bluuebunny/crossref_metadata_2025 huggingface dataset:
Constrictive Pericarditis in Childhood Due to Mediastinal Irradiation
Authors: GREENWOOD RONALD D. , ROSENTHAL AMNON , CASSADY ROBERT , JAFFE NORMAN , NADAS ALEXANDER S.
Published: June 2012

Between 1955 and 1972, eight children receiving mediastinal irradiation for intrathoracic malignancy developed constrictive pericarditis. Six of these followed irradiation for Hodgkin's disease and represent 7% of 86 children receiving irradiation for that disease. In patients with Hodgkin's disease, the development of constrictive pericarditis was related to the dose of radiation and the use of orthovoltage technique. Constrictive pericarditis has not yet developed among the 44 children radiated by supravoltage technique. Symptoms of constrictive pericarditis occurred an average of 15 months (4/12 to 3 2/12 years) after irradiation and were preceded in five of the eight patients by acute pericarditis. Prominent clinical findings included dyspnea, Kussmaul sign, pulsus paradoxicus, hepatomegaly, cardiomegaly and electrocardiographic evidence of low QRS voltages with ST-T wave changes. Pericardiectomy was performed in six patients and resulted in immediate but only transient symptomatic relief. There was no operative mortality. Death occurred in six of the eight patients (1 5/12 to 6 6/12 years following irradiation) due to cardiac disease in three, progression of the malignancy in two and infection in one. In addition to constrictive pericarditis, extensive myocardial fibrosis and involvement of the antero-lateral papillary muscle and chordae tendineae of the mitral valve were demonstrated at postmortem examination. These factors may explain the progression of cardiac disease despite an initial symptomatic improvement following pericardiectomy.
The Differential Diagnosis of Levo-Transposed or Malposed Aorta
Authors: FREEDOM ROBERT M. , HARRINGTON DONALD P. , WHITE ROBERT I.
Published: June 2012

The levo-transposed aorta has previously been considered diagnostic of corrected transposition of the great arteries and hence ventricular inversion in situs solitus. Increasing experience with conotruncal abnormalities has shown that an abnormally leftward aorta may be found in patients with normally related ventricles (D-ventricular loop) and hemodynamically complete transposition of the great arteries; anatomically corrected L-malposition of the great arteries; and rarely in patients with D-ventricular loop, double outlet right and left ventricles. Thus the levo-positioned aorta should suggest a wider spectrum of cardiovascular abnormalities than previously thought. The specific angiocardiographic features of levo-transposition, anatomically corrected malpositions, and D-ventricular loop with levo-transposed aorta are presented in detail; and their differential diagnosis from the very uncommon D-loop, double outlet right and left ventricles with an L-malposed aorta is considered. The role of selective biplane angiocardiography in the assessment of these conotruncal abnormalities is stressed.
Right Aortic Arch
Authors: KNIGHT LAURA , EDWARDS JESSE E.
Published: June 2012

An analysis was made of 78 pathologic specimens in which a right aortic arch was present. In four, the right arch was part of a double aortic arch. In 74 cases the right aortic arch was the only arch. The cases of right aortic arch could be subdivided into two groups as follows: (1) that with a retroesophageal aortic segment (three cases) and (2) that without a retroesophageal segment (71 cases).

The latter cases could be subdivided according to the nature of the origin of the branches of the arch as follows: (1) mirror image branching (60 cases), (2) aberrant left subclavian artery (ten cases) and (3) isolation of left subelavian artery (one case).

Congenital heart disease, of which the tetralogy of Fallot was the most common, was observed in each of the cases of right arch without retroesophageal aortic segment. Such an association was seen in one of three cases of right aortic arch with retroesophageal aortic segment and in three of the four cases of double aortic arch.

The potential for significant tracheal and esophageal obstruction is present in double aortic arch, in right aortic arch with retroesophageal segment and in right aortic arch without retroesophageal segment but with an aberrant left subelavian artery. In the latter condition, significant esophageal and tracheal compression depends upon the presence of a left-sided ductus arteriosus. This state was observed in five of ten cases with right aortic arch and aberrant left subelavian artery.
Reversal of Abnormal Platelet Aggregability and Change in Exercise Tolerance in Patients with Angina Pectoris Following Oral Propranolol
Authors: FRISHMAN WILLIAM H. , WEKSLER BABETTE , CHRISTODOULOU JAMES P. , SMITHEN CHARLES , KILLIP THOMAS
Published: June 2012

Nineteen patients with severe but stable angina pectoris who had positive ECG response to exercise on a bicycle ergometer and 11 normal subjects were studied. Patients received placebo for six weeks and were then randomized into placebo (n = 9) and propranolol (n = 10) treatment groups. Threshold for platelet aggregation in response to adenosine diphosphate (ADP) was measured in fresh platelet rich plasma.

Mean concentration of ADP necessary for a biphasic threshold aggregation response was 1.56 µM (geometric mean) in patients and 3.85 µM in normals (
P
< 0.01). Serial studies with placebo showed no significant change in ADP threshold. With propranolol, 80 mg/day, platelet aggregation in response to ADP was entirely normalized; 3.79 µM ADP produced maximal aggregation compared to 1.32 µM before therapy (
P
< 0.01). No additional changes were noted with propranolol, 160 mg/day. In the propranolol-treated patients (80 mg/day) who demonstrated reduction in ADP-induced platelet aggregation, total work during exercise increased by 128%, from 765 ± 125 (standard error of mean) kpm during the control period to 1,- 792 ± 285 kpm (
P
< 0.01).

Thus patients with angina and abnormal exercise tolerance demonstrate increased platelet aggregability
in vitro
which is restored toward normal with propranolol in dosage sufficient to improve exercise tolerance.
Evaluation of the Ability of Echocardiography to Measure Acute Alterations in Left Ventricular Volume
Authors: REDWOOD D. R. , HENRY W. L. , EPSTEIN S. E.
Published: June 2012

Measurement of acute serial changes in left ventricular volume is often desirable. Although left ventricular volumes estimated echocardiographically correlate well with results of angiographic methods, the sensitivity with which echocardiography can detect acute alterations in volume is unknown. Accordingly, the effect on transverse left ventricular dimension of interventions known to alter left ventricular volume (tilting and administration of nitroglycerin and phenylephrine) was studied in six normal subjects. Tilting significantly reduced end-diastolic dimension (from 48 ± 1.7 to 41.8 ± 1.5 mm,
P
< .01) and end-systolic dimension (from 32.2 ± 0.6 to 27.5 ± 0.8 mm,
P
< .001). Nitroglycerin also reduced end-diastolic dimension (from 44.8 ± 2.3 to 39.8 ± 2.1 mm,
P
< .02) and end-systolic dimension (from 30.2 ± 1.3 to 26.5 ± 1.2,
P
< .005). In contrast, phenylephrine increased end-diastolic dimension (from 42.3 ± 2.6 to 45.6 ± 2.6 mm,
P
< .025) but did not significantly alter end-systolic dimension (from 28.9 ± 2.0 to 31.8 ± 2.9 mm). Mean rate of circumferential fiber shortening (mean Vcf) was not altered significantly by tilting or by phenylephrine, but was increased by nitroglycerin (from 1.3 ± 0.1 to 1.7 ± 0.1 circ/sec,
P
< .005). In addition, a study of eight patients with chronic rheumatic mitral valve disease showed that there was a positive correlation between the percentage change in R-R intervals and the percentage change in transverse diastolic dimension (
y
= .22
x
- 10,
r
= 0.68). These results indicate that the anticipated changes in left ventricular volume are readily detected by echocardiography. Thus, this noninvasive technique may be uniquely valuable in situations in which it is desired to make serial measurements of left ventricular volume.
Termination and Inhibition of Recurrent Tachycardias by Implanted Pervenous Pacemakers
Authors: MOSS ARTHUR J. , RIVERS ROBERT J.
Published: June 2012

Three patients are described with recurrent paroxysmal tachycardia who required implanted pervenous demand pacemakers for the control of repetitive tachyarrhythmias. One patient had frequent weekly episodes of life-inhibiting supraventricular tachycardia (SVT) lasting hours to days and refractory to antiarrhythmic drugs. A coronary sinus atrial demand pacemaker at 72 beats per minute was implanted. During the subsequent two months, the patient quickly terminated nine episodes of SVT by activating the generator with an external magnet and competitively pacing the atrium. The second patient had frequent daily episodes of SVT and secondary angina despite vigorous antiarrhythmic medication. Demand ventricular pacing at a rate of 88 beats per minute prevented the recurrence of SVT during the seven month follow-up. A third patient with an old myocardial infarction had frequent biweekly episodes of ventricular tachycardia (VT) refractory to conventional treatment. A ventricular demand pacemaker was implanted, and three episodes of VT were terminated by magnetically activated competitive ventricular pacing at 64 beats per minute. Augmentation of the demand pacemaker rate to 86 beats per minute inhibited the recurrence of VT during a five month follow-up. The rates of the tachycardias were less than 160 beats per minute in all three cases, and evidence suggests a re-entrant or reciprocating mechanism for the tachyarrhythmias. The electrophysiologic rationale for pacemaker therapy in certain types of recurrent SVT and VT is discussed.
Cholinergic Innervation of the Canine and Human Ventricular Conducting System
Authors: KENT KENNETH M. , EPSTEIN STEPHEN E. , COOPER THEODORE , JACOBOWITZ DAVID M.
Published: June 2012

Augmentation of vagal tone increases ventricular fibrillation threshold (VFT) under nonischemic and ischemic conditions and protects against spontaneous ventricular fibrillation during experimental myocardial infarction. The purpose of this study was to identify the anatomic pathways responsible for this cholinergically-mediated enhanced electrical stability and to determine whether or not these pathways are present in human hearts. Rich cholinergic innervation of the sinoatrial node, atrioventricular node, and atrial myocardium was confirmed in both canine and human hearts. Although sparse cholinergic innervation was present in ventricular myocardium, numerous cholinergic nerve fibers were present in ventricular conduction tissue of both canine and human hearts. To determine whether these cholinergic fibers mediate the protective effects of vagal stimulation, cholinergic fibers to the ventricular conducting system were ablated in dogs. The ablation procedures used resulted in histologic absence of cholinergic nerves in the ventricular conducting system; innervation of the atrium, however, was histologically intact. In these animals vagal stimulation no longer increased VFT but still caused slowing of the sinus rate. The effect of vagal stimulation on VFT was shown to be independent of adrenergic innervation in a group of catecholamine depleted animals (6-hydroxydopamine). We conclude that 1) the enhanced ventricular electrical stability produced by vagal stimulation in dogs is mediated by cholinergic nerve fibers which supply the ventricular conduction system, and 2) this anatomic pathway is present in human hearts.
Aortic Valve Replacement With and Without Coronary Artery Bypass Surgery
Authors: BERNDT THEODORE B. , HANCOCK E. W. , SHUMWAY NORMAN E. , HARRISON DONALD C.
Published: June 2012

Twenty-eight patients who underwent aortic valve replacement and coronary artery bypass grafts (group A) were compared, with respect to clinical presentation, operative mortality and morbidity and follow-up clinical status, with 40 patients who had normal coronary arteriograms and underwent aortic valve replacement only (group B). Groups A and B had a similar incidence of angina pectoris, cardiomegaly, and radiographic evidence of congestive heart failure prior to operation. Group A had a higher incidence of positive history of congestive heart failure, electrocardiographic changes indicative of an old myocardial infarction, and pure aortic regurgitation or mixed aortic stenosis-aortic regurgitation. In patients with pure aortic stenosis, the aortic valve area was greater and the aortic valve gradient was lower when there was associated coronary artery disease. The operative mortality was 14.3% in group A; 0% in group B. Postoperative morbidity was similar, except for a higher incidence of perioperative myocardial infarction in group A (10.7% vs 0%). There have been no late deaths in group A; four in group B. In the survivors, 23 of 24 group A and 36 of 36 group B patients are in NYHA class I or II, with good relief of symptoms. We conclude that the diagnosis of coronary artery disease in aortic valve disease is difficult to make without coronary arteriography. Combined aortic valve replacement and coronary artery bypass graft surgery carries a higher operative mortality than aortic valve replacement or coronary artery bypass graft surgery alone, but the clinical results at 1-3 year follow-up are equally satisfactory.
Late Results Following Emergency Saphenous Vein Bypass Grafting For Unstable Angina
Authors: BONCHEK LAWRENCE I. , RAHIMTOOLA SHAHBUDIN H. , ANDERSON RICHARD P. , MCANULTY JOHN A. , ROSCH JOSEF , BRISTOW J. DAVID , STARR ALBERT
Published: June 2012

Fifty-five consecutive patients with intermittent resting chest pain persisting more than 24 hours after hospitalization and accompanied by ECG changes representative of ischemia were operated urgently more than one year ago. Recent cases with shorter follow-up are excluded. Twenty-eight patients had single grafts, 23 had double grafts, three had triple grafts, and one a quadruple graft. There were three operative deaths (5%) and one sudden late death (2%). There were six early Mls and three late Mls. Follow-up ranges from 12 to 52 months (mean 24 months) with nine patients followed for four years. Actuarial analysis indicates a projected survival rate of 93% three years postoperative. Twenty-three survivors are Functional Class (FC) I, 19 are FC II, and eight are FC III. Functional class could not be determined in one survivor. Thirty patients had postoperative angiography one week to 32 months postop. 35/51 grafts were patent. Only three patients had no patent grafts. There were no significant differences between mean preoperative and postoperative left ventricular end-diastolic pressures (assessed in 20 patients) or ejection fractions (assessed in ten patients). The extremely low mortality early and late postop (7%), the low incidence of Ml (16%), and the excellent functional results after extended follow-up indicate that emergency saphenous vein bypass grafting is an effective therapy for unstable angina.
Scintiphotographic Evaluation of Patients with Suspected Left Ventricular Aneurysm
Authors: RIGO PIERRE , MURRAY MALCOLM , STRAUSS H. WILLIAM , PITT BERTRAM
Published: June 2012

Twenty-two patients with a history of myocardial infarction and suspected of having a left ventricular aneurysm were evaluated by routine clinical studies, gated cardiac blood pool scanning, and contrast left ventriculography.

Thirteen patients were found to have a localized left ventricular aneurysm and nine demonstrated diffuse left ventricular hypokinesis on contrast angiography. The patients with localized left ventricular aneurysms could not be separated from those with diffuse left ventricular hypokinesis on the basis of the routine clinical evaluation including the chest roentgenogram or the finding of ST-segment elevation in the electrocardiogram. Scintiphotographic studies identified the nine with diffuse hypokinesis and twelve of the thirteen with a localized left ventricular aneurysm. In one patient with a calcified left ventricular aneurysm filled with clot, the cardiac blood pool scan showed an area of akinesis which corresponded to that seen on contrast angiography, but the aneurysm could not be detected.

In nineteen of the patients in whom adequate measurements were obtained, left ventricular end-diastolic volume and ejection fraction by both contrast angiography and gated cardiac blood pool scintiphotography demonstrated a good correlation,
r
= 0.92 and 0.87, respectively. There was also a good correlation between the extent of left ventricular akinesis seen on contrast angiography and gated scintiphotography,
r
= 0.97.

This study demonstrates that biplane gated cardiac blood pool scans are useful in differentiating patients with localized left ventricular aneurysms from those with diffuse left ventricular hypokinesis.
Limitation of Correction of Frequency Dependent Artefact in Pressure Recordings Using Harmonic Analysis
Authors: KROVETZ L. JEROME , JENNINGS RUFUS B. , GOLDBLOOM STEPHEN D.
Published: June 2012

Frequency dependent phase and amplitude distortion may theoretically be minimized using correction formulae derived from a model which assumes that water-filled catheter-manometer systems are analogous to an oscillating mass attached to a spring and damping pot. This study defines the practical limits of this correction technique using harmonic analysis of simultaneously recorded water-filled and catheter-tip manometer systems.

Some improvement was obtained in tracings recorded with underdamped, high frequency response systems. In no case were exact duplications of the catheter-tip tracings obtained. Divergence of measured
vitro
frequency response from actual in
vivo
frequency response was one source of these discrepancies. Loose coupling of the components of the system also changed the behavior from that of the assumed simple mechanical model and at times prevented adequate correction.

Catheter-tip manometers, in spite of their expense and relative fragility, still appear to be the best means at present of obtaining accurate pressure tracings, particularly at high heart rates or where time derivatives are to be computed.
Long-term Changes of Serum Cholesterol with Cholesterol-altering Drugs in Patients with Coronary Heart Disease
Authors: DETRE KATHERINE M. , SHAW LAWRENCE
Published: June 2012

In a controlled secondary prevention trial of estrogen and cholesterol-lowering drugs on 570 veterans, all of whom had had one or more episodes of acute myocardial infarction, changes in serum cholesterol were followed for at least five years. The findings included the following:

1) Estrogen, 1.25 mg daily, had no appreciable effect on cholesterol level.

2) Aluminum nicotinate, 4 g/day, resulted in a 20% reduction in cholesterol level for about 2½ years after which levels slowly rose to a level 12% below the baseline level in good adherers; poor adherers had smaller ultimate changes.

3) Dextrothyroxine, 4 mg/day, had a sustained cholesterol-lowering effect of approximately 7% throughout the study.

The above values were obtained after adjusting for an underlying upward trend in all cholesterol values during the five-year observation period.

4) Discontinuation of both aluminum nicotinate and dextrothyroxine resulted in a significant rise in cholesterol within three months.

5) The 6% rise in the cholesterol level found in the control group over five years of follow-up could be attributed to aging and laboratory drift.

6) Regression toward the mean rather than pharmacological effect accounted for the greater response to treatment of patients with high initial cholesterol.
Deductive Echocardiographic Analysis in Infants with Congenital Heart Disease
Authors: SOLINGER ROBERT , ELBL FRANCISCO , MINHAS KAREEM
Published: June 2012

A step-by-step approach to cardiac diagnosis utilizing a chest X-ray and echocardiography is described and used to study a normal infant and six infant patients with angiocardiographically-proven complex congenital heart malformations.

The heart is divided into three major anatomical segments in order to localize the atrial and ventricular chambers and determine the relationship of the great arteries. The atrial chambers are localized by noting the position of the liver on the X-ray. The right atrium is on the same side as the liver with few exceptions. The ventricular chambers are localized by echocardiographically identifying the tricuspid and mitral valves. They are a part of the morphologically right and left ventricles, respectively. As a general rule, the atrioventricular valve whose anterior leaflet is continuous with the posterior margin of a semilunar valve is the mitral valve. The atrioventricular valve whose anterior leaflet is not continuous with a posterior semilunar valve margin is the tricuspid valve. When the tricuspid valve is to the right of the mitral valve, the ventricles are in their normal positions (ventricular d-loop); when it is to the left, the ventricles are inverted (ventricular l-loop). The relationship of the great arteries is determined by echocardiographically identifying the semilunar valves and noting their positions relative to each other, the interventricular septum and the ventricular chambers. In a ventricular d-loop, the aortic valve is usually to the right of the pulmonary valve. In a ventricular l-loop, the opposite is true. As much as a 17% error may exist when transposition of the great arteries is a component of the malformation. Therefore, as additional aids in semilunar valve identification the R-C intervals of the valves (interval between R wave of electrocardiogram and valve closure on echogram) and outside diameters of the valve roots are measured. Usually the R-C interval is longer and, in the absence of pulmonary stenosis, the outside diameter greater for the pulmonary valve. The segmental diagnoses are then combined to obtain the "type" of heart, and a careful search is made for associated defects.

Using this approach, the positions of the atrial and ventricular chambers and the relationship of the great arteries were accurately determined in the six complex cardiac malformations studied.
Familial Atrial Dysrhythmia with A-V Block
Authors: AMAT-Y-LEON FERNANDO , RACKI ANTHONY J. , DENES PABLO , EICK ROBERT E. TEN , SINGER DONALD H. , BHARATI SAROJA , LEV MAURICE , ROSEN KENNETH M.
Published: June 2012

This study is of a family with a syndrome of atrial fibrillation or flutter with advanced or complete atrioventricular (A-V) block, involving four members in two generations. Less serious arrhythmias were documented in another 15 members (three generations). Inheritance was by autosomal dominance with varying degrees of expression. An atrial biopsy was obtained in one of the members, a 40-year-old female who had atrial flutter with advanced A-V block proximal to the His bundle (H-V interval of 39 msec). Intracellular action potential (IAP) recordings from this tissue revealed: 1) partially depolarized cells with depressed IAP amplitude, 2) phase IV diastolic depolarization with spontaneous firing, 3) diminished excitability and responsiveness, and 4) decremental conduction with local block and re-entry. Histological findings revealed vacuolar degeneration, hypertrophy, and early necrosis of atrial cells.

In conclusion, the multiple IAP and pathologic abnormalities provide a basis for atrial dysrhythmia in this family. The etiology of the disease is unknown.
The Effect of Changes in Rate and Rhythm on Supernormal Excitability in the Isolated Purkinje System of the Dog
Authors: SPEAR JOSEPH F. , MOORE E. NEIL
Published: June 2012

Microelectrode techniques were used to investigate the effects of rate and rhythm changes upon the period of supernormal excitability during repolarization in isolated canine right and left bundle branch and Purkinje fibers. The same microelectrode was used for both intracellular stimulation and recording. Excitability curves (strength-interval curves) were measured as the minimum depolarizing current required to re-excite the fiber during repolarization of a conducted action potential. During the supernormal period it required an average of 17.0 ± 4.6 SD % less than diastolic current to re-excite the fibers throughout the left and right bundle branch-Purkinje system. The supernormal period of excitability in the bundle branch-Purkinje system was voltage dependent, reaching minimum current requirements at 74.3 ± 5.8 SD mV. Excitability curves of conducted action potentials were determined at basic cycle lengths ranging from 1000 to 300 msec and following single and multiple premature beats. The decrease in action potential durations associated with shorter cycle lengths was not accompanied by a corresponding shortening of the supernormal period of excitability. Therefore, at shorter cycle lengths the supernormal period encompassed a greater proportion of the total action potential; in some cases as much as 50% of the total action potential duration exhibited a period of supernormal excitability. The supernormal period of excitability could be eliminated by perfusing the tissues in elevated potassium (5.0 and 7.5 mM) Tyrode's solution. The possible implications for the generation of re-entrant arrhythmias are discussed.
Chagasic Cardiopathy
Authors: COSSIO PATRICIO M. , LAGUENS RUBEN P. , DIEZ CARLOS , SZARFMAN ANA , SEGAL AMADA , ARANA ROBERTO M.
Published: June 2012

An antibody reacting with endocardium, vascular structures and interstitium of striated muscle (EVI antibody), by the indirect immunofluorescence technique, was recently described in Chagas' disease. In the present report the identification of tissue structures responsible for the EVI reaction was studied by means of ultrastructural immunochemical methods. Positive reactions were observed in the plasma membrane of the heart and skeletal muscle fibers and endothelial cells of blood vessels.

Absorption of positive sera with
T. cruzi
abolished both patterns observed by electron microscopic methods. These results are in agreement with observations performed with the indirect immunofluorescence technique.
Massive Pulmonary Emboli Diagnosed and Followed in Progress by Lung Imaging and Radionuclide Pulmonary Angiography
Authors: KLEIN E. W. , MCCARTEN KATHLEEN , DIMCHEFF D. G. , COLVIN J. T.
Published: June 2012

A dramatic case of occlusion of the right pulmonary artery is presented. The diagnosis was clearly established by means of a lung scan and a radionuclide pulmonary angiogram. The entire course of the disease process was followed by radionuclide studies with a gradual but persistent return to normal. Due to the preciseness of the evidence presented, contrast angiography was not. thought necessary.
Coronary collateral function in patients without occlusive coronary artery disease.
Authors: Goldstein R E , Michaelis L L , Morrow A G , Epstein S E
Published: June 2012

Little is known of the functional capacity of coronary collaterals in humans without occlusive coronary artery disease. We, therefore, measured peripheral coronary pressure (PCP) and retrograde flow (RF) from coronary arteries at aortic valve replacement in seven patients without occlusive coronary artery disease. Using a T-connection interposed in left (LCA) and right (RCA) coronary perfusion lines, data were obtained during brief proximal occlusion of each line. PCP was expressed as a fraction of perfusion pressure (PP), and collateral resistance (CR) was calculated as PP/RF. Median values were as follows: (a table was included). In contrast, previous studies of well-collateralized distal segments of diseased coronary arteries revealed mean RF 15.7, CR 5.1 and PCP/PP 0.50. Under the conditions of study, all vessels interconnecting the non-diseased RCA and LCA delivered flow and pressure less readily than collaterals to a single distal segment of a diseased coronary artery. Thus, collaterals in patients without diseased coronary arteries have an extremely limited capacity to transmit either flow or pressure. The absolute values of RF were small relative to the muscle mass perfused by each coronary artery, suggesting that perfusion of only one coronary artery in man during operation may not provide substantial perfusion for large portions of myocardium. Comparison of performance of collaterals supplying atherosclerotic and nonatherosclerotic coronary arteries indicates that proximal occlusion may be an important factor stimulating enhancement of collateral function. Moreover, the nitroglycerin-induced improvement in collateral function seen in patients with chronic occlusive coronary disease was not demonstrable in patients without coronary occlusion. Thus, coronary collaterals may acquire nitroglycerin responsiveness as a result of changes induced by chronic coronary occlusion.
Intravenous nitroglycerin in acute myocardial infarction.
Authors: Flaherty J T , Reid P R , Kelly D T , Taylor D R , Weisfeldt M L , Pitt B
Published: June 2012

Vasodilator therapy has been shown to improve ventricular function in patients with left ventricular failure complicating acute myocardial infarction. Sublingual nitroglycerin also improves ventricular function in these patients but its effects are transient and variable. Infusion of intravenous nitroglycerin in 12 patients with acute infarction resulted in a decrease in left ventricular filling pressure from a mean of 22 plus or minus 2 mm Hg to 12 plus or minus 1 mm Hg (P less than 0.001) associated with a 7 mm Hg decrease in mean arterial pressure (P less than 0.05). Since stroke work index did not change significantly, this represents and improvement in ventricular performance and/or an alteration in ventricular compliance. All six patients in whom serial precordial mapping studies were performed showed a decrease in sigma ST (P less than 0.001). These findings suggest that intravenous nitroglycerin improved left ventricular function and decreased the extent of myocardial ischemia. Longer infusion may act to preserve borderline ischemic myocardium and thus limit infarct size.
Postural changes in left ventricular and mitral valvular dynamics in the systolic click - late systolic murmur syndrome.
Authors: Fontana M E , Wooley C F , Leighton R F , Lewis R P
Published: June 2012

Marked changes in the auscultatory pattern with posture have been noted in patients with mid-systolic clicks and/or late systolic murmurs (MSC-LSM). MSC tend to move earlier in systole and LSM become longer and often louder when patients assume upright posture. Systolic prolapse of the mitral leaflets with mild regurgitation account for MSC-LSM; earlier and greater prolapse with more and prolonged regurgitation associated with a reduced left ventricular volume (LVV) in the upright position would explain the auscultatory changes. Twenty-two patients with MSC-LSM were studied supine and at 45 degrees head-up tilt, recording intracardiac pressures, cardiac outputs, systolic time intervals, and performing LV cineangiography. Systolic prolapse of one or both mitral leaflets was demonstrated in all patients. Left ventricular end-diastolic and end-systolic volumes both decreased significantly at 45 degrees in all sixteen technically satisfactory studies. Greater mitral prolapse was noted upright in 12 of 14 studies with enough sinus beats to judge. The amount of mitral regurgitation was mild in all, and changes in amount from supine to upright posture could not be discerned angiographically. THE FINDINGS, SUGGEST THAT THE AUSCULTATORY CHANGES OCCURRING WITH UPRIGHT POSTURE IN PATIENTS WITH MSC-LSM are related to greater prolapse of the mitral leaflets which is associated with a small LVV in the upright position.
Bacterial endocarditis in subjects 60 years of age and older.
Authors: Thell R , Martin F H , Edwards J E
Published: June 2012

Forty-two cases of bacterial endocarditis with pathologic confirmation are reviewed. Infection was restricted to one or both left-sided valves in 31 cases, right-sided valves in five cases, and valves in both sides of the heart in six cases. In those specimens available for review, underlying valvular disease was identifiable in 24 of 38 cases (63%). The common underlying diseases, in order of decreasing frequency, were calcified or otherwise deformed aortic valves (11 cases) and rheumatic fibrosis of the mitral valve (eight cases). The floppy mitral valve was the underlying condition in two cases and amyloid infiltration of the tricuspid valve in one. Among the 34 cases from which a specific organism was identified, the dominant organisms were Staphylococcus (14 cases) and various types of Streptococci(ten cases). Fungi were the causative organisms in two cases. The clinical suspicion for the presence of bacterial endocarditis was low (40% of 40 cases with adequate data). In those cases with adequate data, murmurs were present in 68% and fever in 93%. Of those patients with fever, clinical diagnosis was made or suspected in only 38%. When a murmur was present, the clinical diagnosis was made or suspected in 54% of the cases, while when a murmur was absent the disease was suspected in only 9% of the cases. The clinical diagnosis of bacterial endocarditis in older subjects depends upon 1) knowledge that the disease may occur in such subjects and 2) recognition that, although fever is commonly present, murmurs may be absent.
Return of normal conduction after paroxysmal heart block. Report of a case with major discordance of electrophysiological and pathological findings.
Authors: Rosen K M , Wu D , Kanakis C , Denes P , Bharati S , Lev M
Published: June 2012

This report describes a 52-year-old male with paroxysmal heart block as well as left and right bundle branch block, resulting in Stokes-Adams attacks. The patient experienced a return to 1:1 atrioventricular (A-V) conduction with narrow QRS within 48 hours of the attacks and heart block never recurred. Electrophysiological studies three weeks later revealed a narrow QRS, a normal H-V interval (36 msec), 1:1 A-V conduction up to an atrial paced rate of 210 beats/min, and normal refractory periods with atrial extrastimulus techniques (His-Purkinje system refractory periods less than 370 msec). The patient died from a cerebral embolus incurred during diagnostic left heart catheterization two days after electrophysiological studies. Postmortem examination revealed calcific aortic stenosis with calcific impingement upon the pars membranacea resulting in compression of the distal His bundle and marked disruption of the proximal portions of both bundle branches. This report documents a major limitation of electrophysiological studies, this limitation being that these studies may be totally normal on one occasion in a patient with pathologically significant chronic conduction disease, which may become clinically manifest on another occasion.
Transposition of the great arteries. Results of treatment with early palliation and late intracardiac repair.
Authors: Gutgesell H P , McNamara D G
Published: June 2012

A longitudinal study was made of 62 patients with dextro-transposition of the great arteries. The patients were managed with balloon atrial septostomy (BAS), palliative surgery if any operation was needed in the first year of life, and Mustard intra-atrial baffle repair after one year of age. Of the 47 patients with intact ventricular septum (IVS) treated in this manner, 41 (87 percent) were living at three months of age, 36 (77 percent) at one year, and 31 (66 percent) at two years of age. Survival rates were lower at each age for patients with associated ventricular septal defect (VSD). In relation to therapeutic interventions in the 62 patients, there were six medical deaths within one week of BAS, three deaths during palliative operations, and eight deaths associated with 31 Mustard procedures. Three patients with IVS and five with VSD developed pulmonary vascular obstructive disease, and two patients suffered strokes. In view of the relatively low mortality rate after the neonatal period and our good results with palliative surgery, we continue to defer the Mustard procedure to the second year of life. This is in contrast to the policy of some centers which now advocate elective intracardiac repair in the first year of life.
Ultrastructure of crista supraventricularis muscle in patients with congenital heart diseases associated with right ventricular outflow tract obstruction.
Authors: Jones M , Ferrans V J , Morrow A G , Roberts W C
Published: June 2012

Ultrastructural studies were made of operatively resected crista supraventricularis muscle in 59 patients with congenital heart diseases, or whom 54 had obstruction to right ventricular outflow. Relationships of anatomic diagnosis, age, peripheral arterial oxygen saturation (PAO2), peak right ventricular systolic pressure gradient and right ventricular end-diastolic pressure (RVEDP) to hypertrophic changes, abnormalities of cellular and myofibrillar orientation, and degenerative alterations were determined. Changes directly related to hypertrophy were: cell diameters greater than 20 mu, irregular cell shape, lobulated nuclei, multiple intercalated discs, dilated T tubules, abnormal Z bands, and increased numbers of ribosomes. Abnormalities of cellular or myofibrillar orientation were focal in distribution and occurred in 12 patients, most of whom had elevated RVEDP, decreased PAO2, markedly enlarged cells, and interstitial fibrosis. Interstitial fibrosis was prominent in 19 patients and was associated with cellular hypertrophy, elevation of RVEDP, and increased age of the patients. Degenerative changes (myofibrillar lysis, abnormally small mitochondria, myelin figure formation, and proliferation of sarcoplasmic reticulum in cardiac muscle cells ocurred in six patients and correlated with increased age, decreased PAO2, and elevated RVEDP. Mitochondria containing glycogen deposits were present in 17 patients, most of whom had decreased PAO2. The variability of morphologic manifestations of chronic cardiac hypertrophy and the relationships of hypertrophic changes to orientation abnormalities and degenerative alterations are discussed.
Problems in the recognition of conduction disturbances in the His bundle.
Authors: Schuilenburg R M , Durrer D
Published: June 2012

Two cases with conduction disturbances in the His bundle are described. In each it was not possible to obtain both components, H and H', of the "split" His bundle potential at one time from a single bipolar electrode catheter with an interelectrode distance of 10 mm. Initial failure to record the proximal His component (H) let to the incorrect diagnosis of block located within the atrioventricular (A-V) node, of third degree, in patient A, and of first to second degree in patient B. However, careful withdrawal of the catheter resulted in the appearance of proximal components (H), accompanied by disappearance of the distal components (H') of the His bundle potential. Apparently the lesion in the His bundle and the recording electrodes were spatially related in such a way that the bipolar electrode could not override the lesion. In view of these findings it is advocated that in patients the A-V conduction disturbances the His bundle catheter should be withdrawn carefully, if the initial recording reveals His bundle potentials bearing a time relation to the ventricular complexes, or advanced carefully, if these His potentials are related to the atrial activations, in order to demonstrate the (co)existence of a lesion in the His bundle. Search for a proximal His potential by withdrawal of the catheter should be done, if possible, while the atrium is paced at a rate in excess of the spontaneous sinus rate since the H potential may be obscured by the atrial complex if the A-V nodal transmission time is short at the spontaneous rate, as was the case with patient A. In patient B the not yet described phenomenon of bradycardia-dependent block within the His bundle was observed.
Echocardiographic analysis of mitral valve motion after acute myocardial infarction.
Authors: Bergeron G A , Cohen M V , Teichholz L E , Gorlin R
Published: June 2012

To examine the effects of acute myocardial infarction on mitral valve diastolic velocity, echocardiograms were performed in 18 patients on admission, daily in the Coronary Care Unit, and at 3-day intervals during the remainder of hospitalization. These patients were divided into three groups based on the time interval between onset of symptoms and initial echocardiogram. Five of six patients admitted within 5 hours of onset of myocardial infarction had a triphasic response of mitral valve diastolic velocity with a transient rise above initial values, followed by a fall to below initial values, and then a slow rise during recovery. Seven of eight patients admitted 1-2 days after onset of myocardial infarction had a biphasic response, i.e., a fall from initial values and then a slow rise. Four patients admitted later in the course of myocardial infarction had a monophasic response, i.e. low initial velocity followed by a slow recovery. We conclude that in patients with myocardial infarction the mitral valve diastolic velocity following myocardial infarction shows a triphasic response which may appear biphasic or monophasic depending on the interval between myocardial infarction and admission. The temporal pattern of mitral valve diastolic velocity changes may reflect the dynamic alterations of myocardial function and compliance that are occurring after acute myocardial infarction and during the recovery period.
The echocardiographic determination of mitral valve opening and closure. Correlation with hemodynamic studies in man.
Authors: Rubenstein J J , Pohost G M , Dinsmore R E , Harthorne J W
Published: June 2012

The ability of the echocardiogram to define mitral valve opening and closure was assessed by simultaneously recording the echocardiogram of the anterior leaflet (ECHO) with intracardiac pressures, aortic second sound, and ECG on 38 occasions in 14 patients undergoing cardiac catheterization. Hemodynamic opening and closure were defined by intersection of the pulmonary wedge and left ventricular pressures and the onset of left ventricular systole. The onset of the most rapid anterior motion (D') in early diastole and termination of the last rapid posterior movement in end diastole (Co) were used as echocardiographic markers of mitral valve opening and closure. Intervals measured included: the isovolumic relaxation period (IRP) from A2 to either hemodynamic (IRPH) or echocardiographic (IRPE) opening; the Q to closure interval (QCI) from the Q wave to either hemodynamic (QCIH) or echocardiographic (QCIE) closure; and diastolic filling period (DFP), either hemodynamic (DFPH) or echocardiographic (DFPE). The following significant (P less than .01) regression equations resulted: IRPE equals (.97) IRPH plus 30 (sem plus or minus 8 msec) r equals .89; QCIE equals (.68) QCIH plus 37 (sem plus or minus 7 msec) r equals .71; DEPE equals (.98) DFPH plus 10 (sem plus or minus 18 msec) r equals .98. Thus hemodynamic markers of opening and closure systematically precede echocardiographic markers of opening (D') and closure (Co) and the diastolic filling periods are equal within 10 msec. It is concluded that the echocardiogram of the anterior leaflet is a reliable indicator of hemodynamic markers of opening and closure of the mitral valve in man and is useful in the noninvasive determination of certain systolic and diastolic time intervals.
Thickenings in the coronary arteries in infancy as an indication of genetic factors in coronary heart disease.
Authors: Pesonen E , Norio R , Sarna S
Published: June 2012

In Finland, mortality from coronary heart disease is high, and much higher in the eastern than in the western countries. Both left and right coronary arteries of 141 children who died under one year of age at the Children's Hospital, University of Helsinki, were investigated. Thirty-two of these children formed a western and 41 an eastern group according to the birthplaces of their grandparents in Finland. Correlations were tested between this geographical distribution and some dimensions of the coronary arteries, as well as other clinical variables. The inner vascular layers of the left coronary arteries were found to be thicker in the eastern group (P less than 0.05 in analysis of variance and P less than 0.01 in regression analysis). No other significant correlations were observed. This association of infants having thick inner vascular layers in the coronary artery with a population group where mortality from coronary heart disease (CHD) is very high supports the hypothesis that the thickenings are prearteriosclerotic. The difference found between the arteries of the western and eastern groups might be due to a difference in the vulnerability of the inner vascular wall to extrinsic deleterious factors. The association substantiates the existence of a genetic component in the etiology of CHD and supports the theory that two separate groups of settlers originally colonized Finland.
Familial atrioventricular heart block; an autosomal dominant trait.
Authors: Waxman M B , Catching J D , Felderhof C H , Downar E , Silver M D , Abbott M M
Published: June 2012

A family of 28 individuals spanning four generations was investigated because of a finding of complete heart block in five members and the existence of a low degree of atrioventricular (A-V) heart block in a sixth member. The disorder was characterized by 1) adult onset in all, 2) complete A-V heart block in five and first degree A-V heart block in one, 3) sinus bradycardia in three, 4) atrial fibrillation in five, 5) abnormal QRS complex in five, 6) ventricular tachycardia in three, 7) left ventricular enlargement in all, and 8) mitral insufficiency in five. Proximal location of the A-V heart block was suggested by the fact that atropine caused acceleration of the ventricular rate and by the presence of a His bundle potential preceding the QRS complexes. Involvement of the distal conducting system was indicated by the widened QRS complex and a prolonged H-V interval. Pathologic examination in one case showed extensive sinus node fibrosis and interruption of the A-V node-His bundle connection. This disorder is probably due to an autosomal dominant trait.
Effect of digoxin on atioventricular conduction. Studies in patients with and without cardiac autonomic innervation.
Authors: Goodman D J , Rossen R M , Cannom D S , Rider A K , Harrison D C
Published: June 2012

The effect of digoxin on atrioventricular (a-v) conduction was compared in five patients with an intact cardiac autonomic nervous system (Group I) and seven patients who had undergone cardiac transplantation (Group II), in whom we have previously shown the transplanted heart to be completely denervated. Small decreases in the atrial effective refractory period (ERP) (from 262 plus or minus 12 to 254 plus or minus 11 msec) and atrial functional refractory period (FRP) (from 304 plus or minus 12 msec) were observed in Group I patients after digoxin, but these changes were not significant. However, significant increases in the A-V nodal ERP (from 315 plus or minus 18 msec to 351 plus or minus 17 msec, P less than 0.05), and A-V nodal FRP (from 426 plus or minus 42 to 460 plus or minus 46 msec, P less than 0.01) were produced by digoxin and were unrelated to changes in cycle length. In Group II patients with denervated hearts, changes in atrial ERP (from 246 plus or minus 4 to 243 plus or minus 6 during spontaneous sinus rhythm; from 204 plus or minus 10 to 216 plus or minus 8 msec during atrial pacing) and atrial FRP (from 311 plus or minus 12 to 316 plus or minus 11 msec during spontaneous sinus rhythm; from 254 plus or minus 12 to 260 plus or minus 10 msec during atrial pacing) were not significant. However, in contrast to the Group I patients, the digoxin-induced changes in A-V nodal ERP (from 280 plus or minus 22 to 297 plus or minus 18 msec during atrial pacing) and FRP (from 368 plus or minus 18 to 377 plus or minus 18 msec during spontaneous sinus rhythm; from 334 plus or minus 13 to 346 plus or minus 16 msec during atrial pacing) were also statistically insignificant. Our results demonstrate that the electrophysiologic effects of digoxin on atrioventricular conduction in man are most marked in the atrioventricular node and are dependent on cardiac innervation