bluuebunny/crossref_metadata_2025 huggingface dataset:
Studies of Hemodynamic Changes in Humans Following Induction of Low and High Spinal Anesthesia
Authors: SANCETTA SALVATORE M. , LYNN R. BEVERLEY , SIMEONE FIORINDO A. , SCOTT ROY W. , HECKMAN GLADYS , JANOUSKOVEC HANNA
Published: June 2012

After a lapse of some years, surgeons and anesthesiologists alike are re-exploring the use of high spinal anesthesia, which is designed to produce a "useful" hypotension coupled with maximal relaxation. In the present study the hemodynamic changes induced by low and high spinal anesthesia, the latter arbitrarily defined as ablation of sympathetic, sensory and somatic nerves fibers above the fourth dermatomic segment, have been investigated in a series of waking patients not undergoing surgery.
Relationship between Ballistocardiographic Forces and Certain Events in the Cardiac Cycle
Authors: TANNENBAUM OSCAR , SCHACK JEROME A. , VESELL HARRY
Published: June 2012

The temporal relationships of the various waves of the ballistocardiogram have been studied by means of simultaneously recorded electrocardiograms, femoral pulses, and electrokymograms of the great vessels and heart chambers. A modification of the Dock type of electromagnetic, undamped, direct ballistocardiograph has been employed in this study of 23 normal individuals. The total duration of mechanical systole in the great vessels has been found to correspond closely to the H-L interval. The HIJKL complex of the ballistocardiogram appears to be entirely related to the events of ventricular systole. The M, N and O waves represent after-waves occurring during diastole.
Role of the Liver in Excretion and Destruction of Digitoxin
Authors: ST. GEORGE SHIRLEY , BINE RENÉ , FRIEDMAN MEYER
Published: June 2012

The role of the liver in the excretion and destruction of digitoxin was studied in the rat, rabbit, dog and man (in part). It was found that no more than 10 per cent of a given dose of digitoxin is excreted in the bile of the animals tested and none could be detected in the bile of two human subjects. Evidence was obtained which suggested that in the rat and rabbit, the liver was able to destroy a large amount of injected digitoxin.
Induced Hypercholesterolemia and Atherogenesis
Authors: PAGE IRVINE H. , BROWN HELEN B.
Published: June 2012

An attempt has been made to elicit atherosclerosis in rats by duplicating as far as possible those conditions which in other animals are atherogenic. By making the rats hypothyroid and feeding cholic acid and cholesterol, severe hypercholesterolemia and abnormal beta-lipoproteins appeared along with heavy lipid infiltration of the kidneys, liver, heart and aorta. Aortic and coronary atherosclerosis might have been expected in rats exposed to so much atherogenic material in the blood, but it was not found. Despite lipid infiltration in the intima of the vessels, no appreciable tissue reaction to it occurred; we believe the lack of tissue response is one of the chief causes for the failure of atherosclerosis to develop. Thus tissue response and receptivity to lipid deposition seem to be important mechanisms in atherogenesis.
Pulmonary Embolism
Authors: WOLFF LOUIS
Published: June 2012

The incidence and importance of bland pulmonary embolism as a cause of morbidity and mortality have been emphasized. The pathologic physiology, the clinical picture, the laboratory findings, the diagnosis, and the treatment have been discussed. Venous thrombosis in the lower extremities is the most common immediate cause of pulmonary embolism, but clinical evidence of its presence is frequently lacking. It is difficult to prevent venous thrombosis in spite of the employment of numerous prophylactic measures. Although the diagnosis of pulmonary embolism is easy in some cases, it may be impossible in others. Statistical proof of the effectiveness of treatment is difficult to obtain, but clinical experience appears to indicate that the aforementioned therapeutic procedures are worthwhile. It is evident that many important problems relating to thromboembolism remain unsolved.
The Renal Excretion of Digitoxin in the Acute and Chronic Cardiac Patient
Authors: FRIEDMAN MEYER , ST. GEORGE SHIRLEY , BINE RENÉ , BYERS SANFORD O.
Published: June 2012

The renal excretion of digitoxin was studied in cardiac patients who were (1) decompensated and (2) compensated. It was found that the renal excretion of digitoxin was not changed in patients suffering from left ventricular failure alone but diminished considerably during the first 24 hours of decompensation in patients suffering from both right and left ventricular failure. Patients who were maintained in a good state of compensation by adequate digitalization were found to excrete 30 to 40 per cent of their daily dose of digitoxin. Patients overdigitalized were found to excrete 70 or more micrograms of digitoxin a day. The maximal amount of digitoxin able to be destroyed in the body was considered to be approximately 50 µg. per day, a finding which explains why dosages in excess of 0.15 mg. almost invariably lead to overdigitalization.
Estrogen-Induced Regression of Coronary Atherosclerosis in Cholesterol-Fed Chicks
Authors: PICK RUTH , STAMLER JEREMIAH , RODBARD SIMON , KATZ LOUIS N.
Published: June 2012

The present study demonstrates that estrogens reverse previously induced coronary atherosclerosis in cholesterol-fed cockerels, despite the continued presence of the atherogenic stimulus in the diet. Aorta atherogenesis remains unaffected. Hypercholesterolemia is moderately enhanced by estrogen administration; total cholesterol-lipid phosphorus (C/P) ratios are depressed to normal levels, consequent upon estrogen-induced hyperphospholipemia.
Mitral Stenosis with Exertional Cyanosis and Pulmonary Hemosiderosis
Authors: WIER JAMES A. , PICCOLI AMO J. , GREENE DAVID G. , GREENE CLAYTON W.
Published: June 2012

A patient with mitral stenosis is reported who suffered from exertional cyanosis for the last eight years of his life. Radiologic examination of his chest demonstrated a diffuse pulmonary hemosiderosis, which was confirmed at autopsy. Physiologic studies in the last few weeks of life showed that the cyanosis was not due to impairment of oxygenation of the blood in the lungs but rather to slowed circulation, possibly augmented by local changes in the anatomy of the vessels of the skin.
Studies on Acute and Chronic Toxicity of Tetraethyl Ammonium Ion (Etamon)
Authors: KEITH JULIAN F. , GREEN HAROLD D. , WILLIAMS S. CLAY , DAVIS CORNELIUS C.
Published: June 2012

Studies were done using dogs to determine: (1) the ED
50
of Etamon when given as an infusion over 30 minutes; (2) the possibility of an accumulative toxicity when Etamon is given in multiple small doses over long periods of time; and (3) the effect of various measures in preventing death after the administration of a lethal dose (LD
100
) of Etamon. The ED
50
of Etamon given as an infusion was found to be nearly twice that of Etamon given as a fast injection intravenously. There seemed to be an accumulative toxic effect following the use of Etamon in multiple small doses over a long period of time as evidenced by the difference between the ED
50
of those receiving a single large infusion and those receiving multiple small infusions. Intermittent controlled positive pressure respirations were found to be effective in preventing death after the infusion of a lethal dose of Etamon.
An essential view in coronary arteriography.
Authors: Nath P H , Velasquez G , Castaneda-Zuniga W R , Zollikofer C , Formanek A , Amplatz K
Published: June 2012

A significant stenosis of the left main coronary artery is associated with a significant mortality and is one of the major indications for aortocoronary bypass surgery. The diagnosis of this lesion on clinical grounds is inconsistent and should be established by angiography. All routine projections during coronary arteriography cause foreshortening of the left main coronary artery. Well-collimated anteroposterior and shallow right and left anterior oblique views show the main segment best. These views also show the proximal segments of circumflex and anterior descending branches, and should be routinely used during every coronary arteriogram.
Exercise and human collateralization: an angiographic and scintigraphic assessment.
Authors: Nolewajka A J , Kostuk W J , Rechnitzer P A , Cunningham D A
Published: June 2012

The effect of exercise on the development of intercoronary collaterals and on left ventricular function is controversial. Twenty male patients (mean age 48 years, range 36-54 years) who had suffered an acute myocardial infarction were randomly allocated to an exercise group (10 patients) and a control group (10 patients). Both groups underwent coronary angiography, left ventricular function studies and myocardial perfusion studies with labeled microspheres, before and after the 7-month experimental period. Both groups had similar extent of disease as measured angiographically and both had mild progression of disease. Neither group showed changes in extent of callateralization, myocardial perfusion or left ventricular function. The exercise group had a significant increase in anginal threshold and a significant (p less than 0.01) decrease in heart rate at a given work load. Exercise, therefore, does not appear to affect progression of disease, myocardial perfusion, extent of collateralization, or left ventricular function in patients with coronary artery disease.
Oxygen consumption and hemodynamic response of exercises used in training of patients with recent myocardial infarction.
Authors: Fletcher G F , Cantwell J D , Watt E W
Published: June 2012

We investigated oxygen consumption (ml/kg/min) and hemodynamic response (peak heart rate-systolic blood pressure product) to individual exercise activities before and after exercise training in 22 male postmyocardial infarction patients (PMIP). Activities included swimming, walk/jogging, volleyball, calisthenics and exercise dance routines. Oxygen consumption was determined immediately after exercise by the Douglas bag gas collection procedure and, in selected patients, by a Max Planck respirometer during exercise. Hemodynamic data were obtained by pulse count and cuff sphygmomanometer. The increase in oxygen consumption and the decrease in rate-pressure product after each activity were significant (p less than or equal to 0.01). There were no differences in oxygen consumption between the Max Planck respirometer technique and collection (Douglas bag method) immediately after exercise. The oxygen consumption obtained for PMIP compared with available cumulative data on normal subjects is significantly variable, suggesting the need for caution when prescribing exercise for the PMIP based on energy costs of standard exercise measurements in normals. This was particularly relevant because of the significantly high oxygen consumption incurred during swimming.
The extraction of circulating catecholamines by the lungs in normal man and in patients with pulmonary hypertension.
Authors: Sole M J , Drobac M , Schwartz L , Hussain M N , Vaughan-Neil E F
Published: June 2012

We directly measured the net pulmonary extraction of circulating norepinephrine, epinephrine and dopamine in control patients and patients with primary or secondary pulmonary hypertension. Mixed pulmonary artery norepinephrine, epinephrine and dopamine were 314 +/- 13 pg/ml, 102 +/- 9 pg/ml, 51 +/- 5 pg/ml, respectively, for the control group; values were similar in patients with pulmonary hypertension. The pulmonary extraction of norepinephrine was 25.4 +/- 2.6% (clearance 266 +/- 62 ng/min) in control patients; epinephrine and dopamine were not extracted. There was no net extraction or production of any of the three catecholamines by the lungs in any of the patients with pulmonary hypertension. We conclude that the lungs play a significant role in the inactivation of circulating norepinephrine in man. This metabolic function of the lungs appear to be lost in pulmonary hypertension.
Changes in diastolic time with various pharmacologic agents: implication for myocardial perfusion.
Authors: Boudoulas H , Rittgers S E , Lewis R P , Leier C V , Weissler A M
Published: June 2012

Diastolic time (DT) is calculated as the cycle length (RR) minus electromechanical systole (QS2). The ratio of DT (RR-QS2) to RR interval times 100, or the percent diastole (%D), varies nonlinearly with heart rate (HR), increasing rapidly with decreasing HR. The effect of commonly used cardioactive agents on %D was studied in five groups of normal subjects. In group 1 (n = 12), propranolol (160 mg daily) increased %D from 55.9 +/- 1.7 to 64.7 +/- 1.3 (p less than 0.001) by slowing HR. In group 2 (n = 12), dobutamine (2.5 micrograms/kg/min) increased %D from 56.4 +/- 1.4 to 61.8 +/- 1.3 (p less than 0.005) by shortening the QS2. In group 3 (n = 10), Cedilanid-D (1.6 mg i.v.) increased %D from 55.5 +/- 1 to 63.2 +/- 0.7 (p less than 0.001), both by slowing the HR and shortening the QS2. In group 4 (n = 12), isoproterenol (2 micrograms/min) increased HR and shortened the QS2 significantly. The net result was a significant reduction of %D from 56.1 +/- 1.4 to 53.5 +/- 1.1, (p less than 0.05). In group 5 (n = 15), a 100-mg bolus of i.v. lidocaine did not have a significant effect on %D. This study indicates that cardiovascular drugs may have significant effects on the relative duration of diastole either by affecting HR or the duration of systole. This may have clinical implications for patients with coronary artery disease and patients with left ventricular hypertrophy, since in both cases coronary flow in mostly diastolic.
Dynamic geometry of the left atrium and left ventricle in acute mitral regurgitation.
Authors: Sasayama S , Takahashi M , Osakada G , Hirose K , Hamashima H , Nishimura E , Kawai C
Published: June 2012

The instantaneous transverse diameter of the left atrium, left ventricular free wall segment length (SEG), and the long axis of the anterior papillary muscle (APM) length were measured throughout the cardiac cycle, using ultrasonic dimension gauges together with left atrial and left ventricular pressures in 12 open-chest dogs. During atrial contraction, left atrial diameter decreased from 19.7 to 18.7 mm, while left ventricular dimensions increased simultaneously. During ventricular ejection, percent shortening was 26% in SEG and 10% in APM, while atrial diameter increased continuously to 20.5 mm, with a concomitant rise in the v wave of left atrial pressure. After normal mitral valve opening, left atrial diameter decreased rapidly simultaneously with the y descent of atrial pressure. Graded mitral regurgitation was then produced by sectioning the chordae tendineae. With moderate mitral regurgitation, end-diastolic length of the SEG increased by 27%, while extent of shortening (delta L) was augmented by 96%. End-diastolic length of the APM increased by 7%, and delta L was augmented by 60%. Left atrial pressure was sharply elevated, with a distinct a wave followed by the more prominent v wave. End-diastolic diameter of the left atrium was enlarged to 22.9 mm with increased atrial shortening and expansion. As mitral regurgitation was increased to a severe degree by additional chordal rupture, end-diastolic length and delta L continued to increase both in SEG and APM. Left atrial pressure was further elevated (a wave 25 mm Hg and v wave 47 mm Hg). Left atrial end-diastolic diameter further increased in 24.9 mm. However, the amplitude of left atrial shortening and expansion decreased remarkably. In severe mitral regurgitation, isoproterenol and nitroprusside decreased left atrial pressure and diameter, restoring more forceful atrial shortening.
Scaling current and energy with body weight: requirements for the transthoracic ventricular defibrillation of calves as they grow from 50 to 150 kg.
Authors: Gold J H , Schuder J C , Stoeckle H , Granberg T A , Dettmer J C , Schmidt D E
Published: June 2012

To test the hypothesis that the effectiveness of a shock in achieving ventricular defibrillation is relatively independent of body weight if electrode diameter is proportional to the one-third power and current is proportional to the two-thirds power of weight, we studied defibrillation rates in 10 calves as they increased weight. At 50 kg, each calf was subjected to 20 fibrillation-defibrillation episodes using 10.3-cm diameter electrodes and 32-amp, 4-msec rectangular pulses for defibrillation. Two days after the original study, each calf underwent 20 additional episodes involving 44-amp pulses. With the specified scaling of electrode diameter and pulse amplitude, the two studies were repeated at weight intervals of 25 kg as the animals grew. Six calves survived. In the study that started with 32-amp pulses, first-shock success values of 28%, 49%, 66%, 51% and 23% were found in the six surviving calves at 50, 75, 100, 125 and 150 kg, respectively. The corresponding values were 93%, 96%, 93%, 94% and 91% in the study that started with 44-amp pulses. While the results of the 32-amp study fail to support our initial hypothesis, those obtained in the 44-amp current study appear compatible with the hypothesis.
Right sinus of Valsalva-right atrial fistula secondary to nonpenetrating chest trauma: a case report with description of noninvasive diagnostic features.
Authors: DeSa'Neto A , Padnick M B , Desser K B , Steinhoff N G
Published: June 2012

A sinus of Valsalva-right atrial fistula secondary to nonpenetrating chest trauma is described. Echocardiogrpahy demonstrated diastolic fluttering of the anterior tricuspid valve, suggesting a left-to-right shunt at the level of the right atrium. External jugular venous pulse tracings revealed large alpha waves and attenuation of the y descent. Cardiac catheterization disclosed a fistulous communication between the right sinus of Valsalva and right atrium. After surgical repair of the fistula, the ultrasonic recording and external pulse tracing reverted to normal. We believe this is the first description of such a shunt after blunt thoracic trauma.
Platelet survival time and thromboembolism in patients with mitral valve prolapse.
Authors: Steele P , Weily H , Rainwater J , Vogel R
Published: June 2012

Thromboembolism (TE) occurs in about 20% of patients with rheumatic mitral valve disease, and platelet survival time in these patients has correlated with TE. In patients with mitral valve prolapse, TE appears to occur very infrequently. Platelet survival (autologous labeling with chromium-51) was performed in 26 patients with mitral prolapse. Five patients had a history of stroke, as well as normal cerebrovascular arteriography and shortened platelet survival (average half-time +/- SEM 2.3 +/- 0.18 days; normal half-time 3.7 +/- 0.03 days; n = 26; p less than 0.01). Platelet survival was shortened in seven of 21 patients without TE (33%) (3.3 +/- 0.06 days; p less than 0.01 vs patients with TE). In 138 patients with rheumatic heart disease, platelet survival was shortened in 40 of 41 (98%) with a history of TE (2.3 +/- 0.08 days) and in 76 of 97 (78%) without TE (2.9 +/- 0.07 days; p less than 0.001 vs patients with TE). In patients with mitral prolapse, sulfinpyrazone increased platelet survival (2.4 +/- 0.16 to 2.7 +/- 0.19 days; n = 7; p less than 0.05). Our results suggest that platelet survival time is shortened in patients with mitral prolapse and rheumatic heart disease who have had TE. Of those without TE there is an increased frequency of shortened platelet survival in patients with rheumatic heart disease (78%) compared with those with mitral prolapse (33%), consistent with the infrequency of TE in mitral prolapse.
Increased mitral-aortic separation in discrete subaortic stenosis.
Authors: Rosenquist G C , Clark E B , McAllister H A , Bharati S , Edwards J E
Published: June 2012

We recently speculated that mitral-aortic separation (MAS) might be increased in discrete subaortic stenosis (DSS). We have examined this hypothesis in 22 heart specimens in which the subaortic obstruction originated on the muscular ventricular septum below the right aortic sinus, either as a discrete band, an accumulation of several bands or a diffuse ridge, and extended posteriorly into the MAS or anterior leaflet of the mitral valve or both, with a variable relationship to the aortic cusps and sinuses. No specimen had ventricular septal defect, supravalvular aortic stenosis or other features of Shone syndrome. The mean MAS was nearly twice that of 80 normal specimens (4.9 vs 2.5 mm), the range of MAS was increased from normal (0.11 vs 0.7 mm) and the mean diameter of the aortic annulus was decreased compared with the normal specimens, data that will be of interest to echo- and angiocardiographers in the clinical description of DSS, and to the surgeon who must resect these lesions.
Subxiphoid two-dimensional imaging of the interatrial septum in infants and neonates with congenital heart disease.
Authors: Bierman F Z , Williams R G
Published: June 2012

The interatrial septum (IAS) was studied by subxiphoid two-dimensional echocardiography (S2DE) in 88 infants under 12 months of age who weighed 1.2-9.1 kg. The IAS was adequately displayed in 87 of 88 patients. The morphology, presence and localization of defects in the IAS were evaluated by S2DE and retrospectively related to the findings at cardiac catheterization. In seven patients with no interatrial communication at cardiac catheterization, the IAS was straight, with an area of central thinning corresponding to the veil-like cover of the septum primum over the foramen ovale. The morphology of the IAS with a stretched, patent foramen ovale (56 patients) indicated the coexistence of a right or left ventricular volume or pressure overload, and was readily distinguishable from the IAS with a secundum type communication (13 patients). In patients with a stretched, patent foramen ovale and left ventricular overload lesions, the IAS was a nearly homogenous, curvilinear structure bowing into the right atrium, with a small area of septal dropout at the superior rim of the septum primum. In the presence of right ventricular overload lesions, the central defect of the foramen ovale was associated with a redundant flap valve of the septum primum billowing into the left atrium. In secundum type communications, the centrally located defect represented a deficiency rather than a redundancy of the septum primum. Balloon atrial septostomy (BAS) in 17 patients produced a secundum-type defect bordered by the flail remnants of the torn septum primum. Blalock-Hanlon septectomy (two patients) resulted in a large, posterior, sinus venosus-type communication which incorporated the preexisting BAS. Ostium primum defects (seven patients) were distinguished from the secundum lesions by their eccentric position in the IAS adjacent to the atrioventricular ring.
Determination of right atrial and right ventricular size by two-dimensional echocardiography.
Authors: Bommer W , Weinert L , Neumann A , Neef J , Mason D T , DeMaria A
Published: June 2012

No data are available on determining right atrial and right ventricular size by two-dimensional echocardiography. We performed two-dimensional echocardiograms on eight human right-heart casts obtained at autopsy and on 50 patients who underwent complete left- and right-heart catheterization. Measurement of individual dimensions of the long and short axes of the right atrium and ventricle from right heart casts closely correlated with the volume of these structures as determined by water displacement. Further, individual dimensions by cross-sectional echo correlated well with actual casts dimensions. Subsequently, echocardiographic measurements of right atrial and ventricular long and short axes were obtained in the apical four-chambered view in a group of normals and compared with a group of patients with right ventricular volume overload states. Mean values for right atrial short-axis and long-axis measurements were greater in right ventricular volume overload patients than in normals: 6.5 +/- 0.3 vs 3.6 +/- 0.1 cm, and 6.0 +/- 0.3 vs 4.2 +/- 0.1 cm, respectively (both p less than 0.001). In addition, measurements of both individual dimensions as well as planed area of the right ventricle were greater in right ventricular volume overload patients than in normals: maximal short axis 6.1 +/- 0.3 vs 3.5 +/- 0.2 cm, mid-short axis 6.1 %/- 0.4 vs 2.8 +/- 0.2 cm, and area 40 +/- 2.6 vs 18 +/- 1.2 cm2 (all p less than 0.001). There were no differences in right ventricular long-axis measurement. Two-dimensional echocardiography provided better separation of normals from right ventricular volume overload patients than did M-mode techniques. Thus, two-dimensional echocardiography, with the apical four-chambered view, enables accurate visualization of the right atrium and ventricle in almost all patients. Futher, measurements of right atrial and right ventricular size by two-dimensional echocardiography readily distinguish normal patients from those with right ventricular volume overload.
Loss of the improvement of angina between 1 and 7 years after aortocoronary bypass surgery: correlations with changes in vein grafts and in coronary arteries.
Authors: Campeau L , Lespérance J , Hermann J , Corbara F , Grondin C M , Bourassa M G
Published: June 2012

Improvement of effort angina following pure aortocoronary bypass graft surgery was related to postoperative control angiographic studies of grafts and coronary arteries in 75 unselected patients. Clinical and angiographic evaluations were carried out at approximately 1 year and at 5 to 7 years after surgery. At 1 year, 61 (81.3%) were improved (52 without angina and 9 with partial improvement by at least two functional classes), whereas 14 were unimproved (18.7%). At approximately 6 years, loss of improvement (reappearance of angina or aggravation by at least two functional classes) was observed in 22 of the 61 improved patients, representing an attrition of 36.1% over a 5-year period. Graft occlusion or a narrowing of over 50% was observed in two of the 39 patients in whom improvement had continued (5.1%), whereas it was found in six of the 22 patients (27.3%) whose results deteriorated (p less than 0.05). Similarly, progression to occlusion of a preexisting stenosis of over 50% or appearance of a new stenosis of over 50% in a major coronary artery (distal to a graft or in an unbypassed artery) was observed in five of the 39 patients with continued improvement (12.8%) and in 11 of the 22 patients whose condition deteriorated (p less than 0.01). Changes in a graft or in a coronary artery were noted in 63.6% (14/22) of the patients with loss of improvement as compared to only 18% (7/39) of the patients whose improvement did not deteriorate. Improvement of angina was also evaluated in all survivors among our first 500 cases who had preoperative effort angina and pure bypass surgery with or without angiographic studies. Of these 260 patients, 70.4% were angina-free or improved by two to three functional classes at 1 year, and only 41.9% at 7 years after surgery. It is concluded that the effect of aortocoronary bypass graft surgery is transient in a high proportion of patients and that deterioration of results is related to late graft modifications and progression of atherosclerosis, particularly in ungrafted coronary arteries.
Effects of nitroprusside and dopamine on pulmonary arterial vasculature in children after cardiac surgery.
Authors: Stephenson L W , Edmunds L H , Raphaely R , Morrison D F , Hoffman W S , Rubis L J
Published: June 2012

The hemodynamic effects of nitroprusside and dopamine were studied in 28 children early after intracardiac repair. Children were placed in six groups, five according to their anatomic lesion and one made up of those who had postoperative pulmonary artery hypertension, to evaluate the possible differences in response of the pulmonary arterial vasculature to the drugs. Seven children had repair of an atrial septal defect; six, repair of tetralogy of Fallot; four, repair of ventricular septal defect; five, surgery for pulmonary stenosis; one, closure of a left ventricular to right atrial tunnel; and five, postoperative pulmonary artery hypertension. Dopamine was infused at 8 microgram/kg/min, and nitroprusside at 3 microgram/kg/min. With dopamine, the heart rate increased an average of 10% and the cardiac index 11%; both increases were statistically significant. Changes in systemic and pulmonary vascular resistance, however, were not. With nitroprusside, the heart rate increased an average of 9% and the cardiac index 5%, while there was a significant decrease in both systemic (-20%) and pulmonary (-27%) vascular resistance. With the combination of dopamine and nitroprusside, both the cardiac index (+13%) and heart rate (+20%) increased significantly while systemic vascular resistance fell an average of 23% from control, and the pulmonary vascular resistance decreased 21%. Drug response among all five anatomic subgroups tended to be similar. We conclude that an afterload-reducing agent, such as nitroprusside and an inotropic drug such as dopamine, may have potential clinical advantages when used together in children providing heart rate does not become excessive.
Femoral artery pressure measurement during aortography.
Authors: Brewster D C , Waltman A C , O'Hara P J , Darling R C
Published: June 2012

Femoral artery pressure (FAP) measurements were carried out to evaluate the hemodynamic significance of aorto-iliac occlusive disease in 150 patients (173 limbs) at the time of transfemoral angiography. Clinical assessment based upon traditional criteria of claudication level, pulse examination, and monoplane angiography were at variance with the results of this physiologic testing in approximately one-third of the patients. Results were most variable, and FAP testing most helful in evaluating patients with moderate diffuse disease on angiography, who are usually difficult to evaluate clinically. Strong correlation existed between FAP evaluation and the results of arterial reconstructive surgery. Of the patients with a positive FAP result who underwent proximal vascular reconstruction, 96% had satisfactory relief of ischemic symptoms despite uncorrected distal disease in the majority. In contrast, 57% of the patients undergoing proximal operation despite a normal FAP result were unrelieved of symptoms and required subsequent distal procedures. Similar correlation existed with results of femoro-popliteal and femoro-femoral grafting. This simple physiologic test has been found of great value in selecting the proper level of arterial reconstruction and in accurately predicting the results of surgery.
Protection of mitochondrial function during ischemia by potassium cardioplegia: correlation with ischemic contracture.
Authors: Sink J D , Pellom G L , Currie W D , Chitwood W R , Hill R C , Wechsler A S
Published: June 2012

The effect of potassium cardioplegia on mitochondrial function was evaluated in the ischemic isolated rat heart. Mitochondrial function as well as adenosine triphosphate (ATP) levels were determined at the initiation of ischemic contracture, at the completion of ischemic contracture, and 20 minutes following contracture completion. Group I received no cardioplegia prior to ischemia, while Group II received potassium cardioplegia prior to the onset of ischemia. The respiratory control index (RCI), which is the primary measure of the intactness of mitochondrial function, was calculated with both a NAD (nicotinamide adenine dinucleotide)-linked substrate and a FAD (flavin adenine dinucleotide)-linked substrate. Potassium cardioplegia significantly delayed ischemic contracture initiation and completion. Although the RCI and ATP levels decreased significantly at successive levels of contracture, there was no difference in the RCI or ATP content between Group I and Group II at contracture initiation or completion. Unlike previous investigations that have used a time-base to examine mitochondrial function and acute cardiac ischemic injury, we correlated mitochondrial function with the measurable physiologic event ischemic contracture. The data indicated that potassium cardioplegia preserved ATP content and mitochondrial function, and that contracture initiation and completion correlate well with specific ATP levels and mitochondrial respiratory control. The relationship between mitochondrial function and ATP content indicates that the beneficial effect of potassium cardioplegia on mitochondrial function may be secondary to the preservation of high-energy phosphate levels which provide energy for mitochondrial maintenance.
Long-term serial angiographic studies after coronary artery bypass surgery.
Authors: Guthaner D F , Robert E W , Alderman E L , Wexler L
Published: June 2012

Twenty-six patients underwent repeat coronary angiography 5--8 years after saphenous vein coronary artery bypass surgery (SVCABG). These patients were selected from the first cohort of 117 patient who had SVCABG because they had obtained essentially complete relief of angina, and because all grafts were patent at initial angiography 11.2 months (mean) after surgery. Of the 39 grafts (1.5 grafts per patient) patent at 1 year, 34 (87.2%) were patent at reexamination 76 months (mean) (range 65--103 months) after SVCABG. Graft occlusion could not be predicted by the early angiographic appearance of the graft itself or its proximal or distal anastomosis. In some cases, narrowing or irregularity consistent with intimal hyperplasia appeared to progress, while in others it developed at late follow-up. Progressive narrowing occurred in 96% (22 of 23 grafted vessels) of the native coronary arteries proximal to the graft anastomosis. Progresssion to a stenosis greater than 75% or total occlusion was seen distal to the graft anastomosis in eight of 39 grafts (20%). Of 103 non-bypassed major vessels, 56% showed some progression of disease and half of these progressed to significant stenoses (greater than 75% luminal narrowing). There were no apparent predictors to indicate whether progression in nongrafted coronary arteries would occur preferentially in a previously stenotic or nonstenotic vessel, although 80% of vessels with initial stenoses greater than 75% progressed to total occlusion.
Influence of aortic insufficiency on the hemodynamic significance of a coronary artery narrowing.
Authors: Feldman R L , Nichols W W , Pepine C J , Conti C R
Published: June 2012

The coronary hemodynamic effects of controlled aortic insufficiency (AI) were studied in 10 dogs. Coronary blood flow (CBF), before and during reactive hyperemia (RH) with graded coronary diameter narrowings (CN), aortic (Ao) and left ventricular (LV) pressures (P), and aortic blood flow (AoF) were recorded. Opening an adjustable basket catheter, positioned across the aortic valve, created reversible AI quantitated from phasic AoF. AI was regulated so that mean CBF was similar with or without AI. During AI, heart rate and systolic AoP were unchanged, but diastolic AoP declined 14 mm Hg (mean) and end-diastolic LVP increased 8 mm Hg, both p less than 0.05. With CN greater than or equal to 85%, mean CBF decreased with or without AI. Coronary resistance was similar with or without AI. During AI with no CN, peak RH CBF declined significantly and was similar to peak RH with 70% CN without AI. Furthermore, AI with 60% CN caused additional reduction in peak RH and was similar to peak RH with 80% CN without AI. These data suggest that CBF reserve, exposed during RH, is decreased during AI. With AI, a given CN has coronary hemodynamic properties similar to higher degrees of CN without AI. These results may relate to clinical findings of ischemia in patients with AI and no or moderate CN.
An evaluation of the left atrial/aortic root ratio in children with ventricular septal defect.
Authors: Lester L A , Vitullo D , Sodt P , Hutcheon N , Arcilla R
Published: June 2012

Echocardiograms were performed in 80 infants and children with isolated ventricular septal defect (VSD) who underwent cardiac catheterization. The pulmonary-to-systemic flow ratio (Qp/Qs) was correlated with the echocardiographic left atrial-to-aortic root diameter ratio (LA/Ao), and a relatively poor correlation (r = 0.62) was found. The end-systolic diameters of the left atrium and aorta at the level of the aortic root, obtained from lateral cineangiograms of 55 of the 80 patients, were compared with the corresponding echocardiographic dimensions. To assess the possible effect of transducer beam angulation upon the echocardiographic determinations, the angiographic measurements were made at 0 degrees position (perpendicular to the frontal plane) and at angles of 5 degrees, 10 degrees, 15 degrees and 20 degrees from zero, using the aortic root center as the point of intersection. The echocardiographic and angiographic aortic root measurements were comparable (r = 0.95), and the angiographically derived aortic diameter did not vary with different angle projections. However, the left atrial angiographic dimensions were significantly influenced by the angle of projection. We conclude that the echocardiographic LA/Ao ratio cannot reliably estimate the severity of the shunt flow in VSD.
Routine primary repair vs two-stage repair of tetralogy of Fallot.
Authors: Kirklin J W , Blackstone E H , Pacifico A D , Brown R N , Bargeron L M
Published: June 2012

Fifteen of 194 patients (7.7%) with tetralogy of Fallot operated upon since January 1, 1972 under a protocol of routine primary repair despite young age died in-hospital. Most deaths were from low cardiac output. Young age and smallness of size increased the risk of operation. No deaths occurred among patients older than 4 years. High hematocrit was also a risk factor. Transannular patching has an independent effect in increasing risk. The post-repair ratio of peak pressure in the right ventricle to that in the left did not exert an independent effect. To project current risks of a two-stage approach, we determined that five of 158 patients (3.2%) died in-hospital after secondary intracardiac repair after a previous Blalock-Taussig or Waterston anastomosis between 1967--1978. Using these data and those we have published on the risk of shunting, we project that except in very small babies, the risks of hospital death of a two-stage approach are not less than those of primary repair done without a transannular patch, except when body surface area is less than about 0.35 m2. When a transannular patch is used in the primary repair, the two-stage approach is projected to be safer when the child has a body surface area of about 0.48 m2 or smaller.
Physiologic determinants of the electrocardiographic diagnosis of left ventricular hypertrophy.
Authors: Antman E M , Green L H , Grossman W
Published: June 2012

The relative importance of left ventricular (LV) geometry, wall thickness, and mass on the inscription of left ventricular hypertrophy (LVH) on the ECG was examined in 93 patients; 36 had no LVH on the ECG, 10 had borderline voltage for LVH, and 47 had LVH on the ECG. LV cineangiograms in the right anterior oblique projection were analyzed for LV end-diastolic volume, free wall thickness (h), semiminor radius (R), LV mass index (LVMI), and the geometric relations described by h/R, mass/volume, and h . R. Although mean LVMI was greater in patients whose ECG voltage was either borderline or diagnostic of LVH, increased LVMI also occurred without LVH on the ECG. None of the variables (h, R, h/R or mass/volume) reliably indicated when LVH would be inscribed on the ECG. The product of h . R, however, defined three electrocardiographic groups; all patients with LVH on their ECG had h . R greater than 2.6 cm2. Wall thickening sufficient to result in an increased LV mass did not result in LVH on the ECG unless sufficient concurrent chamber dilatation was present. Thus, a critical geometric relationship resulting from the interplay of wall thickness and chamber dilatation is necessary for LVH to appear on the ECG. This finding is consistent with the solid-angle theory of electrocardiography as it relates to ventricular hypertrophy.
Early closure of the tricuspid valve in a case of Ebstein's anomaly with type B Wolff-Parkinson-White Syndrome.
Authors: Koiwaya Y , Narabayashi H , Koyanagi S , Matsuguchi H , Tanaka S , Imaizumi T , Kuroiwa A , Nakamura M , Hirata T
Published: June 2012

Echocardiographic studies of a 19-year-old female with Ebstein's anomaly and type B Wolff-Parkinson-White syndrome showed an earlier closure of the anterior tricuspid leaflet (ATL) than of the anterior mitral leaflet (AML), contrary to the previous reports. The interval between the closure of the ATL and the AML was 20 msec and 30 msec, respectively, before and after administration of edrophonium chloride. However, closure of the AML preceded that of the ATL after administration of atropine sulfate and during supraventricular tachycardia by 10 msec and 60 msec, respectively, concomitant with the shortening of the duration of the QRS complex. We conclude that early closure of the ATL may depend on preexcitation of the right ventricle.
Effect of septal myotomy and myectomy on left ventricular systolic function at rest and during exercise in patients with IHSS.
Authors: Borer J S , Bacharach S L , Green M V , Kent K M , Rosing D R , Seides S F , Morrow A G , Epstein S E
Published: June 2012

Patients with idiopathic hypertrophic subaortic stenosis (IHSS) have supernormal left ventricular systolic function at rest. Septal myotomy/myectomy reduces outflow obstruction and symptoms. However, it has been proposed that operation causes myocardial damage, with consequent reduction in left ventricular function and potentially deleterious long-term consequences, despite relief of symptoms. To evaluate the effect of myotomy and mylectomy on left ventricular function, we employed noninvasive radionuclide cineangiography at rest and during maximal exercise in21 consecutive patients with IHSS, before and 6 months after operation. In 30 normal subjects, the ejection fraction (EF) was 57 +/- 2% at rest and 71 +/- 2% during exercise. Before operation in patients with IHSS, the EF was supernormal at rest (76 +/- 2%, p less than 0.001), and normal during exercise (71 +/- 3%, NS). All patients improved from NYHA functional class III-IV preoperatively to class I-II postoperatively; the maximal provocable gradient invariably diminished (average, 100 +/- , mm Hg preop, 33 +/- 9 mm Hg postop, p less than 0.001). Postoperatively, the EF at rest was 67 +/- 2%, still supernormal, but less than that noted preoperatively (p less than 0.001). During exercise, the EF was 66 +/- 4%, only mildly diminished (p less than 0.01) from that preoperatively. We conclude that muscle resection during myotomy and myectomy usually does not cause any important impairment of global left ventricular function at rest or during exercise stress.
Reentrant ventricular arrhythmias in the late myocardial infarction period. 7. Effect of verapamil and D-600 and the role of the "slow channel".
Authors: El-Sherif N , Lazzara R
Published: June 2012

Reentrant ventricular arrhythmias (RVA) were analyzed in dogs 3--7 days after ligation of the anterior descending coronary artery using averaged "composite" recordings of electrical activity of reentrant pathways (RP) from the epicardial surface of the infarction zone (IZ). Verapamil (V) and D-600 (D) (0.2--0.5 mg/kg i.v.) resulted in slight-to-moderate improvement of conduction in RP with abolition of spontaneous RVA and RVA initiated by premature depolarizations. The effect of V was not blocked by pretreatment with propranolol (0.5 mg/kg i.v.). Using a standard microelectrode technique and strips of epicardial muscle from the IZ, D (0.5--1 X 10(-6) g/ml) slightly improved the upstroke velocity and membrane responses of depressed ischemic cells. In contrast, tetrodotoxin (5 X 10(-7) g/ml) further depressed or abolished action potentials of ischemic cells. We conclude: 1) the moderate antiarrhythmic effect of V and D on RVA is the result of improved conduction in RP; 2) this action is partly explained by improvement of a depressed sodium channel and is not related to catecholamine release; 3) slow-response action potentials play no significant role in the genesis of ischemia-related RVA, which probably results from depression of the fast response.
Concealed nonparoxysmal junctional tachycardia.
Authors: Wyndham C R , Dhingra R C , Smith T , Best D , Rosen K M
Published: June 2012

Electrophysiologic studies were performed in a patient who had an apparently uncomplicated complete trifascicular block. His bundle recordings revealed atrioventricular dissociation with: 1) an atrial rate of 58 beats/min, 2) an idioventricular escape rate of 45 beats/min, and 3) nonparoxysmal junctional tachycardia (His bundle rhythm) at a rate of 65--85 beats/min. The latter arrhythmia was electrocardiographically silent, influencing neither atrial nor ventricular events. The arrhythmia probably reflected digitalis intoxication (digoxin level of 3.3 ng/ml). A repeat electrophysiologic study 4 days after digoxin was discontinued revealed complete trifascicular block (distal to H) with intact conduction between the atrium and the His bundle (AH of 150 msec). Thus, electrophysiologic study demonstrated an electrocardiographically silent but clinically relevant arrhythmia, suggesting that His bundle recording should be part of diagnostic study during temporary pacemaker implantation in patients with atrioventricular block.
Comparison of M-mode and cross-sectional echocardiography in infective endocarditis.
Authors: Wann L S , Hallam C C , Dillon J C , Weyman A E , Feigenbaum H
Published: June 2012

Cross-sectional and M-mode echocardiograms were performed on 23 consecutive patients with infective endocarditis. Both M-mode and cross-sectional echocardiography identified vegetations in 18 patients, 10 of whom required valve replacement within 1 month of presentation. Cross-sectional echocardiography alone identified a vegetation in one patient with a prosthetic valve. Neither technique identified vegetations in five instances. The size and shape of a vegetation on cross-sectional echocardiography did not accurately predict the need for early valve replacement of the incidence of major peripheral emboli.
Can cardiac tamponade be diagnosed by echocardiography? Experimental studies.
Authors: Martins J B , Kerber R E
Published: June 2012

The purpose of this study was to determine if respiratory variation and/or absolute size of echocardiographically measured right or left ventricular internal dimension at end-diastole (RVIDd or LIVIDd) are accurate indicators of the presence or severity of cardiac tamponade. We measured RVIDd or LVIDd by echocardiography in nine closed-chest, spontaneously breathing dogs in control and during hypotensive tamponade. With tamponade, the end-expiratory RVIDd and LVIDd were significantly smaller than control. Inspiratory increases in RVIDd and decreases in LVIDd were exaggerated during tamponade. Because of the wide range and overlap of RVIDd and LVIDd, no single expiratory value or amount of respiratory change indicated the presence or severity of tamponade. We conclude that if serial echocardiograms show a pericardial effusion, a decreasing end-expiratory RVIDd and LVIDd and an increasing percentage change in ventricular diameter with inspiration, a progressive degree of tamponade should be suspected However, a single echocardiogram cannot accurately predict the presence or severity of tamponade.