bluuebunny/crossref_metadata_2025 huggingface dataset:
Contrasting rates of reversal of digoxin toxicity by digoxin-specific IgG and Fab fragments.
Authors: Lloyd B L , Smith T W
Published: June 2012

Both heterologous IgG and Fab fragments of appropriate affinity and specificity have been shown capable of reversing advanced cardiac glycoside toxicity. Fab fragments are more rapidly excreted and theoretically have a smaller risk of unwanted immunologic effects, but relative rates of toxicity reversal have not been established. Rates of reversal of advanced digoxin toxicity by digoxin-specific IgG and Fab fragments were therefore compared in a dog model of advanced digoxin intoxication. Initial studies confirmed more rapid distribution of sheep Fab fragments (M.W. 50,000) than of the parent IgG molecule (M.W. 150,000) after intravenous injection. Twenty-five pentobarbital-anesthetized dogs were given 0.3 mg/kg digoxin intravenously, resulting in rapid onset of ventricular tachycardia in all animals. Eight dogs subsequently given nonspecific IgG or Fab died in asystole or ventricular fibrillation an average of 55 minutes after digoxin administration. Ten of 11 dogs given 1.33 moles of binding sites per mole of digoxin as intact IgG returned to sinus rhythm at a mean time of 85 minutes after antibody infusion. In contrast, six of six dogs given an equivalent dose of specific Fab fragments returned to sinus rhythm in a significantly shorter mean time of 36 minutes (P less than 0.01). Variability of time to arrhythmia reversion was less in Fab-treated dogs. These data demonstrate a decisive advantage of specific Fab fragments over intact IgG for potential clinical use in advanced, life-threatening digoxin intoxication.
Electrocardiographic findings in patients with obstructive and nonobstructive hypertrophic cardiomyopathy.
Authors: Savage D D , Seides S F , Clark C E , Henry W L , Maron B J , Robinson F C , Epstein S E
Published: June 2012

One hundred and thiry-four patients with hypertrophic cardiomyopathy were evaluated by standard 12-lead electrocardiography. Normal electrocardiograms were extremely uncommon, occurring in less than 7% of each subgroup of patients (i.e., those with or without either symptoms or obstruction to left ventricular outflow), with the exception of those who were both asymptomatic and had no left ventricular outflow obstruction. Even in this subgroup, however, normal electrocardiograms occurred in only 27% of patients. Repolarization abnormalities and left ventricular hypertrophy were the most common abnormalities, occurring in 81% and 62%, respectively, of the total population. A broad spectrum of other electrocardiographic abnormalities was found, but none was unique to hypertrophic cardiomyopathy. Patients with vs those without electrocardiographic left ventricular hypertrophy or left atrial abnormality had significantly (P less than 0.005) greater mean ventricular septal thickness (22 +/- 0.6 vs 19 +/- 0.6 mm) and left atrial dimension (48 +/- 1 vs 40 +/- 1 mm) measured by echocardiography, and signficantly (P less than 0.01) higher mean pulmonary capillary wedge pressure (16 +/- 1 vs 10 +/- 1 mm Hg) and left ventricular end-diastolic pressure (20 +/- 1 vs 15 +/- 1 mm Hg). The high prevalence and diverse nature of electrocardiographic abnormalities suggest that any patient with an unusual and unexplained electrocardiogram should be suspected of having hypertrophic cardiomyopathy even if the physical examination is normal, as is often the case in patients without obstruction.
A multivariate approach for interpreting treadmill exercise tests in coronary artery disease.
Authors: Berman J L , Wynne J , Cohn P F
Published: June 2012

To determine the value of a multivariate approach for the analysis of the treadmill exercise tolerance test (ETT), 237 patients referred for evaluation of chest pain who underwent a standard Bruce protocol ETT and coronary arteriography were studied. Predictive value of a positive ETT was 0.78 (43/55) using 1.0--1.9 mm ST segment depression criterion, 0.97 (59/61) using greater than or equal to 2.0 mm ST segment depression. When the 1.0--1.9 mm ST criterion was combined with peak systolic blood pressure-heart rate product (double product) less than or smaller than 23,000, exercise duration less than 6 minutes, and ST depression for greater than 3 minutes into recovery, predictive value improved to 0.89 in 18 patients with any two of the above. Predictive value for multivessel disease was also improved using non-ST criteria. Predictive value of a negative ETT for absence of coronary artery disease was 0.60 (29/48), and was 0.86 (12/14) if double product was greater than or equal to 30,000. Presence of chest pain during ETT did not improve predictive value of any type of test. Digitalis ingestion in 33 patients was not associated with decreased predictive value of a positive test. These data suggest that the predictive value of both positive and negative ETT in a symptomatic population can be improved with a multivariate approach.
Fulminant beriberi heart disease with lactic acidosis: presentation of a case with evaluation of left ventricular function and review of pathophysiologic mechanisms.
Authors: Attas M , Hanley H G , Stultz D , Jones M R , McAllister R G
Published: June 2012

Cardiac beriberi is considered a rare disease in western society. A patient with fulminant Shoshin-type beriberi was studied in the acute phase and found to have severe metabolic acidosis, high output biventricular failure, and markedly low systemic vascular resistance. Red blood cell transketolase activity was abnormally low. Following treatment with thiamine, diuretics, digitalis and oxygen, all abnormalities disappeared. The historical background of the disease is reviewed along with a discussion of pathophysiologic mechanisms responsible for the hemodynamic profile and lactic acidosis. Angiographic and hemodynamic data on the patient presented suggest relative depression of left ventricular function in the acute phase of beriberi. Since beriberi is uncommonly encountered, emphasis is placed on diagnostic and therapeutic implications of the disease which may not be widely appreciated.
Angiotensin converting enzyme inhibition in patients with congestive heart failure.
Authors: Gavras H , Faxon D P , Berkoben J , Brunner H R , Ryan T J
Published: June 2012

The etiology of afterload elevation in congestive cardiac failure is unclear, but experimental evidence suggests a role for the renin-angiotensin system in maintaining elevated peripheral vascular resistance. The angiotensin converting enzyme inhibitor SQ20,881 was administered to eight patients with congestive cardiac failure (four hypertensives, four normotensives) during or one day after diagnostic cardiac catheterization. Various hemodynamic measurements performed before and during blockade indicate that this agent caused improvement in cardiac function in all patients by decreasing afterload. This improvement correlated with the decrease in total vascular resistance but was independent of the baseline blood pressure and plasma renin activity. These results suggest that inhibition of angiotensin converting enzyme is a worthwhile approach to the treatment of congestive heart failure, although its exact mechanism of action remains unclear.
Chronic aortic regurgitation: the effect of aortic valve replacement on left ventricular volume, mass and function.
Authors: Gaasch W H , Andrias C W , Levine H J
Published: June 2012

Serial echocardiographic left ventricular (LV) studies were performed in 19 patients before (preop) and after (postop) aortic valve replacement (AVR) for chronic aortic regurgitation (AR); the effect of AVR on LV volume, mass and function was determined from the echocardiographic data. In the 12 patients who were considered to have successful surgical results, the average LV end-diastolic dimension fell from a preop value of 6.9 +/- 0.2 cm to 5.5 +/- 0.2 cm (P less than 0.01) at the time of the early postop study (seven to 10 days). Muscle cross-sectional area (CSA) derived from dimension and wall thickness data was used as an index of LV muscle mass (preop CSA = 26 +/- 1.3 cm2); CSA was unchanged at the early postop study, but subsequently fell to near normal within six months after AVR (20 +/- 1 cm2, P less than 0.01). There was a trend toward improvement in systolic performance by the late postop studies (12+ months). In two out of three patients with postop paravalvular AR, LV dimension increased after an initial fall. Four patients without paravalvular AR failed to show a significant reduction in LV dimension in the postop studies. In this group the preop studies showed a tendency toward a large end-diastolic dimension and decreased fractional shortening, but the single preop parameter which differentiated these four from the successfully treated group was an end-diastolic radius-to-wall thickness (R/Th) ratio greater than or equal to 4. Thus, successful AVR for chronic AR results in the normalization of LV volume and a decrease in LV muscle mass to near normal. The R/Th ratio has important prognostic value which appears to be independent of fractional shortening in some patients with chronic AR.
Staged surgical management of tetralogy of Fallot in infants.
Authors: Stephenson L W , Friedman S , Edmunds L H
Published: June 2012

A cohort of 61 consecutive patients 24 months of age of younger had palliative shunts for symptoms of tetralogy of Fallot during a 12-year period. Thirty-six of these patients have been followed through definitive intracardiac repair or to death. For analysis palliative operations were separated into two six-year periods, 1965--1970. During the first period seven of 30 infants operated on died; all 31 infants operated on during the second period survived. The Waterston anastomosis was performed most frequently (67%) during the first period; the Blalock-Taussig anastomosis was performed in 68% of infants during the second period. Of 54 hospital survivors, three died before definitive intracardiac repair. Two of the three interim deaths were related to heart disease. Twenty-six of the remaining 51 patients have had definitive intracardiac repair with two deaths (8%). Twenty-four in this group had intracardiac repair since 1973 with one hospital death (4%). The cumulative mortality for the entire cohort is 25%, but more recent experience (1971--77) indicates a cumulative mortality near 5%. The recent mortality rate for staged management is less than the 14% rate reported by others for primary intracardiac repair of tetralogy of Fallot in 205 infants. We conclude that primary intracardiac repair has important advantages for infants with tetralogy of Fallot who have favorable anatomic features and no other associated cardiac lesions or medical problems. Staged management of tetralogy of Fallot is still recommended for infants with unfavorable anatomy, additional lesions or associated medical problems.
Noninvasive assessment of left ventricular function from the mitral valve echogram. Relation of final anterior mitral leaflet closing velocity to peak dp/dt and aortic velocity.
Authors: Jugdutt B I , Lee S J , McFarlane D
Published: June 2012

Since final mitral valve (MV) closure and aortic ejection velocity are mediated by the same forces in early left ventricular (LV) contraction, the rate of final MV closure (BC slope) should reflect LV performance. We first verified whether peak final closing velocity (ds/dt) of the anterior MV leaflet (AMVL) is related to peak aortic ejection velocity (V) and LV dp/dt in 18 open-chest dogs. We then checked the validity of the relations in man. Our approach was to measure peak ds/dt, peak aortic acceleration (dV/dt) and peak LV dp/dt using electronic differentiation of analog signals of the AMVL echogram, V and LV pressure. In dogs, resting ds/dt averaged 26.9 +/- 9.0 (SD) cm/sec and changed significantly (P less than 0.001) after isoproterenol, propranolol, coronary ligation and aortic cross-clamping. We found good (P less than 0.001) correlations between ds/dt and V (r = 0.82), dV/dt ( r = 0.67) and dp/dt (r = 0.73). In man, resting ds/dt averaged 25.5 +/- 1.6 cm/sec in six normals. In 40 patients with coronary artery disease, restind ds/dt was lower (15.7 +/- 4.4 cm/sec; P less than 0.001) in the 19 with resting LV end-diastolic pressure (LVEDP) greater than 12 mm Hg. Resting ds/dt correlated closely with V (r = 0.82, N = 10), dp/dt (r = 0.93, N = 6), resting LVEDP (r = -0.67, N = 40), angiographic ejection fractions (r = 0.62, N = 40) as well as manually obtained BC slopes (r = 0.93, N = 40). Thus, final MV closing velocity provides a useful and simple means for the objective noninvasive assessment of LV performance.
Lung biopsy in congenital heart disease: a morphometric approach to pulmonary vascular disease.
Authors: Rabinovitch M , Haworth S G , Castaneda A R , Nadas A S , Reid L M
Published: June 2012

Fifty patients with congenital heart disease, ages 2 days-30 years (median 12 months) at cardiac surgery, underwent lung biopsy to assess pulmonary vascular disease (PVD). Twenty-six had ventricular septal defects (VSD), 17 d-transposition of the great arteries (D-TGA), and seven, defects of the atrioventricular canal (AVC). Quantitative morphologic data was correlated with hemodynamic data. Three new grades of PVD were observed. Abnormal extension of muscle into peripheral arteries (grade A) was found in all patients; all had increased pulmonary blood flow. In addition, 38 of 50 patients had an increase in percentage arterial wall thickness (grade B); this correlated with elevation in pulmonary artery (PA) pressure (r = 0.59). Another 10 of 50 patients had, in addition to A and B, a reduction in the number of small arteries (grade C); nine of 10 were patients with elevated PA resistance greater than 3.5 mu/m2 (P less than 0.005). All three patients with Heath-Edwards changes of grade III or worse also had grade C. Reduction in peripheral arterial number probably precedes obliterative PVD and may identify those patients in whom, despite corrective surgery, PVD will progress.
Asymptomatic coronary artery disease: angiographic assessment of diabetics evaluated for renal transplantation.
Authors: Weinrauch L , D'Elia J A , Healy R W , Gleason R E , Christleib A R , Leland O S
Published: June 2012

Twenty-one insulin-dependent diabetics with azotemic nephropathy were evaluated for renal transplantation by selective coronary angiography and cine left ventriculography. All had hypertension, retinopathy, neuropathy, and required salt restriction plus diuretics for volume overload. There was no clinical or electrocardiographic evidence of ischemic coronary artery disease in twenty. Ten patients (five males, five females, mean age 29.3 years; mean duration of diabetes 21.9 years; mean serum cholesterol 239 mg%) had significant coronary artery disease, seven demonstrating focal abnormalities in left ventricular wall motion. Two patients (one male, one female; mean age 36.5 years; mean duration of diabetes 28.5 years; mean serum cholesterol 250 mg%) had no significant coronary artery disease, but demonstrated diffusely abnormal left ventricular wall motion with diminished ejection fraction. Thirty-eight percent had significant coronary artery disease unpredictable by electrocardiographic or clinical data. The finding of no significant coronary artery disease in 52% of a group with severe renal-hypertensive complications of diabetes is surprising. Two patients may have a demonstrated cardiomyopathy.
Cardiac sarcoid: a clinicopathologic study of 84 unselected patients with systemic sarcoidosis.
Authors: Silverman K J , Hutchins G M , Bulkley B H
Published: June 2012

Although sarcoid may involve the myocardium, there is little information on its incidence or significance. We studied 84 consecutive autopsied patients with sarcoidosis. The patients ranged in age from 18--80 years (average 46 years) and 61% were women; 23 (27%) of them had myocardial granulomas. In eight (35%) these were clinically silent, and in 15 (65%) there was a history of heart failure and/or arrhythmias and conduction defects. Of the 23 patients, only four (17%) had grossly evident, widespread myocardial lesions: three of these four (75%) had documented arrhythmias. All four had sudden, unexpected death at an average age of 36 years; in only two had sarcoid been suspected during life. The other 19 patients (83%) had microscopically evident granulomatous involvement. Of these, eight (42%) had a thythm or conduction disturbance and three (16%) sudden death, although none of those who suffered sudden death had a recognized rhythm or conduction disturbance. Nine (15%) of those without cardiac sarcoidosis had a rhythm or conduction disturbance and eight (13%) suffered a sudden death. The results show that although myocardial involvement occurs in at least 25% of patients with sarcoid, it most often involves a small portion of myocardium and is clinically silent. Since some of the 61 patients in whom myocardial lesions were not identified may still have had small microscopic granulomas, the true incidence of myocardial sarcoid may be even greater than suggested here. Rhythm and conduction disturbances are more common in the cardiac sarcoid group, but the findings suggest that only the small subset of patients with severe, grossly evident myocardial sarcoid are at increased risk for sudden death.
Myocardial release of lactate, inosine and hypoxanthine during atrial pacing and exercise-induced angina.
Authors: Kugler G
Published: June 2012

The coronary venous efflux of lactate, inosine and hypoxanthine during pacing-induced angina has been compared with myocardial extraction of the catabolites during exercise-induced angina. Inosine and hypoxanthine were analyzed by enzyme assay after separation by column chromatography. Myocardial lactate extraction at rest (15 +/- 9%, mean +/- SD) was converted to production levels (-34 +/- 26%) during pacing-induced angina (p less than 0.0005) and increased (24 +/- 13%) during exercise (p less than 0.05). The arterial values at rest (850 +/- 330 mumol/1) were unchanged during pacing and increased five-fold during exercise (4380 +/- 1860 mumol/1). The mean myocardial inosine extraction at rest (33 +/- 10%) was transformed to release values (-41 +/- 30%) during pacing (p less than 0.0005) as well as during exercise (-20 +/- 27%) (p less than 0.0005). The hypoxanthine extraction at rest (25 +/- 11%) decreased during pacing (-7.8 +/- 29%) (p less than 0.0025) and exercise (10 +/- 25%) (NS). The slight increase of arterial inosine and hypoxanthine values was not significant. Myocardially produced lactate, a sensitive marker of pacing-induced ischemia, was obscured by elevated arterial concentrations during exercise. However, inosine significantly correlated with lactate during pacing, and was useful in detecting ischemic myocardial energy deficiency during exercise-induced angina.
Diabetes and cardiovascular risk factors: the Framingham study.
Authors: Kannel W B , McGee D L
Published: June 2012

The impact of cardiovascular disease was compared in non-diabetics and diabetics in the Framingham cohort. In the first 20 years of the study about 6% of the women and 8% of the men were diagnosed as diabetics. The incidence of cardiovascular disease among diabetic men was twice that among non-diabetic men. Among diabetic women the incidence of cardiovascular disease was three times that among non-diabetic women. Judging from a comparison of standardized coefficients for the regression of incidence of cardiovascular disease on specified risk factors, there is no indication that the relationship of risk factors to the subsequent development of cardiovascular disease is different for diabetics and non-diabetics. This study suggests that the role of diabetes as a cardiovascular risk factor does not derive from an altered ability to contend with known risk factors.
Use of treadmill score to quantify ischemic response and predict extent of coronary disease.
Authors: Cohn K , Kamm B , Feteih N , Brand R , Goldschlager N
Published: June 2012

In this study we assessed whether various responses to exercise testing could be quantified in order to derive the probabilities of presence of coronary disease, and if present, to assess its severity. A treadmill score based on the exercise response was determined in 405 patients who had both treadmill tests and coronary angiograms. The score was derived using discriminant function analysis, by weighting and combining depth and configuration of ST depression (downsloping, horizontal or slowly upsloping), timing onset and duration of ischemia, grading ventricular arrhythmias, heart rate and blood pressure change, coexistence of exercise-induced chest pain and sex. The treadmill score was effective in detecting coronary disease (lesions with an greater than or equal to 50% narrowing), with a predictive accuracy (PA) (probability that a subject manifesting a positive test has disease) of 87%, a true negative rate (TNR) (probability of a subject with a negative test having no disease) of 80%, and sensitivity of 94%. The treadmill score also detected severe disease (triple-vessel, main left and/or greater than 90% proximal occlusion of the left anterior descending artery), with a PA of 73%, TNR of 79% and sensitivity of 82%. We conclude that the exercise response, expressed numerically as a treadmill score, permits analysis of most of the relevant data from exercise testing, increases test accuracy by 10-15% compared with standard criteria for treatmill test interpretation, and enables the derivation of probability statements for presence and severity of coronary disease. The validity of any prediction on the basis of exercise performance may thus be quantitatively judged.
Clinically practical lead systems for improved electrocardiography: comparison with precordial grids and conventional lead systems.
Authors: Lux R L , Burgess M J , Wyatt R F , Evans A K , Vincent G M , Abildskov J A
Published: June 2012

The use of limited leads for estimating total body surface potential distributions was investigated as a practical solution to the problem associated with extensive electrocardiographic sampling used in surface potential mapping. Two practical, limited lead sets of 32 leads each were derived and contrasted to a set of 30 precordial leads similar to those used in ST-segment and QRS mapping for estimating infarct size, and to a set of nine leads simulating those used in conventional 12-lead examinations. The two arrays, one of which excluded posterior sites for use in recumbent patients, showed little difference in ability to estimate 192 lead measured maps (average rms voltage error of 35 muV and average correlation coefficient of 0.97). The 30- and 9-lead arrays consistently showed twice the voltage (72 muV) and poorer pattern estimation (average correlation coefficient of 0.91) than either of the 32 lead arrays. These findings indicate the need for 20-35 properly located electrodes for accurate total body surface potential estimation. They also show that there is no difference in the abilities of a 30-lead precordial array and conventional leads to estimate maps.
Variables predictive of survival in patients with coronary disease. Selection by univariate and multivariate analyses from the clinical, electrocardiographic, exercise, arteriographic, and quantitative angiographic evaluations.
Authors: Hammermeister K E , DeRouen T A , Dodge H T
Published: June 2012

A progression of univariate followed by multivariate analyses was applied to 46 variables selected from the clinical examination, exercise test, coronary arteriography, and quantitative angiographic assessment of left ventricular function in patients with coronary disease to determine those variables most predictive of survival. For the 733 medically treated patients, the final Cox's regression analysis showed that the left ventricular ejection fraction was most predictive of survival, followed by age, number of vessels with stenosis(es) greater than or equal to 70%, and ventricular arrhythmia on the resting electrocardiogram. For the 1870 surgically treated patients, ventricular arrhythmia on the resting electrocardiogram was most predictive of survival followed by ejection fraction, heart murmur, left main coronary artery stenosis greater than or equal to 50%, and use of diuretic agents.
Carotid baroreflex function in young men with borderline blood pressure elevation.
Authors: Eckberg D L
Published: June 2012

Carotid baroreflex function was assessed in 10 normotensive young men and 20 age-matched subjects with borderline hypertension (successive blood pressures above and below 140/90 mm Hg) by measuring sinus node responses to brief neck suction. Subjects with borderline hypertension were divided into two equal groups according to their average systolic arterial pressures. Baroreflex responses were reset to function at higher pressure levels than normal in subjects with mild borderline hypertension, but reflex sensitivity was normal. Responses were also reset in subjects with more severe borderline hypertension, but reflex was subnormal. The results suggest that a gradation of baroreflex responsiveness exists among patients classified as having borderline hypertension: Subnormal responsiveness was found in those subjects whose resting average systolic arterial pressure was greater than or equal to 140 mm Hg.
Aspirin-induced increase in collateral flow after acute coronary occlusion in dogs.
Authors: Capurro N L , Marr K C , Aamodt R , Goldstein R E , Epstein S E
Published: June 2012

Aspirin (acetylsalicylic acid) has inhibitory effects on platelet function and prostaglandin synthesis. Since alterations in either platelet function or prostaglandin-mediated vascular responses could influence blood flow to ischemic myocardium, we tested the effects of aspirin on coronary collateral flow after acute occlusion of the left anterior descending coronary artery in dogs. Aspirin dose (600 mg i.v.) consistently inhibited in vitro ADP-induced platelet aggregation. In 13 open-chest dogs, regional myocardial blood flows (radioactive microsphere technique) were determined at 5 minutes and 4 hours after occlusion). In seven of these dogs, aspirin (600 mg i.v.) was administered 1 hour before occlusion. In the aspirin-treated dogs, collateral flow increased significantly (p less than 0.05), from 0.09 +/- 0.02 ml/min/g at 5 minutes to 0.15 and 0.02 ml/min/g 4 hours after occlusion. Collateral flow was not significantly altered over 4 hours in control dogs. The aspirin-induced increase in collateral flow was confined to epicardium (12 +/- 4% of normal zone flow at 5 minutes to 23 +/- 4% at 4 hours after occlusion).
Aberrant coronary artery origin from the aorta. Report of 18 patients, review of literature and delineation of natural history and management.
Authors: Liberthson R R , Dinsmore R E , Fallon J T
Published: June 2012

To clarify the natural history and management of patients with aberrant origin of a coronary artery from the aorta, we reviewed 18 patients whose right (RCA) or left (LCA) coronary artery arose aberrantly and passed between the aorta and right ventricular infundibulum. Nine patients had aberrant LCA. Three young males died suddenly after exertion, each with proximal focal LCA stenosis. None of the six adults with angina (ages 36-70 years) studied angiographically had proximal LCA stenosis. Unlike the young, "sudden death-prone" patients in whom coronary bypass of proximal stenosis may have prophylactic value, our older patients with aberrant LCA did not have proximal stenosis or sudden death, and therefore LCA bypass for sudden death prophylaxis is not warranted. Nine patients (ages 18-60 years) had aberrant origin and course of the RCA. Seven patients studied angiographically because of angina had no focal proximal RCA stenosis, but two patients had hypoplastic RCA ostia. Although a potential concern in these latter patients, sudden death has not been reported with aberrant RCA, therefore in the absence of syncope, RCA bypass for sudden death prophylaxis is not indicated.
Regional ejection fraction: a quantative radionuclide index of regional left ventricular performance.
Authors: Maddox D E , Wynne J , Uren R , Parker J A , Idoine J , Siegel L C , Neill J M , Cohn P F , Holman B L
Published: June 2012

Radionuclide measurements of regional left ventricular ejection fraction were evaluated as a quantitative index of regional left ventricular function. Left ventricular regional ejection fractions were derived from background-corrected, time-activity curves in 43 patients assessed by both gated equilibrium radionuclide angiocardiography and left ventricular contrast angiography. From a single, modified left anterior oblique projection, the regional change in background corrected counts was determined in each of three anatomic regions. The normal range for regional radionuclide ejection fraction was determined in 10 patients with normal contrast ventriculograms and without obstructive coronary artery disease at coronary arteriography. Regional ejection fraction was compared with percent segmental axis shortening and extent of akinetic segments in corresponding regions of the contrast ventriculogram. Radionuclide and roentgenographic methods were in agreement as to the presence or absence of abnormal wall motion in 83 of 99 left ventricular regions (84%) in 33 patients evaluated prospectively. Comparison of regional ejection fraction demonstrated significant differences between regions with roentgenographically determined normokinesis (75 +/- 3%, mean +/- SEM), hypokinesis (44 +/- 3%, p less than 0.0005) and akinesis (24 +/- 5%, p less than 0.005). We conclude that the left ventricular regional ejection provides a reliable quantitative assessment of regional left ventricular performance.
Effect of left ventricular akinesis on cardiac performance. Experimental study using a new model.
Authors: Maggs P R , Nener T P , Ellis F H
Published: June 2012

The understanding of left ventricular failure and cardiogenic shock after myocardial infarction has been facilitated by a two-component model proposed by Swan et al. which views the left ventricle as consisting of a clearly defined infarcted portion and a normally functioning remainder. Although appealing, this model is difficult to substantiate experimentally. We describe a new experimental preparation in which the infarct is stimulated by replacing part of the left ventricular wall with an inert patch of Dacron material. In 18 dogs studied after replacing varying amounts of left ventricular contractile mass with noncontractile patches, the left ventricular end-diastolic pressure rose in proportion to the size of the patch. Contractility was unchanged, and overall left ventricular pump function was normal. These data support the conceptual model. The experimental preparation is applicable to other studies of left ventricular akinesis.
Echocardiographic estimation of ventricular hypoplasia in complete atrioventricular canal.
Authors: Mehta S , Hirschfeld S , Riggs T , Liebman J
Published: June 2012

Echocardiograms from 10 patients with complete atrioventricular canal (CAVC) were compared with autopsy specimens to determine the capabilities of echocardiography in identifying patients with ventricular hypoplasia. On the basis of echographic ventricular size, patients could be divided into three groups: 1) "balanced" CAVC patients had both increased right and left ventricular end-diastolic dimensions (RVED and LVED) and an increased RVED/LVED ratio; 2) "dominant left ventricular" CAVC patients had an increased LVED and small or normal RVED and a diminished RVED/LVED ratio; 3) "dominant right ventricular" CAVC patients had an increased RVED, but small LVED, and increased RVED/LVED. There was complete agreement between echographic ventricular dominance and pathologic findings. This study demonstrates that echocardiography may be valuable in assessing ventricular dominance in the presence of CAVC.
Mitral valve closure in atrial flutter.
Authors: Greenberg M A , Herman L S , Cohen M V
Published: June 2012

12 patients who had atrial flutter without clinical, echocardiographic or angiographic evidence of aortic insufficiency were studied with simultaneous echo- and phonocardiograms. In patients with high-grade atrioventricular (AV) block, the mitral valve opened and closed with each flutter wave. Of seven patients, two had persistent and five had intermittent early mitral valve closure before QRS inscription. In five patients (three with 2:1 AV block) the mitral valve closed on time. In one patient with a mitral valve prosthesis, echocardiography and cinefluorography demonstrated closure during mid-diastole, with reopening in late diastole after a flutter wave. Final valve closure occurred before the onset of the QRS, and each closure was associated with a click. Simultaneous phonocardiographic analysis in these patients demonstrated that the first heart sound intensity was inversely related to the degree of mitral valve preclosure. This relationship was independent of the length of the RR interval. Thus, atrial flutter independent of any other cause of abnormal hemodynamics may produce early mitral valve closure. The echocardiographic finding of premature mitral arrhythmias, may not have the same diagnostic or prognostic significance previously described in patients with sinus rhythm and normal AV conduction.
Impaired maximal rate of left ventricular relaxation in patients with coronary artery disease and left ventricular dysfunction.
Authors: Papapietro S E , Coghlan H C , Zissermann D , Russell R O , Rackley C E , Rogers W J
Published: June 2012

It has been suggested that the rate of left ventricular (LV) relaxation is related to the inotropic state, end-systolic fiber length and peak LV pressure, but little information is available regarding the rate of LV relaxation in patients with coronary artery disease (CAD) and LV dysfunction. To assess the rate of LV relaxation we obtained high-fidelity LV pressure measurements with manometer-tip catheters in 39 patients. The signal was analyzed by a digital computer to yield the maximal rate of pressure rise (pos dP/dt) and the maximal rate of pressure fall (neg dP/dt). Selective coronary arteriography and biplane LV angiography with determination of LV volumes, ejection fraction (EF) and percent abnormally contracting segments (ACS) when present, were performed in all patients. In 10 patients with normal LV function (EF greater than 0.50, no asynergy) mean neg dP/dt (2074 +/- 121 mm Hg/sec) was significantly (p less than 0.01) greater than in 29 patients with CAD and LV dysfunction (1695 +/- 66 mm Hg/sec). In nine patients with LV dysfunction and EF less than 0.35, mean neg dP/dt was reduced to 1405 +/- 107 mm Hg/sec, significantly (p less than 0.01) lower than in patients with normal LV function. Neg dP/dt correlated well with pos dP/dt (r = 0.75), with EF (r = 0.74), and with ACS (r = -0.74), and less well with LV end-systolic volume (r = 0.67). There was very poor correlation between neg dP/dt and peak LV pressure (r = 0.30). These data suggest that the rate of LV relaxation, as assessed by neg dP/dt, is impaired in patients with CAD and LV dysfunction, and the extent of impairment is related to the severity of the dysfunction as determined hemodynamically by pos dP/dt, and angiographically by EF and ACS. In these patients the maximal rate of LV relaxation is inversely related to LV end-systolic volume, and is not related to peak LV pressure.
Graphic Representation of Electrocardiographic Leads by Means of Fluid Mappers
Authors: MCFEE RICHARD , STOW ROBERT M. , JOHNSTON FRANKLIN D.
Published: June 2012

A new method for the study of electrocardiographic leads is described. It makes use of plaster models having the same shape as the body in the frontal (or other) planes through which water flows in sheets. The flow of water is approximately analogous to the flow of electric currents through the body, and the flow lines are made visible by small crystals of soluble dye. If fluid passes in and out of the flow space from points that correspond to the location of electrodes of the electrocardiographic leads, the flow lines may be used to study the effects that electromotive forces arising in the heart have on these leads. With these models it is possible to study many different kinds of leads and the effects of variations of body shape, position of the heart, and electric conductivity of the tissues on them. Preliminary observations largely concerned with standard, unipolar extremity and chest leads are reported.
Neurohemodynamics of Pulmonary Edema
Authors: SARNOFF STANLEY J. , SARNOFF L. CHARLOTTE
Published: June 2012

The authors criticize the concept of "neurogenic pulmonary edema" as resulting from an increase in pulmonary capillary permeability mediated by nerve impulses to those vessels. They show that one of the methods used to produce "neurogenic pulmonary edema" markedly elevates systemic and pulmonary vascular pressures, the latter to levels high enough to produce pulmonary edema. Vagotomy and/or upper thoracic sympathectomy do not prevent the elevation of pulmonary vascular pressures. Blockade of the sympathetic innervation to the systemic vascular bed lowers the systemic vascular pressures and brings the pulmonary vascular pressures back to normal. The control of pulmonary vascular pressures by sympathetic impulses to the systemic vascular bed is demonstrated.
The Circulatory Effects of Roniacol
Authors: ROBACK G. S. , IVY A. C.
Published: June 2012

The vasodilatory effects of nicotinic alcohol tartrate (Roniacol) were tested on 12 normal adult males, utilizing digital venous occlusion plethysmography, brachial and digital artery oscillometry and flicker photometry. Orally administered Roniacol in single doses up to 200 mg. has no significant effect on the auscultatory blood pressure, pulse rate, or peripheral arterial circulation of normal individuals.
The Action of Norepinephrine, Epinephrine and Isopropyl Norepinephrine on the Rhythmic Function of the Heart
Authors: NATHANSON MORRIS H. , MILLER HAROLD
Published: June 2012

The actions of norepinephrine and isopropyl norepinephrine on the rhythmic property of the heart were studied and compared with that of epinephrine. Norepinephrine does not abolish cardiac standstill by carotid sinus stimulation, has no effect on the ventricular rate of heart block and induces a sinus bradycardia. Isopropyl norepinephrine acts similarly to epinephrine in that it abolishes the induced cardiac standstill, increases the ventricular rate of heart block and produces a sinus tachycardia. In the treatment of cardiac arrest, the isopropyl compound appears to possess optimum features as it is very potent in the prevention of cardiac standstill and does not predispose to ventricular fibrillation.
Further Studies on the Effect of Arteriovenous Fistulas and Elevations of Sinus Pressure on Mortality Rates Following Acute Coronary Occlusions
Authors: SMITH GEORGE , DEMMING JAMES , ELEFF MORTON , ECKSTEIN RICHARD W.
Published: June 2012

Observations were made on the mortality rates within the first hour following acute ligation of the circumflex artery. The experiments were divided into the following groups: (1) those with arteriovenous fistulas, (2) those with elevation of coronary sinus pressure, (3) those with complete coronary sinus occlusion, and (4) those with arterialization of the coronary sinus. There was a mortality of 70 per cent in the first group, 30 per cent in the second group, 40 per cent in the third group, and no deaths in the fourth group. The results indicate that arterialization of the coronary sinus provides the greatest protection against ventricular fibrillation and that such arterialization provides the only practical means of chronically elevating coronary sinus pressures to effective levels.
The Inhibition of Coronary Atherosclerosis by Estrogens in Cholesterol-Fed Chicks
Authors: PICK R. , STAMLER J. , RODBARD S. , KATZ L. N.
Published: June 2012

Chronic administration of estrogens parenterally inhibits coronary atherogenesis in cockerels fed a cholesterol-supplemented diet, although no such prophylactic effect was observed against aorta atherogenesis. This protection of the coronary vessels is associated with depression of the plasma total cholesterol-lipid phosphorus ratio toward normal levels consequent upon estrogen-induced hyperphospholipemia.
Observations on the Fate of Ingested Cholesterol in Man
Authors: BIGGS M. W. , KRITCHEVSKY D. , COLMAN D. , GOFMAN J. W. , JONES H. B. , LINDGREN F. T. , HYDE G. , LYON T. P.
Published: June 2012

Tritium-labeled Cholesterol has been used to study several aspects of exogenous cholesterol metabolism in man. The rate and magnitude of the appearance of ingested cholesterol in the various blood compartments has been followed. Fecal excretion of the labeling material was measured. Cholesterol of dietary origin was demonstrated in a human atherosclerotic aorta.
Surgical Treatment of Coarctation of the Aorta in a Ten Week Old Infant: Report of a Case
Authors: KIRKLIN JOHN W. , BURCHELL HOWARD B. , PUGH DAVID G. , BURKE EDMUND C. , MILLS STEPHEN D.
Published: June 2012

Although most patients with coarctation of the aorta survive to early adult life, it has been adequately demonstrated that some patients die in infancy and early childhood as a result of their coarctation. In selected cases, then, operation is advisable at a very early age. Cardiac failure in a 10 week old infant necessitated operation at this age in the case reported.
The Mechanism and Incidence of Cardiovascular Changes in Paget's Disease (Osteitis Deformans)
Authors: SORNBERGER C. FRANKLIN , SMEDAL MAGNUS I.
Published: June 2012

Although abundant evidence of concomitant cardiovascular disease is scattered throughout the literature on osteitis deformans, appreciation of the etiologic relationship between the two diseases has been lacking. This paper shows that cardiovascular disease accompanying extensive osteitis deformans may result from: (1) excessive demand on the heart from increased vascularity of affected bones; (2) the influence of concomitant arteriosclerosis apparently exceeding the normal for the age concerned; (3) characteristic thoracic spine deformities which compromise cardiorespiratory function, and (4) hypertension. Fifty-four cases are presented. The incidence of cardiovascular disease exceeds that in the general population of the same age and corresponds with the extent of skeletal involvement.
Increased Urinary Urobilinogen Following Acute Myocardial Infarction
Authors: EVANS JOHN M. , WOOD ORLYN H. , BREW ELEANOR M.
Published: June 2012

A study was conducted of the serial urinary urobilinogen excretion in patients with acute myocardial infarction, using Watson's semiquantitative method. Increased excretion was observed in some 90 per cent of the subjects with infarcts confirmed by the electrocardiogram and in more than half of the subjects where the electrocardiogram was not conclusive. The degree and duration of increased urinary urobilinogen had no apparent bearing upon prognosis. It is postulated that the altered urobilinogen excretion is induced by hepatic effects of the stress reaction incident to acute myocardial infarction.
Left axis deviation: a reassessment.
Authors: Perloff J K , Roberts N K , Cabeen W R
Published: June 2012

This report deals with the ramifications of the concept of left axis deviation. In early life, the leftward shift of the frontal plane QRS axis is determined chiefly, if not solely, by the relative weights of the ventricles. Once adult ventricular weight ratios are reached, there is a long period of axis stability, then a gradual leftward drift of the QRS, governed principally by left anterior fascicular conduction. Thus, the normal QRS axis is age-dependent, and left axis deviation must be considered accordingly.
Temporary left ventricular bypass: factors affecting patient survival.
Authors: Bernhard W F , Berger R L , Stetz J P , Carr J G , Colo N A , McCormick J R , Fishbein M C
Published: June 2012

Circulatory support (range, 2 hours-8 days) was undertaken in eight cardiac surgical patients (with two survivors) exhibiting intractable cardiogenic shock. A paracorporeal, pneumatic, xenograft-valve pump was interposed between the left ventricular apex and ascending aorta. Pumping lowered left atrial and ventricular pressure while maintaining cardiac output (1.8--2.6 l/min/m2). Following implantation, plasma hemoglobin and erythrocyte mechanical fragility values were elevated but decreased to normal when renal function was not impaired. Mild thrombocytopenia was noted in three patients and was severe in five others with persistent hemorrhage. Anticoagulation agents were used during tapering of pump flow (three patients) after 100, 105 and 120 hours of bypass. Otherwise, for the major portion of the interval of mechanical circulatory support, anticoagulants were not administered. Despite this fact, no systemic embolization was detected in any of the patients. It appears that assist pump support can be life-saving in acute left ventricular failure in patients following cardiac surgery.
Emergency coronary artery revascularization: a possible therapy for acute myocardial infarction.
Authors: Phillips S J , Kongtahworn C , Zeff R H , Benson M , Iannone L , Brown T , Gordon D F
Published: June 2012

Cardiac muscle death caused by coronary artery occlusion is a dynamic process that often takes hours or days. Emergency revascularization (saphenous vein bypass graft (SVBG) during acute myocardial infarction (MI) can interrupt myocardial necrosis, salvage ischemic myocardium and revascularize vessels with obstructive lesions not involved in the MI. In this report we describe a preliminary experimental study of 75 patients in which emergency SVBG was the therapy for acute MI. Group 1, 16 patients, required vasoactive medications and/or intraaortic balloon pumping to maintain their blood pressure preoperatively. There was one operative death and two late deaths. Group 2 consisted of 59 hemodynamically stable patients. There were no deaths. The average preop CPK in group 1 was 892 vs 504 in group 2 (p greater than 0.05). Surgical techniques were routine. The average time from the onset of chest pain that continued to surgery was 6.5 hours. Forty patients were restudied. Post- vs presurgical hemodynamics revealed ejection fraction increased by 34% (p greater than 0.05), left ventricular end-diastolic pressure reduced by 40% (p greater than 0.01). End-systolic and end-diastolic volume reduced by 30% (p greater than 0.05), and 15% (p greater than 0.01), and stroke volume improved 25% (p greater than 0.05). Operative mortality was 1.3% and late mortality 2.8%. These results suggest that cautious continued trial of emergency SVBG in patients with evolving MI is warranted.
In vitro hydrodynamic comparison of mitral valve bioprostheses.
Authors: Gabbay S , McQueen D M , Yellin E L , Frater R W
Published: June 2012

With the use of the pulse duplicator built in our laboratory, the hydrodynamic characteristics of three sizes of the four commercially available mitral bioprostheses, Hancock, Carpentier-Edwards, Angell-Shiley, and Ionescu-Shiley, were studied and compared. A wide range of performance was found: for example, during pulsatile testing, at peak flow of 15 1/min (corresonding to a normal resting cardiac output) transvalvular gradients varied from as high as 20 mm Hg (Angell-Shiley) to 5 mm Hg(Ionescu-Shiley) in the 25 mm mounting diameter size. Effective orifice areas (EOA) are significantly different in valves of the same mounting size, e.g., at peak flows of 20 1/min, the Ionescu-Shiley 25 provides an EOA of 1.7 cm2 while the Angell-Shiley provides only 1.17 cm2. The EOAs of all bioprostheses have been found to increase with increasing flow (e.g., from 10--30 1/min peak flow, the Hancock 25 changed from 1.25 cm2 to 1.50 cm2). The Gorlin formula, as constituted for calculating the area of stenotic mitral valves, is inappropriate for prosthetic valves. But the discharge coefficients of the bioprostheses have been found to be around 1 when the planimetered area of the open valve orifice is determined at a given flow. By using this discharge coefficient, the Gorlin formula will give an excellent estimate of the true orifice area of mitral bioprostheses.