bluuebunny/crossref_metadata_2025_split huggingface dataset:
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.
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.
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.
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).
Repair of Mitral Incompetence Secondary to Ruptured Chordae Tendineae
Authors: MANHAS DEV R. , HESSEL EUGENE A. , WINTERSCHEID LOREN C. , DILLARD DAVID H. , MERENDINO K. ALVIN 
Published: June 2012

Twenty-two patients with ruptured chordae tendineae are presented. Etiology was rheumatic heart disease in seven patients, bacterial endocarditis in four patients, both rheumatic heart disease and endocarditis in two patients, trauma in one patient, and aortic regurgitation in one patient. Exact cause of rupture was unknown in seven patients. Plastic repair of the leaflet and/or posteromedial annuloplasty was done in all the patients. In two patients the annuloplasty broke down soon after the operation and necessitated valve replacement. There was one hospital death. One patient died two years after operation probably because of cerebral embolism; a large thrombus was found in the left atrium at autopsy. All survivors have been followed for 7 months to 8 years and, except for two, are either working full-time or leading an active life.
In ruptured chordae early and five-year results after repair of the leaflet and/or posteromedial annuloplasty are very good irrespective of the left atrial enlargement and "V" wave size. Results were better in the rheumatic group than in the nonrheumatic group. In our opinion this method of treatment is superior to prosthetic valve replacement for this condition, except if the annulus is thin and attenuated.
Suicidal and Accidental Digoxin Ingestion
Authors: SMITH THOMAS W. , WILLERSON JAMES T. 
Published: June 2012

Clinical and serum digoxin concentration data are presented for five cases of accidental or suicidal ingestion of large amounts of digoxin. Three patients, 20 years of age or less, were without previous evidence of heart disease and responded with the development of atrioventricular block or sino-atrial exit block, which was reversed in two instances by atropine. The third died with refractory hyperkalemia, suggesting generalized inhibition of the cellular sodium-potassium transport system. Ventricular ectopic beats did not occur in any of these three. In contrast, two patients with preexisting advanced coronary artery disease developed multifocal ventricular premature beats, ventricular tachycardia, and ventricular fibrillation as initial manifestations of toxicity.
Serum digoxin levels 4 or more hours after each ingestion were markedly in excess of those ordinarily encountered in patients receiving usual therapeutic doses, reaching levels as high as 42 ng/ml. Apparent serum half-times between 5 and 48 hours after each ingestion were shorter than those usually observed with normal therapeutic doses of digoxin.
Direct Correlation of External Systolic Time Intervals with Internal Indices of Left Ventricular Function in Man
Authors: MARTIN C. EDWIN , SHAVER JAMES A. , THOMPSON MARK E. , REDDY P. SUDHAKAR , LEONARD JAMES J. 
Published: June 2012

Direct correlation of externally measured systolic time intervals with internally measured indices was obtained using catheter-tip micromanometers in six patients who had normal coronary arteriograms. Simultaneous recordings were made of central aorta and left ventricular pressure, maximum rate of rise in left ventricular pressure (dp/dt), external carotid pulse, external and internal sound, and electrocardiogram. Acute interventions were used to vary the indices by a variety of mechanisms including changes in contractility, preload, afterload, and heart rate. The initial values and the changes in these values produced by acute interventions are identical for left ventricular ejection time (LVET) whether measured externally (range 175 to 385 msec) or internally (range 169 to 392), r = 0.99. Although the absolute values differed for internally measured isovolumic contraction time (internal ICT), externally measured ICT, and preejection time (PEP), there was good linear correlation between the changes observed in these values following the interventions. Changes in PEP and internal ICT showed excellent linear correlation (r = 0.94) and were also alike in absolute value following the interventions. The interval from the Q wave of the electrocardiogram to rise in left ventricular pressure (electrical-mechanical delay) did not change significantly during these interventions. During a period of spontaneous isorhythmic dissociation there was close tracking between beat-to-beat changes in PEP and internal ICT and between externally and internally measured LVET. Following acute interventions PEP and left ventricular dp/dt changed inversely.
Externally measured systolic time intervals have therefore been shown in man to correlate well with directly measured internal indices, both in steady-state conditions and during a series of acute interventions. This convenient and atraumatic method has been shown to be a valid and sensitive measure of myocardial performance.
Abnormal Circulatory Responses to High Altitude in Subjects with a Previous History of High-Altitude Pulmonary Edema
Authors: HULTGREN HERBERT N. , GROVER ROBERT F. , HARTLEY L. HOWARD 
Published: June 2012

In five men with a history of susceptibility to high-altitude pulmonary edema (HAPE), hemodynamics and pulmonary gas exchange were measured at sea level, and again 24 hours following ascent to an altitude of 3,100 m.
At sea level, all findings were essentially normal including a mean pulmonary arterial pressure [See Equation in PDF File] of 13.8 ± 1.9 mm Hg. None of the subjects developed clinically detectable pulmonary edema at altitude. Wedge pressures and cardiac output remained normal. [See Equation in PDF File] increased remarkably, being 38.8 ± 10.3 mm Hg at rest and 53.2 ± 11.6 mm Hg during moderate exercise. Acute relief of hypoxia only partially relieved this pulmonary hypertension.

Arterial blood gases were normal at sea level. In spite of hyperventilation at altitude, arterial O
2
pressure was only 50.8 ± 6.1 torr at rest and fell to 41.4 ± 3.3 torr during exercise due to a widening of the alveolar-arterial O
2
pressure difference to 28.0 ± 6.8 torr.

Hence, these men susceptible to HAPE developed excessive pulmonary hypertension and impaired pulmonary O
2
exchange without detectable pulmonary edema following ascent to high altitude. The increase in pulmonary vascular resistance is only partially explained by hypoxic pulmonary vasoconstriction.
Digoxin Metabolism in Obesity
Authors: EWY GORDON A. , GROVES BERTRON M. , BALL MICHAEL F. , NIMMO LANA , JACKSON BARBARA , MARCUS FRANK 
Published: June 2012

A single intravenous dose of tritiated digoxin was given to five obese patients before and after a mean loss of 102 pounds in weight. There were no significant differences in the blood concentrations of digoxin before and after the weight reduction. Likewise, there were no significant differences in the blood concentrations of digoxin when these data were corrected for fat-free body weight.
These findings are consistent with the thesis that fat-free body weight is a more important determinant of the blood concentration of digoxin than total body weight is.
The clinical implication of this study is that digoxin dosage may be erroneously high if calculated on the basis of total body weight for obese individuals.
His Bundle Electrogram in Bundle-Branch Block
Authors: RANGANATHAN N. , DHURANDHAR R. , PHILLIPS J. H. , WIGLE E. D. 
Published: June 2012

Because a great majority of patients with chronic complete heart block have bilateral bundle-branch lesions, it becomes important to recognize earlier degrees of bilateral bundle-branch block. The H-V interval in the His bundle electrogram during unilateral bundle-branch block reflects the conduction primarily through the contralateral bundle branch, and thus the His bundle electrogram in bundle-branch block (BBB) provides information regarding the functional status of the contralateral bundle branch in addition to helping in the localization of defects elsewhere in the conduction system.
His bundle electrograms were obtained in 20 patients with BBB and 13 patients without BBB. The following results were obtained from this study: (1) Prolonged P-R interval in the absence of BBB indicated delayed conduction through the A-V node. (2) Prolonged P-R interval in the presence of BBB indicated delayed conduction through the contralateral bundle branch or through the A-V node, or both. (3) Delayed conduction through the contralateral bundle branch in BBB occurred in the presence of a normal P-R interval and could only be detected by demonstrating a prolonged H-V time in the His recording. (4) In alternating BBB the His recording clearly demonstrated that the changing P-R interval was related to varying conduction through the bundle branches. (5) Finally, it has been demonstrated that the Wenckebach (Mobitz type I) type of decremental conduction can occur in the bundle branches or Purkinje system as well as in the A-V node.
It is concluded that His bundle electrograms provide valuable information concerning the nature and management of conduction disturbances in patients with bundle-branch disease.
Truncal Valve Abnormalities in Infants with Persistent Truncus Arteriosus
Authors: GELBAND HENRY , VAN METER SHARON , GERSONY WELTON M. 
Published: June 2012

Clinical data on 12 patients under 6 months of age are presented together with the necropsy evidence of truncus arteriosus. Five patients had normal truncal valves and seven had markedly deformed and incompetent valves. Among the group of infants with truncal valve insufficiency, the cause of death was refractory congestive heart failure in each instance, whereas the patients with normal truncal valves succumbed from other causes.
Pathologic examination of the abnormal truncal valves revealed cusps which were thickened by fibrous nodules. Combined heart-lung weight in patients with deformed truncal valves had a mean increase of 85% above normal values, while in the group of patients with normal truncal valves the mean increase was 17%. Similar results were observed when liver weights were compared.
The major clinical findings among the group of patients with truncal insufficiency were bounding peripheral arterial pulses, early diastolic decrescendo murmurs, and congestive heart failure which was refractory to medical treatment and, in one instance, surgical palliation. It is suggested from the data that deformities of the truncal valves are a primary cause of early mortality among infants with truncus arteriosus.
Metabolic Response during Impending Myocardial Infarction
Authors: OLIVER M. F. 
Published: June 2012

The immediate local metabolic response of the myocardium to acute regional ischemia is determined by an interaction of various influences. These include: (1) the extent of and the variability in reduction of blood flow; (2) the degree and persistence of hypoxia; and (3) the effects of local release of catecholamines, particularly in relation to loss of intracellular potassium.
The subsequent metabolic response of the myocardium is partly dependent on the degree of impairment locally of normal myocardial metabolism and partly on the systemic reaction to increased catecholamine activity and hence on: (1) adipose tissue lipolysis; (2) hepatic and muscle glycogenolysis; (3) insulin suppression; and (4) growth hormone and cortisol activity. These determine the extent of the uptake from blood of FFA and glucose by the ischemic myocardium.
There is increasing evidence that high arterial concentrations of FFA can depress myocardial performance by leading to ventricular arrhythmias and decreased contractility. This effect probably depends on a critical interaction between the local concentration of FFA, catecholamines, and hypoxia.
Metabolic intervention in the management of heart attacks should accordingly be directed toward reducing mobilization of adipose tissue FFA and increasing myocardial glycolytic activity.
Tachyarrhythmias in Myocardial Infarction
Authors: DESANCTIS ROMAN W. , BLOCK PETER , HUTTER ADOLPH M. 
Published: June 2012

Tachyarrhythmias occur in about one third of patients with acute myocardial infarction (MI), and may precipitate serious consequences when they arise. Mechanisms of arrhythmogenesis in MI are imperfectly understood, but five categories of factors contributing to ectopic tachycardias are discussed. These include metabolic, anatomic, autonomic, hemodynamic, and iatrogenic causes. Each of the atrial, junctional, and ventricular tachyarrhythmias is briefly considered, and therapy is outlined.
Prevention of tachyarrhythmias and prompt treatment when they occur have substantially reduced mortality in acute MI, and constitute a primary objective of coronary care. However, better understanding of mechanisms of arrhythmogenesis, better systems of automated monitoring, and better modes of therapy, especially antiarrhythmic drugs, are urgently needed.