bluuebunny/crossref_metadata_2025 huggingface dataset:
Radioimmunoassay for human myoglobin. Initial experience in patients with coronary heart disease.
Authors: Reichlin M , Visco J P , Klocke F J
Published: June 2012

A radioimmunoassay for human myoglobin has been used to study the serum myoglobin level in 13 normal individuals and 68 patients admitted to a Coronary Care Unit because of chest pain. Values in normal individuals ranged from 3 to 75 and averaged 25 +/- 23 (SD) ng/ml. Thirty-two patients with myocardial infarction initially examined within 12 hours of the onset of chest pain all showed clear-cut elevations in serum myoglobin, peak values ranging from 200 to 5500 and averaging 1368 +/- 1357 ng/ml. Seventeen patients with clinically atypical chest pain and no subsequent evidence of myocardial necrosis had myoglobin levels in the normal range, as did 11 of 19 patients with chest pain thought clinically to represent myocardial ischemia but no subsequent evidence of myocardial necrosis by conventional criteria. The final eight patients in the latter group showed mild elevations of serum Mb, peak values ranging from 102 to 280 and averaging 162 +/- 52 ng/ml; the basis for these elevations remains to be clarified.
Mummification of the infarcted myocardium by high dose corticosteroids.
Authors: Kloner R A , Fishbein M C , Lew H , Maroko P R , Braunwald E
Published: June 2012

There is evidence that glucocorticoids reduce infarct size but their use in myocardial infarction remains controversial because of their potential adverse effects on healing of the infarct. To investigate the healing process, rats received either four parenteral doses of 50 mg/kg of methylprednisolone (MP) or saline 5 min, 3,6 and 24 hr after coronary occlusion and their hearts were examined by light and electron microscopy 48 hr and seven days after occlusion. At 48 hr, in five untreated rats, only 12 +/- 7% of injured myocytes showed the persistence of striations and a relatively intact sarcolemma despite loss of nuclei and hence appeared "mummified" whereas in six MP-treated rats 72 +/- 8% of myocytes exhibited this appearance (P less than 0.001). In treated rats there were fewer phagocytes than in controls. At seven days, in seven MP-rats, mummified cells were still more prominent than in five untreated rats and there were fewer phagocytes and less collagen. In conclusion, high dose of MP delays the inflammatory process and retards the disintegration of necrotic myocytes, resulting in impaired healing.
Alpha and beta adrenergic effects on human atrial specialized conducting fibers.
Authors: Mary-Rabine L , Hordof A J , Bowman F O , Malm J R , Rosen M R
Published: June 2012

We determined the effects of epinephrine on automaticity and action potential characteristics of right atrial specialized fibers (RAF) from human atria obtained during cardiac surgery. RAF were studied with standard microelectrode techniques during superfusion with Tyrode's solution at 37 degrees C. A biphasic response to epinephrine was seen, rate slowing at low agonist concentrations and increasing at high concentrations. The epinephrine-induced slowing of spontaneous rate was due to a decrease in the slope of phase 4 depolarization. At the high epinephrine concentrations RAF hyperpolarized. The alpha-adrenergic blocker, phentolamine, shifted the dose-response curve upward and to the left and enhanced the hyperpolarization of RAF. The beta blocker, propranolol, shifted the curve to the right and decreased the degree of hyperpolarization. Our study suggests the presence of alpha and beta receptors in RAF. The alpha response consists of a slowing of rate, the beta response of an acceleration of rate and hyperpolarization of RAF.
Cardiac trauma from angiographic injections. A quantitative study.
Authors: Abbott J A , Lipton M J , Kosek J , Hayashi T , Lee F C
Published: June 2012

To relate angiographic injections to potential cardiac trauma, we verified a mathematic theory that allows quantitative definition of the kinetic energy content of contrast jets emanating from the exit holes of angiographic catheters. Cineangiographic recordings of a range of jets of known energy content were obtained in 18 cardiac canine experiments and energy content and dissipation were quantified precisely from center line to jet edge. All contrast jets produced in clinical angiographic practice were turbulent, even those from hand injections into the coronary arteries. Energy content was related to an estimated cardiac wall damage threshold. At energy levels and damage thresholds predicted by the theory and computations, a traumatic spectrum was found by cineradiology and microscopic examination. A unique curve independent of jet Reynolds number was discovered relating the penetration of the contrast jet into the intravascular blood to the potential for cardiac trauma. This curve allowed ready calculation of hydraulic energy dissipation for any clinically used angiographic catheter and the definition of safe operational injection flow rates. Thus potential cardiac trauma can be anticipated and prevented.
Studies on the mechanism of sinus node dysfunction in the sick sinus syndrome.
Authors: Jordan J L , Yamaguchi I , Mandel W J
Published: June 2012

The intrinsic heart rate (IHR) was determined in 17 patients with symptomatic sinus bradycardia by administering atropine 0.04 mg/kg and propranolol 0.2 mg/kg, i.v. In this way, sick sinus (SSS) patients with intrinsic sinus node (SN) dysfunction could be distinguished from those patients with disturbed autonomic regulation of SN function. Sick sinus syndrome patients with normal corrected sinus node recovery time (SNRTC), adjusted for the magnitude and direction of autonomic chronotrophy, consistently had normal IHRs and therefore abnormalities of autonomic regulation. Sick sinus syndrome patients with abnormal adjusted SNRTC consistently had abnormal IHRs and therefore abnormalities of intrinsic SN function. We conclude that more than one pathophysiologic mechanism can produce the clinical manifestations of sick sinus syndrome and that abnormal prolongation of SNRTC is dependent upon the underlying mechanism of sinus node dysfunction.
Prevalence and characteristics of disproportionate ventricular septal thickening in patients with coronary artery disease.
Authors: Maron B J , Savage D D , Clark C E , Henry W L , Vlodaver Z , Edwards J E , Epstein S E
Published: June 2012

Echocardiographic or necropsy studies were performed in 151 patients with coronary artery disease. Prevalence of disproportionate septal thickening (septal to free wall ratio greater than or equal to 1.3) was 11%. An abnormally increased septal-free wall ratio in these patients had two principal etiologies. First, it was a manifestation of genetically transmitted hypertrophic cardiomyopathy, as evidenced by disproportionate septal thickening in first degree relatives. Second, it was due to disproportionate septal thickening which did not appear to be a manifestation of genetically transmitted hypertrophic cardiomyopathy. This latter conclusion was suggested by negative echocardiographic studies in some families of patients with both coronary artery disease and disproportionate septal thickening. In addition, numerous disorganized cardiac muscle cells, characteristically present in patients with genetically transmitted hypertrophic cardiomyopathy, were absent from the septum of all patients with disproportionate septal thickening studied at necropsy. Although the mechanism responsible for this secondary type of disproportionate septal thickening is unknown, our results indicate that the presence of disproportionate septal thickening in a patient with coronary artery disease does not, per se, indicate the coexistence of genetically transmitted hypertrophic cardiomyopathy.
Left ventricular anomalies associated with Ebstein's malformation of the tricuspid valve.
Authors: Monibi A A , Neches W H , Lenox C C , Park S C , Mathews R A , Zuberbuhler J R
Published: June 2012

Seventeen patients with Ebstein's malformation of the tricuspid valve have been evaluated. The majority of patients (11/17) presented in the newborn period with cyanosis and cardiomegaly. The remainder (6/17) were referred because of cardiomegaly on chest X-ray and/or a heart murmur heard on routine examination. Three patients have died; one in the newborn period and two suddenly at the age of 11 and 15 years. Thirteen patients have undergone right and left heart cardiac catheterization within the last seven years. Twelve of these 13 patients (92%) had angiocardiographic left ventricular contraction abnormalities. Five patients also had mitral valve prolapse associated with left ventricular dysfunction. Since many patients with Ebstein's anomaly may have significant left ventricular abnormalities, careful and systematic evaluation of the left ventricle is warranted.
The rate of atherosclerosis change during treatment of hyperlipoproteinemia.
Authors: Blankenhorn D H , Brooks S H , Selzer R H , Barndt R
Published: June 2012

The rate of change of femoral atherosclerosis has been determined in 25 treated hyperlipoproteinemic patients. There were 13 Type II patients and 12 Type IV patients. Serial angiograms had been performed at an interval averaging 13 months. Film densities were analyzed by digigal image processing to yield a computer estimate of atherosclerosis (CEA). Serial measurements of CEA on each patient were used to determine atherosclerosis percent change per month in that patient. CEA percent change per month was significantly correlated ;ith triglyceride and cholesterol level. Lower lipid levels were associated with more rapid regression. When hyperlipoproteinemic types were considered separately, significant single correlates were confined to Type IV. Triglyceride level and CEA/age significantly predicted atherosclerosis change rate and accounted for 72% of the variability observed in Type IV patients.
Efficacy of dopamine, dobutamine, and epinephrine during emergence from cardiopulmonary bypass in man.
Authors: Steen P A , Tinker J H , Pluth J R , Barnh;rst D A , Tarhan S
Published: June 2012

Hemodynamic effects of dobutamine and dopamine (both 5, 10, 15 microgram/kg/min) and epinephrine (0.04 microgram/kg/min) were studied immediately following cessation of cardiopulmonary bypass in 34 patients with preoperative evidence of left ventricular dysfunction. Significant increases in mean cardiac index were seen with dobutamine (15, 25, and 26% respectively), and epinephrine (30%). The largest increases occurred with dopamine (44, 53, and 64 percent respectively). Responses varied from patient to patient, however. Seven patients developed marked output increases without concomitant increases in arterial pressure, whereas seven others showed "satisfying" increases in arterial pressure without appreciable output increases. Heart rate increases were small and few arrhythmias were noted. We conclude that dopamine, epinephrine, and dobutamine all are effective inotropic agents during the immediate post-bypass period, with variations discussed in detail. None possess the disturbing chronotropic and arrhythmogenic effects of isoproterenol (previously studied). Efficacy of administration of inotropic drugs seems best assessed by serial output measurements during this period.
De subitaneis mortibus. XXVIII. Apoplexy of the heart.
Authors: James T N
Published: June 2012

Apoplexy of the heart can be responsible for sudden and for recurring instability of cardiac rhythm and conduction, and for the clinical counterparts of syncope and sudden death. Every pathophysiological mechanism which produces cerebral apoplexy has its counterpart in apoplexy of the heart. Among the mechanisms documented are thrombosis, embolism and rupture of those special vessels supplying the sinus node, atrioventicular (A-V) node and His bundle. Apoplexy of the heart can occur either with or without significant or recognizable ventricular myocardial infarction. Acute vascular accidents within the critical centers of cardiac impulse formation and conduction deserve more frequent consideration in the explanation of unusual cases of "epilepsy", of seizure disorders of the elderly, of neurologic manifestations (which may be secondary as well as primary) of systemic diseases such as lupus erythematosus or thrombotic thrombocytopenic purpura, and indeed of every case of otherwise unexplanined syncope or sudded death at any age.
A criss-cross heart with concordant atrioventriculo-arterial connections. Report of a case.
Authors: Sato K , Ohara S , Tsukaguchi I , Yasui K , Nakada T , Tamai M , Kobayashi Y , Kozuka T
Published: June 2012

A distinctive angiographic appearance is described in a case of "criss-cross" heart with concordant atrioventriculo-arterial connections. The atrial situs was normal, and the morphological right ventricle was superior to the left ventricle, and the ventricular septum was horizontal in position. Both ventricleswere connected by a small ventricular septal defect. The aorta was situated anteriorly and to the right of the pulmonary artery. Although the cardiac segment was the apparent [S,L,D] type, the heart had conconrdant atrioventriculo-arterial connections. The ventricular rotation of the solitus heart about the longitudinal and the anteroposterior axis affected the atrioventricular flows, the plane of the ventricular septum, the inflow and outflow tracts of the ventricles, the interrelationship of the great arteries, and the course of the left coronary artery. Using the recent definition of criss-cross heart, we classified the heart as solitus-concordant (l-rotated) -normal.
Re-entrant ventricular arrhythmias in the late myocardial infarction period. 5. Mechanism of action of diphenylhydantoin.
Authors: El-Sherif N , Lazzara R
Published: June 2012

The mechanism of action of diphenylhydantoin (DPH) on re-entrant ventricular arrhythmias (RVA) was studied in dogs 3-7 days following ligation of the anterior descending coronary artery utilizing direct recordings of the re-entrant pathway (RP) from the epicardial surface of the infarction zone (IZ). DPH in a therapeutic dose consistently prolonged refractoriness of potentially RP in the IZ. This resulted in further impairment and/or block of conduction in the RP and was directly responsible for DPH ability to abolish RVA. On the other hand, DPH had no significant effect on conduction in the adjacent normal zone. Prior to abolition of RVA initiated by premature beats (PBs), DPH resulted in: 1) narrowing of the critical range of coupling intervals of PBs that resulted in re-entry (i.e., the re-entry zone), 2) shift of the narrowed re-entry zone to longer cardiac cycle lengths, and 3) lengthening of the coupling interval of the first re-entrant beat, as well as slowing the rate of re-entrant tachycardia. Thus DPH, similar to lidocaine, owes its antiarrhythmic action in RVS to its selective depressant effect on ischemic cells forming part of the RP.
The noninvasive diagnosis of right ventricular infarction.
Authors: Sharpe D N , Botvinick E H , Shames D M , Schiller N B , Massie B M , Chatterjee K , Parmley W W
Published: June 2012

We evaluated scintigraphy and echocardiography for the diagnosis of right ventricular (RV) infarction. Of 26 patients with acute transmural myocardial infarction (MI), six with inferior MI had abnormal radionuclide uptake localized to the RV free wall on infarct scintigraphy or segmental akinesis of the RV free wall on gated radioangiography or both. These six patients with RV involvement (group I) were compared with the remaining nine with inferior MI (group II) and 11 with anterior MI (group III). RV/LV area ratios determined radioangiographically were significantly greater in group I than group II in diastole and systole. Echocardiographic RV enddiastolic dimension and RV/LV end-diastolic dimension ratio were significantly greater and RV stroke work index was significantly lower in group I than in group II. Predominant RV involvement in inferior MI may occur commonly. Anatomic and functional evidence of this diagnosis can be obtained noninvasively.
Cross-sectional echocardiographic detection of aortic obstruction. 2. Coarctation of the Aorta.
Authors: Weyman A E , Caldwell R L , Hurwitz R A , Girod D A , Dillon J C , Feigenbaum H , Green D
Published: June 2012

Cross-sectional echocardiographic studies of the aortic arch and proximal descending aorta were performed in 18 patients with coarctation of the aorta and 20 normal subjects. In normals the aortic arch and proximal descending aorta appeared as an arcuate, echo-free structure curving across the plane of the scan. There were no localized changes in aortic diameter and the amplitude of aortic systolic pulsation was symmetrically maintained throughout the scan plane. Visualization of this region was possible in 16 of 18 patients with coarctation. In each of these cases there was a localized area of decrease in aortic diameter in the region of the left subclavian artery which corresponded to the angiographic appearance of the coarctation. In addition prominent systolic pulsation of the aortic arch proximal to the region of obstruction was evident. Cross-sectional echocardiography may offer a useful noninvasive method for direct visualization of aortic coarctation.
Failure of high doses of propranolol to reduce experimental myocardial ischemic damage.
Authors: Peter T , Heng M K , Singh B N , Ambler P , Nisbet H , Elliot R , Norris R M
Published: June 2012

Myocardial creatine phosphokinase (CPK) activity and myocardial blood flow (MFB, 15 +/- mu microspheres) were measured at 24 hours after ligation of the left anterior descending coronary artery in nine untreated anesthetized dogs, in eight dogs pretreated with intravenous propranolol 5 mg/kg and in eight which had both pretreatment as well as infusion of propranolol (1.25 mg/kg/hour) after occlusion. Loss of CPK activity from the border and center zones of the myocardial infarct was similar in extent in dogs which had pretreatment but no infusion of propranolol as it was in the control group. Loss of CPK from the center zone was greater (P less than 0.005) in dogs receiving pretreatment followed by constant infusion of the drug. Propranolol had no significant effect on collateral blood flow to the border or center zone of the infarct. In separate experiments, there was no important difference in hemodynamic measurements, except a slower heart rate (P less than 0.01), when pretreated dogs were compared with control dogs up to 2 hours after coronary ligation. We conclude that propranolol given in this dose does not influence nyocardial damage, on the basis of regional myocardial blood flow or tissue CPK depletion values at 24 hr after coronary occlusion.
Effects of a cardiac glycoside in combination with propranolol on the ischemic heart of conscious dogs.
Authors: Vatner S F , Baig H , Manders W T , Murray P A
Published: June 2012

The effects of coronary occlusion and of subsequent propranolol and ouabain administration were examined in 12 conscious dogs. Overall left ventricular (LV) function was assessed by measurement of LV pressure and dP/dt, and regional myocardial function was assessed by measurements of segment length (SL), velocity of SL shortening and regional myocardial "work," i.e., pressure-length loops in normal and moderately and severely ischemic zones. Regional intramyocardial electrograms were measured at the same sites as function along with regional myocardial blood flow as determined by the radioactive microsphere technique. Coronary occlusion resulted in graded loss of function from the normal to severely ischemic zones, along with graded flow reductions and graded elevation of the ST segment. Propranolol, 1 mg/kg, depressed overall LV function and function in the normal zone more than in ischemic zones. Propranolol reduced flow to the normal zone and increased flow to ischemic zones, while not affecting ST-segment elevation significantly. In the presence of occlusion and propranolol, ouabain, 20 microgram/kg, improved overall LV function as well as regional function in the normal, moderately ischemic and severely ischemic zones. In addition, ouabain reduced ST elevation and increased blood flow further in moderately and severely ischemic zones. Most strikingly, ouabain returned normal systolic shortening to eight severely ischemic segments which were previously akinetic.
A guide to the radiographic identification of prosthetic heart valves.
Authors: Mehlman D J , Resnekov L
Published: June 2012

To facilitate the radiographic identification of prosthetic heart valves, radiographic silhouettes of various aortic, mitral and tricuspid valve prostheses were analyzed and shematized. Forty different prosthetic valve models (heterograft and mechanical) were obtained from seven domestic manufacturers. Each prosthesis was positioned to approximate the aortic, mitral or tricuspid valve anulus plane. The valves were then radiographed and photographed as they would appear in posteronanterior and left lateral chest radiographs. The radiographic silhouettes were examined and a scheme was designed to enable easy, yet accurate, differentiation of the many heart valve prostheses. Illustrations of the various valve types are presented as they would appear in routine chest radiographs.
Effect of nitroprusside on regional myocardial blood flow in coronary artery disease. Results in 25 patients and comparison with nitroglycerin.
Authors: Mann T , Cohn P F , Holman L B , Green L H , Markis J E , Phillips D A
Published: June 2012

The effect of nitroprusside on regional myocardial specific blood flow (RMBF) was evaluated in 25 patients with the xenon-133 washout technique. Six patients were normal (group 1), six patients had coronary artery disease without collateral vessels (group 2), and thirteen patients had coronary artery disease with collateral vessels (group 3). In group 1, RMBF was unchanged following nitroprusside. RMBF decreased significantly in both group 2 and group 3, including seven patients in group 3 with high-grade collateral vessels. The results were compared to the effect of nitroglycerin in 31 patients previously studied using the same technique. Mean arterial pressure and pressure-rate product were comparably reduced by both drugs. In contrast to the findings with nitroprusside, after sublingual nitroglycerin RMBF decreased markedly in normals and increased in patients with coronary artery disease and high-grade collaterals. The data suggest that nitroprusside may primarily affect resistance vessels within the coronary circulation, as opposed to the effect of nitroglycerin on conductance vessels. Thus, nitroprusside could result in redistribution of blood flow away from ischemic areas and potentially increase ischemic injury in some patients with coronary artery disease.
Etiology of the negative chronotropic responses to transient coronary artery occlusion in the anesthetized rhesus monkey.
Authors: Alter W A , Hawkins R N , Evans D E
Published: June 2012

Etiology of the negative chronotropic response to coronary artery occlusion was studied in chloralose-anesthetized monkeys. One-minute occlusion of the circumflex (CIRC) coronary artery resulted in marked negative chronotropic responses and consistent alterations in atrial electrograms. These responses were dependent on interruption of flow to a small proximal CIRC branch, and postmortem examination revealed that it perfused the sinus node region. The negative chronotropic response was not dependent on any apparent neural reflexes because it was not affected by autonomic blockade. Coronary artery occlusion in anesthetized monkeys can result in significant decreases in heart rate and changes in atrial electrical activity when flow to the pacemaker region is interrupted. We suggest that (1) rhesus monkeys may be suitable for study of the sick sinus syndrome, and (2) atropine-resistant bradycardia and atrial arrhythmias observed in postinfarction patients may be due to sinus node artery blockade.
Effect of acute volume alterations on norepinephrine and dopamine-beta-hydroxylase in normotensive and hypertensive subjects.
Authors: Lake C R , Ziegler M G
Published: June 2012

Fifty-six patients with essential hypertension and 29 normotensive controls were hospitalized and volume expanded with saline or volume depleted with furosemide. We measured plasma norepinephrine (NE) and dopamine-beta-hydroxylase (DBH) to evaluate their sympathetic nervous activity. NE and DBH levels and their response to volume changes were the same in normal and hypertensive subjects. Volume depletion increased plasma NE in recumbent subjects by 50% and in standing subjects by 75% but did not alter DBH. Volume expansion with 2 liters of normal saline did not generally alter plasma NE, but led to a small decrease in DBH. Hypertensives have normal plasma levels of NE and DBH and normal responses of NE and DBH to alterations in volume and posture. The human sympathetic nervous system increases NE output during volume depletion, but fails to decrease NE during volume expansion.
Determinants of growth in patients with ventricular septal defect.
Authors: Levy R J , Rosenthal A , Miettinen O S , Nadas A S
Published: June 2012

Growth status was studied in 1210 patients with ventricular septal defects (VSD) participating in the Joint Study on the Natural History of Congenital Heart Defects. A total of 793 patients were managed medically and 194 underwent successful surgical repair. Admission measurements revealed height and weight status to be subnormal and related to physiological severity and age. Successful repair resulted in significant increase in weight but not height. Medical therapy was associated with little change in the subnormal growth pattern. Multivariate analysis revealed determinants of admission height for all patients with VSD to be presence of extracardiac anomalies, birthweight below 2.5 kg, admission age greater than 2 years, history of heart failure and pulmonary/systemic pressure ratio. The same determinants were noted for admission weight with addition of pulmonary/systemic flow ratio. It is conluded that the severe growth disturbance in patients with VSD is only in part due to abnormal postnatal hemodynamics. Intrauterine and genetic factors and low birthweight also play a role and help explain the incomplete growth response after successful surgery.
Left ventricular function following attempted surgical repair of tetralogy of Fallot.
Authors: Rocchini A P , Keane J F , Freed M D , Castaneda A R , Nadas A S
Published: June 2012

Left ventricular function was assessed by angiographic methods in 40 patients (ages 3-27), 1-12 years following repair of tetralogy of Fallot. Twenty of the 40 patients (group A) had a satisfactory repair with a pulmonary-systemic flow ratio (Qp/Qs) less then or equal to 1.5 and a right ventricular systolic pressure of less than or equal to 60% of the left ventricular value. The other 20 patients (group B) had a Qp/Qs greater than 1.5 and/or a right ventricular systolic pressure greater than 60% of the left ventricular value. Group A patients had a normal left ventricular end-diastolic volume (LVEDV), end-diastolic pressure (LVEDP), ejection fraction (LVEF), and mass (LVM), while the group B patients had significantly elevated LVEDV, LVEDP, LVM, and a significantly depressed LVEF. These findings indicate that patients with a satisfactory hemodynamic repair of tetralogy of Fallot have normal left ventricular function while patients with postoperative unsatisfactory hemodynamics have significantly impaired left ventricular function.
Endomyocardial disease and eosinophilia. Report of a case.
Authors: Jaski B E , Goetzl E J , Said J W , Fishbein M C
Published: June 2012

While an association between blood eosinophilia and endomyocardial disease has been recognized, the role of the eosinophil in the pathogenesis of the cardiac lesions remains uncertain. In a 69-year-old-man with large cell carcinoma of the lung, marked eosinophilia was stimulated by and progressed with the course of the neoplasm which was producing an eosinophil chemotactic factor. Peripheral blood eosinophils were vacuolated and degranulated while those in the bone marrow were morphologically normal. Clinical evidence of cardiac dysfunction developed one month prior to death. At autopsy, 12 months after the onset of symptoms, endomyocardial disease was present. There were numerous eosinophils in the damaged myocardium and surrounding the pulmonary neoplasm. In patients with endomyocardial disease and eosinophilia, the eosinophil may be directly cardiotoxic or a primary mediator of cardiac damage; therapeutic attempts to reduce the number of eosinophils might be benefit.
Physiologic improvement following coronary artery bypass surgery.
Authors: Miller D W , Bruce R A , Dodge H T
Published: June 2012

In this study the effects of coronary artery bypass surgery on ventricular function were evaluated at rest by quantitative analysis of segmental wall motion on cineventriculography, and during maximal treadmill exercise by measurement of serial cardiac outputs (Fick method) with the use of indwelling pulmonary artery and radial artery catheters. The patient had single vessel coronary disease and exertional angina. Following placement of a bypass graft to the proximally occluded left anterior descenting coronary artery, and despite the presence of arterial hypoxemia secondary to interstitial pulmonary fibrosis, a striking increase in maximal cardiac output occurred, mediated by a rise in both maximal heart rate and stroke volume. In this patient, resting ventricular volumes and ejection fraction were normal both before and after surgery, but preoperative abnormalities in extent of segmental wall motion, identified quantitatively, were restored to normal after bypass grafting. These investigations indicate that bypass surgery can provide substantial physiologic benefits in addition to providing subjective relief of anginal symptoms.
Anticoagulant therapy and central nervous system complications in patients with prosthetic valve endocarditis.
Authors: Wilson W R , Geraci J E , Danielson G K , Thompson R L , Spittell J A , Washington J R , Giuliani E R
Published: June 2012

Among 52 cases of prosthetic valve endocarditis, adequate anticoagulant therapy was administered in 38 and discontinued or given in subtherapeutic dosage in 14. Our data suggest that anticoagulant therapy does not appreciably increase morbidity or mortality in patients with prosthetic valve endocarditis. On the contrary, in our patients the incidence of major clinical CNS (central nervous system) complications was increased and the mortality was higher if anticoagulant therapy was discontinued. CNS complications occurred in 10 of the 14 patients without adequate anticoagulant therapy and in three of the 38 with adequate anticoagulant therapy. Mortality was 57% among those treated without adequate anticoagulation and 47% among those with adequate anticoagulation. At autopsy, CNS complications were thought to be the primary cause of five of the eight deaths in cases without adequate anticoagulation.
Effect of timolol plus hydrochlorothiazide plus hydralazine on essential hypertension.
Authors: Aronow W S , Van Herick R , Greenfield R , Alimadadian H , Burwell D , Mann W
Published: June 2012

The effect on hypertension of hydrochlorothiazide 100 mg daily plus timolol 20-60 mg daily versus hydrochlorothiazide plus placebo and of hydrochlorothiazide plus timolol plus hydralazine 40-200 mg daily versus hydrochlorothiazide plus placebo plus hydralazine was evaluated in a double-blind, randomized, crossover study in 38 patients with hypertension. Hydrochlorothiazide plus timolol was more effective than hydrochlorothiazide plus placebo in lowering both supine and standing systolic and diastolic blood pressures. Hydrochlorothiazide plus timolol plus hydralazine was a very effective regimen in lowering both supine and standing systolic and diastolic blood pressure. The patients tolerated this regimen well with greater hypotensive activity and a lower incidence of side effects than on hydrochlorothiazide plus placebo plus hydralazine.
Junctional pacemakers in man. Response to overdrive suppression with and without parasympathetic blockade.
Authors: Narula O S , Narula J T
Published: June 2012

This study analyzes the response to overdrive suppression of junctional pacemakers (JP) and correlates it with symptoms in 21 patients. Junctional rhythm (JR) was seen in 5 patients with intact A-V conduction, and in 16 with complete heart block, the JPs were located proximal to or within the His bundle (BH). Junctional recovery time (JRT) was measured following atrial or ventricular pacing during control and after atropine (2-2.5 mg). Control cycle length of the JR ranged from 835-2100 msec (mean 1402) and the corrected JRT (CJRT) ranged from 75 to greater than or equal to 7510 msec (mean 2966). Following atropine, the cycle length ranged from 660 to 2000 msec (mean 1115) and the CJRT ranged from 90 to greater than 6000 msec (mean 2050). All symptomatic patients were treated with permanent ventricular demand pacemakers and followed clinically from 6-72 months (mean = 35). Symptomatic patients could not be differentiated from asymptomatic patients on the basis of control heart rates, chronotropic response to atropine, and/or the site of origin of the JP as determined with BH recordings. However, presence or absence of symptoms of syncope and dizziness were well correlated with a CJRT greater than or less than 200 msec, respectively, either following atropine or during control. The determination of CJRT both before and after parasympathetic blockade provides a simpler and more reliable method for the therapeutic evaluation of patients.
Evaluation of R wave amplitude changes versus ST-segment depression in stress testing.
Authors: Bonoris P E , Greenberg P S , Christison G W , Castellanet M J , Ellestad M H
Published: June 2012

Exercise ECGs and coronary angiograms were reviewed in 266 patients (81 normals and 185 with significant coronary artery disease). Thirty-three false positive and 96 false negative ST responses to stress testing were purposely chosen to determine if the R wave could reduce the number of false ST responses. R wave amplitude changes were measured in the control and in the immediate postexercise period. An increase or no change in R wave was taken as evidence of an abnormal response, while a decrease in the R wave was a normal response. The sensitivity by ST segment was 48% and the specificity was 59%. These values were low because of the large number of false positive and negative ST responses in the study. It was our purpose to determine if these lowered values could be significantly improved by the R wave. Using R wave criteria, the sensitivity was 63% (P is less than 0.01) while the specificity was 79% (P is less than 0.01). The sensitivity and specificity of stress testing can be significantly improved using R wave changes.
Cardiovascular complications during exercise training of cardiac patients.
Authors: Haskell W L
Published: June 2012

The occurrence of major cardiovascular complications during exercise training of cardiac patients in 30 cardiac rehabilitation programs in North America was determined by questionnaire. These programs conducted medically supervised cardiac exercise classes in 103 locations and reported information on 13,570 participants who accumulated a total of 1,629,634 patient hours of supervised exercise. Cardiovascular complications were reported as nonfatal or fatal and included cardiac arrest, myocardial infarction and other. A total of 50 cardiac arrests were observed during exercise, 42 of which were successfully resuscitated while eight were fatal. Seven myocardial infarctions were reported; five were nonfatal and two were fatal. Four other fatalities were reported due to acute cardiopulmonary disorders. The average complication rate for all programs was one nonfatal and one fatal event every 34,673 and 116,402 patient hours of participation, respectively. Complication rates are lower in programs which continuously monitor the electrocardiogram during exercise and are lower when only the experience since 1970 is evaluated. These data support the recommendation that medically prescribed and supervised exercise can be performed reasonably safely by medically selected cardiac patients.
The bruit of carotid stenosis versus radiated basal heart murmurs. Differentiation by phonoangiography.
Authors: Kistler J P , Lees R S , Friedman J , Pressin M , Mohr J P , Roberson G S , Ojemann R G
Published: June 2012

Phonoangiography, quantitative analysis of arterial bruits, has been shown to provide accurate noninvasive diagnosis of uncomplicated carotid arterial stenosis, but had not been tested where cervical bruits from other sources were present. In this study, 27 carotid bruits in 15 consecutive patients with carotid bruits and basal heart murmurs were analyzed by phonoangiography. Tape recordings were made over the base of the heart and along the course of the carotid arteries in the neck; spectral analysis was performed as previously described. The spectral shape of the basal heart murmurs was recognizable and amplitude decreased with distance from the heart, althouth a secondary, lower amplitude, maximum often occurred over the carotid bifurcation. Intrinsic carotid bruits, by contrast, were always maximal over the bifurcation, and although they radiated both proximally and distally, were not detectable over the chest wall. In quantitative terms, the correct diagnosis as to the presence and extent of carotid stenosis was made in 25 of 27 cases (92%) despite the presence of a radiated murmur. Phonoangiography is capable of accurate differentiation of radiated murmurs from intrinsic carotid bruits and of quantitation of the latter even in the presence of radiated sounds.
Long-term mitral valve replacement in young children. Influence of somatic growth on prosthetic valve adequacy.
Authors: Friedman S , Edmunds L H , Cuaso C C
Published: June 2012

Long-term clinical and laboratory findings in three children who required mitral valve replacement below age four years are reported. In each instance a second valve replacement was necessary approximately 8 1/2 years after the initial one, following a two and one-half fold increase in body weight. Inadequate mitral valve orifice size was found in each instance, producing a hemodynamic picture equivalent to mitral stenosis: congestive heart failure, pulmonary hypertension and atrial fibrillation. A second valve was placed without mortality in each instance and relieved the mitral valve obstruction. Pulmonary vascular resistance increased postoperatively in two patients and failed to decrease in the third. Pulmonary arterial hypertension and left ventricular hypertrophy persisted as long as 13 to 37 months after the second valve placement in all patients. The consequences of increasing body size and the long-term interposition of a rigid prosthesis in a growing heart introduce additional complications to mitral valve replacement in childhood. Frequent hemodynamic observations and the use of a prosthesis other than the ball-cage variety is recommended for improved management.
The murmur of pulmonic regurgitation in tetralogy of Fallot with absent pulmonic valve.
Authors: Fontana M E , Wooley C F
Published: June 2012

Absent pulmonic valve (APV) in tetralogy of Fallot produces a pulmonic regurgitation murmur (PRM) which is usually late in onset after A2, low pitched, and of crescendo-decrescendo character. We have seen three adult patients with tetralogy of Fallot with APV and have done intracardiac sound and pressure studies in two. The PRM was loudest in the RV outflow tract (RVOT), where the onset was earlier than the murmur recorded on the chest wall. The crescendo portion of the PRM occurred during an abnormally slow decline in the RVOT pressure pulse after the crossover of PA and RVOT pressures. The RVOT pressure reached its minimum 30 msec after the RV body pressure, resulting in a pressure gradient between the two. The PRM peaked 30 msec later in the RV body than in the RVOT. The delayed precordial onset of the PRM after A2 is likely due to failure of transmission of early vibrations through the chest wall. The morphology of the PRM in tetralogy of Fallot with APV may be related to delayed relaxation with altered diastolic compliance of the RVOT which is subjected to a large regurgitant volume from the massively dilated pulmonary arteries.
Lactic dehydrogenase isoenzyme determination in the diagnosis of acute myocardial infarction.
Authors: Vasudevan G , Mercer D W , Varat M A
Published: June 2012

Lactic dehydrogenase (LD) isoenzymes were determined by a rapid, simple technique and their utility in the diagnosis of acute myocardial infarction (AMI) was evaluated. LD isoenzymes were separated by ion-exchange column chromatography using DEAE-Sephadex. The cardiac fractions (LD-1 and LD-2) were measured separately on an Abbott ABA-100 analyzer and ratio of LD isoenzyme 1 to LD isoenzyme 2 (LD1:2) calculated. Daily serum samples were obtained from 100 patients selected only for a history of chest pain of abrupt onset. In 47 patients whose diagnosis was acute myocardial infarction (AMI), confirmed by typical clinical presentation and typical rise in cardiac-specific creatine kinase isoenzyme (MB(, peak LD1:2 ranged from 0.77 to 2.26. In 44 patients without AMI, peak LD1:2 ranged from 0.25 to 0.76. In two patients with electrocardiographic changes chest pain occurred two and five days previously; there was no rise in MB, but LD1:2 was elevated. Four patients with small AMI had no rise in LD1:2. Three more patients (one with active hemolysis) had false positive results. Thus, there was a sensitivity of 96% and a specificity of 97% when the cut-off point was LD1:2 = 0.76. LD1:2 is not quite as sensitive or specific as MD, but the ratio allows for the diagnosis of infarction in cases where MB has already returned to normal.
QT interval prolongation as predictor of sudden death in patients with myocardial infarction.
Authors: Schwartz P J , Wolf S
Published: June 2012

Fifty-five patients with recent myocardial infarction and 55 healthy controls, matched for age, sex, race, height, weight, education and job, had an electrocardiogram taken every two months for seven years. Twenty-eight patients and one control had a sudden cardiac death. The QTc (mean of all values recorded) was found prolonged in one control (2%), five of 27 surviving patients (18%) and in 16 of 28 patients who had sudden death (57%). The difference between surviving and sudden death patients is significant (P less than 0.01). It is interesting that the only control with a long QT was the one when died suddenly of myocardial infarction. Among patients with previous myocardial infarction a prolonged QTc constitutes a 2.16 times greater risk for sudden death. We conclude that a constant prolongation of QTc in patients with myocardial infarction may help, with other risk factors, in defining a subgroup at higher risk for sudden death.
Prediction of multivessel disease after inferior myocardial infarction.
Authors: Chaitman B R , Waters D D , Corbara F , Bourassa M G
Published: June 2012

We correlated clinical parameters with angiographic findings in 108 men with a previous isolated inferior myocardial infarction, to determine if these parameters could predict accurately which patients had multivessel disease. Of 71 men in angina class 2-3, 42 had three vessel disease versus only seven of the 37 who were either asymptomatic or angina class 1 (P less than 0.001). Multivessel disease was present in 35 of the 36 who had anterior ST-T abnormalities at rest (P less than 0.001) and 16 of the 17 with cardiomegaly. Among men 55 years and older, the incidence of multivessel disease was 94% compared to 70% in men less than 55 (P less than 0.03). We conclude that functional angina class, age, and the presence of resting anterior ST and T abnormalities are highly predictive of associated left system disease in survivors of inferior infarction.
Variability, reproducibility, and applications of precordial ST-segment mapping following acute myocardial infarction.
Authors: Hardarson T , Henning H , O'Rourke R A , Karliner J S , Ryan W , Ross J
Published: June 2012

In 58 patients with uncomplicated acute anterior myocardial infarction, a mean decline in the sum of ST segments (sigmaST) of 34% was observed when comparing sigmaST values recorded at 3-6 hours with those recorded at 6-9 hours after the onset of symptoms (P less than 0.05). The mean absolute difference between 19 paired readings 1-2 hours apart was 2.9 +/- 3.0 mm and between 29 readings 2-4 hours apart 3.0 +/- 3.0 mm. However, the mean absolute difference between 38 paired readings 4-8 hours apart was 12.2 +/- 11.8 mm with a wide range of differences. Left ventricular failure and pericarditis were also associated with significantly higher sigmaST values. We conclude that there is a complex relationship between ST-segment elevation and a number of clinical factors during the first 48 hours after infarction. Nevertheless, precordial mapping remains a useful method for the evaluation of short-term (less than 4 hours) therapeutic interventions, if other relevant variables are unaltered and if carefully matched control groups are employed.
Conditions for vasodilator-induced coronary steal in experimental myocardial ischemia.
Authors: Becker L C
Published: June 2012

The conditions for coronary steal were determined using the two vasodilators--dipyridamole and nitroglycerin--in anesthetized dogs after ligation of the left anterior descending coronary artery (LAD). Previous studies have shown that when the non-ligated coronary arteries are normal, collateral flow increases after dipyridamole. This study utilized a model in which the distal LAD was ligated and the proximal LAD and left circumflex (LC) arteries were stenosed. Heart rate and blood pressure were kept constant. In 20 dogs, 1-1.5 mg/kg dipyridamole caused a decrease in flow to the ischemic region as measured by radioactive microspheres (0.19 to 0.14 ml/min/g, P = 0.05) while flow increased four-fold to surrounding nonischemic myocardium. The decrease in collateral flow was confined to the epicardial half of the ischemic region (0.26 to 0.14 ml/min/g, P less than 0.001) and was associated with an increase in sigmaST from 30.9 to 44.7 mV (P less than 0.01). In five dogs nitroglycerin, 5 microgram/kg/min, produced no significant changes in collateral flow or flow to other parts of the LV, and sigmaST was unchanged. Vasodilator-induced coronary steal therefore appears to require 1) an arteriolar-type dilator like dipyridamole and 2) stenoses of the arteries supplying collateral flow to the ischemic region. The steal phenomenon is probably caused by a decrease in pressure distal to the stenoses in these vessels, resulting in reduced driving pressure for collateral flow.
Left main coronary artery stenosis: the influence of aortocoronary bypass surgery on survival.
Authors: Campeau L , Corbara F , Crochet D , Petitclerc R
Published: June 2012

A retrospective study was carried out in 114 unoperated and 197 operated patients having left main coronary artery (LMCA) stenosis greater than or equal to 50%. Including the operative mortality of 9.1%, survival at seven years was significantly greater following pure aortocoronary bypass graft surgery, 77.5% as compared to 48.5% for the unoperated patients (P less than 0.01). The surgical mortality was significantly less during the last five years (1972-1976), 6.2% as compared to 17% during 1969-1971 (P less than 0.025). The three year survival in patients operated since 1972 was 90.2% as compared to 60.4% for unoperated patients. Survival remained significantly higher in the operated patients when studied as subsets on the basis of the severity of the LMCA stenosis (less than 70% as opposed to greater than or equal to 70%), and on the extent of associated obstructive disease of major coronary arteries (0-1 versus 2-3 arteries). It was significantly higher, however, only in operated patients with associated stenosis greater than or equal to 70% of the right coronary artery. Survival was higher following surgery only when the ejection fraction was at least 0.45, or the left ventricular end-diastolic pressure below 20 mm Hg.