bluuebunny/crossref_metadata_2025 huggingface dataset:
The Genesis of QRS Changes Produced by Selective Coronary Arteriography
Authors: MAYTIN ORLANDO , CASTILLO CESAR , CASTELLANOS AGUSTIN
Published: June 2012

Selective coronary arteriography produces characteristic ST-T changes associated with significant axis shifts. In patients with normal control ÂQRS (mean, +88.6°;
sd
± 12.2°) left coronary injections induced an important leftward deviation of the ÂQRS: mean, +8.2°;
sd
, ±49.1° (
P
< 0.001). Right coronary artery opacification changed the ÂQRS from a control mean of +66.5°;
sd
, ±17.2° to a mean of 89.3°;
sd
, ±16.7° (
P
< 0.001). Left axis shifts after left coronary artery injections were significantly more marked than right axis deviation after right coronary injections. Important increases (beyond 0.02 sec) in ventricular activation time were not observed. These electrocardiographic abnormalities were attributed to the transient ischemic or toxic effect produced by the bolus of dye. This could result in different degrees of complete or incomplete block in the divisions of the left branch or in an extensive peripheral block affecting large areas of the subendocardial regions of the heart.
Aortic Regurgitation with Ventricular Septal Defect
Authors: SOMERVILLE JANE , BRANDAO A. , ROSS DONALD N.
Published: June 2012

Twenty patients with ventricular septal defect and aortic regurgitation had surgical correction using cardiopulmonary bypass. Direct suture of the ventricular defect through the aorta and repair or replacement of the aortic valve were performed. Homograft replacement of the aortic valve was preferred to repair and was associated with less aortic regurgitation after operation. There were one operative death and one late death due to aortic regurgitation. Follow-up for 1 to 6 years showed that 17 of the 18 survivors have had a satisfactory result.
Ultrasonic Cardiac Echography for Determining Stroke Volume and Valvular Regurgitation
Authors: POPP RICHARD L. , HARRISON DONALD C.
Published: June 2012

The ventricular dimensions of 51 patients with heart disease were determined by ultrasonic echography during cardiac catheterization. These data were used to calculate end-diastolic and end-systolic volumes and stroke volume, using a prolate ellipse as a geometric model of the left ventricle. In 30 patients without valvular regurgitation the stroke volumes determined by the echographic method were compared with those determined simultaneously by the standard Fick method with a correlation coefficient of r = 0.966. In 21 patients with valvular regurgitation, the severity of regurgitation was estimated by comparing the forward stroke volume determined by the Fick method with the total left ventricular stroke volume determined by the echographic method. These calculations of regurgitation correlated reasonably well with the degree of valvular regurgitation estimated from angiocardiographic study. It is suggested that these echographic determinations of stroke volume are an atraumatic, safe, and acceptable method in patients without valvular regurgitation. Moreover, these preliminary studies suggest that the severity of valvular regurgitation can be estimated by utilizing ultrasound echocardiography.
Left Ventricular Chamber Volume, Mass, and Function in Severe Coronary Artery Disease
Authors: RACKLEY CHARLES E. , DEAR H. DAVIS , BAXLEY WILLIAM A. , JONES WILLIAM B. , DODGE HAROLD T.
Published: June 2012

Twenty-three patients, 15 of whom had clinical and electrocardiographic evidence of previous myocardial infarction, were studied by coronary arteriography and biplane angiocardiography. End-diastolic volume ranged from 55 to 317 ml/m
2
, left ventricular mass from 83 to 294 g/m
2
and ejection fraction from 0.13 to 0.75. An increased enddiastolic volume was associated with an increased left ventricular mass (r = 0.77,
P
< 0.01). In 15 of the 23 patients mitral regurgitant volume ranged from 0.7 to 4.7 L/min/m
2
and an end-diastolic volume greater than 154 ml/m
2
was associated with mitral regurgitation. The ejection fraction was significantly reduced in the absence as well as the presence of mitral regurgitation. These observations on coronary artery disease in 23 patients with refractory angina pectoris or persistent congestive heart failure, or both, reveal that in this group of patients (1) a dilated left ventricle was hypertrophied and the extent of hypertrophy was proportional to the dilatation; (2) an enlarged left ventricle was frequently associated with mitral regurgitation; and (3) dilatation, hypertrophy, and mitral regurgitation were interpreted as manifestations of reduced left ventricular performance.
Analysis of R-R Intervals in Patients with Atrial Fibrillation at Rest and During Exercise
Authors: BOOTSMA BERT K. , HOELEN ADRIAAN J. , STRACKEE JAN , MEIJLER FRITS L.
Published: June 2012

Serial autocorrelation functions and histograms of R-R intervals in patients with atrial fibrillation, with and without digitalis, at rest and during exercise, were produced by a computer. At rest with and without digitalis the first and higher order coefficients did not differ from zero. During exercise (also with and without digitalis) only the first autocorrelation coefficient became slightly positive (in the order of 0.07) whereas the form of the histograms was profoundly altered by both exercise and digitalis. The change in form of the histograms reveals the change in electrophysiologic properties of the A-V conduction system. Since the serial autocorrelation functions were not influenced by digitalis and only slightly by exercise, the conclusion seems justified that the refractory period of, and the concealed conduction in, the A-V system cannot be (solely) responsible for the random nature of the ventricular rhythm in patients with atrial fibrillation. The effect of randomly spaced atrial impulses of random strength reaching the A-V node from random directions can explain these results.
Congestive Heart Failure in Infancy Treated by Early Repair of Ventricular Septal Defect
Authors: DAICOFF GEORGE R. , MILLER ROBERT H.
Published: June 2012

Six patients, ages 6, 10, 11, 15, 22, and 33 months, in severe congestive heart failure unresponsive to intensive medical therapy underwent operative closure of large ventricular septal defects successfully. The intraoperative management and the postoperative care are presented in detail. Our early results are gratifying and justify early closure of life-threatening ventricular septal defects in infants.
Hemodynamic Evaluation of Intra-Aortic Balloon Pumping in Man
Authors: BUCKLEY MORTIMER J. , LEINBACH ROBERT C. , KASTOR JOHN A. , LAIRD JOHN D. , KANTROWITZ ARTHUR R. , MADRAS PETER N. , SANDERS CHARLES A. , AUSTEN W. GERALD
Published: June 2012

Intra-aortic balloon pumping is effective in reducing left ventricular peak systolic pressure and increasing cardiac output in patients with severe cardiogenic shock secondary to acute myocardial infarction. Associated with these effects is a reduction in intravenous catecholamine requirements and increased sensitivity to diuretics. Reduction in left ventricular end-diastolic pressure is implied by improvement in arterial blood gas saturation (reduced arterioalveolar gradient) and was shown directly in one patient. Total myocardial oxygen consumption is probably reduced by counterpulsation. Platelet levels have not fallen significantly with adequate heparinization and the slow infusion of low molecular weight dextran. No complications have occurred related to femoral artery cannulation, nor has there been significant damage to the aorta.

The findings suggest that this system is a safe means of assisting the failing left ventricle. The high mortality in this series (seven of eight patients) is related to the extent of irreversible myocardial damage which may be reduced by more aggressive, earlier application of counterpulsation.
Sodium-Excreting Ability Before and After Intracardiac Surgery
Authors: PACIFICO ALBERT D. , DIGERNESS STAN. , KIRKLIN JOHN W.
Published: June 2012

Twenty-two patients were studied before, early after (2 to 4 weeks), and late after (6 to 12 months) open intracardiac surgery. Their urinary sodium excretion was measured during an eight-day period of oral sodium loading and the results compared with normal values previously established by Braunwald and colleagues.

Eight patients had normal urinary sodium excretion preoperatively. Two of six studied late postoperatively had abnormally low urinary sodium excretion at that time, both having had abnormally low excretion when studied early postoperatively. Fourteen patients had abnormally low urinary sodium excretion preoperatively. Nine of the patients from this group had normal sodium excretion when studied late postoperatively. Early postoperatively, 3 of 13 patients studied had abnormally low sodium excretion: one died three months later; one still had abnormally low excretion when studied late postoperatively; and one was not studied late after operation. No correlation existed between urinary sodium excretion and cardiac output, creatinine clearance, or intracardiac pressures.

Abnormally low sodium-excreting ability early postoperatively is a poor prognostic sign. Most patients with impaired sodium-excreting ability preoperatively regain normal ability late after intracardiac repair of their mechanical defect.
Totally Cloth-Covered Prostheses
Authors: HODAM ROBERT , STARR ALBERT , RAIBLE DON , GRISWOLD HERBERT
Published: June 2012

This report deals with our experience with totally cloth-covered prostheses over a 28-month period from April, 1967 to August, 1969. During this interval 223 patients were treated with an operative mortality of 11%. The earliest model cloth-covered prosthesis proved in some instances to have an excessively large transprosthetic gradient.
8,9
The introduction of the composite seat design, however, has resulted in a prosthesis with very favorable hydraulic characteristics, as shown by late postoperative catheterization studies.

Early follow-up data indicate that the composite seat style prostheses have a favorably low rate of thromboembolic complications. In 88 patients receiving this style valve, there have been no early emboli and only one late embolus, despite the fact that a portion of the group are not taking anticoagulants. We stress, however, that these still represent short-term observations and must stand the test of time. Until the results of the double-blind study are completed, we continue to recommend long-term anticoagulation for all patients in whom this can be safely done.

The composite seat style totally cloth-covered prosthesis is recommended for all patients who are reoperated for ball variance. We also feel it should be considered strongly for young persons undergoing aortic valve replacement and for patients who for medical or social reasons cannot be safely anticoagulated.
Anastomosis of the Internal Mammary Artery to the Distal Left Anterior Descending Coronary Artery
Authors: GREEN GEORGE E. , STERTZER SIMON H. , GORDON RICHARD B. , TICE DAVID A.
Published: June 2012

Postmortem studies suggest that segments of the left anterior descending coronary artery measuring 1.5 mm are rarely diseased. Bypass grafting to such segments has been performed in 31 patients. Ten patients having internal mammary to left anterior descending anastomosis have angiographically patent grafts 2 to 13 months after operation.

Symptoms of angina as well as symptoms of left ventricular failure have been strikingly relieved.
Thromboembolism
Authors: MUSTARD J. F. , PACKHAM M. A.
Published: June 2012

Thromboembolism may be considered as one of the manifestations of the response of blood to injury. Other manifestations of this include hemostasis, increased vessel permeability, and vasculitis; disturbances of the microcirculation may lead to tissue injury and organ dysfunction. The factors that can initiate these changes by stimulation of platelets are exposure of subendothelial tissue (collagen, basement membrane) and intravascular stimuli such as antigen-antibody complexes, viruses, bacteria, and endotoxin. These stimuli have a number of effects on blood; the interaction of the platelets with the above stimuli leads to the release of platelet constituents including ADP; the ADP causes the platelets to adhere to each other; the aggregated platelets cause acceleration of clotting; this and changes in blood flow promote the formation of fibrin around the platelet aggregates. Some of the stimuli such as collagen and antigen-antibody complexes also activate blood coagulation through factor XII; some of the materials released from these platelets affect the vessel wall. The initial platelet mass is transformed to a fibrin mass. There are compounds that inhibit the platelet release reaction, platelet aggregation, and blood coagulation and activate the fibrinolytic mechanism. It appears that by the selective use of these compounds we can improve our management of all aspects of thromboembolic disease related to vascular and intravascular stimuli.
The Wolff-Parkinson-White Syndrome
Authors: COLE JAMES S. , WILLS ROBERT E. , WINTERSCHEID L. C. , REICHENBACH DENNIS D. , BLACKMON J. R.
Published: June 2012

Two patients with WPW syndrome underwent surgery to ablate accessory conduction pathways. Endocardial and epicardial mapping in both patients had indicated an area of early right ventricular depolarization. Surgical transection of the areas of early depolarization failed in both cases to normalize the electrocardiogram. In the first patient, additional resection in the area of the A-V node failed to produce heart block and the ECG remained abnormal. However, the paroxysmal tachycardia ceased, and she has remained asymptomatic and active 12 months after surgery. In the second patient, as the A-V node was about to be sectioned, pressure and procaine near the A-V node caused the ECG to normalize transiently and after resection permanently. Microscopic study of this tissue showed "P cells." Postoperatively the patient demonstrated normal A-V nodal function. He was discharged with a normal ECG but expired soon after discharge. Postmortem examination of the heart demonstrated the A-V node and bundle of His plus the location of the resection adjacent to the bundle of His. These two cases illustrate disparities between electrophysiologic mapping and actual site of the accessory conduction pathway. In one of the cases an accessory bundle was demonstrated histologically.
Evaluation of Pulmonary Arterial End-Diastolic Pressure as an Indirect Estimate of Left Atrial Mean Pressure
Authors: JENKINS B. S. , BRADLEY R. D. , BRANTHWAITE M. A.
Published: June 2012

Simultaneously recorded values for mean left atrial pressure (LAMP) and end-diastolic pulmonary arterial pressure (PAEDP) were compared in 28 patients with acute or chronic cardiac disease. Atrial pressure was varied by alterations in blood volume or the administration of inotropic agents. One hundred twenty paired values were divided into three groups according to the pulmonary vascular resistance which was calculated on each occasion. Although LAMP and PAEDP were shown to correlate significantly at all levels of pulmonary vascular resistance, worthwhile estimates of LAMP could only be obtained from PAEDP when the pulmonary vascular resistance was normal.
Influence of Sodium Balance on the Ability of Diuretics to Inhibit Tubular Reabsorption
Authors: EARLEY LAURENCE E. , MATRINO JOSEPH A.
Published: June 2012

Chlorothiazide and ethacrynic acid were given to normal humans and patients with cirrhosis and ascites, with replacement of urinary losses, to obtain information on (1) the influence of different states of sodium balance and excretion on the effectiveness of the drugs in blocking tubular reabsorption and promoting excretion of sodium, and (2) the influence of different states of sodium balance on reabsorption of sodium by different segments of the nephron of man. The results demonstrated that in normal man the natriuretic response to these agents is markedly influenced by the existing state of sodium balance. The differences in response to the drugs related both to differences in the filtered load of sodium and to differences in the fraction of filtered sodium reabsorbed at the diuretic-sensitive distal tubular sites. Sodium loading in the presence of a mineralocorticoid was associated with a thiazideinduced increment in the excretion of sodium which was 10 times greater than that observed during sodium depletion. This effect is suggestive of decreased proximal tubular reabsorption. In patients with cirrhosis and sodium retention the fraction of filtered sodium reabsorbed at both diuretic-sensitive tubular sites was diminished, suggesting increased proximal tubular reabsorption. In addition to demonstrating a striking influence of sodium balance on the natriuretic response to the diuretics, the results suggest that in man sodium diuresis is associated with decreased fractional reabsorption by the proximal tubule and increased fractional and absolute sodium reabsorption by the distal tubule. In patients accumulating edema and ascites, an increase in the fractional reabsorption of sodium appears to occur in the proximal tubule and could account for limited effectiveness of the diuretic agents.
The Role of Renin in the Exaggerated Natriuresis of Hypertension
Authors: KRAKOFF LAWRENCE R. , GOODWIN FRANK J. , BAER LESLIE , TOMUES MANUEL , LARAGH JOHN H.
Published: June 2012

Hypertensive patients were classified according to their plasma renin response when challenged by the potent diuretics, ethacrynic acid (50 mg IV), or furosemide (40 mg IV), into renin-unresponsive and renin-responsive groups. In the latter plasma renin activity rose by at least 0.5 ng of angiotensin/ml/hr after the diuretic. The response to volume expansion with 2 L of isotonic saline infused over 60 min was then studied. Peak rate of sodium excretion after saline loading was 994±186 µEq/min in the renin-unresponsive group and peak urine flow was 11.9 ± 2.1 ml/min. In the renin-responsive hypertensives peak sodium excretion was 448 ± 149 µEq/min and peak urine flow was 5.4 ± 1.5 ml/min. Both the sodium excretion and urine flow responses were significantly higher (
P
< 0.05) in the renin-unresponsive group. The degree of saline-induced diuresis and natriuresis was not related to the preexisting level of aldosterone production. Plasma renin changed little in either group during saline infusion but tended to be higher at all times in the renin-responsive subjects. The enhanced capacity of the renin-unresponsive hypertensive subjects to excrete a salt load suggests either a functionally significant degree of extracellular fluid volume expansion or a direct role for renin in the natriuresis accompanying volume expansion.
The Atrioventricular Conduction System in Persistent Common Atrioventricular Canal Defect
Authors: FELDT ROBERT H. , DUSHANE JAMES W. , TITUS JACK L.
Published: June 2012

Serial histologic sections of the atrioventricular (A-V) conduction system were studied in four hearts with persistent common A-V canal, and the anatomic findings were related to the abnormal ECG patterns. Two hearts were examples of the partial form and two of the complete form of A-V canal. The major anatomic abnormalities were: (1) postero-inferior displacement of the A-V node; (2) relatively short distances between the A-V node and the origin of the left bundle branching; (3) marked posteroinferior displacement of the left bundle branching system; and (4) relative hypoplasia of the anterior (superior) left bundle branches. The anatomic configuration of the A-V conduction system in A-V canal could result in relatively early impulse propagation to the posterior aspect of the ventricular septum as suggested by reported electrophysiologica studies. The anatomic findings are considered to be related closely to the known ECG patterns of A-V canal.
Cardiac Output Response to Exercise in Patients with Inferior Vena Caval Ligation
Authors: VARAT MURRAY A. , FOWLER NOBLE O. , ADOLPH ROBERT J.
Published: June 2012

Studies were carried out to determine whether hemodynamic alterations may follow inferior vena caval (IVC) ligation. Five patients, aged 29 to 49 years, who had been operated upon 2 to 5 years previously, and five normal controls, aged 39 to 44 years, were studied at rest and during graded submaximal treadmill exercise. There were no significant differences in heart rate, right atrial pressure, brachial arterial pressure, oxygen consumption, or cardiac output between the patients and normals in the supine rest and head-up tilt positions. During treadmill exercise the heart rate and oxygen consumption were comparable in the two groups, but the cardiac output response was definitely diminished in the patient group. This was reflected in the exercise factor, that is, the increase in cardiac output per 100 ml increase in oxygen consumption. The mean exercise factor was 406 ml for the patient group and 726 ml for the controls, a significant difference (
P
< 0.001).

It is concluded that the cardiac output response to upright exercise may be impaired in patients with IVC ligation. Inadequate venous return following IVC ligation may explain the persistent postoperative exertional dyspnea that has been noted in our patients.
The Relationship of Alterations in Systolic Time Intervals to Ejection Fraction in Patients with Cardiac Disease
Authors: GARRARD CLIFFORD L. , WEISSLER ARNOLD M. , DODGE HAROLD T.
Published: June 2012

The relationships between the systolic time intervals determined from simultaneous recordings of the electrocardiogram, the phonocardiogram, the carotid arterial pulse tracing, and direct measures of left ventricular performance as assessed angiographically by measurement of left ventricular stroke volume (SV), end-diastolic volume (EDV), and ejection fraction (EF) were studied in 68 patients with a wide variety of cardiac diseases. The systolic intervals, the pre-ejection period (PEP), the left ventricular ejection time (LVET), and the ratio PEP/LVET, each correlated significantly with angiographically determined EF and EDV. Closest correlation was observed between PEP/LVET and EF (r = -0.90). The systolic intervals correlated only slightly with the angiographically determined SV. These data lend additional evidence supporting the use of systolic time intervals as a non-invasive measure of left ventricular performance in patients with cardiac disease.
Prediction of Coronary Heart Disease Based on Clinical Suspicion, Age, Total Cholesterol, and Triglyceride
Authors: PAGE IRVINE H. , BERRETTONI J. N. , BUTKUS ANTANAS , SONES F. MASON
Published: June 2012

Our results, based on the definition of coronary heart disease by cinearteriography, show that definite relationships exist among incidence of coronary heart disease (CHD), age, total cholesterol (TC), and total triglycerides, with less definite ones between free cholesterol, and phospholipids for a specific group of 450 male patients referred to the Cleveland Clinic because of suspected coronary heart disease. Equations and graphs of the association of incidence of CHD with these conditions are presented. The relationships were strong enough to be of aid in discriminating CHD from normal; the most useful being age, TC, and TG.

Incidence determinations were presented in terms of total incidence and incidence associated with the variable itself. Coronary angiography demonstrated 350 CHD and 100 normals or a ratio of 3.5 to 1. This ratio is a reflection of the high accuracy with which physicians suspect CHD.

Age and TC were good discriminators in these patients suspected of CHD. An improved relationship and better discrimination was obtained by relating incidence simultaneously to age, TC, and TG. The probability of having CHD is the total incidence corresponding to the patient's age, TC, and TG. The probability level of 0.90 gave 95% assurance of a correct prediction for the physician-selected group of patients. Twenty-nine per cent of them had probabilities above 0.90.
The P Wave and P-R Interval
Authors: WALDO ALBERT L. , VITIKAINEN KARI J. , KAISER GERARD A. , MALM JAMES R. , HOFFMAN BRIAN F.
Published: June 2012

The atria of 37 patients were paced from selected sites during cardiac surgery. When the atria were paced from endocardial sites low in the right atrium, the P waves in ECG leads II, III, and aV
F
were shown to be either negative, biphasic, or positive, depending on the site paced. When the endocardial sites were paced, the P-R intervals were, almost without exception, less than 0.12 sec. When those endocardial sites closest to the A-V junction were paced, the P-R intervals were always less than 0.12 sec. When the atria were paced, from the epicardial sites, the P-R intervals were always greater than 0.12 sec. Negative P waves in ECG leads II, III, and aV
F
were recorded when the atria were paced from the postero-inferior left atrium and the caudal right atrium. The P-R interval did not always reflect the initial period of atrial activation because an isoelectric interval, generally of 0.01 to 0.025 sec, was frequently present between the onset of atrial stimulation and the first clear evidence of the P wave in the ECG. The implications of these results are discussed.
The Mechanism of Supraventricular Tachycardia
Authors: BIGGER J. THOMAS , GOLDREYER BRUCE N.
Published: June 2012

In six successive patients, none of whom had the Wolff-Parkinson-White syndrome, recurrent episodes of paroxysmal supraventricular tachycardia (SVT) were analyzed to determine the mechanism by which this arrhythmia is initiated and sustained. In each patient, simultaneous intracavitary atrial electrograms and surface electrocardiograms were recorded during the onset of numerous spontaneous episodes of SVT. Atrial premature depolarizations (APD) produced by programmed stimulation sequences were used to measure atrioventricular refractory periods and to produce atrial echoes and episodes of SVT. Stimulated APDs introduced during sustained episodes of SVT either altered its behavior or terminated it. The electrophysiologic behavior of SVT in these patients strongly suggests that the mechanism responsible for paroxysmal supraventricular tachycardia is atrial reentry utilizing the A-V conducting system.
The Mechanism of Synchronization in Isorhythmic A-V Dissociation
Authors: LEVY MATTHEW N. , EDFLSTEIN JOSEF
Published: June 2012

The electrocardiographic patterns recorded from seven patients with isorhythmic A-V dissociation fall into two distinct groups. In pattern I, the P wave fluctuates cyclically back and forth across the QRS complex. The mechanism responsible for this type of A-V synchronization represents a typical biologic feedback control system. The P-R interval is a determinant of stroke volume, which in turn influences the arterial blood pressure. The blood pressure has an inverse effect on the discharge frequency of the S-A node through the baroreceptor reflex. The S-A nodal frequency then affects the P-R interval, to close the feedback loop. In pattern II, the P wave is in a fairly constant position relative to the QRS complex. It is usually coincident with the QRS complex or appears on the ST segment or first half of the T wave. The mechanism producing synchronization in pattern II type of isorhythmic dissociation has not been established conclusively.
Left Ventricular Performance Following Correction of Free Aortic Regurgitation
Authors: GAULT JAMES H. , COVELL JAMES W. , BRAUNWALD EUGENE , ROSS JOHN
Published: June 2012

Left ventricular (LV) myocardial contractility, or inotropic state, was characterized in terms of the instantaneous relations between velocity of circumferential fiber shortening (V
CF
), determined cineangiographically, and LV wall tension (hoop stress), calculated from LV dimensions and pressure, in five patients before and 7 to 10 mo after aortic valve replacement for free aortic regurgitation. Preoperatively the cardiac index was reduced or the LV end-diastolic pressure was markedly increased (or both occurred) in four patients, in each of whom depression of inotropic state was documented by a reduced V
CF
at maximum wall tension, ranging from 0.13 to 1.07 circumferences (circ)/sec (normal, > 1.40 circ/sec) at wall tensions of 318 to 464 g/cm
2
(normal, 178 to 417 g/cm
2
). In one patient in whom LV end-diastolic pressure and cardiac index were normal preoperatively, V
CF
was 1.66 circ/sec at a maximum tension of 440 g/cm
2
. Following operation, LV end-diastolic pressure fell in the four patients with depressed inotropic state (average decrease, 23 mm Hg) and cardiac index increased (average increase, 0.93 L/min/m
2
). However, no change in the tension-velocity relation was observed postoperatively, V
CF
ranging from 0.27 to 1.14 circ/sec in these patients, indicating that no change had occurred in the inotropic state. In addition, a fixed abnormality in diastolic LV pressure-volume characteristics, determined from preoperative and postoperative measurements of pressure and radius during diastole, had occurred in patients with depressed myocardial function. In contrast, in the patient with normal myocardial function, LV end-diastolic radius was reduced by 33% postoperatively while end-diastolic pressure was unchanged, suggesting reversal of stress relaxation, or creep, following relief of volume overload.
Studies of the Central and Peripheral Hemodynamic Effects of Amyl Nitrite in Patients with Aortic Insufficiency
Authors: DELIUS WOLFRAM , ENGHOFF EBBA
Published: June 2012

The cardiovascular reaction induced by amyl nitrite was studied in a main group of 11 patients with pronounced and isolated aortic insufficiency, and in an additional and more heterogeneous group of seven patients with moderate aortic insufficiency combined with other lesions, by measuring left ventricular end-diastolic pressure, systemic and peripheral arterial pressures, cardiac output, peripheral blood flow, and venous tone.

Total peripheral resistance decreased, but local vascular resistance differed significantly between the upper and the lower extremities. In most cases arterial dilatation in the forearm (mainly muscle) was found. Simultaneously, there was uniform vasoconstriction in the calf (mainly muscle) which was interpreted to be secondary (baroreceptor reflex). This regional difference in circulatory reaction was also manifested in a pronounced change of the contour of the brachial arterial pulse, while the femoral arterial pulse was practically unchanged. The hand blood flow (skin) decreased while the foot blood flow did not change significantly.

A marked fall in systemic arterial pressure and in left ventricular end-diastolic pressure was clearly demonstrated, and secondarily there was a rise in heart rate as well as a pronounced venoconstriction in both the upper and lower extremities, also interpreted to be secondary (a baroreceptor reflex). There was good correlation between maximal increase in heart rate and maximal increase in venous tone and also between the augmentation in heart rate and cardiac output. An elevation in stroke volume was noted in most cases. The reaction to amyl nitrite was not significantly different in the two groups of patients.
Atrial Ectopic Activity Associated with Sinus Bradycardia
Authors: GOEL BRIJ G. , HAN JAOK
Published: June 2012

Five cases of atrial ectopic activity associated with sinus bradycardia are reported. The ectopic activity was abolished in all cases when the sinus rate was increased spontaneously or by atropine. The report demonstrated that the incidence of ectopic activity increases in the atrium at the slower basic rates as it does in the ventricle. It was emphasized that atrial ectopic activity associated with sinus bradycardia should be treated by atropine or by rapid pacing of the atrium because atrial premature beats have the potential of inducing more serious atrial tachyarrhythmias. The possible role of the vagus nerves in facilitating the induction of atrial tachyarrhythmias was discussed, and it was suggested that atropine may have an added benefit of reducing the likelihood of development of atrial tachyarrhythmias.
Site of Heart Block in Acute Myocardial Infarction
Authors: ROSEN KENNETH M. , LOEB HENRY S. , CHUQUIMIA RUBEN , SINNO M. ZIAD , RAHIMTOOLA SHAHBUDIN H. , GUNNAR ROLF M.
Published: June 2012

Bundle of His electrograms were recorded in eight patients with acute myocardial infarction and heart block. Three patients with diaphragmatic myocardial infarction (DMI) and one with subendocardial infarction were characterized by slowing or block above the bundle of His and A-V junctional escape rhythms during periods of advanced or complete block. An additional patient with DMI had block in the His bundle itself. Intraventricular conduction in the above patients was characterized by normal H-Q intervals (35 to 60 msec) and absence of widened QRS. In contrast, three patients with anterior infarction (AMI) manifested complete block below the bundle of His and idioventricular escape. P-H intervals were normal (80 to 140 msec) and A-V conduction was considered unaffected. Our electrophysiologic observations coupled with previous clinical, anatomic, and pathologic findings suggest that the heart block in DMI is usually due to an ischemic lesion of the A-V node, while heart block in AMI is due to necrosis involving both bundle branches.
Systolic Phases of the Cardiac Cycle in Children
Authors: GOLDE DAVID , BURSTIN LUIS
Published: June 2012

The duration of the systolic phases of the cardiac cycle in 390 normal children was determined from high-speed simultaneous recordings of the electrocardiogram, phonocardiogram, apexcardiogram, and carotid pulse. Data were obtained on children 1 mo to 13 years of age and analyzed to define the independent effects of aging and heart rate on the systolic intervals. Electromechanical systole (Q-II) was found to prolong with increasing age in children with the same heart rate. Pre-ejection period was also prolonged in older children and occupied an increased percentage of total systole. The interval from onset of contraction to first sound varied inversely with heart rate and was independent of age. Electromechanical delay and isometric contraction time were directly related to age and independent of rate. Ejection time varied directly with age and inversely with heart rate but occupied a smaller percentage of systole in older children. Alterations in systolic phase duration occurring with maturation reflect the normal functional adaptation of the developing heart. Measurement of these phases can provide useful information relative to cardiac function in children.
Percutaneous Heart Catheterization in Infants and Children
Authors: KIRKPATRICK STANLEY E. , TAKAHASHI MASATO , PETRY EUGENE L. , STANTON ROBERT E. , LURIE PAUL R.
Published: June 2012

In this prospective study of 150 consecutive heart catheterizations, the percutaneous method of right and left heart catheterization was used in 127 patients. In infants and children weighing more than 10 pounds, the percutaneous method was found to be an effective technic associated with a 3% incidence of diminished arterial pulses in the catheterized limb. All patients in this weight group, except one, had left heart catheterization by this technic. The method was deemed time-saving compared to a cutdown, and complications related to the use of end-hole catheters and guide wires were minimal.

With regard to venous catheterization, a previous femoral vein cutdown contra-indicated application of the percutaneous method to the same vein, while a previous saphenous vein cutdown did not interfere. A vessel catheterized percutaneously may be recatheterized without difficulty.

Thrombi in the arterial catheter and small size of the patient were two factors which had significant correlation with the delay in return of distal pulses to normal. Palpation of distal pulses before and at intervals following the catheterization was found to be the most satisfactory way of detecting arterial complications.
A Mechanism for "False" Inhibition of Demand Pacemakers
Authors: LASSETER KENNETH C. , BUCHANAN JACK W. , YOSHONIS KARL F.
Published: June 2012

Certain variations in discharge rate of demand pacemakers may be associated with intermittent fractures and resulting resistance changes in the electrode-lead system. These variations in rate are related to inhibition of the demand circuit of the pacemaker. Most pacemakers produce a biphasic output pulse which results in a low amplitude current during the interval between stimuli. Therefore, sudden changes of resistance in the electrode-lead system will produce a potential change at the pacemaker terminals which is of sufficient magnitude to be interpreted as spontaneous ventricular depolarization and inhibit the demand pacemaker. Such inhibition may occur in the absence of other signs of lead fracture and present a difficult differential diagnostic problem of pacemaker malfunction.
Dicrotic Pulse after Open Heart Operation
Authors: BARNER HENDRICK B. , WILLMAN VALLEE L. , KAISER GEORGE C.
Published: June 2012

A palpable dicrotic pulse was observed in 18 patients after open heart operation, usually after prosthetic replacement for aortic regurgitation (14 of 18 patients). Two patients had a ventricular septal defect, one had aortic stenosis, and one, mitral insufficiency. The ages of the patients ranged from 9 to 63 years, but the dicrotic pulse was more prominent and persisted longer in younger patients. The dicrotic pulse usually appeared within 48 hours of operation, persisted 1 to 60 days and was always in a brachiocephalic distribution. Determinants of the dicrotic pulse include the stroke volume, the duration of systole, the distensibility of the arterial system, the peripheral reflection coefficient, and the systemic blood pressure. Impaired cardiac function with a low cardiac output was probably the most significant factor in the occurrence of a dicrotic pulse in this series of patients.
Longevity of Parents and Grandparents in Relation to Coronary Heart Disease and Associated Variables
Authors: HAMMOND E. CUYLER , GARFINKEL LAWRENCE , SEIDMAN HERBERT
Published: June 2012

This paper is based upon an analysis of data from a prospective epidemiological study in which a large number of men and women were traced for six years after they answered a detailed questionnaire. The subjects were divided into seven groups according to the longevity of their parents and grandparents. Death rates from coronary heart disease, hypertensive heart disease, and stroke were found to be considerably higher among subjects with short-lived parents than among subjects with long-lived parents. This was found to be the case for coronary heart disease among men without a history of high blood pressure or diabetes, who were not seriously overweight, who took some exersise, and who never smoked cigarettes regularly.
Bundle Branch and Ventricular Activation in Man
Authors: ROSEN KENNETH M. , RAHIMTOOLA SHAHBUDIN H. , SINNO M. ZIAD , GUNNAR ROLF M.
Published: June 2012

His (H), right bundle branch (RB), and left bundle branch (LB) potentials were recorded by electrode catheters passed into the left and right ventricles in seven patients without conduction defects. In another three patients, H and LB were recorded. Initial ventricular activation was considered to coincide with the onset of the QRS (Q). The following intervals were measured in milliseconds: H-Q, LB-Q, RB-Q, H-LB, H-RB, and LB-RB. The average and range of these was as follows: H-Q 46 (39-54), LB-Q 27 (24-30), RB-Q 25 (20-27), H-LB 20 (14-28), H-RB 21 (15-29), and LB-RB 2 (1-10). LB-RB was 3 msec or less in six of seven patients. Coupled atrial pacing produced delays in H-RB without effect on H-LB and LB-Q. The production of incomplete and complete right bundle branch block was related to increase in the LB-RB interval. One patient developed left bundle branch block (LBBB) during coupled pacing with delay of LB while RB-Q remained unchanged. H-Q intervals were measured in three additional patients with rate related LBBB during both control and block. Prolongation of H-Q was less than 3 msec during LBBB. It is concluded that the proximal left and right bundle branches are usually activated simultaneously in man, and that block of either bundle without contralateral bundle delay does not significantly delay the onset of ventricular activation.
Use of Aortic Valve Homografts for Aortic Valve Replacement
Authors: WALLACE ROBERT B. , GIULIANI EMILIO R. , TITUS JACK L.
Published: June 2012

One hundred sixty-nine patients underwent replacement of the aortic valve with an aortic valve homograft; of these patients 17 had concomitant commissurotomy or annuloplasty for an associated mitral valve lesion. Homografts were prepared by sterilization with beta-propiolactone solution and stored in Hanks' solution, or were prepared by sterilization with irradiation and stored at -70 C. Operative mortality was 5.3%. Thirty (19%) of the 160 surviving patients had an aortic diastolic murmur at the time of hospital dismissal, and five of these patients had hemodynamically significant homograft incompetence.

For 156 patients, follow-up was longer than 6 months; among the 147 patients who survived operation, there were 12 late deaths. Eighty-four per cent (132) of these 156 patients were alive and well 6 to 54 months after operation. Six patients have required reoperation for valve incompetence. An aortic diastolic murmur was present in 43% of patients. Five patients had significant valve incompetence; four of these patients are markedly improved over their preoperative status. Thromboembolism has been a rare complication despite the fact that anticoagulant therapy was not used. Late calcification of the homograft valve has been noted in only one patient.
Banding of the Pulmonary Artery
Authors: HUNT CARL E. , FORMANEK GUSTAVE , LEVINE MYRON A. , CASTANEDA ALDO , MOLLER JAMES H.
Published: June 2012

The results of banding of the pulmonary artery in 111 children with cardiac malformations associated with excessive pulmonary blood flow are presented. Thirty-three of these children died, eleven either of late band complications or after a corrective operation. Patients with ventricular septal defect represent the largest group of malformation among the 111 patients.

The overall mortality for banding in patients with isolated ventricular septal defect is 10%, as compared to 36% in patients with ventricular septal defect complicated by an associated lesion. In all infants with ventricular septal defect banded under age 3 months the mortality is 59%, as compared to a mortality of 21% in those banded after age 3 months and only 7% if banded after age 1 year. The overall mortality figures for pulmonary arterial banding have not changed appreciably since 1966; future improvement in banding mortality will depend on improved postoperative management of these infants.

Serial hemodynamic studies in patients banded under the age of 2 years have shown a fall in the pulmonary resistance toward normal, with none showing a progression of pulmonary vascular disease. In several patients thickening of the pulmonary valve occurred as a complication of banding.
Electrophysiological Significance of First Degree Atrioventricular Block with Intraventricular Conduction Disturbance
Authors: ROSEN KENNETH M. , RAHIMTOOLA SHAHBUDIN H. , CHUQUIMIA RUBEN , LOEB HENRY S. , GUNNAR ROLF M.
Published: June 2012

His bundle electrograms (H) were recorded in 27 patients with PR prolongation and intraventricular conduction disturbances. The PR interval was subdivided into P-H (normal 80-140 msec), a measure of atrioventricular (A-V) conduction, and H-Q (normal 35-55 msec), a measure of intraventricular conduction. In 12 patients with left bundle-branch block (LBBB), P-H varied from 115-410 msec (mean 173 msec), and was prolonged in eight patients. H-Q varied from 39-125 msec (mean 80 msec), and was prolonged in 10 patients. In eight patients with right bundle-branch block (RBBB), P-H varied from 146-450 msec (mean 206 msec), and was prolonged in all patients. H-Q ranged from 41-65 msec (mean 51 msec), and was slightly prolonged in three patients, all of whom had, in addition, evidence of left anterior or posterior hemiblock. Seven patients with lesser intraventricular conduction defects all had prolonged P-H intervals, with normal H-Q intervals. With atrial pacing at increased heart rates, block proximal to H occurred in all groups. Three patients with LBBB developed block distal to H with atrial pacing, and one additional patient with LBBB and one patient with RBBB and left posterior hemiblock developed block distal to H following atropine administration.

In conclusion, most patients with PR prolongation and intraventricular conduction defects had prolongation of P-H, suggesting A-V nodal disease. In addition, the patients with LBBB usually had significant H-Q prolongation, suggesting bilateral bundle-branch disease. In the group with RBBB, H-Q prolongation was less common and less marked, and, when present, occurred in patients with evidence of left anterior or posterior hemiblock.
Effects of Isoproterenol on the Pulmonary Circulation in Patients with Chronic Obstructive Lung Disease
Authors: FERRER M. IRENÉ , ENSON YALE , KILCOYNE MARGARET M. , HARVEY RÉJANE M.
Published: June 2012

Isoproterenol produced an increase in pulmonary blood volume and pulmonary blood flow without a significant change in pulmonary vascular pressures in 14 patients with obstructive lung disease, six of whom had cor pulmonale. These findings are consistent with a vasodilating effect on the pulmonary vasculature. Evidence is presented that muscular pulmonary arteries constricted by hypoxia were affected by the drug. There is little to suggest that the compliance of the elastic arteries was altered by isoproterenol.
Changes in the Hemostatic Mechanism After Myocardial Infarction
Authors: GOLDENFARB PAUL B. , CATHEY MARY H. , ZUCKER STANLEY , WILBER PATRICIA , CORRIGAN JAMES J.
Published: June 2012

Plasma coagulation factors, adenosine diphosphate-induced platelet aggregation, and fibrinolytic activity were studied in male survivors of myocardial infarction and in healthy normal men. Infarction survivors had significant elevations of factors VIII and X and of adenosine diphosphate-induced platelet aggregation. The fibrinolytic system was altered toward reduced plasminogen activation, increased antiurokinase activity, and elevated antiplasmin activity. These findings suggest that some men with prior myocardial infarction have a heightened tendency to thrombogenesis. This tendency may represent a response to previous cardiac insult or may contribute to its pathogenesis.
Diseases of the Mitral Valve in Infancy
Authors: DAVACHI FARZIN , MOLLER JAMES H. , EDWARDS JESSE E.
Published: June 2012

A pathologic study of mitral valvular lesions among 55 infants revealed 29 cases in which the mitral valve was the site of a primary congenital malformation and 26 cases in which the mitral lesion was an acquired infarction of papillary muscles secondary to some other malformation.

Among the 29 cases with primary congenital anomalies of the mitral valve, there were 41 lesions represented. Congenital anomalies were identified according to the four components of the valve as follows: leaflets, commissures, chordae tendineae, and papillary muscles. The most common basis for primary congenital mitral valvular disturbance was an abnormality of the papillary muscles. In this group, parachute mitral valve and abnormal position of papillary muscles associated with endocardial fibroelastosis were most common (eight and 10 examples, respectively). Anomalous mitral arcade and obstructing papillary muscles were observed four and three times, respectively.

Involvement of leaflets was the second most common type of congenital anomaly, being observed 11 times. In this group, in order of decreasing frequency, were supra-valvular ring (five cases), accessory mitral valvular tissue (three cases), "Ebstein's" malformation of the left atrioventricular valve in corrected transposition (two cases), and cleft mitral valve (one case).

Commissural fusion was observed once and, in two cases, involvement of multiple components of the valve was observed.

Among the 26 examples of infarction of papillary muscles, exclusive of 10 cases with endocardial fibroelastosis, the fundamental congenital anomalies included aortic stenosis (15 cases), coarctation of the aorta (six cases), and anomalous origin of the left coronary artery from the pulmonary trunk (five cases).