bluuebunny/crossref_metadata_2025 huggingface dataset:
Experimental Acute Myocardial Infarction
Authors: EPSTEIN STEPHEN E. , BEISER G. DAVID , ROSING DOUGLAS R. , TALANO JAMES V. , KARSH RICHARD B.
Published: June 2012

The majority of deaths from acute myocardial infarction (AMI) occur prior to the arrival of medical aid and appear to be due to ventricular fibrillation (VF). Since the premature ventricular contraction and bradycardia are believed to predispose to VF, it has been suggested that administration of atropine or lidocaine during the prehospital phase of AMI may effectively reduce mortality in AMI. To test the efficacy of these drugs in treating arrhythmias during the acute phase of AMI we studied 72 closed-chest conscious dogs in which AMI was produced by inflating a balloon cuff previously implanted around the left anterior descending coronary artery. Ventricular arrhythmias developed in 52 dogs either during occlusion or within 2 min of release of occlusion. Arrhythmias were treated by (1) atropine, (2) atrial pacing, (3) lidocaine, or (4) atropine plus lidocaine. Of the 18 dogs that developed VF, all had ectopic ventricular beats that followed a preceding beat (R-R
PVC
interval) by ≤0.43 sec; no dog with a ventricular arrhythmia that exhibited only R-R
PVC
intervals >0.43 sec developed VF. On this basis arrhythmias were defined as "benign" (R-R
PVC
>0.43 sec) or "malignant" (R-R
PVC
≤0.43 sec). Using this classification, we found that benign arrhythmias were successfully suppressed by atropine (10 of 13 arrhythmias), pacing (nine of 11), and lidocaine (three of five); however, atropine suppressed only two of 18, pacing two of 14, and lidocaine none of six malignant arrhythmias. We conclude that (1) not all ventricular arrhythmias are potentially lethal and (2) while atropine, pacing, and lidocaine successfully suppress most benign arrhythmias, they appear considerably less effective in suppressing those faster arrhythmias that frequently lead to the precipitation of VF.
Identification of Ischemic Area of Left Ventricle by Visualization of
43
K Myocardial Deposition
Authors: BOTTI ROBERT E. , MACINTYRE WILLIAM J. , PRITCHARD WALTER H.
Published: June 2012

A new method to determine myocardial blood distribution was used to study a patient with a recent large transmural anterior myocardial infarct. The method consisted of injecting
43
potassium into a peripheral arm vein and recording the radioactivity over the chest with a scintillation (Anger) camera. Elimination of noncardiac radioactivity in the analysis of data was accomplished by recording the rapid passage of injected
99m
technetium through the heart. The cardiac deposition of the potassium was visualized by identifying the contour of the heart from the technetium scan. In this patient deposition of
43
potassium was markedly reduced in the septal region of the myocardium. This correlated well with the ischemic area suggested by coronary angiography, which demonstrated proximal occlusion of the left anterior descending coronary artery and absence of obstructive disease in the other coronary arteries. Intracoronary artery injection of
43
K gave confirmation of decreased deposition in the same area. This method should prove helpful in the study of certain clinical problems, such as the evaluation of the patency of coronary artery bypass grafts.
Radiologic Appearance of the Azygos Vein in Cardiovascular Disease
Authors: HEITZMAN E. ROBERT
Published: June 2012

Although the usual appearances of the azygos arch on plain chest radiographs are well known, there are less common radiographic presentations which may be misconstrued as mediastinal nodes or masses. The size of the anterior azygos arch measured perpendicular to the right main bronchus should not exceed 7 mm. In the rare case of congenital aneurysmal dilatation of the azygos arch, its size may be much greater and can be confused with a mediastinal mass. Enlargement of the azygos vein can also result from increased pressure in the right ventricle or as the result of increased flow through the azygos system. Increased flow can result from congenital abnormalities or from caval obstruction.
The Sick Sinus Syndrome
Authors: FERRER M. IRENÉ
Published: June 2012

A review of the sick sinus syndrome (SSS) is presented stressing its multifaceted expressions, with slow and fast heart rates, syncopal and dizzy attacks, and rather vague nature early in its course. All ages are affected and the diagnosis must be considered if there is a modest degree of sinus bradycardia (SB), even if asymptomatic, as SB is less benign than was heretofore thought. Inappropriate or relatively slow sinus rates (RSSR) under stressful conditions are equally as important as SB. Inadequacy of the sinoatrial node (SAN) may be manifested by one or more of the following: (1) persistent severe and unexpected sinus bradycardia; (2) cessation of sinus rhythm (sinus arrest) for short intervals during which no other (escape) rhythm arises, or for somewhat longer periods with replacement of sinus rhythm by an atrial or junctional rhythm; (3) long periods of sinus arrest without the appearance of a new pacemaker and resulting in total cardiac arrest (ventricular arrhythmias may then follow); (4) chronic atrial fibrillation because the SAN is permanently silent, or repeated episodes of transitory atrial fibrillation due to total cessation of sinus rhythm at these times. Atrial fibrillation is often, but not always, accompanied by a slow ventricular rate (not produced by digitalis but resulting from an accompanying organic A-V block and the patient has binodal disease); (5) inability of the heart to resume sinus rhythm following cardioversion for atrial fibrillation (most likely if the ventricular rate is slow as mentioned above); and (6) episodes of sinoatrial exit block which are not related to drug therapy. These six items form the indirect evidences for the SSS and represent primary physiologic manifestations. Provocative tests are of value although not wholly satisfactory. Therapy for the chronic form will eventually be a ventricular artificial pacemaker. The natural history of the SSS is imperfectly known but probably covers 5-10 years, at least.
Refractory Supraventricular Tachycardias
Authors: TICZON ANDRES R. , WHALEN ROBERT W.
Published: June 2012

This essay is designed to review some of the basic and more recent contributions to our understanding of supraventricular tachyarrhythmias, their mechanisms, pertinent points in diagnosis, and treatment. Supraventricular tachycardia is discussed under the concept of reentrant mechanisms versus accelerated ectopic pacemakers. Atrial fibrillation and flutter, multifocal atrial tachycardia, supraventricular tachyarrhythmias associated with brady-tachy syndrome, and supra-ventricular tachycardias in ventricular preexcitation are likewise discussed. An outline of the different forms of therapy for refractory supraventricular tachyarrhythmias is provided.
Myocardial Blood Flow in Coronary Artery Disease
Authors: KNOEBEL SUZANNE B. , MCHENRY PAUL L. , BONNER ANTHONY J. , PHILLIPS JOHN F.
Published: June 2012

Sixteen patients, 10 with significant three-vessel coronary artery disease (>50% occlusion of each vessel) and six without coronary disease, had nutrient myocardial blood flow, cardiac output, pressure time/min and arterial pressure determinations at rest, with atrial pacing and with right atrial pacing plus nitroglycerin. In the patients with coronary disease, nutrient myocardial blood decreased an average of 16% (
P
< 0.001) with pacing alone but increased by 22% (
P
< 0.001) from the pacing flows with the addition of 0.4 mg sublingual nitroglycerin at the same pacing rate. The directional changes in myocardial blood flow were unrelated to perfusion pressure or pressure work. In the patients without coronary disease, opposite effects were observed. With right atrial pacing, nutrient myocardial blood flow increased by 23% (
P
< 0.02). With the addition of nitroglycerin, myocardial blood flow decreased by 15% (
P
< 0.02). These changes were directionally related to changes in pressure-work of the heart It is suggested that the findings in this study are consistent with observations made in the experimental animal which indicate that the effect of nitroglycerin may be partly due to a redistribution of myocardial blood flow.
Comparison of Methyllidocaine and Lidocaine on Arrhythmias Produced by Coronary Occlusion in the Dog
Authors: GILLIS RICHARD A. , LEVINE FREDERICK H. , THIBODEAUX HAROLD , RAINES ARTHUR , STANDAERT FRANK G.
Published: June 2012

Methyllidocaine, a quarternary ammonium derivative of lidocaine, was tested as a treatment for the ventricular ectopic beats occurring in unanesthetized dogs 24 hours after two-stage ligation of the anterior descending branch of the left coronary artery. The electrocardiogram (lead II) and electroencephalogram were recorded. Methyllidocaine (4 and 8 mg/kg) injected i.v. during a 1-min period produced a significant reduction in ectopic beats with no significant increase in EEG activity. Lidocaine (4 and 8 mg/kg) administered similarly caused similar antiarrhythmic effects but produced a significant increase in EEG activity. A dose of 8 mg/kg caused tonic-clonic seizures in three of five dogs. Both drugs were also given i.v. (15 mg/kg) to unanesthetized cats. Methyllidocaine did not induce convulsions in four of four animals whereas lidocaine induced convulsions in three of three animals. It is concluded that methyllidocaine is as effective an antiarrhythmic agent as lidocaine but does not possess the central nervous system excitatory actions observed with lidocaine.
Assessment of Ventricular Function after Acute Myocardial Infarction by Plasma Volume Expansion
Authors: LOEB HENRY S. , RAHIMTOOLA SHAHBUDIN H. , ROSEN KENNETH M. , SINNO M. ZIAD , CHUQUIMIA RUBEN , GUNNAR ROLF M.
Published: June 2012

In order to see if changes in preload could be used to help assess left ventricular function, 24 patients with uncomplicated acute myocardial infarction (AMI) received plasma volume expansion (PVE). In eight patients (group A) cardiac index (CI) increased by 20% or more, and in 16 patients (group B) CI increased by less than 20% or decreased. By plotting left ventricular stroke-work index (LVSWI) against left ventricular end-diastolic pressure (LVEDP) before and after PVE, the ventricular function curves upon which the heart was operating could be assessed. In group A patients the values moved upward and to the right, while in group B the values during PVE moved horizontally or downward and to the right suggesting that at rest these hearts were operating at the peak of their function curves.

Patients in group B had a higher incidence of anterior infarction and a lower control mean arterial pressure than patients in group A, but other clinical and control hemodynamic values did not differ between the two groups. Follow-up data suggest that patients in group B may have had a higher mortality within the first 6 months following AMI.

Changing preload by PVE appears to be a safe and potentially useful means of assessing ventricular function following AMI and deserves further study.
Plasma Concentration and Urinary Excretion Kinetics of Acetyl Strophanthidin
Authors: SELDEN RICHARD , KLEIN MICHAEL D. , SMITH THOMAS W.
Published: June 2012

The pharmacokinetics of acetyl strophanthidin (AS) were studied in dogs and human subjects by the use of a newly developed radioimmunoassay. This method has a sensitivity of 0.1 ng of AS per ml and is applicable to direct measurement of AS in unextracted plasma, urine, or bile. After administration of a single intravenous (i.v.) dose of 1.0 mg of AS to 17-25-kg mongrel dogs, the principal exponential decline of plasma AS concentration began 20-60 min after the injection and had a mean half-life (T
½
) of 83 ± 19 min (
sd
). Mean total urinary excretion of AS was 13.3 ± 4.8% of the i.v. dose and occurred with a mean T
½
of 79 ± 10 min. Biliary excretion of AS accounted for only 1.5-2.1% of the i.v. dose. After i.v. administration of 1.0 mg of AS to seven human subjects, the principal exponential decline of plasma AS concentration began 10-30 min after the infusion and had a mean T
½
of 2.3 ± 0.2 hours. Urinary excretion of AS, studied in two patients, accounted for an average of 21.8% of the i.v. dose and occurred with a mean T
½
of 2.4 hours. Thus the plasma level T
½
of AS in human subjects is about tenfold shorter than the 22-hour T
½
previously observed for the relatively short-acting cardiac glycoside ouabain, in agreement with the known brief duration of pharmacologic effects of acetyl strophanthidin.
Immediate and Remote Prognostic Significance of Fascicular Block during Acute Myocardial Infarction
Authors: WAUGH ROBERT A. , WAGNER GALEN S. , HANEY THOMAS L. , ROSATI ROBERT A. , MORRIS JAMES J.
Published: June 2012

The electrocardiograms of 538 patients with acute myocardial infarction were searched to identify all instances of atrioventricular (A-V) and intraventricular (I-V) conduction disturbances. Data concerning mode of therapy and clinical complications were obtained by review of the record. These variables were then analyzed for significance in relation to the development of type II A-V block acutely and syncope or sudden death during the first year of follow-up.

The most accurate predictor for both these events was the status of A-V conduction in combination with the status of I-V conduction. At highest risk (50%) for type II progression were patients with acute adjacent fascicular block plus P-R prolongation, i.e., left anterior hemiblock plus right bundle-branch block (RBBB), or left bundle-branch block (LBBB), or patients with acute nonadjacent fascicular block, i.e., RBBB plus left posterior hemiblock or alternating bundle-branch block. The nonpaced survivors from this same group, plus any other patients with transient type II progression, were also at high risk (45%) for syncope or sudden death in follow-up. No syncope or sudden death has occurred in seven patients with type II progression discharged with a pacemaker. All other patients were at lower risk for these acute and chronic complications.

Thus, the electrocardiogram in acute myocardial infarction can identify a high-risk group for acute type II progression in whom prophylactic pacer insertion may be beneficial. Similarly, the electrocardiogram can identify a high-risk group for syncope or sudden death in follow-up and implicates progression to higher degrees of A-V block as an important pathophysiologic mechanism.The possible role of permanent pacemaker therapy in preventing syncope or sudden death in this high-risk group is also suggested.
Pediatric Radiocardioangiography
Authors: STOCKER F. P. , KINSER J. , WEBER J. W. , RÖSLER H.
Published: June 2012

On the basis of a comparison of the shunt diagnoses in 73 radiocardioangiographic examinations with those from cardiac catheterization supplemented by operation and/or autopsy findings, it is shown that an intravenous injection of
99m
technetium pertechnetate with subsequent evaluation using a scintillation camera and computerized regional time-activity curves is very accurate for the qualitative diagnosis of both left-to-right and right-to-left shunts down to the order of 1.2:1. The advantages of the method are: (1) it is quick (5-10 min for the patient, 20-30 min for the further processing and evaluation); (2) it is safe (extremely low radiation exposure enabling repeated examinations); (3) it is effortless for the patient (thus well suited for use in critically ill patients); and (4) it is applicable with the same accuracy in all age groups (including very young infants and neonates). Thus, the RCG is a promising method for ambulatory diagnosis of questionable heart disease, for the precatheterization workup, and for repeated follow-up studies, i.e. postoperative patients.
Newer Aspects of Echocardiography
Authors: FEIGENBAUM HARVEY
Published: June 2012

The recent increase in interest in echocardiography is partially due to the feasibility of using this technic to evaluate left ventricular performance in a noninvasive manner. It has been demonstrated that one can obtain an internal dimension of the left ventricular cavity and that this dimension is closely related to the corresponding volumes in uniformly contracting ventricles. Thus in patients with valvular heart disease, congenital heart disease, or cardiomyopathy, echocardiography provides an excellent noninvasive means of estimating diastolic volume, systolic volume, stroke volume, ejection fraction, and mean rate of circumferential shortening. In patients with segmental left ventricular disease, such as with coronary artery disease, these dimensions may not be true reflectors of the corresponding volumes. In such ventricles one probably should use echocardiography to evaluate the motion of individual segments of the chamber. To evaluate overall left ventricular function, one could use the mitral valve echoes to estimate mitral valve flow and left ventricular diastolic pressure. Echocardiography also provides a method of measuring wall thickness of the posterior left ventricular wall and the interventricular septum.

Many echocardiographic technics for the diagnosis of congenital heart disease have recently been described. Most of these technics obviously need further substantiation; however, the size of the list is impressive and makes one feel that even the more complicated forms of congenital heart disease may be unraveled with echocardiography. The use of a strip-chart recorder has greatly improved and broadened the echocardiographic examination. Besides making the examination technically easier, it provides a means of appreciating the interrelationship of many cardiac echoes.

A critical problem facing echocardiographly is the maintenance of high-quality examinations. Unfortunately the examination is not easy, and it requires a well-trained, highly skilled individual. The acceptance of the technic by the clinician has produced a demand which exceeds the available manpower to do adequate echocardiography. As a result much of the echocardiography being done is totally inadequate. The technic is still new and relatively unproven, and it cannot tolerate much abuse by people not well trained. One possible safeguard to the maintenance of high-quality echocardiography is for clinicians to be familiar with what a good echocardiogram looks like. The difficulty with echocardiography is mainly in doing the examination. not necessarily in the interpretation. Thus if the technical quality can be maintained, there is no doubt that echocardiography will play an increasingly important role in clinical cardiology.
Spontaneous Laceration of Ascending Aorta
Authors: MURRAY CHARLES A. , EDWARDS JESSE E.
Published: June 2012

Spontaneous laceration of the ascending aorta may result in (1) through-and-through laceration causing hemopericardium, (2) limited intramural dissection of blood (incomplete dissecting aneurysm), or (3) classical dissecting aneurysm. The latter is the most common manifestation. Background conditions include either extensive cystic medial necrosis (as may be seen in Marfan's syndrome) or hypertension. The latter condition is universally associated with cystic medial necrosis but classically the medial lesion is of minimal degree. Aortic stenosis may be an underlying cause of spontaneous laceration of the ascending aorta.
Wolff-Parkinson-White Syndrome
Authors: NARULA ONKAR S.
Published: June 2012

Recent developments in the field of electrophysiology and surgical therapy in selected cases of Wolff-Parkinson-White syndrome (W-P-W) support the concept of anomalous A-V pathways. Impulse transmission usually occurs simultaneously through both the normal and anomalous pathways resulting in a fusion QRS complex. Atrial tachycardia is usually due to reentry through the normal and anomalous A-V pathways. However, reentry may occur independently in the A-V node alone exclusive of the anomalous pathway. Anomalous connections, despite varying anatomic locations, may result in similar electrocardiographic manifestations characteristic of W-P-W. His bundle recordings together with electrophysiologic studies may be clinically useful (1) to differentiate various types of anomalous connections, (2) for possible determination of the reentry circuit, (3) to predict the maximum ventricular rate possible during supraventricular tachycardia by evaluating the refractory period of the A-V pathways, or (4) to compare the efficacy of different drugs in a given patient. Surgical interruption of the anomalous pathway in selected cases with W-P-W (type B) is feasible but is most commonly not necessary. The indications for medical and surgical management of symptomatic cases with W-P-W are reviewed.
Digitalis Intoxication in Patients with Atrial Fibrillation
Authors: KASTOR JOHN A.
Published: June 2012

The characteristic arrhythmias induced by digitalis glycosides in patients with atrial fibrillation are illustrated, and their mechanisms are described. The two effects of the drug which are most important in the genesis of such disturbances are: production of A-V nodal block and arousal of subsidiary pacemakers. These properties account for slow ventricular responses, escape beats, and nonparoxysmal junctional tachycardia. Less commonly observed arrhythmias include exit block from junctional pacemakers, and bidirectional tachycardia which may reflect blocking actions of digitalis in subnodal tissues. The recent development of His bundle electrocardiography and the immunoassay method of blood level determination permit more accurate appraisal of the clinical status of patients in whom digitoxicity is suspected. Treatment of junctional rhythms due to digitalis intoxication is usually passive. The occasional use of drugs, pacing, or cardioversion is discussed.
Left Ventricular Function and Hypertrophy in Cardiomyopathy with Depressed Ejection Fraction
Authors: FEILD BOLLING J. , BAXLEY WILLIAM A. , RUSSELL RICHARD O. , HOOD WILLIAM P. , HOLT JOHN H. , DOWLING JOHN T. , RACKLEY CHARLES E.
Published: June 2012

Left ventricular (LV) function and hypertrophy, assessed during cardiac catheterization by quantitative biplane angiocardiography, were related to postcatheterization course in 36 patients found to have cardiomyopathy with depressed ejection fraction (EF). EF ranged from 0.09 to 0.41, LV mass (M) from 99 to 317 g/m
2
, LV end-diastolic volume (V) from 104 to 347 ml/m
2
, and ratio of M/V from 0.66 to 1.63. In this study, EF was used as an index of LV function; M/V ratio was considered to represent a relative degree of LV hypertrophy. Postcatheterization survival rates (PCSR) for all patients at 12, 24, and 36 months were 68.8 ± 7.8%, 49.9 ± 9.2%, and 32.8 ± 10.2%. The 36-month PCSR was significantly higher for patients (N = 15) with EF ≥ 0.20 (75.1 ± 14.5%) than for those (N = 21) with EF < 0.20 (0%) (
P
< 0.01). The 36-month PCSR was also significantly higher for patients (N = 19) with M/V ratio ≥ 0.90 (53.6 ± 14.8%) than for those (N = 17) with M/V ratio < 0.90 (12.4 ± 10.4%) (
P
< 0.05). M/V ratio appeared to influence survival at least in part independently of EF. For patients with EF ≥0.20 M/V ratio ≥ 0.90 was associated with a higher 36-month PCSR (100%) than was M/V ratio < 0.90 (25.0 ± 6.5%). Likewise, for patients with EF < 0.20, M/V ratio ≥ 0.90 was associated with a higher 24-month PCSR (65.1 ± 16.8%) than was M/V ratio < 0.90 (6.8 ± 9.1%); but at 36 months, PCSR was < 10% for both subgroups.

Patients (N = 16) with mitral regurgitation (MR) > 0.70 liters/min/m
2
had a mean value for V (212.9 ± 74.1 ml/m
2
) significantly larger than for those (N = 20) without MR or with MR < 0.70 liters/min/m
2
(168.8 ± 40.7 ml/m
2
) (
P
= 0.0278). Although this suggests that dilatation of the mitral valve annulus contributed to the development of the regurgitation, the large overlap in V values implies that additional mechanisms played a role.

This study describes quantitatively a spectrum of hemodynamic abnormalities in patients who had cardiomyopathy with depressed EF, and demonstrates that the present series of patients had a high postcatheterization mortality rate. Both EF and M/V ratio were of prognostic value and thus appear to be useful indices for classifying such patients.
Symptomatic Atrial Septal Defect in Infancy
Authors: HUNT CARL E. , LUCAS RUSSELL V.
Published: June 2012

Atrial septal defect of the ostium secundum variety (ASD) is uncommonly diagnosed in infancy and rarely results in congestive heart failure (CHF). Eleven patients with uncomplicated ASD who developed CHF between 6 days and 13 months of age are presented.

The diagnosis of ASD was documented by cardiac catheterization in all 11 patients. Left-to-right shunt ranged from 52 to 80%. Right ventricular pressure was near systemic levels in two patients and at least somewhat elevated in the other nine. Total pulmonary resistance (TPR) was within normal limits in all 11. No left ventricular obstructive lesions were found. Although one patient had unusual thickening of the left ventricular myocardium, and the left ventricular cavity was enlarged in two other cases, no specific abnormality in left or right ventricular function could be defined.

Spontaneous closure of the ASD did not occur in any of our patients. Since spontaneous closure even of a large ASD can occur, however, it seems advisable to defer elective surgical closure until after 2 years of age if successful medical management can be achieved. In those patients in whom early surgery is not necessary, the clinical course usually becomes that of a typical ASD by age 2 years.
Assessment of Left Ventricular Performance in Man
Authors: PETERSON KIRK L. , UTHER JOHN B. , SHABETAI RALPH , BRAUNWALD EUGENE
Published: June 2012

A three-dimensional construct of the tension-velocity-length relations of the intact human heart has been obtained in 17 patients by measurement of instantaneous ascending aortic flow velocity, left ventricular (LV) high-fidelity pressure, and end-diastolic volume. Left ventricular instantaneous volume was determined by subtracting the integral of the flow trace, obtained with an electromagnetic velocity catheter, at each 5-sec interval from the end-diastolic volume measured on a biplane left ventriculogram. By utilizing a thin-walled spherical model for the LV, instantaneous velocity of circumferential fiber shortening (V
CF
), wall tension, and circumferential length were calculated and plotted with the aid of a computer on a three-dimensional perspective graph. The resulting tension-velocity-length relations in seven patients with normal LV function were clearly separated from those of 10 patients with abnormal LV function. Of velocity indices alone, peak V
CF
in circumferences/sec (circ/sec) provided the best statistical separation between the groups with normal and abnormal ventricular function (2.54 ± 0.18 [
sem
] circ/sec and 1.09 ± 0.15 circ/sec, respectively) (
P
< 0.001). The time to peak V
CF
averaged 194 ± 13.2 msec and 167 ± 9.3 msec in the patients with normal and abnormal ventricular function, respectively (
P
> 0.05). Likewise, V
CF
at peak tension was significantly greater in the patients with normal as opposed to abnormal LV function (1.77 ± 0.10 and 0.93 ± 0.15 circ/sec, respectively) (
P
< 0.001). Time to peak tension was 138 ± 14.8 msec and 182 ± 17.1 msec in the normal and abnormal patients, respectively (
P
> 0.05). Mean V
CF
also served to separate the two groups, averaging 1.35 ± 0.07 and 0.72 ± 0.10 circ/sec in the patients with normal and abnormal ventricular performance, respectively (
P
< 0.001). Peak wall tension did not differ significantly between the two patient groups, averaging 231.4 ± 15.7 and 273.3 ± 16.4 g/cm in the patients with normal and abnormal ventricular function, respectively. Peak instantaneous power was higher in the normal compared to the abnormal group, averaging 8.39 ± 0.83 and 5.91 ± 0.60 kg-cm/sec per cm of circumference, respectively (
P
< 0.05). It is concluded that a three-dimensional construct of left ventricular circumferential velocity, tension, and length during ejection is readily obtainable during diagnostic cardiac catheterization and provides a sensitive and comprehensive description of LV myocardial function in man.
Clinical Course of Patients with Normal, and Slightly or Moderately Abnormal Coronary Arteriograms
Authors: BRUSCHKE ALBERT V. G. , PROUDFIT WILLIAM L. , SONES F. MASON
Published: June 2012

In a series of 500 patients who had normal coronary arteriograms or narrowings < 50% of the lumen diameter the subsequent clinical course was studied. The minimum follow-up period was 5 years. In 342 patients with entirely normal coronary arteriograms there were only two (0.6%) presumed cardiac deaths and three (0.9%) acute myocardial infarctions within 5 years; both incidences are about half the expected rates in the average unselected population of the United States matched by sex and age. In 101 patients with mild abnomalities (<30% narrowing of the lumen diameter) the prognosis was less good than in the normal group but still better than in the average population. In 57 patients with moderate abnormalities (30 to less than 50% narrowing) there were three (5.3%) presumed cardiac deaths and two (3.5%) myocardial infarctions within 5 years; both incidences are higher than in the average population. Serial arteriograms were made in 20 cases and showed progression of the disease in the majority of cases with moderate narrowings, but progression or development of narrowings in only one of the cases with normal arteries or mild narrowings. Other determinants included in this study appeared to have limited predictive value regarding the clinical course.

It is concluded that the coronary arteriogram contains major predictive information. Normal findings indicate an excellent prognosis regardless of other diagnostic parameters; moderate abnormalities indicate the early phase of an essentially progressive disease.
Deleterious Effects of Bretylium in Cats with Digitalis-Induced Ventricular Tachycardia
Authors: GILLIS RICHARD A. , CLANCY MARGARET M. , ANDERSON REBECCA J.
Published: June 2012

The effect of bretylium on ventricular tachycardia induced by digitalis was studied in Dialurethane-anesthetized cats with continuous monitoring of the electrocardiogram and arterial blood pressure. Ventricular tachycardia was produced by repeated injections of deslanoside (25 µg/kg) at 15 min intervals. Only one of eight animals showed conversion of ventricular tachycardia to sinus rhythm with bretylium administration (2-100 mg/kg i.v.). In each animal, bretylium increased the ventricular rate. The effect of bretylium (30 mg/kg i.v.) on duration of ventricular tachycardia induced by deslanoside (0.75 µg/kg/min) was also studied. Duration was shortened from 65 ± 8.0 min to 7 ± 1.0 min, but the reduction was due to the intervention of either ventricular fibrillation or severe hypotension caused by bretylium. Pretreatment with propranolol (0.5 mg/kg i.v.) prevented these deleterious effects and unmasked an antiarrhythmic effect of bretylium since duration of ventricular tachycardia was significantly shorter (40 ± 6.0 min) than the controls (65 ± 8.0 min). In addition, an antiarrhythmic effect of bretylium was noted when it was administered as a dose of 30 mg/kg ip to animals 24 and 4 hours prior to deslanoside intoxication; 231 µg/kg deslanoside were now required for inducing ventricular tachycardia as compared to 175 µg/kg deslanoside in controls. Thus, bretylium given alone during a digitalis-induced ventricular tachycardia increases both the rate of ventricular tachycardia and the likelihood of ventricular fibrillation. These deterious effects appear to be related to a norepinephrine-releasing action and may be avoided by either pretreatment with propranolol or administration of bretylium several hours prior to digitalis intoxication.
Echocardiographic Detection of Regional Myocardial Infarction
Authors: KERBER RICHARD E. , ABBOUD FRANCOIS M.
Published: June 2012

Posterior wall velocities have been advanced as a useful technic for the assessment of left ventricular function. To evaluate the echocardiographic effects of regional myocardial infarction on posterior wall motion (PWM), measurements were obtained in 22 open-chest dogs. Coronary artery ligation produced infarction of the apex in 11 dogs (group I) and the posterior wall in 11 dogs (group II). Echoes were thus received from noninfarcted myocardium in group I and from infarcted myocardium in group II. Postinfarct recordings in group I showed no significant changes in posterior wall velocities or excursion. In contrast, group II showed striking changes in the contour of PWM with a large initial posterior displacement (aneurysmal bulging) during isometric contraction, followed by a slow anterior movement during ventricular ejection and then a rapid anterior recoil motion during isometric relaxation. Mean posterior wall velocity fell from 31 ±
se
3 mm/sec preinfarct to 13 ± 4 postinfarct (
P
< 0.01); from 33 ± 4 to 21 ± 5 mm/sec during atrial pacing pre- and postinfarction (
P
< 0.05); from 30 ± 3 to 18 ± 3 mm/sec during volume loading with dextran 20 ml/kg (
P
< 0.01); and from 32 ± 4 to 5 ± 2 mm/sec during aortic constriction (
P
< 0.01). Corresponding reductions in posterior wall systolic excursion were observed.

Simultaneous hemodynamic measurements revealed moderate depression of ventricular performance in group II, but there was no significant correlation between the changes in hemodynamic parameters and echocardiographic velocities following infarction.

We conclude that the marked changes in PWM following posterior infarction were due to echocardiographic detection of dyskinesis in the infarcted area rather than to generalized changes in ventricular function. Posterior wall velocities are not a reliable index of left ventricular performance when localized dyskinesis, as indicated by abnormal PWM, is present.
Intraaortic Balloon Pumping for Ventricular Septal Defect or Mitral Regurgitation Complicating Acute Myocardial Infarction
Authors: GOLD HERMAN K. , LEINBACH ROBERT C. , SANDERS CHARLES A. , BUCKLEY MORTIMER J. , MUNDTH ELDRED D. , AUSTEN W. GERALD
Published: June 2012

The intraaortic balloon pump (IABP) has been employed in the management of five patients with ventricular septal rupture (VSD) and six patients with acute mitral regurgitation (AMR) following myocardial infarction. All patients were in cardiogenic shock which responded poorly to medical therapy including pressor and inotropic agents. IABP resulted in significant clinical and hemodynamic improvement in all cases.

In patients with VSD, IABP produced a fall in wedge (PCW) pressure from 17 ± 4 (
sd
) to 13 ± 4 mm Hg (
P
< 0.01) while mean arterial pressure increased from 68 to 73 mm Hg. Systemic A-V O
2
difference fell from 9.7 ± 2.4 to 8.1 ± 2.4 vol % (
P
< 0.05) while pulmonary A-V O
2
difference was unchanged. Thus the pulmonic/systemic flow ratio (P/S) declined in all patients. In patients with AMR, PCW fell from 25 ± 4 to 20 ± 4 mm Hg (
P
< 0.02) with a significant diminution in "V"-wave amplitude. Cardiac output (CO) rose from 3.1 ± 0.9 to 3.7 ± 1.0 liters/min (
P
< 0.01). All patients underwent coronary angiography without complication in preparation for emergency surgery.

IABP reduces AMR following acute myocardial infarction and reduces the P/S in VSD by a selective augmentation of systemic CO. Such direct therapy acutely stabilizes these severely ill patients. Detailed angiography may then be performed safely.
Intraaortic Balloon Pumping for Control of Recurrent Myocardial Ischemia
Authors: GOLD HERMAN K. , LEINBACH ROBERT C. , SANDERS CHARLES A. , BUCKLEY MORTIMER J. , MUNDTH ELDRED D. , AUSTEN W. GERALD
Published: June 2012

Eleven patients were studied because of recurrent angina at rest. In five cases ischemic pain developed 3-10 days after acute myocardial infarction. Pain recurred in all cases despite therapy with bedrest, oxygen, heparin anticoagulation, nitrates, and whenever possible, beta blockade. Intraaortic balloon pumping with a 30-cc balloon prevented ischemia in nine patients and markedly reduced the frequency of ischemic attacks in two. Coronary angiograms were obtained during circulatory assistance without complication and confirmed proximal coronary artery obstructions in all patients. Saphenous vein aortocoronary bypass grafting was then performed. Intraaortic balloon pumping will effectively control myocardial ischemia resistant to medical therapy.
Diastolic Heart Sounds during Static (Handgrip) Exercise in Patients with Chest Pain
Authors: COHN PETER F. , THOMPSON PETER , STRAUSS WARREN , TODD JAMES , GORLIN RICHARD
Published: June 2012

In order to determine the frequency of third and fourth heart sounds during cardiovascular stress, 61 patients with chest pain syndromes and normal resting phonocardiograms underwent phonocardiography both before and during submaximal handgrip exercise. Cardiac catheterization, selective coronary arteriography, and left ventriculography were performed in all patients. Twenty-nine had phonocardiograms simultaneous with hemodynamic studies. Twenty patients had normal coronary arteriograms; 41 had obstructive coronary artery disease. Fifteen percent of the subjects with normal coronary arteriograms and 54% of the patients with coronary artery disease developed diastolic heart sounds after handgrip exercise (
P
< 0.05). Conversely, 88% of the patients developing a diastolic heart sound had coronary artery disease. (If data from the present study are taken together with the previously reported prevalence of diastolic heart sounds at rest, it is estimated that these sounds can be readily demonstrated in approximately 75% of patients with coronary artery disease). Subjects with normal coronary arteriograms who developed postexercise diastolic heart sounds had a greater elevation in LVEDP and a lower EDVI/EDP ratio than did patients without these sounds, although the differences were not statistically significant. However, patients with coronary artery disease who developed abnormal heart sounds had changes which were significantly different from those who did not (
P
< 0.001 and
P
< 0.05, respectively). These findings suggest that (1) the emergence of diastolic heart sounds during handgrip exercise is a useful clinical adjunct in the diagnosis of coronary artery disease and (2) in patients with coronary artery disease, these sounds are associated with significant elevations in LVEDP, which in turn may be related to altered end-diastolic volume-pressure relationships.
A Study of Ventricular Arrhythmias Associated with Acute Myocardial Infarction in the Canine Heart
Authors: WALDO ALBERT L. , KAISER GERARD A.
Published: June 2012

A study was designed to correlate changes in bipolar epicardial electrograms recorded from normal and acutely infarcted myocardium with the onset of ventricular arrhythmias. Electrodes were sewn to selected sites on the left ventricle, and after control electrograms and ECG's were recorded, the left anterior descending coronary artery was doubly ligated close to its origin. Electrograms recorded from within the infarct initially manifested diminished amplitude and increased duration of the deflection which reflected depolarization. The appearance of ventricular arrhythmias during phase 1 of Harris was associated with the appearance in electrograms recorded from within the infarct of continuous electrical activity which extended beyond the T wave of the preceding beat and preceded the onset of the arrhythmia. During the continuous electrical activity, it was not possible to delineate which deflections of the electrogram reflected depolarization or repolarization and it was suggested that the continuous electrical activity was localized fibrillation. For three experiments in which no arrhythmias occurred during phase 1 of Harris and for all animals which survived into phase 2 of Harris, the absence of ventricular arrhythmias was correlated with the absence of continuous electrical activity or locallized fibrillation recorded from within the area of the infarct.
Effect of Digitalis on Atrioventricular Conduction and Circus-Movement Tachycardias in Patients with Wolff-Parkinson-White Syndrome
Authors: WELLENS HEIN J. , DURRER DIRK
Published: June 2012

During regular driving of the right atrium using the single-test stimulus method, atrioventricular conduction and initiation of tachycardias were studied in six patients with the Wolff-Parkinson-White syndrome (W-P-W), before and 45 min after the administration of ouabain (0.75-1.5 mg into the right atrium).

Following ouabain (1) all patients showed shortening of the refractory period of their anomalous pathway; (2) at least five of them showed lengthening of the refractory period of the A-V nodal-His pathway; and (3) all patients showed prolongation of the A-V nodal transmission time (prolongation of the A-H interval). In four patients who suffered from circus-movement tachycardias these changes resulted in two patients in marked shortening of the range of premature beat intervals during which a tachycardia could be initiated and complete inability to initiate a tachycardia in the other two. These results suggest that digitalis can be of prophylactive value in patients with the Wolff-Parkinson-White syndrome and circus-movement tachycardias.
A Quantitative Evaluation of Heart Size Measurements from Chest Roentgenograms
Authors: GLOVER LESTER , BAXLEY WILLIAM A. , DODGE HAROLD T.
Published: June 2012

In order to assess the accuracy of radiographic parameters of left heart enlargement, quantitative biplane angiographic data was compared to chest X-ray data in 254 adults with various heart diseases. Cardiac silhouette volume measured from PA and lateral chest roentgenograms compared most favorably to the sum of the left ventricular mass, end-diastolic volume, and left atrial maximal volume (r = 0.78,
P
< 0.01; 79% accuracy). The cardiothoracic ratio gave 70% accuracy (r = 0.64,
P
< 0.01). Subgrouping of patients according to specific left ventricular hemodynamic alterations did not improve correlations. The roentgenographic relationship of the left ventricle and inferior vena cava correlated poorly with left ventricular size. Of 99 patients with increased left atrial maximal volumes, 81 had visible posterior displacement of the barium-outlined esophagus by the left atrium.
Reduced Red Cell 2,3-Diphosphoglycerate and Adenosine Triphosphate, Hypophosphatemia, and Increased Hemoglobin-Oxygen Affinity after Cardiac Surgery
Authors: YOUNG JERALD A. , LICHTMAN MARSHALL A. , COHEN JULES , Murphy Marion
Published: June 2012

Serum inorganic phosphorous was decreased significantly on the third postoperative day following cardiac surgery in 18 patients initially studied. Reduced plasma inorganic phosphate has been shown to cause a reduced concentration of red cell organic phosphates, an important determinant of hemoglobin-oxygen affinity. Therefore, 10 consecutive patients were studied to determine if reduced 2,3-diphosphoglycerate (DPG) and adenosine triphosphate (ATP) concentration and increased hemoglobin-oxygen affinity accompanied the fall in serum inorganic phosphate concentration.

A significant fall in 2,3-DPG and an increase in hemoglobin-oxygen affinity was present in red cells of patients studied on the first postoperative day. A reduction in red cell ATP was also present and persisted for 5 days during which time red cell 2,3-DPG returned to levels which were in excess of preoperative values. The reduction in serum inorganic phosphorous followed the reduction in red cell 2,3-DPG and correlated with the reduction in ATP. The latter changes may indicate the diversion of glucose and more specifically 1,3-DPG into the Rapoport-Leubering pathway away from ATP generation at the phosphoglycerate kinase step and the utilization of plasma inorganic phosphate for 2,3-DPG resynthesis. Neither the transfusion of stored blood nor the effect of cardiopulmonary bypass fully explained the reduction in red cell 2,3-DPG and the inefficiency of hemoglobin function postoperatively. Further studies in postsurgical patients are needed to clarify the cause of the changes observed since they are potentially deleterious, especially in the subject with compromised cardiovascular and pulmonary function.
Autonomic and Non-Autonomic Circulatory Components in Essential Hypertension in Man
Authors: KORNER P. I. , SHAW J. , UTHER J. B. , WEST M. J. , MCRITCHIE R. J. , RICHARDS J. G.
Published: June 2012

The circulatory effects of blocking cardiac and peripheral autonomic effectors were studied in 32 subjects with established essential hypertension, and in 15 normotensives. The mean resting arterial pressure, heart rate and total peripheral resistance index (TPRI) were significantly higher in the hypertensives, but cardiac index was the same in both groups. In subjects with blocked cardiac effectors (atropine + beta-blocking drugs, i.v.) the sympathetic constrictor effects on TPRI were estimated from the changes after giving i.v. guanethidine + phentolamine. The autonomic component of TPRI was higher in hypertensives than in normotensives. The residual resistance after `total' autonomic block (non-autonomic TPRI) was higher in hypertensives, accounting for 60 to 80% of the initial difference in resting TPRI between the two groups. With an increase in non-autonomic TPRI, the increased autonomic TPRI effect in hypertension is not necessarily due to increased sympathetic nerve activity. Vagal and cardiac sympathetic effects on heart rate were compared in the two groups. Each estimate was based on the average of the responses to the appropriate blocking drug (1) in subjects not previously given a blocking drug, and (2) in subjects with the other cardiac effector pathway already blocked. The higher heart rate in established hypertension was predominantly due to change in vagal rather than cardiac sympathetic effects.
Direct Arterial Pressure and the Electrocardiogram in Unrestricted Patients with Angina Pectoris
Authors: LITTLER WILLIAM A. , HONOUR A. JOHN , SLEIGHT PETER , STOTT FRANK D.
Published: June 2012

Direct arterial pressure and electrocardiogram have been recorded over a 24 hr period in 8 males with angina pectoris who were completely unrestricted throughout the study. Twenty-five separate episodes of angina occurred, precipitated by exertion, eating, smoking, and anxiety, in addition to 2 spontaneous attacks and 2 episodes of nocturnal angina. All but 2 angina episodes were accompanied by a rise in both arterial pressure and heart rate. In the cases of spontaneous and nocturnal angina these pressure and rate changes began 10-15 min before the pain. In exertional angina these changes were related to the degree of activity involved, while in other instances there was a brief surge of pressure and rate occurring at the time of onset of pain. In each patient pain tended to occur at approximately the same level of pressure-rate product. ST-segment changes in the electrocardiogram showed no consistent pattern, occurring before or after the onset of pain, while in some episodes there was no significant change. A limited number of observations were made on the effect of glyceryl trinitrate and β-adrenergic receptor blocking drugs.
Vitamin E and Its Relation to Heart Disease
Authors: OLSON ROBERT E.
Published: June 2012

Although vitamin E deficiency in ruminants results in conspicuous heart disease, a similar deficiency state in primates appears to spare the heart, even when other systems are affected. No heart disease in man has been related to a vitamin E deficiency. The pharmacologic use of vitamin E in doses 10 to 50 times the daily requirement was recommended in 1947 for the treatment of a variety of cardiovascular disorders, including intermittent claudication, angina pectoris, coronary occlusion, congestive heart failure, thrombophlebitis and thromboembolism, but no evidence of its effectiveness has been convincingly verified during the ensuing 25 years.