bluuebunny/crossref_metadata_2025 huggingface dataset:
Assessment of Cardiac Contractility
Authors: MASON DEAN T. , BRAUNWALD EUGENE , COVELL JAMES W. , SONNENBLICK EDMUND H. , ROSS JOHN
Published: June 2012

It was considered that the relationship between dp/dt and simultaneously developed pressure during the course of isovolumic contraction might afford a more accurate measure of contractility than the maximum rate of intraventricular pressure rise (peak dp/dt). In six cat papillary muscles contracting isometrically from any given preload, the ratio of the rate of tension development (dT/dt) to simultaneously occurring isometric tension always varied directly with the contractile state. This ratio rose slightly as preload was increased, but it was not affected by changes in afterload. In 17 experiments in an intact canine heart preparation in which left ventricular end-diastolic pressure was constant, dp/dt at any given pressure during isovolumetric contraction again was observed to be a function of the contractile state when the latter was enhanced by norepinephrine and acetylstrophanthidin. High-fidelity left ventricular pressures and dp/dt were recorded throughout isovolumic contraction in eight patients. Isoproterenol and exercise raised the level of dp/dt at any given pressure prior to ejection. Interventions known to alter ventricular loading but not to influence the contractile state, such as elevation of ventricular end-diastolic pressure by leg raising and increases in aortic pressure induced by methoxamine, did not influence this relation significantly. In conclusion, the determination of dp/dt and intraventricular pressure throughout isovolumic contraction in the presence of variable arterial pressure and small changes of preload provides a useful, simple, and experimentally verified approach to the assessment of alterations of the contractile state of the heart in intact man.
Combined Papillary Muscle and Left Ventricular Wall Dysfunction as a Cause of Mitral Regurgitation
Authors: MITTAL ARUN K. , LANGSTON MANLY , COHN KEITH E. , SELZER ARTHUR , KERTH WILLIAM J.
Published: June 2012

Papillary muscle infarction was produced in 16 mongrel dogs by placing sutures around the base of one of the papillary muscles. In addition, patchy infarction of the adjacent left ventricular wall was produced by placing an Ameroid constrictor around the appropriate coronary artery. Mitral insufficiency developed in 14 of these animals; it was severe in four and mild to moderate in ten. Mitral insufficiency was not produced by isolated infarction of a papillary muscle or by isolated infarction of the left ventricular wall.

It is concluded that papillary muscle infarction alone does not lead to mitral regurgitation, but that papillary; muscle dysfunction acts in concert with left ventricular wall dyskinesia or dilatation to produce mitral valve incompetency.
Influence of Aortic Coarctation on Pulsatile Hemodynamics in the Proximal Aorta
Authors: O'ROURKE MICHAEL F. , CARTMILL TIMOTHY B.
Published: June 2012

Pressure and flow were recorded in the ascending aorta of three dogs with aortic coarctation, induced surgically 3 months previously, and in three control litter mates. From these data were derived input impedance of the systemic circulation, pulsatile and steady components of external heart work, aortic systolic pressure-time index, and mean systolic and mean diastolic pressures. Results were correlated with intraoperative measurements of aortic pressure in three young patients with aortic coarctation and with records taken in another 24 patients during diagnostic catheterization. Distinctive changes in aortic impedance with coarctation were explained in terms of altered peripheral reflection. Such changes were responsible for characteristic alteration in central aortic pressure pulse contour and for change in other parameters, indicating impaired arterial function in accepting pulsatile flow from the heart. Such changes in the cushioning function appear responsible for many clinical features and complications of aortic coarctation. Surgery is probably justified for restoration of the normal cushioning function of the arterial system as well as for reduction of resistance and mean arterial pressure.
Dimensional Changes of the Human Left Ventricle Prior to Aortic Valve Opening
Authors: KARLINER JOEL S. , BOUCHARD RICHARD J. , GAULT JAMES H.
Published: June 2012

Previous studies of the dynamic geometry of the left ventricle have yielded conflicting results concerning shape changes during the preejection period. Accordingly, left ventricular dimensional changes prior to aortic valve opening in man were analyzed using high-speed biplane cineradiograms exposed in the frontal and lateral projections. In each projection the long axis and three chords perpendicular to it were measured. In six patients without left ventricular disease there was a mean decrease in equatorial diameter of approximately 1 mm before aortic valve opening (
P
< 0.05), without significant change in the long axis, causing an apparent volume decrease of 4.0 ml or 2.8% of end-diastolic volume (EDV). In five patients with wall motion disorders secondary to coronary artery disease the equatorial diameter decreased by an average of 1.5 mm and volume was diminished by 8.3 ml or 3.9% of EDV. In four of seven patients with primary myocardial disease, an increase in the equatorial diameter and a basal chord occurred, while the apical chord decreased, suggesting nonhomogeneous myocardial involvement. In eight patients with mitral regurgitation, the reduction in equatorial diameter averaged 2.8 mm and volume decreased by 16.7 ml or 8.0% of EDV. In normal patients the occurrence of circumferential fiber shortening prior to aortic valve opening under basal conditions can result in as much as a 9% underestimation of contractile element velocity calculated from dp/dt, whereas in patients with mitral regurgitation this figure may be as high as 31%. These studies indicate that, in man, expansion at the minor equator during the preejection period occurs only under highly abnormal conditions. They further suggest that the reductions in shape and volume prior to aortic valve opening may be significant relative to mechanical analyses of this phase of contraction.
Longitudinal Hemodynamic and Clinical Study of Mitral Stenosis
Authors: DUBIN ALBERT A. , MARCH HAROLD W. , COHN KEITH , SELZER ARTHUR
Published: June 2012

Forty-two patients with pure mitral stenosis underwent a prospective, longitudinal study with two or more cardiac catheterizations 1 to 10 years apart and without intervening surgical treatment. The majority of patients had not previously had mitral valve surgery; in 16, the period of observation followed valvotomy. Twenty-seven patients showed evidence of progressive obstruction of the mitral valve; 15 showed no change in the calculated mitral valve area. In the group of patients with
progressive
disease (stenosis or restenosis) there was a consistent clinical and hemodynamic deterioration: 25 of the 27 showed increasing disability. In the
nonprogressive
group, seven of the 15 showed increasing symptomatology, most often related to the development of atrial fibrillation and a fall in cardiac output. Possible causes for the different course of mitral stenosis in the two groups are reviewed. The probability that trauma due to altered flow patterns through a stenotic valve produces progressive stenosis is suggested.
Resting and Postexercise Apexcardiogram Correlated with Maximal Treadmill Stress Test in Normal Subjects
Authors: ARONOW WILBERT S. , CASSIDY JOHN , UYEYAMA RONALD R.
Published: June 2012

Ninety-eight normal subjects, mean age 51 years, who had a maximal treadmill stress test had a satisfactory apexcardiogram at rest and after a double Master's test. The mean resting a-wave ratio was 11.6% in 13 normal subjects with an abnormal maximal treadmill test and 7.8% in 85 normal subjects with a normal treadmill test (
P
< 0.001). The mean postexercise a-wave ratio was 19.7% in 13 normal subjects with an abnormal treadmill test and 12.8% in 85 normal subjects with a normal treadmill test (
P
< 0.001). Four of 13 normal subjects (31%) with an abnormal treadmill test had a resting a-wave ratio of ≥15% compared with two of 85 normal subjects (2%) who had a normal treadmill test (
P
< 0.001). Seven of 13 normal subjects (54%) with an abnormal treadmill test had a postexercise a-wave ratio of ≥20% compared with eight of 85 normal subjects (9%) who had a normal treadmill test (
P
< 0.001).
Influence of Acute Variations in Hematocrit on the QRS Complex of the Frank Electrocardiogram
Authors: ROSENTHAL AMNON , RESTIEAUX NORMA J. , FEIG STEPHEN A.
Published: June 2012

The influence of acute variations in hematocrit on the QRS complex of the Frank scalar electrocardiogram was studied in 31 patients with severe polycythemia secondary to cyanotic congenital heart disease and in eight patients with anemia due to thalassemia. Moderate reduction of the hematocrit in the polycythemic group resulted in a significant increase in the magnitude and a delay in both left maximal spatial voltage (LMSV) and maximal anterior force. Raising the hematocrit in the anemic group decreased the magnitude of LMSV and maximal anterior force. A change in the orientation of the spatial vector frequently accompanied induced variations in the hematocrit. Experimental and theoretical studies suggest that alterations in the hematocrit and, hence, intracardiac electrical resistivity distort the magnitude and orientation of the surface-recorded QRS voltages. It is postulated that the effect of high intracavitary blood hematocrit in polycythemia in reducing early QRS voltages is due to its influence on radial myocardial excitation propagated from endocardium to epicardium. Anemia, on the other hand, enhances the voltages due to radial spread of impulses in the myocardium, resulting in an increased magnitude of the LMSV and usually also of the maximal anterior force.
Myocardial Infarction in Young Women with Normal Coronary Arteriograms
Authors: GLANCY D. LUKE , MARCUS MELVIN L. , EPSTEIN STEPHEN E.
Published: June 2012

Two women, ages 34 and 36 years, suffered an acute transmural anterior myocardial infarction accompanied by typical ECG and serum enzyme changes. At the time of selective cinecoronary arteriography 29 and 57 months later, however, neither had demonstrable narrowing of any coronary artery. Both have persistent ECG changes of an anterior infarct and markedly diminished contractions of a large segment of the anterior wall and apex on left ventriculogram. Neither before nor after infarction has either patient experienced angina pectoris. Both patients are premenopausal, and neither of them has diabetes, hypertension, obesity, valvular heart disease, a lipoprotein abnormality, or a family history of premature coronary arterial disease. Both smoke cigarettes. At the time of infarction one patient was taking an oral contraceptive and the other was 11-days postpartum. The pathogenesis of the myocardial infarcts in these patients is unknown. Embolization or in situ thrombosis of a previously normal anterior descending coronary artery with subsequent clot lysis would explain the infarcts, the normal coronary arteriograms, and the absence of prior or subsequent angina.
"Color Vectorcardiogram" Recorded with a Specially Designed Apparatus for Spatial Representation By Coloring
Authors: KINOSHITA SHINJI , KOBAYASHI TADASHI
Published: June 2012

Using a vectorcardiogram only in the horizontal plane, spots of the vector loop were colored according to a specially designed apparatus, so that changes in height of the spots could be indicated by differences in those colors. Consequently, the spatial vectorcardiogram was represented by a single, colored graph, i.e. a "color vectorcardiogram." By the use of this graph, an attempt was made to facilitate the understanding of vectorcardiography for common clinicians. The colors corresponding to the heights of the deflections in the Y axis were chosen as follows: in a level of the origin or zero point of the vector loop, yellow; above the origin, reddish colors; and below the origin, bluish colors.
S-T-Segment Depression with Near-Maximal Exercise in Detection of Preclinical Coronary Heart Disease
Authors: KATTUS ALBERT A. , JORGENSEN CHARLES R. , WORDEN RALPH E. , ALVARO ANTHONY B.
Published: June 2012

Three hundred and fourteen male insurance underwriters had near-maximal treadmill exercise tests after having been evaluated for coronary risk factors. Thirty subjects developed ischemic-type S-T-segment depression during or after exercise not associated with anginal pain. The abnormal electrocardiographic response correlated significantly with elevated serum cholesterol, abnormal rest electrocardiogram, and history of cardiac symptoms; but not with smoking, high blood pressure, physical inactivity, or family history of coronary disease.

In 2.5 years' follow-up there have been among the 30 ischemic responders to exercise testing three coronary deaths, four myocardial infarctions, two who developed angina pectoris, and one who had a coronary angiogram showing multiple obstructions. None of the normal responders to exercise testing has had a coronary event.
Mechanism of Increased Sodium Reabsorption during Propranolol Administration
Authors: NIES ALAN S. , MCNEIL JAMES S. , SCHRIER ROBERT W.
Published: June 2012

The mechanism of diminished sodium excretion induced by propranolol was investigated in the dog. Propranolol (0.3 to 5 mg/kg) was given intravenously in a bolus to 16 dogs, eight of which had the renal perfusion pressure controlled by a suprarenal aortic clamp. In another group of six dogs propranolol (0.1 to 5 , µg/kg/min) was infused into one renal artery for 45 min. Cardiac output (dye dilution), mean arterial and right atrial pressures, heart rate, renal clearances of inulin, creatinine, and para-aminohippurate, and sodium excretion were measured. Total peripheral resistance, central blood volume, stroke volume, renal plasma flow, renal blood flow, renal vascular resistance, glomerular filtration rate, and filtration fraction were calculated.

Intravenous propranolol resulted in significant decreases in cardiac output (–25%) and heart rate (–14%) and increases in total peripheral resistance (28%) and renal vascular resistance (37%). Renal blood flow decreased by 25% and filtration fraction increased 21% as urinary sodium excretion diminished 36%. Glomerular filtration did not change significantly. Infusions of propranolol into one renal artery resulted in either no change in sodium excretion or bilateral changes; thus an intrarenal effect of the drug was not demonstrable.

The data suggest that the changes in renal hemodynamics associated with propranolol administration are secondary to alterations in systemic hemodynamics, particularly a decrease in cardiac output. These alterations in renal hemodynamics, including an increase in renal vascular resistance and filtration fraction, most likely account for the decrease in sodium excretion rather than a direct effect of propranolol on sodium reabsorption.
Mortality Study of the Significance of Extrasystoles in an Insured Population
Authors: RODSTEIN MANUEL , WOLLOCH LEON , GUBNER RICHARD S.
Published: June 2012

The prognostic significance of extrasystoles was evaluated in 712 insured persons with this finding who were followed for an average period of 18 years. At the end of the study 356 persons were alive and 125 were dead. Two hundred and thirty-one persons had terminated their policies at a prior date by maturity or discontinuance and were not followed further. Although the lack of follow-up to 1968 of this latter group imposes limitations on the results and conclusions of the study, their exclusion resulted in no significant change in the mortality ratio of the remaining group of 481 persons followed to death or the anniversary of their policies in 1968.

The observed mortality ratios showed no appreciable increase in a group of 604 individuals who were considered to have a normal life expectancy except for the presence of extrasystoles at the time of evaluation for insurance. Similar normal mortality ratios were observed in subgroups with simple and complex supraventricular and ventricular extrasystoles. There was no appreciable difference in mortality when those under 40 and those 40 years of age and over at the time of discovery of extrasystoles were compared. There was no significant difference in mortality between those who responded to exercise with an increase in the number of extrasystoles and those who had no change or a decrease immediately after exercise. An increase in the number of extrasystoles per minute was associated with an increase in mortality. There was a low incidence of sudden death among those with supraventricular extrasystoles.

Ventricular extrasystoles, particularly those of complex types, were associated with a high incidence of death from myocardial infarction, often of a sudden nature, particularly in persons under the age of 56 years. There were too few cases of the individual types of complex ventricular extrasystoles to determine whether this was a characteristic of the group as a whole or of one or more of its constituent types. Ventricular extrasystoles in the presence of other cardiac abnormalities and/or elevation of the blood pressure were associated with an increase in mortality. The mortality experience in such persons was distinctly higher than in those with similar degrees of substandard expected mortality whose abnormalities were not of a cardiovascular nature.
Cardiac Arrest in the Critically Ill
Authors: CAMARATA SAMUEL J. , WEIL MAX HARRY , HANASHIRO PAUL K. , SHUBIN HERBERT
Published: June 2012

The events preceding cardiac arrest were investigated in 132 critically ill patients on the basis of the hemodynamic, respiratory, and metabolic status prior to cardiac arrest. Approximately one-half of the patients had respiratory acidosis prior to cardiac arrest and only one of these patients ultimately survived. An additional one-fourth had metabolic acidosis due to progressive perfusion failure (shock), and none survived. In the remaining one-fourth, an immediate catastrophic and potentially preventable event accounted for cardiac arrest, and all but one of the long-term survivors were included in this group. In thirteen patients, obstruction or dislodgment of endotracheal tracheostomy tubes, or interruption of ventilation, was recognized as the immediate cause. In an additional 20 patients, cardiac arrest was associated with an adverse effect of a drug. Twelve instances of cardiac arrest were associated with central venous injection of aminophylline.

The initial cardiac resuscitation attempt was effective in 38% of patients. However, the majority of patients who survived the first episode succumbed after a second or third episode. The cumulative survival was disappointingly small. Only six patients, or 5% of the total group of 132 patients, were long-term survivors. These data may provide the basis for more restricted use of routine and repetitive resuscitative measures particularly for elderly patients in whom acidemia is due to progressive ventilatory or circulatory failure.
Isolated Tricuspid Stenosis
Authors: MORGAN JACOB R. , FORKER ALAN D. , COATES J. R. , MYERS W. S.
Published: June 2012

A case is reported of isolated tricuspid stenosis with a 5-year hemodynamic follow-up after a tricuspid commissurotomy. Fusion of the commissures and chordae tendineae of the tricuspid valve was noted at surgery. There was a history of rheumatic fever, and 5 years after surgery mild mitral stenosis had developed. Seven previously reported cases of isolated tricuspid stenosis have been considered by some authors to be congenital in origin, and, therefore, isolated tricuspid stenosis of rheumatic origin is thought to be established for the first time.
Pulmonary Valve Atresia with Intact Ventricular Septum
Authors: MCARTHUR JOHN D. , MUNSI SUSIL C. , SUKUMAR I. P. , CHERIAN GEORGE
Published: June 2012

A case of pulmonary valve atresia with intact ventricular septum' with long survival in the absence of a patent ductus arteriosus, is presented. The patient, alive at 21 years of age, has the anterior descending branch of the left coronary artery originating from the pulmonary artery. Thus, the pulmonary blood supply is obtained from the right coronary artery via intercoronary anastomoses. No similar case has been reported previously.
Carboxyhemoglobin Caused by Smoking Nonnicotine Cigarettes
Authors: ARONOW WILBERT S. , ROKAW STANLEY N.
Published: June 2012

The effects of increased carboxyhemoglobin levels caused by smoking nonnicotine cigarettes upon exercise-induced angina were investigated in 10 patients. The mean carboxyhemoglobin level after smoking eight nonnicotine cigarettes, one every 30 minutes, rose from 1.58 to 7.79%. Smoking significantly decreased the mean exercise time from the onset of exercise until the onset of angina from 109.8 to 83.5 seconds. There was significantly less of an increase in systolic blood pressure, heart rate, and product of systolic blood pressure times heart rate after exercise-induced angina after smoking compared to the nonsmoking state. Smoking nonnicotine cigarettes increased the carboxyhemoglobin level, decreasing the rate of oxygen deliverability to the myocardium, with angina developing sooner, following less cardiac work.
Supraventricular Tachycardia Initiated by Sinus Beats
Authors: GOLDREYER BRUCE N. , WEISS MELVIN B. , DAMATO ANTHONY N.
Published: June 2012

In the present report, A-V dissociation with concealed retrograde conduction into the A-V node, caused SINUS beats to exhibit antegrade A-V nodal conduction delay sufficient to result in episodes of supraventricular tachycardia (SVT). In this patient, atrial ectopic premature depolarizations were never observed. The primary role of A-V nodal conduction delay in the genesis of paroxysmal SVT is substantiated by this unusual electrophysiological observation.
Sites of Congenital and Surgical Heart Block as Defined by His Bundle Electrocardiography
Authors: ROSEN KENNETH M. , MEHTA ASHWIN , RAHIMTOOLA SHAHBUDIN H. , MILLER ROBERT A.
Published: June 2012

Catheter recordings of His bundle electrograms were obtained in seven patients with congenital heart block (CHB) and in two with surgical heart block (SHB). In the latter two patients block occurred following total correction of tetralogy of Fallot. In six patients with CHB block occurred proximal to H. In one CHB patient block occurred in the His bundle with "split" H potentials. Intraventricular conduction was normal in five of the patients with CHB who had narrow QRS and H-V intervals ranging from 35 to 45 msec. H-V intervals were short in two CHB patients (25 and 30 msec), one of whom had QRS widening with initial slowing. In the latter patient a functioning infranodal bypass (Mahaim tract) inserting into the right ventricular septum could explain the findings. In the two patients with SHB block was distal to H with P-H intervals of 125 msec and 160 msec, respectively.

The degree of bradycardia and the occurrence of symptoms partially correlated with a location of block in or distal to the His bundle. It is suggested that recording of H potentials is useful in the evaluation of children with complete atrioventricular block.
Cholesterol Production in Obesity
Authors: MIETTINEN TATU A.
Published: June 2012

Sterol-balance studies were performed in 10 control subjects, 10 normolipidemic obese patients, and 10 hypertriglyceridemic (type IV, mostly obese) patients on a low-cholesterol solid-food diet. Fecal elimination of cholesterol was markedly elevated in the overweight patients and tended to be high in the hypertriglyceridemic subjects also. A significant correlation was found between body weight and fecal excretion of neutral, acidic, and total steroids, indicating that the greater the body weight the higher was the rate of cholesterol synthesis. Sterol-balance data in obese subjects showed that excess daily cholesterol production roughly amounted to 20 mg/kg of adipose tissue. The control subjects produced only 12 mg/kg of body weight daily. Thus, obesity is associated with an increased rate of cholesterol synthesis in man. However, the correlation between serum cholesterol concentration and cholesterol production was low, suggesting that the overall rate of cholesterol synthesis was not the only factor determining the serum cholesterol level. That enhanced cholesterol production is not an irreversible phenomenon in obese subjects was indicated by the normalization of sterol-balance values in three overweight patients after their weights had been reduced by total fast followed by a low-calorie diet.
Myocardial Perfusion Imaging with Radioactive-Labeled Particles Injected Directly into the Coronary Circulation of Patients with Coronary Artery Disease
Authors: ASHBURN WILLIAM L. , BRAUNWALD EUGENE , SIMON ALLAN L. , PETERSON KIRK L. , GAULT JAMES H.
Published: June 2012

Macroaggregated serum albumin (MAA) particles labeled with
131
iodine (
131
I) or similar particles-labeled with
99m
technetium (
99m
Tc) or both types were injected directly into the coronary circulation of 29 patients at the time of conventional coronary arteriography. Radionuclide images of the distribution of these small (10-60 µ) biodegradable particles in the small vessels of the heart wall were made with a commercial Anger-type scintillation camera in much the same way as routine pulmonary perfusion scans are made. The resulting images depicted the relative regional distribution of blood flow to the myocardium in these patients suspected of having coronary artery disease. The myocardial perfusion images were of good quality and allowed gross assessment of perfusion by way of each major coronary artery. This was done by injecting
99m
Tc-labeled particles into the left coronary artery and
131
I-MAA into the right coronary artery through the coronary artery catheter. Separate or composite images of the relative small vessel perfusion via each vessel injected were obtained by electronic pulse-height discrimination. No untoward reactions followed the intracoronary injection of the labeled particles. From our preliminary experience, we conclude that myocardial perfusion imaging in conjunction with coronary arteriography may prove to be a valuable diagnostic tool in the evaluation of the regional vascular supply to the heart in patients with coronary artery disease.
Silent Mitral Insufficiency in Acute Myocardial Infarction
Authors: FORRESTER JAMES S. , DIAMOND GEORGE , FREEDMAN SHELDON , ALLEN HOWARD N. , PARMLEY WILLIAM W. , MATLOFF JACK , SWAN H. J. C.
Published: June 2012

Severe mitral insufficiency in the absence of an audible murmur was diagnosed by left ventricular angiography in three patients with power failure secondary to acute myocardial infarction during evaluation for mechanical circulatory assist and surgery. Mitral valve prolapse was present in two patients. Postmortem examination did not reveal an anatomic basis for the mitral insufficiency: the valve, papillary muscles, and supporting structures were all grossly normal. A single papillary muscle removed at surgery revealed a marked decrease in force development (0.22 g/mm
2
vs 0.62 ± 0.22 g/mm
2
in eight normal papillary muscles from patients with rheumatic heart disease). During isoproterenol stimulation, force development in this muscle decreased 20%, whereas in the normal muscles force development increased 73 ± 31%. Microscopically, all papillary muscles revealed evidence of extensive necrosis. Silent mitral insufficiency in acute myocardial infarction, therefore, was probably related to diminished flow velocity across the mitral valve secondary to diminished myocardial contractility. Failure to recognize and treat this entity may contribute significantly to the genesis of power failure and ultimate mortality.
Evaluation of Pulmonary Arterial End-Diastolic Pressure as an Estimate of Left Ventricular End-Diastolic Pressure in Patients with Normal and Abnormal Left Ventricular Performance
Authors: BOUCHARD RICHARD J. , GAULT JAMES H. , ROSS JOHN
Published: June 2012

It has been suggested that the pulmonary arterial end-diastolic pressure (EDP) may accurately reflect the level of left ventricular EDP, and therefore be useful in the continuous monitoring of left ventricular EDP in acutely ill patients. Accordingly, pulmonary arterial pressure was recorded simultaneously with left ventricular pressure in 24 patients with normal left ventricular function and in 26 patients with left ventricular myocardial disease and elevated EDP (range 13 to 38 mm Hg; average 22 mm Hg). In patients with normal left ventricular function, the EDPs in the left ventricle and pulmonary artery were equal (range 5 to 12 mm Hg; average 8 mm Hg; maximum difference ± 4 mm Hg). In contrast, in 20 of the patients with impaired left ventricular function, left ventricular EDP was consistently higher than pulmonary arterial EDP, exceeding the pulmonary arterial EDP by 2 to 21 mm Hg (average 8 mm Hg); in 12 of these 20 patients, the pulmonary arterial EDP was 12 mm Hg or less, the upper limit of normal for left ventricular EDP. The left ventricular diastolic pressure prior to atrial contraction correlated more closely with pulmonary arterial EDP. In six patients in whom increases in systemic arterial pressure were induced by methoxamine, and in two patients in whom spontaneous increases in systemic arterial pressure occurred, left ventricular EDP increased by 2 to 11 mm Hg (average 6 mm Hg); pulmonary arterial EDP remained unchanged or increased only slightly (less than 3 mm Hg) in six of the patients, and increased by 4 and 5 mm Hg in the two remaining patients. During increases in heart rate induced by atrial pacing, left ventricular EDP declined in 12 of 14 patients, while pulmonary arterial EDP increased, resulting in a consistent disparity in these pressures (average 11 mm Hg) at heart rates in excess of 124 beats/min.

These data indicate that pulmonary arterial EDP does not provide an accurate estimate of left ventricular EDP in patients with chronic left ventricular disease, and in addition it often fails to reflect acute alterations in left ventricular EDP.
Angiographic Features of Rheumatic and Nonrheumatic Mitral Regurgitation
Authors: WEXLER LEWIS , SILVERMAN JAMES F. , DEBUSK ROBERT F. , HARRISON DONALD C.
Published: June 2012

Left ventricular cineangiography was performed in 37 patients with mitral regurgitation. Twenty-one patients had rheumatic mitral valve disease determined by careful surgical and pathologic examination, 10 had papillary muscle dysfunction, and six had chordae tendineae rupture. Fourteen of the 16 patients considered to have nonrheumatic mitral regurgitation were confirmed surgically; the other two patients developed mitral regurgitation acutely following myocardial infarction. Cineangiograms were evaluated for valve calcification, appearance and mobility of mitral valve leaflets, character of the regurgitant jet, and ventricular contractility. By these criteria, rheumatic mitral regurgitation was distinguished from papillary muscle dysfunction and chordae tendineae rupture in every case. A correct diagnosis of papillary muscle dysfunction was made when focal areas of myocardial dysfunction, determined by comparing tracings of end-systolic and end-diastolic cine frames, occurred at the base of the papillary muscle. However, half the cases of papillary muscle dysfunction had apparently normal contractility. The involved leaflet was correctly identified in the six cases of chordae tendineae rupture.
Atrioventricular Conduction Defects in Patients with Sinus Bradycardia
Authors: NARULA ONKAR S.
Published: June 2012

A-V conduction was analyzed in 75 patients (mean age, 73 years) with sinus bradycardia (SB) by His bundle (BH) recordings. Forty-five of these patients had normal QRS complexes (≦0.10 sec) and 30 had abnormal QRS complexes (≧0.12 sec). The conduction times through the atrium (P-A), A-V node (A-H), and His-Purkinje system (H-V) were measured during normal sinus rhythm and transient right atrial pacing up to rates of 150/min. The normal range of conduction times through various regions is: P-A = 25 to 45 msec; A-H = 50 to 120 msec, and H-V = 35 to 45 msec. Overall A-V conduction was completely normal only in 25 (33%) patients. Of these 25 patients, 20 had a narrow QRS complex and five had an abnormal QRS complex. The remaining 50 patients showed abnormal A-V conduction in one or more regions (P-A in 10, A-H in five, BH in six, H-V in 10, and mixed in 19). In some patients despite normal ECGs, the H-V time was abnormal and 1:1 A-V conduction was present during atrial pacing up to 150/min. An abnormal H-V time in association with a normal QRS complex is suggestive of delay in the His bundle. Fourteen patients were restudied at intervals of 6 months to 2 years. Three of these 14 patients showed prolongation of conduction times over 1½ to 2 years.

Our data demonstrate that SB is often (67%) associated with A-V conduction abnormalities. A-V conduction was abnormal in 56% of patients with normal and 83% with abnormal QRS complexes. The ECG and atrial pacing are of limited value in assessing A-V conduction. The BH recordings in symptomatic patients with sinus bradycardia may be of clinical significance in the selection of site for pacemaker implantation, that is, atrial or ventricular.
Experimental Myocardial Infarction
Authors: KUMAR RAJ , SHARMA G. V.R.K. , MOLOKHIA FAROUK A. , NORMAN JOHN C. , INAMDAR A. N. , MESSER JOSEPH V. , ABELMANN WALTER H. , HOOD WILLIAM B.
Published: June 2012

This study was designed to test the efficacy of glucagon in the treatment of hemodynamic abnormalities of acute and healing experimental canine myocardial infarction. Myocardial infarction was produced in intact, conscious dogs by gradual inflation of a balloon cuff device implanted around the left anterior descending coronary artery 1 to 2 weeks prior to the study. Hemodynamic and metabolic effects of 50 µg/kg of glucagon were assessed serially in the control state, 1 hour after myocardial infarction and again 1 week later. In the control state glucagon improved cardiac performance and increased myocardial oxygen consumption. One hour after acute myocardial infarction glucagon improved cardiac performance and reduced the degree of left ventricular failure, without any increase in myocardial oxygen consumption. Similar effects of glucagon were noted in the healing phase of myocardial infarction. It is postulated that in this animal model in the presence of heart failure due to myocardial infarction there are reciprocal changes in the factors that increase myocardial oxygen consumption (glucagon-induced inotropy) and decrease oxygen consumption (fall in ventricular end-diastolic volume and wall stress), resulting in no net change in oxygen requirement.
An Automated Method for the Measurement of Ventricular Volume
Authors: MARCUS MELVIN L. , SCHUETTE WILLIAM H. , WHITEHOUSE WILLARD C. , BAILEY JAMES J. , GLANCY D. LUKE
Published: June 2012

Several important indices of myocardial performance depend upon accurate and frequent measurement of ventricular volume. Studies employing such measurements have been limited because of the difficulty of manually measuring and calculating volumes frequently enough to obtain meaningful data. We, therefore, have developed an automated method for determination of ventricular volume in man. Left ventricular cineangiograms taken in the right anterior oblique position at 60 frames/sec are projected with a flickerless projector onto a Plumbicon television camera. A second television camera is used by a skilled operator for masking out noncontributory portions of the film and for shading selected areas to facilitate accurate recognition of the opacified chamber. An electronic video-tracking device then simultaneously determines the area and the maximum length of the opacified chamber in each cine frame. These data are recorded as analog signals on magnetic tape. Volumes are calculated by computer and plotted against time. When volumes determined by this automated method are compared with those obtained by manual planimetry, the correlation coefficient is 0.96. Aluminum prolate spheroids, left ventricular casts, and left ventricular cineangiograms were studied. This automated technic permits rapid and accurate measurement of ventricular volume in patients having diagnostic left ventriculograms.
Nuclear Angiocardiography in the Diagnosis of Congenital Heart Disease in Infants
Authors: WESSELHOEFT HADWIG , HURLEY PETER J. , WAGNER HENRY N. , ROWE RICHARD D.
Published: June 2012

Nuclear angiocardiography with a gamma camera, a pinhole collimator, and
99m
Tc pertechnetate was performed on 43 children aged 3 years or less, including 10 neonates. Twenty-six children had congenital heart disease, which was confirmed at cardiac catheterization; the rest had no structural cardiac anomaly. Use of the pinhole collimator allowed magnification of cardiac images, with enhancement of resolution. Sensitivity was improved by positioning the pinhole 14 cm rather than 19 cm from the crystal of the gamma camera. Anterior and left lateral angiocardiograms were obtained with both 35-mm images at 0.3-sec intervals and cine-images at 18 frames/sec.

Abnormalities in origin, size, and position of the great arteries, in chamber configurations, and in the time and course of activity in right and left heart, lungs, and great vessels were used to assist in identification of anomalies such as transposition of the great arteries, pulmonary atresia with intact ventricular septum, truncus arteriosus, and aortic atresia.
99m
Tc in a dose of 18.5 mCi/M
2
of body area was used and produced whole-body and gonadal radiation doses less than 1 rad. The low risk and simplicity of the technic make it promising as a screening procedure and as an adjunct to cardiac catheterization for cyanosed infants.
Glucose Extraction by the Human Myocardium during Pacing Stress
Authors: MOST ALBERT S. , GORLIN RICHARD , SOELDNER J. STUART
Published: June 2012

Glucose extraction by ischemic human myocardium was investigated at the time of diagnostic cardiac catheterization in 27 subjects who had fasted overnight. Paired arterial and coronary sinus blood samples, obtained before and during coronary sinus pacing, were analyzed for glucose and lactate. Pacing to a rate 50 to 70% greater than control or to the development of chest pain induced no significant change in the arterial level of either substrate. No correlation was noted between arterial level and myocardial extraction of either substrate at rest or during stress.

Three groups of subjects were identified: group I: those with lactate extraction at rest and during pacing (n = 13); group II: those with lactate extraction at rest but production during pacing (n = 7); and group III: those with lactate production at rest with augmented production during pacing (n = 5). Two additional subjects produced lactate at rest but were not paced. Glucose extraction increased significantly with pacing tachycardia in group II (0.09 ± 0.03 m
m
to 0.26 ± 0.04 m
m
) and in group III (0.38 ± 0.17 m
m
to 0.58 ± 0.12 m
m
). No significant increase was noted in group I. A significant correlation was noted between glucose extraction and lactate production during pacing when groups II and III were combined (r = 0.81;
P
< 0.001).

Myocardial ischemia in man was associated with augmented glucose extraction. The arterial glucose concentration was not a primary determinant of glucose extraction either before or during induced ischemia.
Effects of Levodopa on Systolic Preejection Period, Blood Pressure, and Heart Rate during Acute and Chronic Treatment of Parkinson's Disease
Authors: WHITSETT THOMAS L. , GOLDBERG LEON I.
Published: June 2012

The effect of levodopa on the externally recorded preejection period (PEP), blood pressure, and heart rate was evaluated in patients with Parkinson's disease during the first 2 weeks of therapy and after 3 months of continuous therapy. During the same time periods, the response of these parameters to graded intravenous doses of dopamine and epinephrine was determined. During the first 2 weeks, levodopa (1.0 and 1.5 g) produced a dose-related shortening of the PEP which was maximal at the time of the 30 or 60-min recordings and remained significant (
P
< 0.05) for 90 min following the 1.0-g dose and for 120 min after the 1.5-g dose. The drug had no effect on heart rate and reduced arterial blood pressure minimally. Propranolol (10 mg by mouth) prevented the shortening of PEP produced by levodopa. After 3 months of therapy, levodopa (1.5 g) failed to shorten the PEP significantly. However, the effect of dopamine and epinephrine on PEP was not significantly different from that obtained during the first 2 weeks of treatment with levodopa. It is concluded that levodopa exerts a positive inotropic effect which is mediated via beta-adrenergic receptors and that tolerance develops by 3 months of continuous administration. The tolerance does not appear to be caused by impaired responsiveness of the heart since the effect of graded doses of dopamine and epinephrine on the PEP was similar during both acute and chronic administration.
Hemodynamics at Rest and during Exercise in Combined Aortic Stenosis and Insufficiency
Authors: ETTINGER PHILIP O. , FRANK MARTIN J. , LEVINSON GILBERT E.
Published: June 2012

The effects of exercise in combined aortic stenosis and insufficiency were evaluated in 10 patients by pressure measurements and the measurement of forward (Q
F
) and regurgitant (Q
R
) flows by simultaneous upstream and downstream sampling using indocyanine green. While heart rate increased, systolic aortic valve pressure gradient (mean, 37 ± 9 mm Hg) did not change. Increased Q
F
(mean, 4.54 ± 0.34 at rest and 6.89 ± 0.42 liters/min with exercise,
P
< 0.001) was balanced by decreased Q
R
(means, 4.09 ± 1.02 and 2.33 ± 0.71 liters/min,
P
< 0.02), and total flow did not change significantly. Although diastolic regurgitant period declined, total diastolic seconds per minute decreased by only 6%, while calculated systemic resistance decreased by 30%. Left ventricular systolic and aortic pressures increased, while left ventricular end-diastolic pressure and diastolic aortic valve gradients were unchanged. Mean systolic aortic valve area, calculated by utilizing total valve flow, was 1.8 ± 0.3 cm
2
in both states.

Thus, exercise reduces regurgitant fraction in mixed aortic lesions as in pure aortic insufficiency. This observation confirms the necessity of measuring total valve flow in evaluation of mixed valve lesions. Reduced regurgitation primarily reflects an altered relationship of peripheral resistance to backflow resistance. While the stenotic valve is demonstrated to behave as a fixed systolic orifice, the diastolic aortic orifice area cannot be calculated from the Gorlin equation as it does not account for peripheral resistance.
Effect of Isoproterenol,
l
-Norepinephrine, and Intraaortic Counterpulsation on Hemodynamics and Myocardial Metabolism in Shock following Acute Myocardial Infarction
Authors: MUELLER HILTRUD , AYRES STEPHEN M. , GIANNELLI STANLEY , CONKLIN E. FOSTER , MAZZARA JAMES T. , GRACE WILLIAM J.
Published: June 2012

The effects of isoproterenol,
l
-norepinephrine, and intraaortic counterpulsation on hemodynamics and myocardial metabolism were evaluated in shock due to acute myocardial infarction. Before treatment, the cardiac index was markedly reduced, averaging 1.35 liters/min/m
2
. Mean aortic pressures ranged from 40 to 65 mm Hg. Decreases in coronary blood flow (mean, 68 ml/100 g/min) and in myocardial oxygen consumption (mean, 8.11 ml/100 g/min) were associated with abnormally high myocardial oxygen extractions (mean, 78%) and with lactate production (mean, 9%). Isoproterenol increased cardiac index 63% and heart rate 26%. Coronary blood flow rose an average of 12 ml/100 g/min in the face of decreased diastolic aortic pressure. Rate of myocardial lactate production increased.
l
-Norepinephrine increased mean aortic pressure and coronary blood flow an average of 21 mm Hg and 27 ml/100 g/min. Mean myocardial oxygen consumption rose 2.24 ml/100 g/min. While myocardial lactate production shifted to extraction (mean, 12%), myocardial oxygen extraction remained abnormally high (mean, 73%). Cardiac index did not change. Intraaortic counterpulsation increased mean aortic pressure and coronary blood flow an average of 15 mm Hg and 23 ml/100 g/min. Myocardial oxygen consumption remained essentially unchanged. Both myocardial lactate and oxygen extraction improved toward normal values (15 and 61%). Cardiac index increased an average of 0.45 liters/min/m
2
.

Hemodynamics and myocardial metabolism then were markedly abnormal in shock due to acute myocardial infarction. Isoproterenol improved cardiac performance but myocardial oxygenation deteriorated. Therefore isoproterenol does not seem to be helpful in coronary shock.
1
-Norepinephrine improved myocardial perfusion and oxygenation, but did not change cardiac output. It appears to be the vasoactive agent of choice in the initial treatment of coronary shock. Intraaortic counterpulsation changed myocardial metabolism toward normal and improved systemic perfusion. Mortality remained unchanged however during the three different therapeutic interventions emphasizing the importance of early recognition of the shock state and of further aggressive diagnostic and therapeutic management.
Relation between Digoxin Arrhythmias and ABO Blood Groups
Authors:   BOSTON COLLABORATIVE DRUG SURVEILLANCE PROGRAM
Published: June 2012

In a series of 1,080 consecutively monitored patients who received digoxin, arrhythmias attributed to the drug were observed in 144 cases (13.3%). The proportion of arrhythmias among 510 patients with blood group O was 10%, while for the 570 patients of groups A, B, and AB (non-O), it was 16.3% (
P
< 0.002). The point estimate of relative risk for non-O patients relative to group O patients with 1.7, with 95% confidence limits of 1.2 and 2.5, and the increase in the risk was most prominent between the ages of 50 and 69 years.
Physiologic Pressure Differences between Main and Branch Pulmonary Arteries in Infants
Authors: DANILOWICZ DELORES A. , RUDOLPH ABRAHAM M. , HOFFMAN JULIEN I. E. , HEYMANN MICHAEL
Published: June 2012

Systolic pressure differences of 6 to 45 mm Hg were found between the main and branch pulmonary arteries in 37 of 242 infants undergoing diagnostic cardiac catheterization. Eleven of these 37 infants were restudied, and all had lost the pressure difference regardless of the underlying cardiac defect. A similar pressure difference was noted in lambs studied at thoracotomy with direct measurement of main and branch pulmonary arterial pressures. Increasing pulmonary blood flow caused a rise in pressure differences and also evoked a difference in some older lambs when none was originally present.

Cineangiography in infants with a pressure difference showed no discrete narrowing or poststenotic dilatation of the pulmonary arteries. The main pulmonary artery was a large domed structure from which relatively small right and left branches arose at sharp angles from the inferior and posterior surfaces. The size, disparity, and angulation probably caused turbulence with, at times, a loss of pressure. Systolic flow murmurs may be common.

In assessment of pulmonary vascular resistance, it is therefore important to recognize that a portion of the total pressure drop across the lungs after birth reflects maturational changes of the larger pulmonary arteries as well as of the muscular arterioles.