bluuebunny/crossref_metadata_2025 huggingface dataset:
Blood-Gas and Hemodynamic Responses to Oxygen in Acute Myocardial Infarction
Authors: DAVIDSON ROBERT M. , RAMO BARRY W. , WALLACE ANDREW G. , WHALEN ROBERT E. , STARMER C. FRANKLIN
Published: June 2012

Blood-gas (Pa

o
o2

) and hemodynamic responses to the inhalation of oxygen were studied in 60 patients with acute myocardial infarction. Patients who were not in heart failure on admission and did not develop signs of heart failure within the next 5 days achieved the same Pa

o
o2

level while breathing 100% oxygen as did patients without acute myocardial infarction. Patients with pulmonary edema or cardiogenic shock had a very poor Pa

o
o2

response to oxygen inhalation. Patients in mild heart failure at the time of study and patients who developed heart failure subsequent to the study had a Pa

o
o2

response intermediate between the other two groups. This rise of Pa

o
o2

with oxygen correlated with the cardiac index and right atrial oxygen prior to inhalation of oxygen. Uncomplicated patients responded to inhalation of oxygen with a decrease of heart rate, cardiac index, stroke index, and cardiac work, and an increase of peripheral resistance. Patients in pulmonary edema or cardiogenic shock or with a low cardiac index or low Pa

o
o2

responded with only a slight increase in peripheral resistance. The Pa

o
o2

achieved while breathing oxygen appeared to determine the type of hemodynamic response to oxygen. Administration of oxygen to patients with acute myocardial infarction is useful in identifying latent heart failure and in predicting the subsequent clinical course of these patients.
Manifest and Concealed Reentry
Authors: GALLAGHER JOHN J. , DAMATO ANTHONY N. , VARGHESE P. JACOB , LAU SUN H.
Published: June 2012

In five patients, bundle of His electrograms were recorded during right ventricular pacing at various cycle lengths. In all patients, as the cycle length of stimulation was decreased, the pattern of retrograde conduction proceeded from 1:1 retrograde conduction to retrograde Wenckebach with or without manifest reentry, to retrograde Wenckebach cycles with concealed reentry. The requisite condition for reentry was a critical retrograde A-V nodal delay. During retrograde Wenckebach cycles, reentry could be either concealed or manifest. Concealed reentry resulted in typical or ordinary Wenckebach cycles on the surface electrocardiogram and manifest reentry resulted in ventricular echo beats. Depending upon the cycle length of stimulation, reentry could be concealed on the surface electrocardiogram but manifest on the His bundle electrogram recording. Concealed reentry could be manifest by turning off the stimulator at the appropriate time in the cardiac cycle while manifest reentry could be concealed by changing the cycle length of stimulation. Reentry with collision of wavefronts within the A-V node or proximal His-Purkinje conduction system explains why the last ventricular impulse is not conducted to the atria during ordinary Wenckebach cycles.
Left Ventricular Function, Metabolism, and Blood Flow in Chronic Cor Pulmonale
Authors: FRANK MARTIN J. , WEISSE ALLEN B. , MOSCHOS CHRISTOS B. , LEVINSON GILBERT E.
Published: June 2012

Left ventricular function, oxidative metabolism, and coronary blood flow were evaluated in 11 patients with chronic cor pulmonale (mean age 53 years) at rest and during stress, and compared with 11 normal subjects (mean age 29 years) studied under similar conditions. The left ventricles of patients with chronic cor pulmonale were normal in regard to contractile state, preload, afterload, coronary blood flow, and myocardial oxidative metabolism. However, the mean cardiac index, stroke volume, stroke work, and left ventricular ejection fraction were below normal, and end-systolic volume was elevated. These differences in performance are consistent with the older mean age of the patients. An alternative explanation is the limit placed on right ventricular stroke volume by the increased afterload (pulmonary vascular resistance). Allowance for these factors permits the conclusion that the left ventricles of patients with chronic cor pulmonale are normal unless involved by a second disease process.
Thirty-Month Follow-Up of Resting and Postexercise Apexcardiogram in Asymptomatic Subjects
Authors: ARONOW WILBERT S.
Published: June 2012

Ninety-eight asmptomatic subjects who had a resting and postexercise apexcardiogram and maximal treadmill stress test (MTST) were clinically evaluated 30 months later. Two of six subjects (33%) with an initially abnormal resting apexcardiogram and two of 92 subjects (2.2%) with an initially normal resting apexcardiogram developed coronary heart disease within 30 months. Three of 15 subjects (20%) with an initially abnormal postexercise apexcardiogram and one of 83 subjects (1.2%) with an initially normal postexercise apexcardiogram developed coronary heart disease within 30 months. Two of four subjects (50%) with an initially abnormal resting apexcardiogram and MTST and two of 94 subjects (2.1%) without both an initially abnormal resting apexcardiogram and MTST developed coronary heart disease within 30 months. Three of seven subjects (43%) with an initially abnormal postexercise apexcardiogram and MTST and one of 91 subjects (1.1%) without both an initially abnormal postexercise apexcardiogram and MTST developed coronary heart disease within 30 months. An abnormal resting apexcardiogram, postexercise apexcardiogram, or MTST correlated with an increased incidence of subsequent coronary heart disease. An abnormal postexercise apexcardiogram plus an abnormal MTST correlated best with an increased incidence of subsequent coronary heart disease.
The His Bundle Electrogram
Authors: HAFT JACOB I.
Published: June 2012

The His bundle electrogram is discussed with respect to its rationale, methods for its recording and evaluation, findings with its use in the various forms of heart block and arrhythmias, its clinical value, and its limitations.
Biochemical "Defect" in the Hypertrophied and Failing Heart
Authors: KATZ ARNOLD M.
Published: June 2012

"It is generally established that the normal heart may become incapable of maintaining an adequate cardiac output or preventing venous engorgement whenever it is presented acutely with an overwhelming load beyond its pumping capacity. This state is not failure of a diseased heart, but it has been designated `failure' by many. It is more difficult to define the situation where such an overload sets up a vicious cycle which progressively potentiates the load upon the heart for hours or days. After a lapse of time, this load strains the mechanisms available for compensation to the point where venous congestion or reduced cardiac output becomes evident. Does this turning point mean that the heart has become abnormal, in a functional sense, and, therefore, is it now to be a case of heart failure in the accepted sense? . . . How much of the circulatory change is due to the load and how much to mechanisms called upon to meet the load? When does myocardial deterioration begin, and when does myocardial failure start? . . . How can one determine whether it is cardiac loading or myocardial failure whch is responsible for invoking the compensatory mechanisms?"
1
Progress Study of 590 Consecutive Nonsurgical Cases of Coronary Disease Followed 5-9 Years
Authors: BRUSCHKE ALBERT V. G. , PROUDFIT WILLIAM L. , SONES F. MASON
Published: June 2012

The clinical progress was studied in a series of 590 patients documented to have significant obstructive disease by coronary arteriography. Ventriculographic findings, age, history, cigarette smoking, hypertension, serum cholesterol, and diabetes were correlated with prognosis. In categories separated on the basis of left ventricular angiogram the 5-year cardiac mortality rates ranged from 25% among patients with normal left ventricles to 69% among patients with dilated and generally poorly contracting left ventricles. Combining the results of coronary and left ventricular angiography yielded a better prediction than either method separately. Most of the other parameters studied were related to a certain extent to mortality, but their predictive power was limited and could partly or entirely be explained by the associated obstructions of the coronary arteries or the condition of the left ventricle. The most significant clinical determinants were the history, the electrocardiogram, and the presence of diabetes mellitus. Particularly high mortality was found in patients with congestive heart failure or electrocardiographic conduction disturbances.
Coronary Artery Bypass
Authors: HALL ROBERT J. , DAWSON JOHN T. , COOLEY DENTON A. , HALLMAN GRADY L. , WUKASCH DON C. , GARCIA EFRAIN
Published: June 2012

From October 1969 through March 1972, 1,276 patients underwent coronary artery bypass at the Texas Heart Institute. Associated conditions included simultaneous valve replacement and resection or repair of ventricular aneurysms or ascending aortic aneurysms. Among the series were 1,105 patients who underwent bypass surgery alone, with or without endarterectomy.

Factors affecting outcome were analyzed and revealed adverse influences including concomitant endarterectomy, female sex, age, evidence of left ventricular failure or serious ventricular dysfunction, and previous myocardial infarction within the month before surgery, but more importantly within the week prior to surgery. Functional class III and IV angina was significantly decreased or totally relieved in a high percentage of patients after bypass surgery, and remains the major indication at this time for myocardial revascularization. Progressive reduction in surgical risk and improvement in patient selection allow coronary artery bypass to be performed currently with an early mortality risk of only 3.7%.
Combined One-Stage Coronary Artery and Valvular Surgery
Authors: MERIN GIDEON , DANIELSON GORDON K. , WALLACE ROBERT B. , RUTHERFORD BARRY D. , PLUTH JAMES R.
Published: June 2012

Fifty patients underwent correction of one or two valvular lesions with concomitant insertion of one to three aortocoronary vein bypass grafts. Hospital mortality was 14% and late mortality was 10%. Factors influencing operative mortality were: (1) mitral valve replacement after myocardial infarction; (2) complete obstruction of a coronary artery preoperatively; (3) high left ventricular end-diastolic pressure at rest preoperatively in patients with mitral valve disease; and (4) use of a single aortocoronary graft in the presence of multiple-vessel disease. For patients with significant associated valvular and coronary artery disease, combined correction yields results that appear sufficiently encouraging, judged by mortality and follow-up, to warrant its continued use in selected cases.
De Subitaneis Mortibus
Authors: JAMES THOMAS N. , CARSON DEREK J. L. , MARSHALL THOMAS K.
Published: June 2012

Necropsy studies of sudden death should always include examination of the conduction system of the heart but seldom do. This case is an example of sudden unexpected death in which there was a fibroma compressing the His bundle. Almost by definition it will be necessary to reconstruct probable clinical events retrospectively in such cases and several such considerations are made here. By studying individual examples and appropriate groups of cases in this way, it should be possible to reduce the number of "unexplained" cases, to formulate reasonable hypotheses for prospective examination, and ultimately to devise means of preventing some of these deaths.
Rate-Dependency of Functional Block in the Human His Bundle and Bundle Branch-Purkinje System
Authors: SCHUILENBURG REINIER M. , DURRER DIRK
Published: June 2012

In eleven patients in whom atrial premature stimulation elicited functional block in the conduction system distal to the atrioventricular (A-V) node, the influence of atrial driving rate was studied. Functional conduction disturbances in the left bundle branch-Purkinje system were produced by driving the atria at a rate just above the spontaneous sinus rate and by introducing premature atrial stimuli. In five patients this was associated with block or delay of conduction in the right bundle branch-Purkinje system and in one with block within the His bundle. In these patients it was shown that the ultimate QRS configuration of the premature beat was determined by different conduction delays in the three parts of the bundle branch system. In three patients complete block of impulse conduction could be produced below the level of the His bundle, in one within the His bundle. In these four patients conduction delay of earlier atrial premature beats within the A-V node with resumption of conduction in the more peripheral pathways, gave rise to the phenomenon of the A-V gap. In two patients functional conduction delay in the contralateral bundle branch caused pseudo-normalization of a pre-existent complete right bundle branch block pattern, indicating that this pattern may not be caused by complete block, but by delayed conduction in the right bundle branch.

In ten of the eleven patients functional block or delay of atrial premature beats in the peripheral conduction system became less pronounced as the driving rate was increased. In nine of these ten the phenomenon disappeared completely at higher rates; in six this occurred with an increase in rate of only 20 beats/min. The A-V gap phenomenon present in four cases at the lowest rate disappeared at higher rates in all four. It was concluded that functional conduction disturbances in the peripheral conduction system are favored by a low basic heart rate and that this rate dependency is caused by a differential influence of heart rate upon the functional properties of the A-V node and of the more peripheral parts of the conduction system.
The Correlation of Coronary Angiography and the Electrocardiographic Response to Maximal Treadmill Testing in 76 Asymptomatic Men
Authors: FROELICHER VICTOR F. , YANOWITZ FRANK G. , THOMPSON A. J. , LANCASTER MALCOLM C.
Published: June 2012

This report presents the results of coronary angiography in 76 asymptomatic aircrewmen with exercise testing responses suggestive of coronary artery disease. There were two subgroups: 18 men with normal resting electrocardiograms; and 58 men with a history of repolarization changes on their resting electrocardiogram after at least one normal ECG. Of the 76 men, 53% had angiographically demonstrated coronary artery disease, and many of them had high risk lesions. Forty-seven percent had no angiographic evidence of lesions and were recommended for return to flying status. Those individuals with normal angiograms will be closely followed at the USAF School of Aerospace Medicine in an effort to determine their natural history and prognosis. The findings in this study, the lack of significant complications resulting from coronary angiography, the concern for public safety, and the economics of maintaining a flying force all support the continued use of elective coronary angiography in selected asymptomatic aircrewmen.
Slow Ventricular Activation in Acute Myocardial Infarction
Authors: BOINEAU JOHN P. , COX JIMMY L.
Published: June 2012

The evolution of premature ventricular contractions (PVCs) in acute myocardial infarction was studied by recording bipolar potentials from the left ventricle before and after coronary artery occlusion in dogs. The potentials were recorded from 154 locations in the left ventricular wall as well as at the endocardial and epicardial surfaces. Desynchronization and marked slowing of previously uniform activation was noted and resembled abbreviated, local fibrillation. The dissociation of excitation was either simple, characterized by fragmentation into single delayed spikes, or complex, characterized by numerous spikes. Sustained, desynchronized activity, confined to local myocardial areas, was observed up to 215 msec after the onset of activation. These local areas of sustained excitation functioned as a source of re-entrant activity and were associated with PVCs. Histochemical stains of myocardium indicated a relationship between the inhomogeneous distribution of ischemia (stain) and the desynchronization of the electrical activity.
Rate Dependent Aberrancy
Authors: FISCH CHARLES , ZIPES DOUGLAS P. , McHENRY PAUL L.
Published: June 2012

Forty patients with "rate dependent aberrancy" (RDA) were studied. This large group of patients permitted a clear definition of the syndrome and recognition of a number of features not previously described. These proved to have a significant bearing on the recognition and differential diagnosis of RDA and non-rate dependent aberrancy.

It was found that a small change in cycle length, perhaps too small to be recognized in the surface ECG, can result in RDA. Consequently, if a critical shortening of cycle length is to be recognized, it is necessary to record not only the onset of aberrant rhythm but also sufficiently long strips with normal intraventricular conduction preceding and following the RDA. In some patients there was no recognizable sudden change in cycle length and the onset of aberrancy was a function of the duration of the accelerated rate. In others only the first cycle of the rhythm with RDA was shortened and the remaining R-R intervals were paradoxically longer than the R-R cycle which initiated the RDA.

The aberrancy in RDA occurred at relatively slow heart rates (in 26 of the 40 patients the rate was below 80), and was frequently independent of any significant changes in the duration of the immediately preceding cycle length. There was a striking prevalence of left bundle branch block, and in 35 of the 40 patients obvious organic heart disease was documented.
Intermittent Parasystole—Mechanism of Protection
Authors: COHEN HOWARD , LANGENDORF RICHARD , PICK ALFRED
Published: June 2012

Analysis of ten cases of intermittent ventricular parasystole suggested temporary loss of protection of the parasystolic focus resulting in discharge and "resetting" of the parasystole by sinus or other supraventricular beats. Parasystolic centers appear to be protected from supraventricular and other ventricular ectopic impulses early in their cycle by their refractory periods, and late in the cycle by diastolic depolarization. Between these two areas of protection is a period of "susceptibility" during which supraventricular beats can discharge the parasystolic focus. This phenomenon accounted for fixed coupling of the first parasystolic beat of a series to a preceding sinus beat. Under certain conditions all parasystolic beats may have such fixed coupling, a new and previously unconsidered mechanism for parasystole with fixed coupling.

In one case of intermittent ventricular parasystole, the parasystole was shown to originate in the posterior fascicle of the left bundle branch on the basis of the shape of the standard electrocardiogram and by His bundle recordings. These parasystolic impulses produced a compensatory pause regardless of whether their discharge was manifest or concealed, and thus imitated a second degree (Type II) atrioventricular (A-V) block. This represents the first description of completely blocked atrial impulses resulting from concealed parasystolic beats arising within the ventricular conduction system.
Ischemic Response to Sudden Strenuous Exercise in Healthy Men
Authors: BARNARD R. JAMES , MACALPIN REX , KATTUS ALBERT A. , BUCKBERG GERALD D.
Published: June 2012

In ten healthy, asymptomatic men, intra-arterial pressure and electrocardiograms were recorded during various types of exercise. Potential subendocardial blood flow was estimated from a diastolic pressure time index (DPTI) and myocardial oxygen requirements estimated from the tension time index (TTI). The ratio DPTI/TTI provided an estimate of the supply/demand relationship With sudden vigorous exercise without warm-up, the DPTI/TTI was below 0.35 in three men who had ischemic electrocardiograms, below 0.44 in three men with minor ST abnormalities, and above 0.44 in four men with normal ST segments. With a prior warm-up exercise, sudden exercise caused no ischemic changes, but DPTI/TTI was below 0.44 in two subjects who had minor ST abnormalities. Maximum treadmill testing produced higher heart rates and TTI than did sudden exercise, but DPTI/TTI was above 0.44 in all cases and no ST abnormalities occurred.

Abnormal electrocardiographic responses produced by sudden, vigorous exercise in normal men may represent subendocardial ischemia caused by a transient, unfavorable alteration in the subendocardial oxygen supply/demand relationship which is predictable from arterial pressure measurements.
Hemodynamic Determinants of Maximal Oxygen Intake in Patients with Healed Myocardial Infarction: Influence of Physical Training
Authors: ROUSSEAU MICHEL F. , BRASSEUR LUCIEN A. , DETRY JEAN-MARIE R.
Published: June 2012

Fourteen patients with a healed myocardial infarction (no angina pectoris) had maximal oxygen intake (V

O
O2

max) determinations and hemodynamic studies at submaximal and maximal exercise levels; seven patients were studied two months after an acute myocardial infarction (untrained group) while seven had followed a physical training program for 13.5 months (trained group). At the maximal exercise level, all patients exhibited a fall in stroke volume which was 15% (untrained group) and 18% (trained group) lower than at submaximal exercise level: this decrease in stroke volume, presumably resulting from myocardial ischemia, was the major factor limiting the V

o
o2

max of the patients. The maximal arteriovenous oxygen (A-V

O
O2

) difference of untrained patients was the same (14.4 ml/100 ml) as for healthy subjects.

Higher V

O
O2

max of trained patients (2.50 vs 2.07 liters/min) resulted almost exclusively from greater maximal A-V

O
O2

difference (16.5 vs 14.4 ml/100 ml); this suggests that long-term physical training increases peripheral extraction of oxygen by the working muscles.
II. Diagnosis of Left Ventricular Hypertrophy and Myocardial Infarction from "Total" Surface Waveform Information
Authors: KORNREICH F. , BRISMEE D.
Published: June 2012

Eight surface leads were found to account for the "total" waveform information in 282 patients (145 normal subjects, 59 patients with LVH, and 78 with myocardial infarction). In each patient the Frank leads were also reconstructed. After time normalization of the eight leads and the XYZ leads and division of the QRS complex into eight equal parts, the resulting variables (64 in the eight lead system and 24 in the Frank lead system) were submitted to multivariate statistical procedures. In a first step, the variables which proved best for the differentiation between normal records and those from patients with LVH or myocardial infarction were selected through stepwise discriminant analysis. A discriminant function was then computed and applied to both pathological groups. The results clearly point up the superiority of the eight lead system. With the level of specificity kept constant at 95%, 91% of the patients with LVH and 95% of the patients with myocardial infarction were correctly classified. With the Frank leads 83% and 85%, respectively, were recognized. The reproducibility of the results also proved to be better with the eight lead system.
The Nature of Treatment Selection in Coronary Artery Disease
Authors: MCNEER J. FREDERICK , STARMER C. FRANK , BARTEL ALAN G. , BEHAR VICTOR S. , KONG YIHONG , PETER ROBERT H. , ROSATI ROBERT A.
Published: June 2012

This report presents our experience with the medical and surgical management of patients with coronary heart disease and uses this experience to document the role of a computerized medical information system in the long-term management of patients with a chronic disease. Of 781 consecutively evaluated patients, 402 were treated medically and 379 were treated with aortocoronary bypass surgery. At two years post-zero time, more than twice as many surgical survivors were pain free, but the survival was the same in the medical (83%) and surgical (85%) cohorts. The medically and surgically treated patients were compared with respect to 89 baseline characteristics. The cohorts were remarkably similar. Correction for baseline inequalities did not affect the fact that two-year survival was the same in both cohorts. One subgroup was identified in which surgically treated patients had a higher two-year survival. Other subgroups were identified in which therapy did not appear to affect two-year survival.
The Influence of Heart Rate and Age on the Systolic and Diastolic Time Intervals in Children
Authors: SPITAELS S. , ARBOGAST R. , FOURON J. C. , DAVIGNON A.
Published: June 2012

The systolic time intervals have been measured in 76 normal children, aged 1 month to 15 years, from simultaneous recordings of the electrocardiogram, phonocardiogram and carotid arterial pulse or apexcardiogram (left or right). Four different statistical methods were applied to study the separate influence of heart rate (HR) and age on these intervals. Left ventricular ejection time (LVET) had a highly significant correlation with HR but none with age. Age alone had a slight but significant influence on pre-ejection period (PEP) and isometric contraction time (ICT). Electromechanical systole (Q-II) varied directly with age and inversely with HR. Right and left total mechanical systole (TMS
R
, TMS
L
) and left isometric relaxation time (IRT
L
) were inversely related to HR, while right electromechanical delay varied only with age. Q to first sound interval (Q-I), interval from onset of contraction to first sound on left and right apexcardiogram (Cl
L
, Cl
R
) and left electromechanical delay (EMD
L
) were found to be constant values. PEP/LVET (0.313,
sd
0.05) and TMS
L
/LVET (1.546,
sd
0.128) were not significantly correlated with HR nor age. Regression equations and mean values are presented to permit rapid estimation of predicted normal values in children. The ratios TMS
L
/LVET and PEP/LVET being unaffected by age or HR, are suggested as practical indices of myocardial function in children.
Unusual Properties of Accessory Pathways
Authors: ZIPES DOUGLAS P. , DEJOSEPH ROBERT L. , ROTHBAUM DONALD A.
Published: June 2012

Electrophysiologic evaluation in five patients who exhibited manifestations of the pre-excitation syndrome and/or supraventricular tachycardia provided functional evidence that the properties of the accessory fibers may be quite variable. The unusual responses to electrical stimulation in these patients included: 1) failure to depolarize the His bundle from the site of ventricular pre-excitation; 2) supraventricular tachycardia with two types of re-entry; 3) anterograde block in the accessory pathway with intact retrograde conduction; and 4) retrograde delay or block in the accessory pathway and atrioventricular (A-V) node with intact anterograde conduction. Understanding these variations may provide important therapeutic implications regarding drug and surgical management.

In addition to these anomalies in conduction over accessory pathways we demonstrated in these patients the occurrence of retrograde functional right bundle branch block and retrograde "gap" phenomenon, and ventricular reciprocation without recording intervening atrial discharge.
The Responsibility of the Physician in the Selection of Patients with Mitral Stenosis for Surgical Treatment
Authors: HARKEN DWIGHT E. , ELLIS LAURENCE B. , DEXTER LEWIS , FARRAND ROBERT E. , DICKSON JAMES F.
Published: June 2012

The anatomy of the mitral leaflets, a classification of the variations in pathologic morphology of rheumatic stenosis, and the evolution of a practical technic for relief of that stenosis while restoring valve action are considered. The life cycle of patients suffering from mitral stenosis is reviewed and a clinical classification of these patients is presented. Some indications and contraindications for surgery are discussed in the light of strength and weakness of present surgical methods. Results of surgical treatment are reviewed.
The George Fahr Lecture
Authors: BURCH G. E. , RAY C. T. , CRONVICH J. A.
Published: June 2012

This is a general theoretic consideration of certain mechanical peculiarities of the human heart. It includes a discussion of mechanical advantages of the average size and average pressures, the effects of various pressures and ventricular volumes on ventricular work and "load," mechanical advantages of the structural arrangement of muscular fibers and manner of contraction, as well as the time course of ventricular work and power produced during a cardiac cycle. The role of the trabeculae carneae and papillary muscles in the emptying of a normal sized ventricle is also discussed.
An Etiologic Concept of Atherosclerosis Based on Study of Intimal Alterations after Shock
Authors: POLLAK O. J.
Published: June 2012

On the basis of analysis of the bibliography of animal experiments and of anatomic observations on autopsy and surgical material from infants and adolescents who experienced shock, a new concept of atherogenesis is formed. Changes in osmotic pressure, plasmatic dyscolloidity and hypoalbuminemia cause hydropic swelling of the intimal endothelial cells followed by increased permeability. Seepage of plasma through injured endothelium results in edema and hyaline-mucoid change of the subintimal ground substance. Lipoproteins are broken down and most of the foreign matter is resorbed. Lipids, namely cholesterol, remain in the subintima, act as irritants and initiate the alterations known as atherosclerosis.
Surgical Closure of an Aortic Septal Defect
Authors: GROSS ROBERT E.
Published: June 2012

Occurring just above the aortic and pulmonic valves, an aortic-pulmonary artery communication gives a left-right shunt which may be indistinguishable by clinical findings from a patent ductus arteriosus. Under some circumstances it is possible to identify the lesion by retrograde aortography. Because of increase in cardiac work, the shunt can produce cardiac strain. Whether or not the communication can be closed surgically depends upon the size of the opening and its distance above the coronary arteries. A case is here reported in which an aortic-pulmonary artery communication has been closed surgically.
Ultrasound Evaluation of Systolic Anterior Septal Motion in Patients With and Without Right Ventricular Volume Overload
Authors: HAGAN ARTHUR D. , FRANCIS GARY S. , SAHN DAVID J. , KARLINER JOEL S. , FRIEDMAN WILLIAM F. , O'ROURKE ROBERT A.
Published: June 2012

Little information is available concerning the normal systolic pattern of movement of the interventricular septum in man. Accordingly, we studied 242 patients without clinical or catheterization evidence of right ventricular volume overload (RVVO) employing the ultrasound continuous recording technique. In the plane of the mitral valve, systolic anterior septal motion (SASM) was present in 111 patients; in 38 patients the septum did not move during systole while in 74 patients, septal motion was variably anterior and posterior during the same recording. Normal posterior septal motion occurred in only 19 patients. However, at or below the level of the chordae tendineae, 226 of the 242 patients (93%) had normal posterior septal motion. The other 16 patients had severely impaired left ventricular function.

In 56 patients with RVVO, 34 had abnormal septal motion at the level of the chordae tendineae (24 with SASM, 7 with variable motion and 3 with no movement).

To evaluate septal motion further, 100 normal subjects were studied using a phased multicrystal ultrasound system designed by Bom which provided a sagittal plane image of the cardiac structures. In all 100 subjects the superior septum moved anteriorly in systole with the aortic root, and the upper one-third of the septum acted as a "hinge" for the lower two-thirds which moved posteriorly. In 8 of 21 patients with RVVO studied by the multicrystal method, the entire septum moved anteriorly during systole; variable patterns occurred in 7 patients, while normal septal motion was present in 6 patients.

We conclude that 1) normal septal motion consists of anterior movement of the superior segment of the septum during systole; 2) below a pivot point, the inferior two-thirds of the septum moves posteriorly during systole; 3) the normal pivot point of the septum frequently results in SASM when recordings are made in the plane of the mitral valve in patients with and without RVVO; and 4) paradoxical septal motion is not always present in patients with RVVO even when echocardiographic recordings are obtained at or below the level of the chordae tendineae.
Effectiveness of Congesting Cuffs ("Rotating Tourniquets") in Patients with Left Heart Failure
Authors: HABAK PHILIP A. , MARK ALLYN L. , KIOSCHOS J. MICHAEL , MCRAVEN DONALD R. , ABBOUD FRANCOIS M.
Published: June 2012

Congesting cuffs or "rotating tourniquets" are often used to treat patients with acute pulmonary edema secondary to left heart failure. The purpose of this study was to evaluate the effectiveness of congesting cuffs in pooling blood in the extremities and decreasing pulmonary congesting pressures in patients with left heart failure and to define optimal congesting cuff pressures. Congesting cuffs on three extremities were inflated to 20, 40, 60 and 80 mm Hg in 16 patients with left heart failure and in 7 normal subjects. The extremities were elevated to collapse the veins before inflating the cuffs. The amount of venous pooling was measured with mercury-in-silastic strain gauge plethysmographs. Inflation of the cuffs produced significantly less venous pooling in patients with heart failure than in normal subjects. Decreases in right atrial pressure during inflation of the cuffs were also significantly less in the patients with heart failure than in the normal subjects. In patients with heart failure, pulmonary congesting pressure (left ventricular diastolic pressure or mean pulmonary arterial wedge pressure) averaged 24.2 ± 1.5 (
se
) mm Hg in the control period and 24.6 ± 2.2, 22.9 ± 1.9, 23.2 ± 2.1 and 20.3 ± 1.6 mm Hg during inflation of the cuffs at 20, 40, 60 and 80 mm Hg, respectively. The decreases in pulmonary congesting pressure (PCP) were not significant (
P
> 0.05) at cuff pressures of 20, 40 and 60 mm Hg. Decreases in PCP were statistically significant at a cuff pressure of 80 mm Hg, but only 6 of 16 patients had decreases greater than 4 mm Hg. The results suggest that in patients with heart failure the effectiveness of congesting cuffs is limited by decreases in venous distensibility which are characteristic of heart failure.
The Pathophysiology of Tachycardia-dependent Paroxysmal Atrioventricular Block After Acute Myocardial Ischemia
Authors: EL-SHERIF NABIL , SCHERLAG BENJAMIN J. , LAZZARA RALPH , HOPE RONALD , WILLIAMS DAVID O. , SAMET PHILIP
Published: June 2012

The pathophysiology of paroxysmal A-V block (PAVB) was studied in 20 anesthetized dogs after ligation of the anterior septal artery. Simultaneous recording of leads II and aV
R
, as well as intracardiac recordings from the His bundle (Hb) and both bundle branches, were monitored. In 18 of 20 experiments, PAVB was localized in the Hb. In all experiments, PAVB occurred subsequent to Mobitz type II A-V block. In eight experiments, PAVB occurred spontaneously during sinus rhythm and was preceded by a period of Wenckebach periodicity superimposed upon a 2:1 A-V block. Vagal-induced slowing of the sinus rate resulted in immediate resumption of 1:1 A-V conduction. In 18 experiments, PAVB was induced by atrial pacing at a critical heart rate in each case (180-300 beats/min). Evidence is presented that A-V conduction was consistently blocked below a critical H-H interval. Slowing the pacing rate, termination of pacinig or increasing the pacing rate until physiological A-V nodal block occurred, all could result in a longer H-H interval and immediate resumption of A-V conduction. When the critical heart rate for PAVB was maintained, a slow idioventricular escape rhythm occurred.

Five patients who developed PAVB after acute myocardial ischemia are also reported providing the clinical counterpart for the experimental observations. In all five cases, PAVB occurred on acceleration of the sinoatrial rate (105-140 beats/min) which was spontaneous in two and induced by drugs given for varied therapeutic indications in three (isoprenaline in two and atropine sulfate in one). In all five, PAVB was associated with Mobitz type II and/or 2:1 A-V block. These experimental and clinical observations suggest that PAVB after acute myocardial ischemia appears to be due to a tachycardia-dependent repetitive concealed conduction in the ischemic His-Purkinje system, probably mainly in the Hb. The clinical observations point out potential consequences of a rapid atrial rate in patients with acute myrocarcial ischemia and type II A-V block.
Clinical Dosimetry During the Angiographic Examination
Authors: WHOLEY MARK H.
Published: June 2012

Data are given on the radiation exposure occurring in high volume angiographic suites to physicians and technical personnel. Emphasis is directed to coronary artery examinations since multiple recording modalities are utilized in these examinations and consequently personnel exposures are greater than in other angiographic studies. A comparison of dose exposures when these examinations are done via the brachial versus the femoral method and an explanation of the higher doses recorded by the brachial method are discussed. A clear health hazard is identified. In those departments with a large volume of angiographic examinations, a periodic rotation of personnel should be instituted. With the availability of inexpensive dose-rate meters, the directors of cardiovascular laboratories should individually monitor and evaluate exposure to their physicians and the technical personnel involved in their examinations.
Concealed Sinus Rhythm
Authors: DEMOTS HENRY , BRODEUR MICHAEL T. H. , RAHIMTOOLA SHAHBUDIN H.
Published: June 2012

A 47-year-old man with a long history of atrial fibrillation presented with a regular rhythm and absent P waves on the surface electrocardiogram. When this rhythm persisted after digitalis withdrawal His bundle electrocardiography demonstrated sinus rhythm. Recognition of concealed sinus rhythm prevents misdiagnosis of digitalis intoxication and inappropriate withdrawal of digitalis therapy.
Supraventricular Origin of Bidirectional Tachycardia
Authors: COHEN STAFFORD I. , VOUKYDIS PANAGIOTIS
Published: June 2012

We have confirmed a supraventricular origin of bidirectional tachycardia with simultaneous standard electrocardiograms and a His bundle electrogram. The patient had sinus rhythm, variable trifascicular block and atrioventricular block below the His bundle. Ventricular excitation varied among three patterns which included right bundle branch block with right axis deviation (RBBB-RAD), right bundle branch block with left axis deviation (RBBB-LAD), and right axis deviation without right bundle branch block (RAD). Sinus beats with alternating patterns of RBBB-RAD and RBBB-LAD resulted in bidirectional tachycardia as did sinus beats with alternating patterns of RBBB-LAD and RAD. Our observations prove that bidirectional tachycardia may be initiated by a supraventricular pacemaker and that the distinguishing bidirectional quality of this arrhythmia need not always occur with constant right bundle branch block.
Left Ventricular Function in Acute Myocardial Infarction Evaluated by Gated Scintiphotography
Authors: RIGO P. , MURRAY M. , STRAUSS H. W. , TAYLOR D. , KELLY D. , WEISFELDT M. , PITT B.
Published: June 2012

Ten normal volunteers and 38 patients with acute myocardial infarction were evaluated by biplane gated blood pool scanning. The mean left ventricular end-diastolic volume in those with infarction was 125 ± 41 ml/m
2
compared to 82 ± 10 ml/m
2
in the normals. The left ventricular end-systolic volume was 82 ± 35 ml/m
2
compared to 35 ± 4 ml/m
2
, and the left ventricular ejection fraction 36 ± 8% compared to 56 ± 3% in the normals. Thirty-six of the 38 patients with infarction had an area of akinesis which ranged from 15 to 59% of the left ventricular wall. Patients with acute myocardial infarction were found to have a significant increase in left ventricular end-systolic volume and decrease in ejection fraction compared to normals. The end-diastolic volume was, however, increased only in those with an elevated left ventricular filling pressure or decreased cardiac index.

Follow-up studies obtained in 20 patients between one week and three months following infarction showed that in the 14 who improved clinically, left ventricular ejection fraction significantly increased from 38 to 45% (
P
< 0.001) while in six who failed to show clinical improvement or worsened, left ventricular ejection fraction remained at 30%.

Left ventricular ejection fraction was significantly greater and the extent of akinesis significantly less in the patients who survived compared to those who died.
Echocardiographic Criteria in the Diagnosis of Idiopathic Hypertrophic Subaortic Stenosis
Authors: ROSSEN RONALD M. , GOODMAN DANIEL J. , INGHAM ROBERT E. , POPP RICHARD L.
Published: June 2012

Echocardiography has proven to be a useful technique in the diagnosis and assessment of therapy in idiopathic hypertrophic subaortic stenosis (IHSS). Asymmetric septal hypertrophy has been described as the pathognomonic anatomic marker of the disease. A characteristic systolic anterior motion of the anterior mitral valve leaflet has been detected in the presence of hemodynamically significant subaortic left ventricular outflow obstruction. An echocardiographic quantification of the outflow gradient (the obstruction index) has been derived previously.

Four patients were studied by ultrasound at the time of cardiac catheterization. All four demonstrated systolic anterior motion of the anterior mitral leaflet in the absence of a resting gradient. In three of the four, the calculated obstruction index predicted hemodynamically significant resting gradients. All four patients were shown to have labile gradients with provocative maneuvers. A fifth patient with abnormal systolic anterior motion demonstrated a close correlation between the obstruction index and resting gradient; however, symmetric hypertrophy of the septum and left ventricular posterior wall was detected by ultrasound. Therefore, the abnormal mitral valve pattern may be seen in the absence of a resting gradient and symmetric left ventricular hypertrophy may exist in the presence of IHSS.
Factors Influencing Prognosis of Bundle Branch Block Complicating Acute Antero-Septal Infarction
Authors: LIE K. I. , WELLENS HEIN J. , SCHUILENBURG REINIER M. , BECKER ANTON E. , DURRER DIRK
Published: June 2012

Of 50 consecutive patients with bundle branch block (BBB) complicating acute antero-septal infarction, 37 died in hospital. Patients with BBB of delayed onset or BBB of short duration had a significantly lower mortality. His bundle recordings were made in 35 patients without pulmonary edema or shock at the time of appearance of BBB. Thirteen of 16 patients with prolonged H-V intervals died compared to nine of 19 with normal H-V intervals (
P
< 0.05). In patients with bifascicular block, 11 of 15 with prolonged H-V intervals developed complete A-V block compared to one of ten with normal H-V intervals (
P
< 0.005).

Twenty-five of 33 patients with normal P-R intervals died compared to eight of 12 with first degree A-V block. Seven of 15 patients with prolonged H-V intervals had normal P-R intervals and four of these seven developed complete A-V block. We conclude that the length of P-R interval has no prognostic significance and is of limited value in predicting both prolonged H-V interval and development of complete A-V block. In contrast, His bundle recordings are of value in identifying patients with BBB complicating antero-septal infarction who are at immediate high risk for development of complete A-V block and death.
Comparison of Regional Myocardial Perfusion Determined by Ionic Potassium-43 to That Determined by Microspheres
Authors: PROKOP EDWARD K. , STRAUSS H. WILLIAM , SHAW JOHN , PITT BERTRAM , WAGNER HENRY N.
Published: June 2012

The ability of ionic potassium-43 (
43
K) to reflect alterations in regional myocardial perfusion was determined by comparing the distribution of this tracer to that of labeled microspheres and flowmeter measurements under several conditions of coronary blood flow. When flow was normal, the regional distribution of ionic
43
K and labeled microspheres were similar. In ischemia induced by partial occlusion and pacing, both
43
K and microspheres showed the same decrease in activity (0.7 of control). When a coronary artery was completely occluded, both tracers were decreased to 0.3 of control. In other experiments, resting coronary blood flow was decreased by 25%, 50% and 75% as determined by flowmeter measurements. When this was done, regional distribution of ionic
43
K and microspheres both decreased in parallel but to a lesser degree than flowmeter data suggesting a contribution from collateral vessels. The endocardial/epicardial activity in the ischemic region also decreased proportionally. However, under conditions of increased flow during myocardial reactive hyperemia,
43
K activity (1.02 of control) did not increase to the same degree as microsphere activity (1.5 of control).
Demonstration of Re-entry within the His-Purkinje System in Man
Authors: AKHTAR MASOOD , DAMATO ANTHONY N. , BATSFORD WILLIAM P. , RUSKIN JEREMY N. , OGUNKELU J. BIMBOLA , VARGAS GUILLERMO
Published: June 2012

Re-entry within the His-Purkinje system (HPS) was consistently observed in 15/24 consecutive patients in whom retrograde refractory period studies were performed using His bundle electrograms and the ventricular extrastimulus method. Within a narrow range of ventricular coupling intervals (V
1
V
2
), V
2
retrogradely conducted to the bundle of His (H
2
) with significant infra-His bundle conduction delay (V
2
H
2
interval). At critical V
2
H
2
delays another beat of ventricular origin (V
3
) followed V
2
and was associated with H
2
V
3
intervals greater than the H-V intervals of sinus beat. It is postulated that V
2
retrogradely blocked within the right bundle branch and activated the bundle of His via the left bundle branch after which antegrade conduction occurred along the right bundle branch producing the V
3
response. In support of re-entry within the HPS are the following: 1) V
3
occurred in a narrow range of V
1
V
2
intervals and critical V
2
H
2
delays, 2) V
3
did not occur when V
2
retrogradely blocked below the bundle of His, 3) V
3
was independent of retrograde A-V nodal delay, 4) V
3
rarely occurred in patients with pre-existing complete right bundle branch block pattern. These results reasonably exclude local re-entry near the site of stimulation.
Systolic Time Intervals in Chronic Obstructive Pulmonary Disease
Authors: HOOPER ROBERT G. , WHITCOMB MICHAEL E.
Published: June 2012

In an attempt to clarify the relationship between left ventricular function and chronic obstructive pulmonary disease (COPD), systolic time intervals (STI) were measured in 12 control subjects and 28 patients with COPD who had only moderate arterial blood gas abnormalities and who had no cardiac symptomatology or clinical evidence of organic heart disease. The patients with COPD were divided into three groups of increasingly severe airway obstruction based on the percent predicted forced expired volume in one second.

Significant differences in pre-ejection period index (PEP
1
) and left ventricular ejection time index (LVET
1
) existed between the control subjects and the patients with the most severe lung disease (Group III). A highly significant difference in PEP/LVET existed between these two groups. The abnormalities of STI demonstrated in these patients are characteristic of left ventricular dysfunction and indicate that subclinical left ventricular dysfunction is frequently present in patients with moderate obstructive lung disease.