an infrequent phenomenon. This difference from the data of studies in which muscular exercise is used is briefly discussed.

Sublingual nitroglycerin decreased aortic, pulmonary arterial, right atrial, and pulmonary capillary venous pressures. Stroke volume and cardiac output were reduced and this reduction was accompanied by a compensatory rise in heart rate. Tension-time index was reduced and during pacing at identical rates never reached the level at which angina pectoris was experienced before nitroglycerin. End-diastolic heart size as estimated from conventional chest roentgenograms was reduced by nitroglycerin at every pacing step in all six patients studied by this method. The conclusions were that at all heart rates studied nitroglycerin (a) decreased atrial pressures, (b) decreased heart size, (c) caused peripheral vasodilatation, and (d) allowed the heart to be driven at a higher rate without production of anginal pain. These hemodynamic changes reflect a decreased oxygen requirement of the heart and are consistent with the pain-relieving properties of nitroglycerin.
Intravenous Use of Diazoxide in the Treatment of Severe Hypertension
Authors: HAMBY WILLIAM M. , JANKOWSKI GERALD J. , POUGET J. MAURICE , DUNEA GEORGE , GANTT CLARENCE L.
Published: June 2012

Thirty-three patients with severe hypertension were treated with rapidly injected intravenous diazoxide. Renal function was measured in nine patients and four underwent cardiac catheterization during renal function studies. Diazoxide had a rapid, profound hypotensive effect. Average decrease in mean arterial pressure was 26%, with an average duration of 16 hours. Drug resistance was not observed. Renal function was not impaired despite maintenance of arterial pressure at or near normal levels. Decreased mean arterial pressure was associated with a decrease in systemic vascular resistance and left ventricular end-diastolic pressure while an increase in cardiac index and heart rate occurred. Urine volume was unchanged, whereas the glomerular filtration rate and the effective renal plasma flow increased but urinary sodium excretion decreased markedly.

Intravenous diazoxide is a practical effective agent for treatment of all forms of severe hypertension.
Hemodynamic Consequences of Physical Training after Myocardial Infarction
Authors: FRICK M. H. , KATILA M.
Published: June 2012

The hemodynamic effects of physical training, three periods weekly for 1 to 2 months, after myocardial infarction were assessed in seven patients by cardiac catheterization at rest and during exercise. The training was followed by reduction in exercise heart rate and tension-time index as determined from brachial artery pressures. Stroke volume during exercise was enhanced. No significant change occurred in the heart volume. Left ventricular function was improved, and a significant increase in the rate of rise of right ventricular pressure occurred. These were interpreted as indicating myocardial hypertrophy, which probably through reduced compliance also accounted for increased ventricular filling pressures. Lactate in arterial blood was reduced during exercise without any change in the arteriovenous oxygen difference. Small and not significant changes occurred in vital capacity, forced expiratory volume, fasting blood sugar, and serum lipids.

Concomitant with the hemodynamic changes exercise tolerance was improved. The data support the thesis that in some patients increased physical activity after myocardial infarction is followed by beneficial hemodynamic effects on the heart and possibly by increased coronary blood flow. The need for proper selection of patients and close medical supervision during training is illustrated and emphasized.
Idioventricular Rhythm in Acute Myocardial Infarction
Authors: ROTHFELD EDWIN L. , ZUCKER I. RICHARD , PARSONNET VICTOR , ALINSONORIN CESAR A.
Published: June 2012

An ectopic ventricular rhythm (IVR) with a rate of 60 to 100/min was detected in 36 of 100 consecutive patients with acute myocardial infarction by constant monitoring of the electrocardiogram. This mechanism was not apparent clinically and was usually transient, lasting 4 to 30 beats. It was frequently associated with inferior myocardial infarction and usually occurred during sinus bradycardia or the slow phase of sinus arrhythmia. Unlike true paroxysmal ventricular tachycardia (PVT), IVR did not progress to ventricular fibrillation and did not influence the prognosis adversely. Recognition of IVR is important in order to avoid unnecessary and perhaps dangerous treatment with cardiosuppressive drugs and electrical cardioversion.
Effect of Ventricular Septal Defect and Patent Ductus Arteriosus on Left Ventricular Pressure in Complete Transposition of the Great Vessels
Authors: SHAHER REDA , KIDD LANGFORD
Published: June 2012

The relationship between the pressures in the left and right ventricles was examined in 80 infants and children who had complete transposition of the great vessels and in whom the presence of a ventricular septal defect or a patent ductus arteriosus was known. All children with obstruction to left ventricular outflow have been excluded. It was found that 92% (34 of 37) of the children with transposition and a ventricular septal defect had left ventricular pressures greater than 70% of the systemic, while 45% (10 of 22) of those with a patent ductus and only 5% (1 of 21) with a closed ventricular septum and no ductus, had pressures in this range. Seventy-six per cent (16 of 21) of the children in this last group had left ventricular pressures less than 50% of the systemic pressure. It is concluded that infants with transposition of the great vessels and a ventricular septal defect stand in high risk of developing obstructive pulmonary vascular disease and therapy should be guided accordingly.
The Force Ballistocardiogram as an Index of Severity in Congenital Aortic Stenosis
Authors: BARGERON L. M.
Published: June 2012

Evidence is presented that the ultra-low frequency force ballistocardiogram is a sensitive index of severity in children with congenital aortic stenosis. In 300 normal children no abnormal tracing was found. In 46 children with clinical aortic stenosis, the ballistocardiogram was abnormal in all patients with a transvalvular peak systolic pressure gradient of over 35 mm Hg.
Effects of Aminophylline on the Pulmonary Circulation and Left Ventricular Performance in Patients with Valvular Heart Disease
Authors: MURPHY GERALD W. , SCHREINER BERNARD F. , YU PAUL N.
Published: June 2012

The effects of aminophylline given intravenously on the pulmonary circulation and left ventricular performance were studied during combined right and transseptal left heart catheterization in 32 patients with mitral and aortic valvular disease. We recorded complete data on the changes of the pulmonary vascular distending pressure (P
D
) and the pulmonary blood volume (PBV) before and during aminophylline infusion in 28 patients. In 19 patients a fall in the P
D
was associated with a rise in the PBV. In eight patients a decline in the P
D
was accompanied by a fall (five patients) or no change (three patients) in the PBV. In a single case, both P
D
and the PBV rose. In the majority of cases, observation of decrease in P
D
and a discordant rise in PBV is new evidence suggestive of a direct active vasodilating effect of aminophylline on the pulmonary vasculature.

Although the cardiac index was unaffected, a positive inotropic effect on the myocardium was documented by a decrease in left ventricular end-diastolic pressure accompanied by an increase in the maximum rate of ventricular pressure rise (LV dp/dt). These findings contrast with those in certain patients with heart failure of nonvalvular origin in whom increases in cardiac index are usually prominent. The salutory effect of aminophylline in acute pulmonary edema is thought to be due to synergistic effects on the systemic circulation, pulmonary circulation, and left ventricular function, all of which tend to produce a fall in P
D
.
Late, Heparin-Induced Bleeding after Retrograde Arterial Catheterization
Authors: BRISTOW J. DAVID , SEAMAN ARTHUR J. , KLOSTER FRANK E. , HERR RODNEY H. , GRISWOLD HERBERT E.
Published: June 2012

Three patients with ball-valve prostheses were given heparin after percutaneous retrograde aortic catheterization from the femoral artery. The drug was given prophylactically in one case and because of the development of signs of systemic embolism soon after catheterization in the other two. After 3 or more days of heparin therapy, serious bleeding developed at the site of percutaneous catheter entry. The timing and incidence of this complication are in marked contrast to experience with this procedure in individuals who did not receive heparin.

Preliminary experience is presented from right and left heart catheterizations in patients whose prothrombin-proconvertin times were allowed to remain in or near the therapeutic range. No hemorrhagic complications were observed.
Intrapericardial Aneurysmal Dilatation of the Left Atrial Appendage
Authors: GODWIN THOMAS F. , AUGER PIERRE , KEY JAMES A. , WIGLE E. DOUGLAS
Published: June 2012

A case of intrapericardial aneurysmal dilatation of the left atrial appendage occurring in a young woman is described. The patient presented with recurrent arrhythmia, which on one occasion was documented to be a supraventricular tachycardia. Routine chest x-ray revealed an abnormal configuration of the left heart border. A precordial scan with
131
I-labeled albumin provided evidence that the mass on the left heart border was blood filled and strongly suggested that it was cardiac in origin. Pulmonary, followed by left atrial, cineangiography provided the definitive diagnosis and demonstrated extremely slow clearance of radiopaque dye from the appendageal aneurysm. Following surgical removal of the aneurysm the tachycardias have not recurred.

The previous experience in the literature with this problem is briefly presented.
REPORT OF COMMITEE ON GRADING LESIONS, COUNCIL ON ARTERIOSCLEROSIS, AMERICAN HEART ASSOCIATION
Authors: MCGILL HENRY C. , BROWN B. W. , GORE IRA , McMILLAN GARDNER C. , POLLAK O. J. , ROBBINS STANLEY , ROBERTS JAMES C. , WISSLER ROBERT W.
Published: June 2012

A committee of pathologists compared four methods of evaluating coronary artery stenosis in the first 6 cm of 30 right coronary arteries. Seven judges twice estimated the percent reduction in lumen and the length of stenosed artery in longitudinally opened arteries, in postmortem angiograms, in casts, and in the three media together. The mean of 14 replicate estimates (seven judges, two rounds) based on the composite media was considered the "truest" value for each artery. Estimates based on casts correlated best with those based on the composite media. Estimates based on arteries and angiograms were consistently lower than those based on casts or on the composite media. Reliability was worst for estimates based on the arteries, intermediate for estimates based on angiograms and the composite media, and best for estimates based on casts. There was significant bias among judges in estimates based on single media, except in length stenosed based on arteries and angiograms. There was also significant bias among judges in both measures of stenosis based on the composite media. Percent reduction in lumen is correlated with length of artery stenosed. When more than half of the first 6 cm is stenosed, the lumen reduction approaches 100%. Either of the two measures, any one of the three single media, or any combination of the three media may be useful in evaluating coronary artery stenosis. Choice of the method depends on the requirements of the study. Artery, angiogram, and cast together seem indicated when clinicopathological correlation is the purpose of the investigation. An investigator must establish the reliability and validity of any method chosen under the conditions of his study.
A Quantitative Angiocardiographic Study of Left Ventricular Hypertrophy and the Electrocardiogram
Authors: BAXLEY WILLIAM A. , DODGE HAROLD T. , SANDLER HAROLD
Published: June 2012

The QRS amplitude, duration, and mean axis direction of the standard 12-lead electrocardiogram were compared with left ventricular mass, volume, wall thickness, and stroke work in 112 adult patients. These patients had normal left ventricles or various degrees of left ventricular dilatation or hypertrophy. Left ventricular volumes and mass were determined by a quantitative angiocardiographic method. A significant but not a close correlation between left ventricular mass and ECG voltage was found. Enddiastolic volume, stroke volume, stroke work, wall thickness, and "total left ventricular volume" (volume of left ventricular muscle and cavity at end-diastole) had generally lesser degrees of correlation with the QRS amplitude than did the mass alone. Subgrouping of patients into those with pressure overload on the left ventricle, volume overload, aortic valve disease, or anatomic left ventricular hypertrophy did not improve correlations. The left ventricular hypertrophy voltage criteria of Sokolow and of Grant were assessed; respectively, 68% and 67% of 75 patients with anatomic hypertrophy had hypervoltage. The direction of the anatomic long axis of the left ventricle was not significantly related to the mean QRS-vector direction.
Notched T Waves in Young Persons with Central Nervous System Lesions
Authors: MILLAR KAY , ABILDSKOV J. A.
Published: June 2012

Eighty-nine abnormal electrocardiograms taken on young persons with central nervous system (CNS) lesions were reviewed. Most had S-T segment and T-wave abnormalities of a nonspecific type. A high incidence of notched T waves was also noted. In this group of patients with CNS lesions the notching may be due to asymmetrical alterations in sympathetic tone to the ventricle.
Surgical Correction of Mitral Insufficiency Due to Ruptured Chordae Tendineae
Authors: GERBODE FRANK , HILL J. DONALD , KELLY JOHN J. , SELZER ARTHUR , KERTH WILLIAM J.
Published: June 2012

During the past six years we have operated on 80 patients with predominant mitral insufficiency. Twenty-two patients had ruptured chordae tendineae. Rheumatic heart disease was frequently the cause when there was considerable valve deformity and ruptured chordae to the anterior mitral leaflet. The etiology of these cases was rheumatic heart disease in only 2 of the 15 patients with ruptured chordae to the posterior leaflet. In eight the etiology was unknown. These cases had a syndrome in which there is an aortic as well as an apical systolic murmur. The left atrium was frequently not so large as in rheumatic mitral insufficiency, and most patients were in sinus rhythm.

Because of a relative excess of reserve tissue of the posterior leaflet, localized rupture of chordae to this leaflet can easily be corrected by a simple plication procedure.
Use of a Polyol in the Prevention of Hemolysis due to an Antifoam Agent in Pump Oxygenators
Authors: WELLS ROE , BYGDEMAN M. STELLAN , SHAHRIARI ALI A. , MATLOFF JACK M. , HARKEN DWIGHT E.
Published: June 2012

Studies of the hematological effects of a polymethylsiloxane defoaming agent used in pump oxygenators have shown it to have significant hemolytic properties. This action is principally a direct one upon the red cell and requires some degree of associated mechanical stress. Pluronic, a nonionic emulsion stabilizer prevents the hemolytic process without interfering with the defoaming process.
Elimination of Sewing Ring-Metal Seat Interface in Mitral Valve Prostheses
Authors: BEALL ARTHUR C. , BLOODWELL ROBERT D. , LIOTTA DOMINGO , COOLEY DENTON A. , DE BAKEY MICHAEL E.
Published: June 2012

In an effort to decrease the incidence of thromboembolic phenomena associated with prosthetic replacement of the mitral valve and to eliminate problems associated with swelling of moving parts employed in cardiac valve prostheses, a new mitral Teflon disc valve made of titanium was designed. The cage legs are covered with Teflon to reduce wear, and the entire sewing ring and base are covered with Dacron velour to encourage rapid tissue encapsulation. After accelerated fatigue testing and animal investigations, preliminary results in a clinical series of 73 patients appear most encouraging. Further time must pass, however, before statistically valid conclusions can be reached.
In Vivo Evaluation of Dacron Velour as a Nonthrombogenic Surface
Authors: SHEA MICHAEL A. , INDEGLIA ROBERT A. , VARCO RICHARD L. , EDWARDS JESSE E. , BERNSTEIN EUGENE F.
Published: June 2012

The healing properties of Dacron velour were evaluated after its implantation in the canine aorta, vena cava, and left atrial appendage. A high incidence of thrombosis was observed, both in sacrificed animals and those that died spontaneously. The thrombus was invariably tightly adherent to the wall of the graft. No evidence of peripheral embolization was apparent. Histologic examination did not reveal anything unique in the healing of Dacron velour but rather it conformed to the healing process previously described with other Dacron vascular prostheses.
Surgery for Massive Myocardial Infarction
Authors: HEIMBECKER RAYMOND O. , LEMIRE GUY , CHEN CHARLES
Published: June 2012

Emergency myocardial infarctectomy has been studied experimentally and clinically. The clinical experience describes encouraging results in two of four consecutive patients. The criteria of patient selection are described, along with a suggestion that associated perforation of the ventricular septum, as documented in three of the patients, makes the operative procedure more difficult and the results less satisfactory.

Experimental myocardial infarction was studied in two groups of calves with a mortality rate of 100%. In the first group emergency resuscitation by massage and bypass produced an initial resuscitation rate of 14% but a survival rate of only 11%. In the second control group of fatal infarction, resuscitation was attempted by 45 minutes of bypass, with improvement in the resuscitation rate to only 23% and proportionate improvement in the survival rate to 18%.

Emergency infarctectomy dramatically increased the initial salvage rate to 100% and improved the survival rate to 41%.
Clinical Experience with the Use of Aortic Valve Homografts for Reconstruction of the Pulmonary Artery, Pulmonary Valve, and Outflow Portion of the Right Ventricle
Authors: WELDON CLARENCE S. , ROWE RICHARD D. , GOTT VINCENT L.
Published: June 2012

Four patients with ventricular septal defect, infundibular right ventricular obstruction, and associated abnormalities of the pulmonary valve or main pulmonary artery have been treated by a combination of ventricular septal defect closure, infundibular myomectomy, and insertion of an aortic homograft into the pulmonary circulation. Pulmonary valvular competence has been restored in all four cases. A single fatality has resulted, and was associated with bacterial destruction of the homograft. The hemodynamics of pulmonary valvular insufficiency are discussed, and indications for homograft replacement of the pulmonary valve are outlined.
Atrial Echo Beats in the Human Heart Elicited by Induced Atrial Premature Beats
Authors: SCHUILENBURG R. M. , DURRER D.
Published: June 2012

In a patient with atrial septal defect and incomplete right bundle-branch block atrial echo beats were observed after atrial premature beats, induced with a gradually decreasing delay during regular driving of the atrium. The time relations of these atrial echo beats could be accurately defined. Considerable prolongation of the atrioventricular (A-V) conduction of the premature atrial response was found to be a necessary condition for the occurrence of atrial reciprocation, which was restricted to small and very circumscript delay ranges.

Three types of atrial echo responses could be discerned. The concept of a dual A-V conduction system was not sufficient to explain the genesis of these three types. The assumption of a third pathway in the upper part of the A-V node was needed. Arguments in favor of a longitudinal dissociation of one of the two pathways postulated in the concept of dual A-V transmission were given.
Hemodynamic Studies on Cholera
Authors: HARVEY RÉJANE M. , ENSON YALE , LEWIS MILENA L. , GREENOUCH WILLIAM B. , ALLY KHAIROON M. , PANNO ROSALIND A.
Published: June 2012

The hemodynamic effects of hypovolemia and acidosis were studied in 23 patients with cholera. Studies were made before and during fluid replacement and administration of alkali.

The major hemodynamic abnormalities encountered before rehydration can be ascribed to a reduction in circulating blood volume. Hypovolemia was associated with a reduction in cardiac output, blood pressures, and central blood volume. Restoration of blood volume returned these variables toward normal.

The chief effect of acidosis appeared to be a redistribution of blood from the peripheral to the central circulation; consequently, central blood volume, lesser circulation pressures, and cardiac output were relatively well maintained despite hypovolemia. Fluid administration without correction of acidosis favored a disproportionate increase in central blood volume, while reduction in hydrogen ion concentration attending fluid replacement resulted in a more even distribution of the circulating blood volume and reduced the possibility of engorgement of the pulmonary bed.

It is postulated that this redistribution of blood stems from peripheral venoconstriction and a reduction in the capacity of venous reservoirs induced by acidosis.
Quantitative Angiocardiography
Authors: MURRAY JOHN A. , KENNEDY J. WARD , FIGLEY MELVIN M.
Published: June 2012

Maximum and minimum volumes of the left atrium (LA) were calculated from the biplane angiocardiograms of 18 men and four women without significant heart disease.

The mean LA maximum volume was 63 cc ± 16 cc; the mean LA minimum volume was 31 cc±10 cc, and their difference, LA cyclic volume change, was 33 cc±13 cc. Larger LA volumes were associated with greater cyclic volume changes. LA cyclic volume changes constituted 38% of LV stroke volume.

No significant correlation between LA volumes and age, sex, surface area, heart rate, LV end-diastolic volume, LV stroke volume, or cardiac output was found.

Volume data in normal subjects support the thesis that the LA serves mainly as a reservoir and conduit for blood destined for the left ventricle and that its contractile function is less important. The relation of LA volume change to LV stroke volume appears abnormal in chronic mitral regurgitation and constrictive pericarditis.
Natural History and Prognosis of Atrial Septal Defect
Authors: CRAIG ROBERT J. , SELZER ARTHUR
Published: June 2012

A series of 128 consecutive cases of atrial septal defect in adult patients was analyzed from the standpoint of the course and prognosis. The ages of the patients ranged from 18 to 67 years and the ratio of men to women was 1 to 2. Age distribution when compared with life expectancy tables indicated reduced life expectancy. Clinical analysis revealed that three quarters of the patients were symptomatic, but symptoms were mild to moderate and usually nonprogressive. Hemodynamic analysis revealed significant pulmonary hypertension in 22% of the series, of which 15% had high pulmonary vascular resistance, and significant arterial hypoxemia in 14%. The most serious risk factor in atrial septal defect is severe pulmonary hypertension. This complication, which develops in about 14% of patients with atrial septal defect when they are between 20 and 40 years of age, may be rapidly progressive, leading to shunt reversal, disability, and death. Once established, pulmonary hypertension may progress even when the defect is surgically closed. Heart failure occurs usually in older individuals and is associated mostly with chronic atrial arrhythmias rather than pulmonary hypertension.
Hemodynamic Effects of Diuresis at Rest and During Intense Upright Exercise in Patients with Impaired Cardiac Function
Authors: STAMPFER MORRIS , EPSTEIN STEPHEN E. , BEISER G. DAVID , BRAUNWALD EUGENE
Published: June 2012

Although diuretic therapy appears to improve the exercise capacity of patients with moderately impaired cardiac function, the hemodynamic basis for this improvement is not clear. It is also unknown to what extent the moderate diuresis that often occurs during the first few days of hospitalization contributes to the normal or nearly normal hemodynamic measurements obtained in certain patients with cardiac impairment who are thought clinically to have signs and symptoms of pulmonary congestion. Accordingly, the circulatory response to moderate diuresis resulting in a loss of weight averaging 3.4 kg was investigated in 15 patients with heart disease. At rest in the supine position mean pulmonary arterial wedge pressure fell after diuresis from an average of 24 to 13 mm Hg. Reductions also occurred in mean pulmonary arterial pressure (42 to 26 mm Hg), mean right atrial pressure (9 to 4 mm Hg), and right ventricular end-diastolic pressure (11 to 6 mm Hg). Cardiac output decreased by an average of 20%, mean systemic arterial pressure by 12%, right ventricular stroke work by 44%, and left ventricular stroke work by 25%. Diuresis also caused similar reductions in these values in the sitting position at rest and during mild and intense levels of treadmill exercise. Despite the reductions in cardiac output, all but one of the patients studied achieved substantial clinical improvement from the diuresis. Such improvement probably resulted from the fact that the beneficial effects of lower pulmonary vascular pressures outweighed the deleterious effect of a reduction in cardiac output. Thus, moderate changes in body weight brought about by either fluid retention or fluid loss may result in substantial alterations in circulatory dynamics. These changes, if unrecognized, can lead to considerable confusion when attempts are made to correlate the hemodynamic findings with the degree of cardiac decompensation as judged clinically.
Left Ventricular Performance During Mild Supine Leg Exercise in Coronary Artery Disease
Authors: MCCALLISTER BEN D. , YIPINTSOI TADA , HALLERMANN FRANZ J. , WALLACE ROBERT B. , FRYE ROBERT L.
Published: June 2012

Left ventricular (LV) performance was studied during mild exercise (100 kg-m/min for 3 minutes) in 19 cases of coronary artery disease (CAD). Each patient suffered from a severe anginal syndrome. None had ventricular aneurysm, cardiomegaly, or clinical heart failure. Mean resting values follow: LV end-diastolic pressure (LVEDP), 19 ± 7 mm Hg; LV systolic pressure (LVSP), 150 ± 16 mm Hg; stroke volume index (SVI), 48 ± 10 ml/beat/m
2
; and LV stroke work index (LVSWI), 81 ± 19 g-m/m
2
. During exercise LVEDP rose to 30 ± 8 mm Hg (
P
≤0.001) and LVS to 160 ± 20 (not significant [NS]); SVI diminished to 46 ± 11 (NS) and LVSWI, to 76 ± 24 (NS). Patients with decreased or asynchronous areas of LV myocardium identified on cine left ventriculograms had higher mean LVEDPs during exercise than did those with normal ventriculograms (34 ± 10 versus 26 ± 4 mm Hg;
P
≤0.05). The difference between responses to exercise of patients who experienced angina during the study and of those who did not was NS. Administration of nitroglycerin reduced the increase in LVEDP during exercise. An abnormality in LV performance-a significant rise in LVEDP without a significant increase in SVI or LVSWI-was observed in 13 of 19 cases of CAD.
Reference to Transposition, Dextrocardia and the Concept of Four Normal Hearts
Authors: STANGER PAUL , BENASSI ROBERT C. , KORNS MICHAEL E. , JUE KENNETH L. , EDWARDS JESSE E.
Published: June 2012

A system of loose leaf diagrams is presented for the purpose of portraying the various types of cardiac structure. Appropriate assembly of the diagrams may be used to define the anatomic details in a given case of which a permanent machine-copy may be made and the basic diagrams re-used.

The diagrams may be used as teaching devices to illustrate the interrelationships between (1) transposition of the great vessels, (2) inversion of the various cardiac chambers and great vessels, and (3) dextrocardia.

The material lends itself to illustration of the concept of "four normal hearts;" that is, the fact that although structurally different, there are four anatomic patterns of heart which allow a normal route for the flow of blood.

The diagrams also may be used to illustrate certain features about potential cardiac transplantation. These include the point that for the recipient with a certain body type (situs solitus or situs inversus), normal channels for the flow of blood may be obtained from a donor with one of three types of cardiac structure. These are either the normal or that of corrected transposition of the same body type as the recipient or complete transposition in a donor with the opposite body type from that of the recipient.
Analysis of T-Wave Abnormalities Associated with Myocardial Infarction Using a Theoretic Model
Authors: MANDEL WILLIAM J. , BURGESS MARY JO , NEVILLE JOHN , ABILDSKOV J. A.
Published: June 2012

The physiological basis of serial T-wave abnormalities associated with myocardial infarction was studied. After coronary artery ligation in dogs, ventricular functional refractory periods (FRPs) were measured at five to eight epicardial, intramural, and endocardial sites. FRPs measured during acute ischemia shortened an average of 26 msec. FRPs measured 24 to 72 hr after coronary ligation were 24 msec longer at ischemic than at nonischemic sites. Alterations of recovery times were analyzed in terms of a repolarization model which related the form of the action potential downstroke to the form of the T wave of the body surface ECG. Observed FRPs were used to infer action potential duration and T waves were derived. Shortening FRPs in the anterolateral wall of the ventricle increased the amplitude of derived T waves in the X lead and caused T-wave inversion in the Z lead. Prolonging FRPs in the same area caused T-wave inversion in lead X and increased T amplitude in lead Z. The form of derived T waves qualitatively corresponded to serial T-wave abnormalities seen in patients with myocardial infarction.
An Appraisal of "Supernormal" A-V Conduction
Authors: MOE G. K. , CHILDERS R. W. , MERIDETH J.
Published: June 2012

Certain temporal patterns of A-V and V-A transmission in experimental preparations resemble phenomena attributed to "supernormal" conduction in the clinic. Detailed study of the properties of the A-V transmission system in such experiments reveals alternative explanations in which supernormality is clearly eliminated. By application of similar principles, supernormality can be eliminated as a factor in most if not all of the published examples. Three major categories can be discerned: (1) occult 2:1 A-V block, in which an idioventricular beat "retracts" an otherwise refractory barrier within the A-V node; (2) alternation between dissociated intranodal transmission pathways; and (3) "ventriculophasic" (vagal) depression of nodal conductivity.
Patent Ductus Arteriosus
Authors: ESPINO-VELA JORGE , CARDENAS N. , CRUZ R.
Published: June 2012

Simple patent ductus
arteriosus with a normal or only slightly elevated pulmonary arterial pressure was associated with an estimated life expectancy of 25 years before the era of cardiac surgery and antibiotics. No information is available regarding current life expectancy because almost all patients undergo surgery as soon as the diagnosis is established. The likelihood of premature death from bacterial endocarditis is estimated to be 14%. The operative mortality is about 0.3%. The patient is cured.

Concerning the
typical hypertensive ductus
with a pulmonary arterial systolic pressure of less than 75% of the aortic systolic pressure, there is no precise information regarding life expectancy. Because of the same susceptibility to bacterial endocarditis and a propensity for progression of pulmonary hypertension, it is assumed that the life expectancy is shorter than it is for patients who have a simple ductus. The operative mortality is 0.5% if the pulmonary arterial systolic pressure is less than 45% of the aortic systolic, and 4% if it is between 45 and 75% of the aortic systolic pressure. The patient is cured.

In
extreme hypertensive ductus
, here defined as a pulmonary arterial systolic pressure greater than 75% of the aortic systolic pressure, the average life expectancy is estimated as being in the twenties. The surgical risk is 18%. If the pulmonary exceeds aortic pressure and the shunt is right to left, the surgical risk approaches 100%. Most patients have reversible pulmonary hypertension and appear to be cured by surgery, but a few do not, and if they survive surgery, they remain as pulmonary vascular cripples postoperatively.
Effects of Beta-Adrenergic Blockade (Propranolol) on Left Ventricular Hemodynamics and the Electrocardiogram During Exercise-Induced Angina Pectoris
Authors: DWYER EDWARD M. , WIENER LESLIE , COX J. WILLIAM
Published: June 2012

The effects of intravenous propranolol were studied in nine patients with ischemic heart disease during cardiac catheterization. Values were obtained at rest and during exercise before and after propranolol. A work load known to produce angina and significant ST depression was selected. Pressures were monitored during exercise and correlated with electrocardiographic changes and appearance of angina. At rest and exercise, propranolol caused a decrease in heart rate, cardiac output, mean systolic ejection rate, stroke volume, left ventricular systolic pressure, first derivative, and work. Left ventricular end-diastolic pressure did not significantly change. Angina, which developed in all nine patients during control exercise, did not appear in four after propranolol, while ECG abnormalities were less marked in all cases. Comparison of exercise responses following propranolol in angina-free patients (four) with those developing angina (five) disclosed a more pronounced negative inotropism in the angina-free group. It is concluded that propranolol is beneficial in angina. Improvement derives primarily from suppression of positive chronotropic and inotropic responses, which are major determinants of myocardial oxygen consumption.
Pressure Flow Studies in Patients Having a Pressor Response to the Valsalva Maneuver
Authors: RUSKIN JEROME , HARLEY ALEXANDER , GREENFIELD JOSEPH C.
Published: June 2012

Blood pressure and flow were measured in the ascending aorta by means of the pressure-gradient technique in five patients with congestive heart failure manifesting a pressor response to the Valsalva maneuver. Beat-to-beat changes in stroke volume, blood pressure, pulse pressure, peak blood flow, duration of systole, duration of ejection, and heart rate were calculated. Stroke volume and blood pressure rose with the onset of straining; blood pressure rose slightly further as stroke volume fell to below control levels at the end of the straining period. Pulse pressure, peak blood flow, and duration of ejection tended to follow stroke volume. Heart rate was unchanged throughout. All parameters returned toward control after release of the strain.
Left Atrial and Left Ventricular Sound and Pressure in Mitral Stenosis
Authors: WOOLEY CHARLES F. , KLASSEN KARL P. , LEIGHTON RICHARD F. , GOODWIN RICHARD S. , RYAN JOSEPH M. , Rieser George F.
Published: June 2012

Left atrial and left ventricular pressure and sound were recorded at the time of mitral commissurotomy in 18 patients with severe, isolated, noncalcific mitral stenosis and sinus rhythm. Catheter tip micromanometers were used, and in eight studies, two equisensitive micromanometers were employed to examine pressure crossover relationships. Analysis of the left atrial and left ventricular sound and pressure crossover relationships is presented; viewed in the perspective provided by cineangiographic studies and surgical observations, a unifying concept of the auscultatory events in mitral stenosis is proposed.

Beginning with left ventricular pressure rise, the left ventricle drives the mitral complex through its ascent (or eversion) phase toward the left atrium, clearing the anterior leaflet from the left ventricular outflow tract. The ascent (eversion) terminates abruptly at the first heart sound (S
1
). Following systole, left ventricular and left atrial pressure fall together after
v
peak, during and after pressure crossover, until the point where left atrial pressure fall ceases abruptly (opening snap notch), left atrial pressure exceeding that in the left ventricle, and the mitral opening snap occurs. During this interval, the mitral valve complex descends or inverts toward the left ventricle and terminates abruptly with the mitral opening snap. Thus, the mitral opening snap may be considered as the reciprocal of the delayed, accentuated S
1
, in noncalcific mitral stenosis in sinus rhythm.
Reciprocal Beating Induced by Ventricular Pacing
Authors: BAROLD S. SERGE , LINHART JOSEPH W. , SAMET PHILIP
Published: June 2012

Ventricular pacing is frequently associated with retrograde ventriculo-atrial conduction. In the absence of atrioventricular (A-V) block, the relatively intact antegrade A-V conduction system supplies the necessary pathway for a re-entry mechanism that may become operative in the presence of delayed retrograde conduction.

Two patients with bradycardia and unimpaired antegrade A-V conduction exhibited reciprocal (echo) beating following nodal beats before ventricular pacing was instituted. After the introduction of an artificial ventricular pacemaker, reciprocal beats followed the paced ventricular beats in both patients.

These observations suggest that a similar mechanism is involved in the production of reciprocal beats linked to impulses originating from the A-V node and the ventricles.

When ventricular pacing is indicated for the treatment of bradycardia in the presence of intact antegrade A-V conduction, a situation which may produce echo beats, demand pacing is considered preferable to fixed-rate pacing as the latter may deliver a stimulus into the vulnerable phase following an echo beat.
Monophasic Action Potentials in Man
Authors: SHABETAI RALPH , SURAWICZ BORYS , HAMMILL WILLIAM
Published: June 2012

Monophasic action potentials with an amplitude of up to 70 mv were recorded with suction electrodes from the endocardial surface of the right atrium and both ventricles during diagnostic cardiac catheterization. The method was simple and safe. The monophasic action potential of human beings had the same shape and the same relation to the electrocardiogram as the transmembrane action potential of animals has. Also changes in heart rate and administration of calcium and digitalis had the same effect on the monophasic action potential of man as on the transmembrane action potential of animals.

When injections of contrast material into the coronary arteries produced T-wave changes, the monophasic action potential from the ventricle perfused by the contrast medium lengthened, but the monophasic action potential from the other ventricle did not change.

Our study suggests that the monophasic action potential may be helpful in estimating the refractory period at the site of recording and in explaining the pathogenesis of abnormal repolarization in the electrocardiogram.
Renin Release in Patients with Benign Essential Hypertension
Authors: KANEKO YOSHIHIRO , IKEDA TAKAO , TAKEDA TADANAO , INOUE GOSUKE , TAGAWA HRROSHI , UEDA HIDEO
Published: June 2012

In 16 of 28 patients with benign essential hypertension, reduction of mean arterial pressure to 75 to 120 mm Hg by infusion of sodium nitroprusside caused significant increase in renin release estimated by the renal-systemic difference of renin activity and renal plasma flow (RPF). The threshold at which renin release increased was shifted to a range that was intermediate between that previously reported for normotensive subjects and that for patients with renovascular hypertension, but the average magnitude of renin release was almost comparable to that in normotensive subjects. In the other 12 patients, no significant renin release occurred during reduction in pressure of comparable degree.

The difference in renin release was difficult to explain by the difference in severity of hypertensive disease or in sodium excretion, but increased renin release was usually associated with a decrease in RBF and a rise in renal vascular resistance, while insignificant release was usually associated with an insignificant change in RBF and a decrease in resistance. The average known duration of hypertension was significantly greater in the unresponsive patients. It is suggested that renal sympathetic nerve activity may be a factor in the variations in renin release in patients with essential hypertension.
A Study of Duroziez's Murmur of Aortic Insufficiency in Man Utilizing an Electromagnetic Flowmeter
Authors: FOLTS JOHN D. , YOUNG WILLIAM P. , ROWE GEORGE G.
Published: June 2012

Femoral arterial blood flow was recorded with an electromagnetic flowmeter at the time of open heart surgery on subjects with and without aortic insufficiency. The records demonstrated that subjects with severe aortic insufficiency and Duroziez's murmur had a large amount of retrograde flow in the femoral artery. Those subjects without significant aortic insufficiency and no Duroziez's murmur had little or no backflow. When only a moderate amount of aortic insufficiency was present, the correlation was less satisfactory. In some subjects who had femoral backflow, a second recording was made from the femoral artery after the aortic valve had been replaced, and in these instances there was no longer any measurable backflow. Postoperatively these patients did not have Duroziez's murmur.

It is concluded that Duroziez's crural murmur in subjects with aortic insufficiency is associated with retrograde diastolic femoral arterial blood flow.
Augmented Sympathetic Neurotransmitter Activity in the Peripheral Vascular Bed of Patients with Congestive Heart Failure and Cardiac Norepinephrine Depletion
Authors: KRAMER RICHARD S. , MASON DEAN T. , BRAUNWALD EUGENE
Published: June 2012

Since there is an overall augmentation of sympathetic nervous activity in patients with congestive heart failure while adrenal medullary function is normal and neurotransmitter stores are diminished in the heart, investigation was directed to the functional status of adrenergic receptors and available norepinephrine stores in the peripheral vascular beds. Blood flow, determined plethysmographically, and vascular resistance, calculated in the calf, following intra-arterial injections of tyramine and norepinephrine in eight patients with congestive heart failure were compared to the responses in nine patients with heart disease but without heart failure. The absolute increase in vascular resistance produced by graded doses of norepinephrine was greater in patients with heart failure. However, the relative augmentation of vascular resistance produced by any dose of norepinephrine was essentially identical in the two groups. In contrast, the vasoconstrictor response to a standard dose of the indirectly acting sympathomimetic agent, tyramine, was markedly enhanced (
P
<0.01) in cases of heart failure, both when this increased response was considered in terms of the relative rise in vascular resistance, and in the quantity of injected norepinephrine required to produce a similar elevation of resistance. Concentration of norepinephrine in atrial tissue, determined at the time of cardiac surgery a few days after completion of the pharmacological studies, was significantly lower in the patients with heart failure. It is concluded that the quantity of endogenous sympathetic neurotransmitter available for release by tyramine from nerve endings in the peripheral arteriolar bed in the calf is not reduced and may even be augmented in patients with heart failure, and that the elevated levels of plasma norepinephrine in the heart failure state are derived, at least in part, from labile adrenergic stores in the peripheral vascular bed.
Multiple Valve Replacement
Authors: BIGELOW JOHN C. , HERR RODNEY H. , WOOD JAMES A. , STARR ALBERT
Published: June 2012

During the past 5½ years 152 patients have undergone multiple valve replacement in this clinic. The operative mortality is 12% and the late mortality 14%. The late complications and functional results of the 112 survivors are reviewed and discussed. Neither severe cardiovascular symptoms nor unfavorable hemodynamic findings are specific contraindications to an operation; however, irreversible disease coexisting in other organ systems is a possible contraindication. A decrease in recent operative mortality and fewer significant complications suggest that this experience should be extended.
Long-Term Physical Training and Cardiovascular Dynamics in Middle-Aged Men
Authors: HANSON JOHN S. , TABAKIN BURTON S. , LEVY ARTHUR M. , NEDDE WILLIAM
Published: June 2012

The effects of a 7-month physical training program on the physiological responses to exercise and work capabilities of seven middle-aged, sedentary men have been evaluated. Testing involved bicycle ergometry and interval treadmill walking, as well as pre- and postconditioning hemodynamic investigations during five levels of treadmill walking up to a 25% grade.

Significant alterations of several parameters were observed in the trained state. Resting and exercise bradycardia were marked, the lowest heart rate registered being 49/min. Maximal physical working capacities and maximal oxygen uptakes were uniformly increased with group means of + 22 and + 18%, respectively. Work load capacities at heart rates 130, 150, and 170 were also augmented.

Resting and exercise cardiac output for a given oxygen uptake declined and produced relative hypokinesis. Stroke volume was greater at moderate and heaviest work loads. Cardiac minute work was reduced despite stroke volume increments.

Pulse wave and arterial pressure analyses indicated that tension-time index and ejection-time index were markedly reduced, while maximal pressure derivative and ventricular ejection rate were increased.

It is concluded that aside from subjective enhancement of well-being, a well-planned physical training program for middle-aged men can develop beneficial economy and efficiency of myocardial function and the oxygen transport system.