bluuebunny/crossref_metadata_2025 huggingface dataset:
Resecting and Grafting of Coronary Artery Aneurysm
Authors: EBERT PAUL A. , PETER ROBERT H. , GUNNELLS J. CAULIE , SABISTON DAVID C.
Published: June 2012

A 31-year-old patient with symptoms suggesting acute myocardial infarction and subsequently found to have a large aneurysm of the circumflex branch of the left coronary artery is presented. This is thought to represent the first patient treated by resection and grafting of a coronary artery aneurysm by use of an interposed saphenous vein graft. The aneurysm was filled with friable blood clots, emphasizing the hazard of future embolizations. The etiology and indications for surgical resection are discussed.
Importance of the Design of an Exercise Protocol in the Evaluation of Patients with Angina Pectoris
Authors: REDWOOD DAVID R. , ROSING DOUGLAS R. , GOLDSTEIN ROBERT E. , BEISER G. DAVID , EPSTEIN STEPHEN E.
Published: June 2012

The severity of angina and the effects of therapeutic interventions in patients with coronary artery disease have been assessed by determining changes in both exercise performance and the triple product (TP) of heart rate, systolic pressure, and ejection time occurring at angina. However, the validity of conclusions based on such changes is uncertain since the effects of different exercise protocols on these variables have not been determined. Twelve patients with angina were studied during upright bicycle exercise; repeated bouts of exercise using a standard protocol of 20-w increments every three minutes produced no consistent changes in TP at angina. When exercise began 20 to 60 w above the work load of the standard protocol that produced angina, exercise capacity was reduced (average 1'40'' vs. 4'40'',
P
< 0.001), and triple product at angina exceeded control anginal values (average 4,840 vs. 4,150,
P
< 0.001). In the control studies nitroglycerin (TNG) and carotid sinus nerve stimulation (CSNS) enabled patients to exercise to a higher level, although the triple product at angina was unaltered. However, at the higher work load TNG and CSNS exerted only minimal effects on exercise capacity, indicating that if the work load is excessive, a reduction in myocardial oxygen consumption produced by a therapeutic intervention may be comparatively minor so that a potentially salutary effect would be masked. We conclude that work loads causing angina in less than three minutes cannot reliably be used for studying the effects of therapy. However, if progressive work loads are chosen which cause angina in the control studies in three to six minutes, exercise capacity and triple product at angina provide important information about the efficacy and mechanism of action of a therapeutic intervention.
The Value of Monitoring Pulmonary Artery Pressure for Early Detection of Left Ventricular Failure Following Myocardial Infarction
Authors: RUTHERFORD BARRY D. , MCCANN WILLIAM D. , O'DONOVAN T. PAUL B.
Published: June 2012

Flow-directed catheters recorded serial changes in mean pulmonary artery pressure (PA) every 4 to 6 hours in 25 patients during the first 4 or 5 days following acute myocardial infarction. On the basis of the PA on admission, patients were divided into three groups. Patients in group 1 had normal PA (10-20 mm Hg) and maintained a stroke volume index (SVI)>35 ml/min/m
2
, a pulmonary artery oxygen saturation (MVSO
2
)>70%, and a normal cardiac index, arterial oxygen saturation,
p
H, and P

CO
CO2

. They developed only minor arrhythmias, no heart failure, and none died. Group 3 consisted of one patient with abnormally low PA (<10 mm Hg) who was hypovolemic. Group 2, those patients with elevated PA (>20 mm Hg) who maintained this elevation over the first 48 hours of monitoring, or showed progressive elevation prior to this, had SVI<35 ml/min/m
2
, MVSO
2
<70%, cardiac index<3 liters/min/m
2
, arterial desaturation, and respiratory alkalosis. They demonstrated clinical evidence of heart failure, had major arrhythmias, and 25% died. Three patients with elevated PA on admission spontaneously returned this pressure to normal over the first 48 hours of monitoring. Each of these patients maintained normal hemodynamics and had a good prognosis. PA was always elevated prior to the usual clinical signs of left ventricular failure. We conclude that PA provides a reliable early objective measure of left ventricular failure and is, therefore, an excellent guide to therapy.
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.
Progressive and Late Obstruction of an Aorto-Coronary Venous Bypass Graft
Authors: GRONDIN CLAUDE M. , MEERE CLAUDE , CASTONGUAY YVES , LEPAGE GILLES , GRONDIN PIERRE
Published: June 2012

Progressive late obstruction of an aorto-coronary venous bypass graft is reported in a 44-year-old man who died of bi-ventricular failure 114 days after surgery. The first portion of the vein graft had a residual lumen of one mm. Histology showed marked intimal fibrosis. Mechanism for this occlusion and fibrosis is unclear. This representsc the first documented case of late obstruction of an aorto-coronary bypass graft with angiographic evidence of early postoperative patency.
Effectiveness of the Rashkind Procedure in Transposition of the Great Arteries in Infants
Authors: BAKER FRANCES , BAKER LENOX , ZOLTUN RICHARD , ZUBERBUHLER J. R.
Published: June 2012

The immediate and long-term efficacy of the balloon atrial septostomy (BAS) was appraised in a series of 43 patients with transposition of the great arteries. Early effectiveness was gauged by changes in oxygen saturation and atrial pressures, and by balloon catheter measurement of the interatrial opening immediately following BAS. BAS was initially effective in 31 cases. In 20 patients the size of the interatrial opening was measured by balloon catheter from three months to three years after initially successful BAS. In 13 of these the opening was less than 12 mm; 7 subsequently required surgical septectomy, and each of the remaining 6 had a ventricular septal defect. In the other 7, the opening was greater than 12 mm; none have required surgical septectomy. A total of 13 patients required late septectomy, with only one death. In contrast, there was a 40% (17/44) surgical mortality with surgical septectomy in a similar group of patients between 1959 and 1966. It is concluded that balloon atrial septostomy is initially effective and relatively safe, but that, particularly in those with intact ventricular septum, surgical septectomy is often required. Balloon catheter measurement of the interatrial opening has been helpful in predicting the necessity for surgical septectomy.
Congenital Fixed Subvalvular Aortic Stenosis
Authors: REIS ROBERT L. , PETERSON LYNN M. , MASON DEAN T. , SIMON ALLAN L. , MORROW ANDREW G.
Published: June 2012

Detailed assessments were carried out before and after operation in 33 consecutive patients with congenital fixed subvalvular aortic stenosis. Effective relief of obstruction to left ventricular outflow can be accomplished at minimal risk in patients with discrete subaortic stenosis, but a pressure gradient may persist after operation because of secondary hypertrophic obstruction which resolves with time. Tunnel subaortic stenosis is characterized by a diffusely narrowed left ventricular outflow tract. When an intraventricular pressure gradient was present in such patients, good but not complete relief of obstruction was achieved. In tunnel deformities with a gradient at the valve or annulus and in subaortic stenosis produced by mitral valve anomalies, operative intervention was ineffective.
Alterations in 2-3 Diphosphoglycerate and O
2
Hemoglobin Affinity in Patients Undergoing Open-Heart Surgery
Authors: BORDIUK JOSEPH M. , MCKENNA PATRICK J. , GIANNELLI STANLEY , AYRES STEPHEN M.
Published: June 2012

Alterations in red blood cell (RBC) 2-3 diphosphoglycerate (2-3 DPG) and hemoglobin affinity for oxygen were studied in 14 patients undergoing heart-lung bypass. RBC 2-3 DPG decreased with institution of bypass and continued to decrease during bypass. The day following heart-lung bypass RBC 2-3 DPG levels returned to normal, but were lower than preoperative control values. In vitro studies demonstrated that a portion of the RBC 2-3 DPG loss is due to circulation of blood through the oxygenator itself. Other factors appear to be involved.

Hemoglobin affinity for oxygen increased during heart-lung bypass in most patients It was found that the increased affinity was less than would be expected relative to the demonstrated RBC 2-3 DPG decrease, and that a progressive decrease in RBC pH partially corrected the alteration in O
2
affinity. Our data suggest that other factors are involved in the demonstrated alteration in hemoglobin affinity for O
2
, and these factors are discussed.
Venous Reconstruction in Postphlebitic Disease
Authors: HUSNI E. A.
Published: June 2012

Venous reconstruction was undertaken in 63 patients with venous insufficiency of the limbs over a six-year period. Of these, 48 were bypass grafts (cross-pubis 27 and saphenopopliteal 21), 8 free grafts, and 7 direct anastomoses. The over-all patency rate was over 70%, indicating that phlebitic damage is often segmental as a result of anticoagulant therapy and can therefore be readily bypassed to restore venous continuity and improve hemodynamics.
Management of Total Anomalous Pulmonary Venous Drainage in Early Infancy
Authors: GERSONY WELTON M. , BOWMAN FREDERICK O. , STEEG CARL N. , HAYES CONSTANCE J. , JESSE MARY JANE , MALM JAMES R.
Published: June 2012

Ten consecutive babies ranging in age from two weeks to five months, with total anomalous pulmonary venous drainage and pulmonary artery hypertension, have undergone surgical correction. Seven have survived, including five of six with supracardiac type and two of three with pulmonary venous drainage to the coronary sinus. Six of the last seven operations have been successful, and there have been no late deaths in the series. Factors considered to be important in successful management include: (1) early cardiac catheterization and surgical intervention; (2) high-flow buffered blood perfusion at normothermia; (3) surgical technique aimed at wider common pulmonary vein-left atrial anastomosis; (4) use of indwelling nasotracheal tube with respiratory support for the initial 24 to 48 hours postoperatively; (5) restricted fluid administration in the early postsurgical period; and (6) detailed attention to acid-base balance.
Acute and Chronic Effects of Normothermic Anoxia on Canine Hearts
Authors: BUJA L. MAXIMILIAN , LEVITSKY SIDNEY , FERRANS VICTOR J. , SOUTHER SHERMAN G. , ROBERTS WILLIAM C. , MORROW ANDREW G.
Published: June 2012

In order to evaluate the acute and chronic effects of normothermic cardiac anoxia, structural and functional observations were made on the hearts of 29 dogs subjected to total cardiopulmonary bypass. Elective, normothermic cardiac arrest was induced by aortic cross-clamping for 30 minutes in 7 dogs and for 45 minutes in 16 dogs. The remaining six dogs, which served as controls, were placed on bypass without aortic cross-clamping. The six control dogs and six of seven dogs subjected to 30 minutes of cardiac anoxia showed excellent cardiac function and minimal myocardial damage; one dog in the latter group that died 6 to 12 hours after bypass showed no myocardial damage. All 16 dogs subjected to 45 minutes of cardiac anoxia showed extensive myocardial damage. Depressed cardiac function was demonstrated in three of five dogs that survived for eight days or longer after bypass. The acute cardiac damage was of the myofibrillar degeneration type and progressed to replacement fibrosis; this damage was selectively localized in the left ventricular papillary muscles and subendocardium.
Effects of Intra-aortic Balloon Pumping on Coronary Flow and Metabolism in Man
Authors: LEINBACH ROBERT C. , BUCKLEY MORTIMER J. , AUSTEN W. GERALD , PETSCHEK HARRY E. , KANTROWITZ ARTHUR R. , SANDERS CHARLES A.
Published: June 2012

Coronary blood flow (CBF) and myocardial oxygen consumption (MVO
2
), myocardial lactate extraction, blood gases, and hemodynamics were measured on and off intra-aortic balloon pumping (IABP) 14 times in 10 patients during treatment of cardiovascular collapse following myocardial infarction. At the time of study an average of 14 hours of IABP had elapsed and all but one patient had stabilized out of cardiogenic shock. With IABP, CBF fell in 7 instances, was unaffected in 3, and rose in 4. Changes in MVO
2
correlated closely with the observed effects on CBF. Lactate extraction and blood gases were not significantly affected. Systolic arterial pressure fell an average of 11 mm Hg with IABP, while mean diastolic pressure rose 8 mm Hg.

These results suggest that the net result of IABP on coronary flow and metabolism depends on the interplay between increased blood flow to ischemic areas provided by increased diastolic perfusion pressure and diminution of blood flow to normal myocardium in which the oxygen requirements are reduced by diminished afterload.
Left Heart Volume Estimation in Infancy and Childhood
Authors: GRAHAM THOMAS P. , JARMAKANI JAY M. , CANENT RAMON V. , MORROW MARY N.
Published: June 2012

Left ventricular (LV) volume determinations by the area-length method were reevaluated in postmortem studies of left ventricles ranging from 0.5 to 90 cm
3
absolute volume. The regression equation relating known and calculated volumes for calculated volumes <15 cm
3
(V' = 0.733V) was found to be significantly different from that for calculated volumes >15 cm
3
(V' = 0.974V - 3.1). From these equations, normal values for cinecardiographic LV end-diastolic volume (LVEDV), LV ejection fraction (LVEF), LV systolic output (LVSO), LV mass (LVM), and left atrial maximal volume (LAMax) were derived from 56 children (19 < 2 years) with normal left ventricles who underwent cardiac catheterization. Values for LVEDV/BSA were significantly less for infants (< 2 years) than for older children (42 ± 10 versus 73 ± 11 cm
3
/m
2
,
P
<0.001). Values for LAMax/BSA were also less for infants than for older children (26 ± 5 versus 38 ± 8 cm
3
/ m
2
,
P
<0.001), and LVEF was significantly increasel for infants (0.68 ± 0.05 versus 0.63 ± 0.05,
P
<0.01). The values for LVM/BSA (88 ± 12 g/m
2
) and LVSO/BSA (4.42 ± 0.95 liters/min/m
2
) were not significantly different for infants and older children. Multiple regression equations were derived for the prediction of normal volume and mass variables from a patient's height, weight, and age. The predicted values can be obtained from nomograms, and estimations of normalcy can be made by comparisons of observed and predicted values with the 95% limits as defined.
Approaches to Sudden Death from Coronary Heart Disease
Authors: LOWN BERNARD , WOLF MARSHALL
Published: June 2012

Sudden cardiac death (SCD) continues unabated. Coronary care units, while effective in lowering hospital mortality, cannot significantly reduce SCD which occurs primarily outside the hospital and accounts for the majority of deaths from coronary heart disease (CHD). In view of the frequent precipitous nature of SCD, only a program which identifies and protects the victim prior to the event can hope to be successful in preventing the majority of SCD. Since it is likely that SCD is due to an arrhythmia, drug prophylaxis might prove effective. In view of the toxicity of currently available agents, it is mandatory to preselect a population at highest risk before embarking on a drug trial. Ventricular premature beats (VPB) may identify subjects susceptible to SCD. Epidemiologic and physiologic information on VPB is reviewed, and proposals are made for studies designed to establish the usefulness of VPB as a risk factor for SCD.
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.
Diastolic Heart Sounds and Filling Waves in Coronary Artery Disease
Authors: COHN PETER F. , VOKONAS PANTEL S. , WILLIAMS RICHARD A. , HERMAN MICHAEL V. , GORLIN RICHARD
Published: June 2012

One hundred thirty selected patieints with chest pain syndromes were studied by apex- and phonocardiography as well as by cardiac catheterization, selective cine coronary arteriography, and cine left ventriculography. Ninety-three patients had coronary artery disease; 37 did not. Abnormal graphic studies were found in 42 patients with coronary artery disease and three patients with normal coronary arteriograms. These abnormalities correlated well with the presence of elevated left ventricular end-diastolic pressure. Third heart sounds were found less frequently than fourth heart sounds and/or abnormal apexcardiographic
a
waves, but when present were usually associated with a depressed cardiac index. Diagnostically, over 90% of all patients with chest pain who exhibited graphic abnormalities had significant coronary atherosclerosis. Normal graphic studies did not rule out coronary artery disease, but did indicate adequate left ventricular function since only 5% of patients with normal graphic studies had elevated left ventricular end-diastolic pressure combined with a low cardiac index.
Myocardial Function in Coronary Artery Disease Determined by Atrial Pacing
Authors: LINHART JOSEPH W.
Published: June 2012

Right atrial pacing was performed in 21 patients with and 10 patients without coronary artery disease (CAD). The values for the control (C) and maximum paced (P) heart rate were similar in all patients. During pacing cardiac output did not change, and mean arterial pressure remained constant except for a slight increase during pacing-induced angina pectoris in 11 patients with CAD. Left ventricular end-diastolic pressure (LVEDP) decreased in the normal subjects (C=9 ± 1, P = 3 ± 1
sem
mm Hg) and in all 10 patients with CAD who did not develop angina (C=5 ± 3, P = 5 ± 1 mm Hg). In 11 patients with CAD, developing angina, LVEDP did not decrease before pain occurred (C=9 ± 1, P = 9 ± 2 mm Hg) and increased during induced angina (P = 14 ± 3 mm Hg). Pacing ventricular function curves (VFC) relating induced changes in LVEDP and stroke work were abnormal in five of 10 patients with CAD and without induced angina when compared to the normal subjects. In patients developing angina, pacing VFC were normal in five of 10 before pain and then became abnormal in four of these five when angina occurred.

Atrial pacing may be used to evaluate ventricular function and may demonstrate abnormalities in patients with CAD even in the absence of pacing-induced angina. Angina pectoris is usually associated with an overall decrease in myocardial function.
Congenital Aortic Stenosis Resulting From a Unicommissural Valve
Authors: FALCONE M. WAYNE , ROBERTS WILLIAM C. , MORROW ANDREW G. , PERLOFF JOSEPH K.
Published: June 2012

Clinical, electrocardiographic, phonocardiographic, radiographic, hemodynamic, and anatomic findings are presented in 21 adult patients with stenotic unicommissural aortic valves. Distinction between congenitally unicuspid and bicuspid aortic valves before operation or autopsy was not possible. Although the basic structure of the valve may render it inherently stenotic, the age at which a murmur was first noted (average, 19 years), the duration of a known murmur (average, 25 years), and the age of onset of first symptoms of left ventricular outflow obstruction (average, 41 years) strongly suggest that stenosis at least in part is acquired. The relationship of the true and false commissures to the coronary arterial ostia could be determined with certainty in 12 patients. The basic division of the aortic valve into left, right, and noncoronary cusps is maintained, but the raphes do not extend to the valve orifice. Because the aortic valve is attached to the ascending aorta at only one point (the true commissure), which is at the level of the orifice, valvotomy is hazardous, and valve replacement appears indicated when operative treatment becomes necessary in the adult patient with a stenotic unicommissural aortic valve.
Effects of Chronic Right Ventricular Volume and Pressure Loading on Left Ventricular Performance
Authors: KELLY DAVID T. , SPOTNITZ HENRY M. , BEISER G. DAVID , PIERCE JOSEPH E. , EPSTEIN STEPHEN E.
Published: June 2012

The effects of chronic right ventricular (RV) distension on left ventricular (LV) function were assessed in dogs 3 weeks after pressure and volume loading of the RV had been produced by the emplacement of a constricting band around the pulmonary artery and the creation of tricuspid insufficiency. This resulted in ascites, RV hypertrophy and dilatation, an increase in RV end-diastolic pressure (EDP), and a reduction of RV and LV norepinephrine concentrations. Peak LV pressure, wall stress, and dp/dt were measured during isovolumic beats at LVEDP's of 1 to 20 mm Hg, and comparisons at matched EDP's were made among the normal, sham-operated, and RV stressed dogs. Under these circumstances, LV function appeared to be depressed appreciably. The effects of RV volume loading on the pressure-volume curve of the LV in the potassium-arrested heart were assessed in a separate group of dogs. The pressure-volume curve of the LV was shifted so that any given LV volume was associated with a higher LV pressure. Thus, when peak pressure and wall stress were related to LV end-diastolic volume rather than to LVEDP, the relationship did not appear to differ from normal; peak dp/dt and peak V
CE
, however, remained depressed. This depression may represent a decrease in LV contractility consequent to the chronic RV stress or may reflect alterations in LV geometry. Thus, when the RV is subjected to a chronic flow and pressure load, assessment of LV function may be unreliable when indices of contractility are employed that require measurements of LVEDP.
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.
Onset of Angina Pectoris in Relation to Circulatory Adaptation during Arm and Leg Exercise
Authors: WAHREN JOHN , BYGDEMAN STELLAN
Published: June 2012

The circulatory adaptation to arm and leg exercise was studied with stepwise increased work loads in 10 patients with signs of coronary artery disease. Both arm and leg exercise elicited angina pectoris in all patients. Anginal pain appeared at the same level of pressure-time per minute (PTM) in the two forms of exercise, but at a smaller work load and a lower pulmonary oxygen uptake during arm exercise than during leg exercise. Heart rate, PTM, and peak systolic, systolic mean, diastolic, and mean arterial pressures all increased more steeply in relation to work load during arm exercise than during leg exercise. The differences in circulatory adaptation during arm and leg exercise are attributed in part to a lower mechanical efficiency and a higher sympathetic outflow during arm exercise. These factors may in turn reflect the involvement of smaller muscle groups and a larger component of static work with trunk muscles during arm exercise. The pattern of response to exercise resembles that seen in healthy subjects and provides a pathophysiologic background for the earlier appearance of anginal symptoms during arm than leg exercise in patients with coronary artery disease.
Early Systolic Clicks due to Mitral Valve Prolapse
Authors: HUTTER ADOLPH M. , DINSMORE ROBERT E. , WILLERSON JAMES T. , DESANCTIS ROMAN W.
Published: June 2012

Four patients had evidence that mitral valve prolapse was the etiology of isolated early systolic clicks that were "ejection" in timing, that is, within 80 msec of the first heart sound (S
1
). Phonocardiography demonstrated movement of the click closer to S
1
(three patients) with no change (three patients) or an increase in click amplitude (one patient) on inspiration. Earlier movement of systolic clicks on inspiration is a known feature of midsystolic clicks related to mitral valve prolapse but not of true aortic ejection sounds. In three patients the early systolic click showed a variable relation to the carotid upstroke, suggesting that the two events were not related. The click of the fourth patient occurred after the carotid upstroke. In one patient the click could be brought out by standing. Apical holosystolic murmurs could be elicited in all patients. Left- and right-heart catheterizations and left ventricular angiograms revealed no evidence of semilunar valve or great vessel root abnormality. Three patients had mitral valve prolapse and mitral regurgitation on left ventriculogram. The cineangiogram on one patient demonstrated maximal prolapse of the mitral valve just before opening of the aortic valve and coincident with the timing of the click. An isolated early systolic click may be due to mitral valve prolapse rather than to the usual ejection phenomena.
Systolic Time Intervals in Severe Aortic Valve Disease
Authors: PARISI ALFRED F. , SALZMAN STEPHEN H. , SCHECHTER ELIOT
Published: June 2012

Systolic time intervals were recorded in 25 consecutive patients before and after aortic valve surgery. Ten patients with dominant aortic stenosis (AS) and 10 with dominant aortic insufficiency (AI) received a Starr-Edwards prosthesis; five underwent repair procedures for AS or subaortic lesions. Before operation, the mean rate-corrected left ventricular ejection time (LVET
c
) was prolonged; postoperatively LVET
c
decreased significantly. Conversely, preoperative mean rate-corrected preejection period (PEP
c
) was short and increased postoperatively. Serial measurement of LVET
c
in a patient who had two aortic valve replacements suggested its value in quantitating prosthetic malfunction.

In AS, preoperative LVET
c
correlated closely with cardiac index; normal ejection times were associated with the most severely depressed flows. Preoperative variations in PEP
c
in AS related inversely to the first derivative of the left ventricular pressure curve (maximal LV dp/dt). In AI, PEP
c
correlated with the quotient:

[see Equation in PDF File]

where Adbp — LVed = transaortic end-diastolic pressure difference (aortic diastolic pressure minus LV end-diastolic pressure), and dp/dt = maximal LV dp/dt. This study identifies the flow and pressure parameters which correlate with abnormalities of PEP
c
and LVET
c
with severe AS and AI. The sensitivity of this technique to the hemodynamic changes of corrective surgery makes it a potentially useful noninvasive means to measure prosthetic valve function.
Determination of Left Ventricular Volumes by Ultrasound
Authors: FORTUIN NICHOLAS J. , HOOD WILLIAM P. , SHERMAN M. EUGENE , CRAIGE ERNEST
Published: June 2012

We compared dimensions of the left ventricular minor axis (S) measured at enddiastole (S
D
) and end-systole (S
S
) by echocardiography with dimensions and left ventricular volumes measured by biplane angiocardiography in 27 patients with diverse cardiac abnormalities. There were high correlations between echographic and angiographic ventricular minor-axis dimensions (r = 0.85 for S
D
and 0.87 for S
S
), between echographic dimensions and ventricular volumes (r = 0.84 for end-systolic volume [ESV] and S
S
, 0.83 for end-diastolic volume [EDV] and S
D
), and between the relative change in the echographic minor axis with systole (% Δ S) and ejection fraction (r = 0.79). Regression formulae were derived from these relationships which allowed calculation of ventricular volumes from echo dimensions alone: ESV = 47 S
D
—120, EDV = 59 S
D
—153. These equations allowed relatively accurate prediction of volumes over a wide range of ventricular sizes. The use of a cube function of the echographic minor axis was an accurate predictor of volumes only in smaller ventricular chambers, but overestimated volumes in larger hearts.
Chronic Intravascular Hemolysis after Aortic Valve Replacement
Authors: EYSTER ELAINE , ROTHCHILD JOHN , MYCHAJLIW OLGA
Published: June 2012

To assess the severity of hemolysis and to determine whether severity of hemolysis was related to type of prosthesis, hematocrit readings (Hct), schistocyte counts (S), reticulocyte counts (R), and determinations of haptoglobin (Hp), lactic acid dehydrogenase (LDH), bilirubin, urinary hemoglobin, and urinary hemosiderin (Hs) were performed on 54 patients who had three different types of aortic ball-valve prostheses. Hemolysis, as determined by absence of haptoglobins or hemosiderinuria or R>3.5% in the absence of bleeding, was detected in 39 of the 54 patients (72%). S, R, LDH, and bilirubin were higher in patients without haptoglobins than in those with haptoglobins (
P
< 0.005). Hematocrits of less than 32% were found in 13 of the 34 patients (38%) with Starr-Edwards valves compared to none of the 11 with Magovern valves (
P
< 0.001) and one of the nine with Cutter (
P
< 0.05) valves. The combination of S>10 per 1,000 cells, R>5%, and LDH>500 mU was observed only with Starr-Edwards valves (16 of the 34 patients) and was not seen in patients with Magovern or Cutter valves (
P
< 0.005). All patients with S>10, R>5%, and LDH>500 mU had hemosiderinuria, and five had hemoglobinuria. Hemoglobinuria was always indicative of severe hemolysis. Hemosiderinuria was rarely detected less than 3 months after operation but was found in 32 of 47 patients so tested (68%) more than 3 months after operation. Hemosiderinuria was found in 25 of 30 patients with Starr-Edwards valves compared to two of the 11 with Magovern valves (
P
< 0.001). Hemosiderinuria was also detected in five of six patients with Cutter valves tested, but in three of these the test was only faintly positive. It is concluded that hemolysis is more severe in the presence of Starr-Edwards valves than Magovern or Cutter valves. Based on these observations, the following criteria for rapid clinical evaluation of cardiac hemolysis are suggested: Mild: Hs or absence of Hp but S<10, R<5, LDH<500; moderate: Hs or absence of Hp but S>10, R>5, LDH>500; severe: all of above plus hemoglobinuria.
Incomplete Right Bundle-Branch Block
Authors: MOORE E. NEIL , BOINEAU JOHN P. , PATTERSON DONALD F. , Alexander James , Kennel A. J.
Published: June 2012

Incomplete right bundle-branch block (IRBBB) usually is thought to be associated with abnormalities of the peripheral Purkinje system. This paper discusses the results of a study of six dogs from the same family and three nonrelated dogs with congenital IRBBB. Cardiac catheterization data were normal, and no evidence or history of cardiac disease was found before or after death. The depolarization sequence of ventricular epicardial activation was determined, and delays in right ventricular (RV) epicardial activation times were observed. Multipoint intramural electrodes were used to study intramural activation of the ventricular septum and free walls. The "electrical thickness" near the base of the RV mass was more than double that of the normal RV mass (9 vs 4 mm). Conduction along the right bundle branch (RBB) was analyzed during cardiopulmonary bypass, and electrograms recorded simultaneously from six sites along the RBB demonstrated that conduction velocity down the bundle was normal. The normal time of activation of the endocardial RV Purkinje fibers demonstrated that conduction in the right peripheral Purkinje system also was normal. Therefore, IRBBB in these dogs did not result from conduction abnormalities within the RV specialized conduction system. Interestingly, six of these dogs were members of the F
1
generation from a mating of a female beagle with pulmonary stenosis and a male beagle with ventricular septal defect. Both defects as well as IRBBB were observed in the F
2
generation. The present findings suggest that IRBBB may be a developmental variation in thickness of the RV free wall rather than an abnormality of the RV conduction system in cases without apparent heart disease. The developmental variant appears to have a genetic basis.
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.
Conduction through a Narrow Isthmus in Isolated Canine Atrial Tissue
Authors: DE LA FUENTE DOMINGO , SASYNIUK BETTY , MOE G. K.
Published: June 2012

Isolated blocks of dog atrial tissue were dissected to provide a narrow isthmus connecting two broader areas. Unidirectional block was readily demonstrable at the junctions of the narrow band with the larger areas. Transmembrane action potentials just proximal to the blocked junction were abbreviated, while only local electronic potentials were recorded beyond. Acetylcholine restored 1:1 propagation in blocked preparations. The model may explain some of the features of intermittent preexcitation.
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.
Electrically Induced Atrial Tachycardia with Block
Authors: DAVIDSON ROBERT M. , WALLACE ANDREW G. , SEALY WILL C. , GORDON MICHAEL S.
Published: June 2012

Atrial tachycardia with block was induced by rapid atrial pacing in a patient with refractory supraventricular tachycardia in an effort to control the ventricular rate. It was initially decided to induce atrial fibrillation as necessary with the use of a permanent radiofrequency-controlled atrial pacemaker. Several days after implantation of the pacemaker, however, rapid atrial pacing produced atrial tachycardia with atrioventricular block rather than atrial fibrillation. Despite this apparent failure, the ventricular rate has been adequately controlled by rapid atrial pacing for the past 9 months. Intermittent induction of atrial tachycardia with block with a permanent radiofrequency atrial pacemaker may represent a useful approach to the treatment of patients with refractory supraventricular tachycardia.
Significance of the Sinus-Node Recovery Time
Authors: NARULA ONKAR S. , SAMET PHILIP , JAVIER ROGER P.
Published: June 2012

The phenomenon of postpacing depression of cardiac pacemakers was utilized to evaluate the sinus-node function in 56 patients by analyzing the sinus-node recovery time (SRT), that is, the interval between the last paced P wave and the following sinus P wave. Corrected SRT (CSRT) is defined as the recovery interval in excess of the sinus cycle (SRT — sinus cycle length). The SRT was measured following sinus-node suppression by (1) isolated premature beats (PABs) and (2) atrial pacing (AP) at rates of 100 to 140/min for periods of 2 to 5 min at each level. Twenty-eight patients had normal heart rates (group A), and 28 patients had sinus bradycardia (SB; group B). Ten of the 28 patients with SB were restudied after receiving atropine (2 mg intravenously). The CSRT with PABs was similar in both group A and group B patients and remained essentially unchanged after atropine despite a decrease in sinus cycle length. The phenomenon of interpolated PABs was demonstrated in seven of the 56 patients. In 27 of the 28 patients with normal heart rates (group A), the CSRT with AP ranged from 110 to 525 msec and was essentially independent of the rate and duration of AP. In the remaining one patient of group A, despite a normal heart rate, the CSRT was prolonged (1810 msec) and directly dependent on the rate and duration of AP. In 12 of the 28 patients with SB, the CSRT was comparable to that in group A (≦525 msec). In the remaining 16 patients with SB (group B), the CSRT ranged from 560 to 3740 msec and was usually directly proportional to the rate and duration of AP. After atropine in most of the patients with a prolonged CSRT, the CSRT remained abnormal whereas in others junctional escape beats appeared first, followed eventually by normal sinus rhythm. In a single patient with SB and an abnormal CSRT, restudy 7½ months later again showed a prolonged CSRT indicating the reproducibility of the measurement. The CSRT with AP provides a potentially useful clinical means of assessing the sinus-node function and thereby aids in the diagnosis of the "sick sinus syndrome." It is stressed that AP was found to be more reliable than PABs in eliciting an abnormal response. Furthermore, a normal sinus (atrial) rate does not necessarily provide assurance of a normal sinus-node response to AP, that is, normal sinus-node function.
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.
Hemodynamic Consequences of Pacing-Induced Changes in Heart Rate in Valvular Aortic Stenosis
Authors: LINHART JOSEPH W.
Published: June 2012

Atrial pacing was performed in 10 patients with various degrees of aortic valvular stenosis (AVS) and the hemodynamics were compared to eight normal subjects. Similar maximum heart rates (135 ± 6/min) in each group resulted in no significant complications or symptoms and no changes in cardiac output or transvalvular pressure difference while stroke work (SW) and volume and left ventricular end-diastolic pressure (LVEDP) declined. A postpacing overshoot in LVEDP (control, 14 ± 2; postpacing, 25 ± 3 mm Hg;
p
= 0.01) which occurred in the cases of AVS probably reflects a decrease in myocardial compliance. Pacing ventricular function curves relating induced changes in SW and LVEDP were generally steeper in patients with AVS than in the normal subjects and were definitely abnormal in three of the former. Pulsus alternans induced in two patients was associated with abnormal myocardial function while the control LVEDP level was not a good indication of the functional response of the myocardium.

Atrial pacing appears to be beneficial in the preoperative evaluation of the patient with AVS when exercise stress may be dangerous because of the possibilities of inducing arrhythmias, syncope, and sudden death. It permits precisely controlled evaluation for preoperative and postoperative comparison.
Microangiography of the Pulmonary Arterial System in "Hypoplastic Left Heart Syndrome"
Authors: GRANT CRAWFORD A. , ROBERTSON BENGT
Published: June 2012

Microangiographic examination of the pulmonary arterial system in 12 newborn infants with concomitant stenosis or atresia of the aortic and mitral orifices showed that the intrapulmonary arterial pattern is influenced by the state of the foramen ovale. In infants with aortic atresia with a prematurely closed foramen ovale, that is cases in which the left side of the heart is a cul-de-sac, there is moderate or prominent tortuosity of the intralobular pulmonary arteries indicating congenital pulmonary hypertension. This feature is less prominent or absent in infants with valvular insufficiency of the foramen ovale, regardless of the postnatal age of the patient.
Left Heart Volume Characteristics with a Right Ventricular Volume Overload
Authors: GRAHAM THOMAS P. , JARMAKANI JAY M. , CANENT RAMON V.
Published: June 2012

Left heart volume characteristics were evaluated by using biplane cineangiocardiography in 18 studies in 15 patients with total anomalous pulmonary venous connection (TAPVC) and in 37 studies on 35 patients with large secundum or sinus venosus atrial septal defects (ASD). Left ventricular end-diastolic volume (LVEDV) was decreased to less than 67% of normal in five of 15 preoperative TAPVC patients, but the average value for the entire group was not significantly different from normal. In ASD patients, the average LVEDV was 87% of normal which was significantly decreased (
P
< 0.001). The ejection fraction was decreased from normal in patients with TAPVC and ASD who were less than 2 years of age (0.62 vs. 0.68,
P
< 0.01), but was normal in older patients. Left ventricular systolic output was significantly decreased from normal in both TAPVC (75% of normal,
P
< 0.001) and ASD patients (81% of normal,
P
< 0.001). Left atrial maximal volume was significantly decreased from normal in TAPVC patients averaging only 55% of normal (
P
< 0.001), but was normal in eight ASD patients. All volume variables increased following corrective surgery in two TAPVC patients and two ASD patients. These studies document that left heart volumes and outputs in infants and children with TAPVC and large isolated atrial defects can be diminished preoperatively.