bluuebunny/crossref_metadata_2025 huggingface dataset:
Prosthetic aortic valvular endocarditis.
Authors: Madison J , Wang K , Gobel F L , Edwards J E
Published: June 2012

Infective endocarditis (IE) continues to be one of the most serious complications following cardiovascular surgery, particularly that for replacement of valves. In order to define more clearly the clinical course and the role of surgical therapy, clinical and necropsy data were reviewed in 16 adult patients with prosthetic aortic valvular endocarditis (PAVE) and compared with the experience cited in the literature. Positive blood cultures were obtained in each of the patients with bacterial endocarditis. Gram positive bacteria predominate and the onset of infection is usually later than 25 days postoperatively. In 11 of 16 patients, aortic insufficiency was recognized. Autopsy material demonstrated large perivalvular abscesses which loosened the attachment of the prosthetic valve in each case and which made successful operation unlikely. Aortic insufficiency appears to be of prognostic importance, since patients who developed aortic insufficiency early in the course of PAVE died. Survivors included patients who made an excellent response to medical therapy and who either did not develop aortic insufficiency or developed aortic insufficiency either late in the course or even after cure of PAVE, Poor response to medical therapy and progressive aortic insufficiency even in the absence of left ventricular failure appear to be indications for prompt surgical replacement of the prosthetic aortic valve.
Echocardiography of the intra-atrial baffle in dextro-transposition of the great vessels.
Authors: Nanda N D , Stewart S , Gramiak R , Manning J A
Published: June 2012

Twelve patients with dextro-transposition of the great vessels (age eight months to four years) were studied by echocardiography following Mustard's procedure. Nine of them had also been studied preoperatively. Postoperatively all patients demonstrated structural echoes in the atrial cavity behind the pulmonary root. In ten, the motion pattern generally resembled that of a stenotic atrioventricular valve iwth a sharp anterior movement followed by flattening in diastole and rapid posterior excursion in systole. The maximum amplitude of motion ranged from 4 to 9 mm (average 6.6 mm). In the remaining two cases, the anterior diastolic movement was attenuated. Similar moving, linear echoes with larger amplitudes of motion (10-14 mm) were observed behind the tricuspid valve in four patients while poorly moving, multiple or thick conglomerate echoes (2-11 mm wide) were detected in seven cases. Echocardiographic contrast studies performed by injecting indocyanine green via catheters placed on either side of the intra-atrial baffle identified it as the source of these echoes. Following operation, coarse diastolic undulations of the mitral valve (ten cases) and the tricuspid valve (nine cases) were noted. Also, fine flutter of both atrioventricular valves, not present before, appeared after operation in three patients. These findings may be related to the altered pathway of blood flow and turbulence resulting from the insertion of the baffle in the atria. Echocardiography appears useful in delineating the character and movement pattern of the intra-atrial baffle and this may have potential in evaluating its long-term functional status.
De subitaneis mortibus. XII. Asymmetrical hypertrophy of the heart.
Authors: James T N , Marshall T K
Published: June 2012

Subjects with asymmetrical hypertrophy of the heart are prone to sudden death. Neither the pathogenesis of the eccentric hypertrophy nor the mechanism of sudden death is fully understood. In this report we describe certain postmortem findings in the hearts of 22 subjects who died suddenly, silently and unexpectedly, and in whom the only significant abnormality at autopsy was asymmetrical hypertrophy of the heart. Deep clefts were present in the septum in seven hearts, the small coronary arteries were abnormally narrowed in ten, the sinus node was sclerosed by fibrosis in 12, there was variable narrowing of the atrioventricular (A-V) node artery in many and the His bundle was too thin in three. There were multiple cysts or channels in the central fibrous body and of the adjacent A-V node and His bundle in four hearts. Most of the hearts displayed a fetal dispersion of the A-V node and His bundle throughout the central fibrous body, but this was particularly conspicuous in 13 hearts. These abnormalities in all parts of the conduction system suggest a variety of possible mechanisms by which the heart could become electrically unstable but do not indicate that one single mechanism is at fault in all. They offer some explanation for the reported high incidence of atrial fibrillation in such patients, and why they fare so badly with this arrhythmia. While the pathogenesis of asymmetrical hypertrophy may in some part be attributable to narrowed small coronary arteries or to an abnormal sequence or speed of septal and ventricular activation or to mechanical deficiency caused by deep septal clefts, none of these features was universally present in our series. Both asymmetrical hypertrophy of the heart and the sudden death which so frequently accompanies it probably develop by a variety of pathogenetic mechanisms.
Anomalous left coronary artery originating from the pulmonary artery. Report on 15 cases.
Authors: Askenazi J , Nadas A S
Published: June 2012

Fifteen infants and children with the diagnosis of anomalous left coronary artery from the pulmonary trunk have been encountered at the Children's Hospital Medical Center, Boston, Massachusetts from 1958 to 1973. After thorough clinical and laboratory evaluation, they have been treated by anticongestive measures. Nine patients have had ligation of the anomalous left coronary artery at its entrance into the pulmonary artery; one patient has undergone coronary bypass surgery. The lelctrocardiogram proved to be the most helpful diagnostic clinical laboratory test, Vectorcardiograms are valuable not only in diagnosis but also in the follow-up of the patients from the prognostic point of view. The most sensitive tool for the definitive diagnosis is an aortic rool angiogram; we have no false negatives or false positives with this method. The twelve patients with complete cardiac catheterization data could be divided into three groups, according to the pressure and magnitude of the left-to-right shunt at the pulmonary level. All patients with an appreciable le?T-TO-RIGHT SHUNT SURVIVED. Patients in whom no left-to-right shunt could be demonstrated by angiography died. Half of the patients with only small left-to-right shunt survived; The results of surgical and medical treatment, were identical within the three groups. Medical management in infancy, according to coronary care principles, with definitive surgical correction at a later age, is the preferred treatment. Ligation of the anomalous left coronary artery is recommended in severely symptomatic infants with documented left-to-right shunt at the pulmonary artery level, who do not respond to medical management.
Cardiopulmonary bypass. Microembolization and platelet aggregation.
Authors: Solis R T , Kennedy P S , Beall A C , Noon G P , DeBakey M E
Published: June 2012

Particulate microemboli and in vitro platelet aggregation were studied in blood of patients during cardiac operations with an electronic particle size analyzer. A small gradient of microemboli developed on passage of blood through a bubble oxygenator but not through a membrane oxygenator. However, with both types of oxygenators, there was a sustained increase in the volume of microemboli in cardiotomy return blood which was much greater than in aterial blood. After cardiopulmonary bypass with both oxygenators, there was a comparable reduction in the volume of circulating platelets which exceeded that of the hemoglobin concentration, indicating platelet loss exceeded that that expected from hemodilution alone. However, the total volume and mean size of platelet aggregates induced in blood of patients after membrane oxygenation was significantly greater than similar measurements after bubble oxygenation. This study shows that membrane oxygenation reduces particulate microembolization and preserves platelet function in patients undergoing cardiac operations when compared to bubble oxygenation.
Blood calcium levels in the presence of arteriographic contrast material.
Authors: Caulfield J B , Zir L , Harthorne J W
Published: June 2012

One of the complications of coronary angiography is a sudden and persistant fall in blood pressure. This may be due to the presence of calcium chelating agents in the vehicle of the radio-opaque compounds. Depressed ambient calcium levels are associated with decreased myocardial contractility and when low enough cause electromechanical dissociation. Simultaneous measurements of radial artery and coronary sinus ionized calcium levels in nine patients during intracoronary injection of the contrast agent revealed a lowering of the level of ionized calcium in the coronary sinus to a point that can be expected to be associated with a decrease in myocardial contractility. This ionized calcium depression was more marked and prolonged in patients with arteriosclerosis, some reaching levels which, if persistent, could result in electromechanical dissociation.
Systemic hemodynamic effects of bethanidine in essential hypertension.
Authors: Chrysant S G , Nishiyama K , Adamopoulos P N , Frohlich E D
Published: June 2012

Although available elsewhere, bethanidine remains under study in the U.S. and its hemodynamic effects are unreported. Therefore, 29 patients with moderately severe essential hypertension received one of four oral dose levels (0.10, 0.25, 0.35, or 0.50 mg/kg) of the postganglionic sympatholytic drug. Blood pressure was reduced only in the 14 patients receiving the highest dose. This was demonstrated within three hours, first by a significant postural hypotension (upright tilt: +14 before vs -19 mm Hg after, P less than 0.001). This orthostatic hypotension effect was associated with a greater fall in cardiac output (13 vs 22%, P less than 0.025) and a diminished reflective increase in total peripheral resistance (19 vs 6%, P less than 0.01); an attenuated Valsalva maneuver overshoot in the supine position was also observed (42 vs 10%, P less than 0.001). Eight of these 14 patients demonstrated supine hypotension associated with either reduced output and/or resistance. Hence, bethanidine is a rather rapidly acting oral sympatholytic agent which reduces blood pressure by producing: (1) decreasec venous return (especially in upright position), suggesting venodilation; (2) arteriolar dilation (supine and upright) reducing peripheral vascular resistance; and (3) attenuated cardiovascular sympathetic reflective adjustments.
Hypertensive pulmonary vascular disease associated with patent ductus arteriosus. Primary or secondary?
Authors: Bessinger F B , Blieden L C , Edwards J E
Published: June 2012

In an infant with patent ductus arteriosus and pulmonary hypertension, elevated pulmonary vascular resistance persisted following ligation of the ductus. Histologic examination of a pulmonary biopsy at two years of age and tissue obtained at autopsy at three years of age showed obstructive pulmonary vascular disease. The question as to whether the organic vascular lesions are secondary to the effects of the patent ductus or part of pulmonary hypertension cannot be resolved. The age of the patient favors a primary etiology.
Evaluation of precordial electrocardiographic mapping as a means of assessing changes in myocardial ischemic injury.
Authors: Muller J E , Maroko P R , Braunwald E
Published: June 2012

Precordial electrocardiographic mapping has been proposed as a method for evaluating the extent of myocardial injury in patients with acute myocardial infarction. To assess the relationship between direct measures of myocardial cell damage and findings obtained by precordial mapping, the left anterior descending coronary artery (LAD) was occluded in dogs instrumented for simultaneous recording of epicardial and precordial electrocardiograms. The sum in millivolts of ST-segment elevation recorded from 30 electrodes placed in a Silastic grid sutured to the epicardium (EPIsigmaST) was compared to that recorded from 30 precordial electrodes (PresigmaST). While ischemic injury was: 1) maintained constant with a fixed occlusion; 2) reduced by partial reperfusion; 3) increased by addition of a second occlusion; or 4) increased repeatedly by intermittent infusions of isoproterenol, EPIsigmaST and PresigmaST were always closely correlated in each of the 16 dogs studied: r equal 0.92 plus or minus 0.01 (SEM). In seven control dogs, 30 minutes after coronary occlusion, PresigmaST had fallen to 77.4 plus or minus 6.6% of its value 15 minutes postocclusion. In seven experimental dogs, two branches of the LAD were occluded. Fifteen minutes after double occlusion, one occlusion was released; 30 min after the initial occlusion PresigmaST had fallen significantly more than control, to 43.1 plus or minus 13.1% of its value 15 minutes postocclusion. Simultaneously, epicardial sites in the reperfused area also showed normalization of ST segments and 24 hours later exhibited normal myocardial creatine phosphokinase activity and normal histologic appearance. During the same experiment, the mean precordial R wave voltage of sites with ST-segment elevations exceeding 0.15 mV 15 minutes following occlusion fell significantly (P less than 0.05) more in the control group (from 1.14 plus or minus 0.15 to 0.75 plus or minus 0.06 mV) than in the reperfused group (from 1.06 plus or minus 0.09 to 0.96 plus or minus 0.17 mV) during the ensuing 45 minutes. Thus, more rapid normalization of PresigmaST or preservation of precordial R wave voltage reflected the actual prevention of myocardial necrosis by reperfusion. These findings demonstrate the usefulness of precordial electrocardiographic mapping for evaluation changes in myocardial ischemic injury. Sites at which appearance of epicardial ST segment is not a reliable index of ischemic injury were associated with the development of intraventricular conduction blocks with Q to intrinsic deflection intervals exceeding 40 mesc or QRS durations exceeding 65 msec; these changes were associated with precordial RSR' configurations. Such sites, whether recorded from precordial or epicardial leads, should be excluded from ST-segment measurements used in the assessment of myocardial ischemia.
Effects of glucose, insulin and potassium infusion on tissue metabolic changes within first hour of myocardial infarction in the baboon.
Authors: Opie L H , Bruyneel K , Owen P
Published: June 2012

The effects of infusions of glucose, insulin and potassium (GIK) on the heart tissue metabolic changes found in adult baboons 60 min after coronary artery ligation were studied. Biopsies taken from 11 baboons without coronary artery ligation gave control values. A second group of 46 baboons had coronary artery ligation. A third group of 17 baboons received an infusion of KCl after coronary artery ligation. A fourth group of 26 baboons received infusion of GIK. Coronary artery ligation resulted in the expected fall of ATP, creatine phosphate, glycogen, tissue (K+/Na+) ratio, and tissue pH, and rise of inorganic phosphate, lactare, lactate/pyruvate ratio and alpha-glycerophosphate in the infarction zones. Compared with ligation, additional infusions of GIK approximately doubled the contents of creatine phosphate and glycogen in the infarct zones, increased the content of ATP in the central infarct zone, and decreased the content of inorganic phosphate in the peripheral infarct zone. Other GIK effects were that the tissue (K+/Na+) ratio rose in the peripheral infarct zone, and the content of both glycogen and lactate rose in the peri-infarct and non-ischemic zones; the pH of tissue homogenates did not decrease. KCl infusions had few effects compared with the ligation group. GIK infusions exerted a beneficial effect when compared with infusions of KCl in that tissue creatine phosphate rose in the peripheral infarct and nonischemic zones; the tissue K+/Na+ ratio rose in the peripheral infarct, peri-infarct, and nonischemic zones; and the lactate/pyruvate ratio fell in the infarct zone. It is proposed that GIK counteracted early tissue metabolic deterioration in the infarcting baboon heart.
The role of an accessory atrioventricular pathway in reciprocal tachycardia. Observations in patients with and without the Wolff-Parkinson-White syndrome.
Authors: Wellens H J , Durrer D
Published: June 2012

To study the pathway of tachycardia in patients with the Wolff-Parkinson-White (WPW) syndrome and reciprocal tachycardias, results from intracavitary recordings and atrial and ventricular stimulation were reviewed in 71 patients with the WPW syndrome and 54 patients without pre-excitation. In all patients a reproducible tachycardia could be initated and terminated by appropriately timed electrical stimuli. The following findings were accepted as suggesting the participation of an accessory pathway in the tachycardia circuit: 1) no increase in ventriculo-atrial conduction (V-A C) time following ventricular stimuli given with increasing prematurity; 2) activation of right or left atrium (depending upon the location of the atrial end of the accessory pathway) prior to activation of atrium in the His bundle lead; 3) slowing of tachycardia following bundle branch block to the ventricle in which the accessory pathway inserts; 4) V-A C time of early stimuli on the ventricle during the tachycardia equal to or less than the V-A c time following QRS complexes during tachycardia; 5) inability to initiate tachycardia or slowing of tachycardia following the administration of drugs affecting the accessory pathway. Accepted as suggestive for atrioventricular (A-V) nodal re-entry were the following factors: 1) activation of atrium following initiation of tachycardia by a single atrial premature beat after activation of the bundle of His but before or simultaneous with ventricular activation in first and subsequent beats of tachycardia; 2) initiation of tachycardia following a gradual increase in V-A C time with the appearance of a His bundle electrogram in between the premature beat and retrograde atrial activation; 3) gradual increase in V-A C time with the appearance of a His bundle electrogram following ventricular premature beats given with increasing prematurity; 4) two-to-one block distal to the A-V node or His bundle with persistance of tachycardia. If only positive findings were accepted, 51 patients of the WPW group used their accessory pathway during tachycardia. In eight patients re-entry was confined to the A-V node. In the remaining 12 patients the mechanism was not clear. Of the patients not showing pre-excitation in A-V direction, 47 patients seemed to have their re-entry circuit in the A-V node, five patients used an accessory pathway in V-A direction, and in two patients the pathway of tachycardia could not be identified.
The effects of ouabain on induction of atrioventricular nodal re-entrant paroxysmal supraventricular tachycardia.
Authors: Wu D , Wyndham C , Amat-y-Leon F , Denes P , Dhingra R C , Rosen K M
Published: June 2012

Electrophysiological studies utilizing His bundle recordings and atrial extra-stimulus technique were performed in 17 patients (pts) with documented paroxysmal supraventricular tachycardia (PSVT) before and after 0.01 mg/kg, i.v., ouabain. Before ouabaine, echozones(EZ) were demonstrated in 11 patients. After ouabain, EZ were abolished in two, decreased in five, unchanged in three, and increased in one. In one patient, EZ was demonstrated only after ouabain. Eleven patients could sustain PSVT before ouabain; after ouabain, only six patients could sustain PSVT. Analysis of A1-A2, H1-H2 curves revealed 11 patients with discontinous (dual pathway) and six patients with smooth conduction curves. In dual pathway patients, both the fast and slow pathway curves were shifted rightward and upward after ouabain. The changes in EZ were dependent upon the relative rightward shifts of the two pathways. In patients with smooth curves, EZ tended to shift rightward with a critical A-H being achieved at longer A1-A2 intervals after ouabain. In conclusion, the effects of ouabain on PSVT were variable. Beneficial effects included abolition or decrease of EZ and loss of the ability to sustain PSVT. Potentially deleterious effects included widening or new de-elopment of EZ.
Sick sinus syndrome after surgery for congenital heart disease.
Authors: Greenwood R D , Rosenthal A , Sloss L J , LaCorte M , Nadas A S
Published: June 2012

The course and prognosis of 16 infants and children with sick sinus syndrome associated with cardiac surgery is reviewed. The dysrhythmia was observed most ofter after extensive atrial reconstructive surgery in patients with transposition of the great arteries and with atrial septal defect. In 12 (75%) of the patients, sick sinus syndrome was detected in the immediate postoperative period. Tachyarrhythmias and bradyarrhythmias were presnet in 12 and isolated bradyarrhythmias in four. Temporary pacing was used in two and permanent pacing was required in five. Death in two non-paced patients was attributable to arrhythmias. Postmortem examination in one patient revealed a suture in the sinoatrial node. Careful attention to the anatomy of the sinoatrial node, its artery and the internodal tracts during surgery may prevent the development of sick sinus syndrome. In patients with dysrhythmia, a careful search should be undertaken to document the abnormal rhythm with the use of Holter monitoring. The insertion of a pacemaker is indicated in patients with tachyarrhythmias requiring cardioversion or antiarrhythmic drug therapy and those without adequate lower escape mechanisms.
Concealed ventricular extrasystoles due to interference and due to exit block.
Authors: Kinoshita S
Published: June 2012

Two cases of sinus rhythm with ventricular extrasystoles are reported in which extrasystoles arising from the same focus obey the rule of "comcealed bigeminy" and the "rule of bigeminy". In a comparatively rapid sinus rhythm, shortening of the sinus cycle favors the appearance of extrasystoles, and the extrasystoles obey the fule of "concealed bigeminy"; namely, sinus impulses intervene between extrasystoles in even numbers. The sinus impulses here include those both conducted and not conducted to the ventricles. Conversely, in a comparatively slow sinus rhythm, interectopic sinus impulses appear in odd numbers only, and the extrasystoles obey the "rule of bigeminy"; namely, lengthening of the sinus cycle favors the appearance of extrasystoles. From these observations, a new mechanism governing both of the rules is suggested as follows. Ectopic impulses arise following all the interctopic sinus beats, but they become concealed extrasystoles of two types. One of them is the "concealed extrasystole due to interference at the external end of the ventricular-ectopic (V-E) junction."The other is the "concealed extrasystole due to exit block within the V-E junction" because of refractoriness following stimulation. They alternate with each other. In the of "concealed begeminy", the last concealed extrasystole intervening between manifest extrasystoles is due to exit block, whereas in the "rule of bigeminy", it is due to interference.
Abnormal left ventricular wall motion at mid-ejection in patients with coronary heart disease.
Authors: Leighton R F , Pollack M E , Welch T G
Published: June 2012

The degree of inward motion at mid-ejection was examined for seven segments on the silhouettes of left ventriculograms taken in the 30 degrees RAO projection in patients with normal coronary arteries. The pattern of wall motion described in these patients was used to distinguish abnormalities in mid-systolic wall motion. One or more abnormally contracting segments were found at mid-ejection of 27 of 42 patients with obstructive coronary artery disease and normal end-systolic wall motion. Of the 57 segments found in these patients, 41 or 72% corresponded to sites of significant coronary artery obstruction. Seven patients had electrocardiographic evidence of prior infarction. Following coronary graft surgery in eight patients improved motion was found in association with graft patency in seven priviously delayed segments and two new areas of delayed wall motion associated with nonpatent grafts and electrocardiographic changes of infarction appeared. We postulate that some of the myocardial fibers in late contracting segments have been injured or infarcted and are able to contract effectively only during the latter half of ejection when ventricular wall tension is reduced.
Three dimensional geometry of acutely ischemic myocardium.
Authors: Marcus M L , Kerber R E , Ehrhardt J , Abboud F M
Published: June 2012

The distribution of coronary flow to small segments of the entire left ventricle (96 per dog; average weight = 0.78 g) was studied in 28 open-chested dogs utilizing 7-10 mu labeled microspheres. Although the flow to large areas of the ventricle was nearly evenly distributed, there was considerable heterogeneity of flow to small adjacent segments of myocardium (average standard deviation of the flow distributions was 17.3 +/- 3.2% of mean lfow). Approximately one-half of the measured heterogeneity of flow could be attributed to various extraneous factors, and one-half appears to be due to inherent heterogeneity of flow in the left ventricular myocardium. In ten of 28 dogs, the mid-circumglex coronary was suddenly occluded, and five minutes thereafter the distribution of left ventricular flow was determined with microspheres labeled with a different isotope. The ischemic regments were separated into three groups: severely ischemic, moderately ischemic, and borderline ischemic. The three dimmensional geometry of the acutely ischemic myocardium was analyzed, and four general conclusions were reached. 1) The percent distribution of severely ischemic segments, moderately ischemic segments, and borderline ischemic segments within an ischemic region varies from animal to animal. 2) Subendocardial segments were more frequently and more severely affected than neighboring mid-wall or epicardial segments. 3) No evidence of an "hyperperfused zone" of myocardium surrounding the ischemic area was found. 4) The flows to segments immediately adjacent to the severely ischemic segments were heterogeneous. Therefore, the concept of a geometrically defined "buffer zone" of moderately ischemic myocardium surrounding and separating severely ischemic from normally perfused myocardium no longer seems realistic.
Comparison of ejection fraction and zonal mean velocity of myocardial fiber shortening.
Authors: Nakhjavan F K , Natarajan G , Goldberg H
Published: June 2012

To determine the extent of cardiac involvement until a diminished ejection fraction (EF) is present, zonal mean velocity of circumferential fiber shortening (Vcf) was measured from the left ventriculogram in 36 patients. The longitudinal axis (apex to mid-point of the aortic valve plane) in right anterior oblique view was divided into four equal parts by three perpeendicular chords. Zonal Vct and percent shortening along the proximal, middle and distal chords were measured. The results of this study indicate that a normal EF is frequently associated with a reduced Vct in one or even two zones. A reduced EF is generally accompanied by a diminished Vct in all three zones of the heart. In addition, a close correlation was found between zonal Vct and percent shortening. Hence the latter, which is much simpler to measure, can be instead of Vct Ejection fraction as a measure of myocardial performance is not as sensitive as Vct, especially in hearts with asynchrony of contraction.
Main left coronary artery disease. Clinical experience from 1964-1974.
Authors: Cohen M V , Gorlin R
Published: June 2012

Obstructive lesions of the main left coronary artery (LCA) were demonstrated angiographically in 73 patients, comprising 4.3% of the total population referred to us for diagnostic evaluation of chest pain. Although there were no specific historical or clinical features which could absolutely distinguish this subgroup from the larger population of coronary artery disease patients, 81% (34/42) of the double Master's exercise tests, in which the patient achieved a heart rate of at least 110 beats/min. demonstrated greater than or equal 2 mm R-ST segmental depression. Of the total group of 73, 32 were evaluated during the six-year period from 1964 to 1971 and a preliminary report made in 1972. The diagnosis in the remaining 41 patients was established in the 1/2 year period from 1971 to 1973. The initial 32 patients were seen before the significance of a main LCA lesion was appreciated. In this subgroup there were five deaths at the time of cardiac catheterization. However, in the more recent group improved recognition of patients with possible main LCA disease prior to catheterization has led to a much lower death rate related to diagnostic catheterization. Only one of the last 41 patients undergoing coronary angiography has died. Nineteen patients were managed medically. Of this group 17 were considered to be under the same risk of death as the surgical candidates. Their mortality rate, as high. The risk of hying was 43.6% after 24 months, 51.1% after 36 months, and 73.6% after 42 months of observation. Although the initial surgical experience, using internal mammary artery implants and saphenous venin bypass grafts, was associated with a high mortality, direct revascularization surgery over the last 2 1/2 years has been accomplished with a perioperative mortality of only 6.2%. All deaths in the group of 40 patients receiving elective revasularization with saphenous vein bypass grafts occurred in the first six months following surgery. The risk of dying was 12.5% after six months of observation and was unchanged for the remainder of the follow-up period. After 21 months the difference in survival between the two groups is statistically significant (P less than 0.05). The one late death among the surgical survivors occurred four months after the operative procedure and was related to noncardiovaxcular surgical complications. The surgical survivors have been followed for an average of 27 months. Thus revascularization surgery has improved the prognosis for patients with main LCA disease. We currently advise prompt evaluation for any patient suspected of having this type of obstruction and urgent idrect revascularization surgery if this lesion is demonstrated angiographically.
Appraisal of sinus node artery disease.
Authors: Engel T R , Meister S G , Feitosa G S , Fischer H A , Frankl W S
Published: June 2012

The relationship of depressed sinus node function to coronary artery disease (CAD) was evaluated. The sinus node artery (SNA) was easily identified in all of 80 unselected normal coronary arteriograms. Angiographic disease of, or significant obstruction proximal to, the SNA was seen in 21% of 80 unselected CAD patients. Heart rate and sinoatrial recovery times (SART) were obtained in 50 consecutive unmedicated patients prior to arteriography. There was no difference between the SART of 23 CAD patients free of SNA involvement (1092 msec +/- 55 sem) and 18 normals (1070 +/- 40 msec). Nine patients with SNA involvement had shorter SART (941 +/- 52 MSEC) than normals (P less than 0.05) or other CAD patients (NS). Similar results were obtained for heart rate. No patient with SNA involvement had a prolonged SART or sick sinus syndrom (SSS). six of the 50 patients studied were symptomatic with SSS. Five of these SSS patients had CAD but none had angiographic evidence of SNA involvement. Obstructions involving the SNA were common in CAD but were not associated with altered heart rate or SART. Patients with SSS exhibited no angiographic evidence of SNA involvement. Therefore, it is unlikely that SSS is related to CAD of the SNA.
Cerebrospinal fluid acidosis complicating therapy of experimental cardiopulmonary arrest.
Authors: Berenyi K J , Wolk M , Killip T
Published: June 2012

Cardiopulmonary resuscitation (CPR) may be followed by slow recovery of brain function. The possible role of bicarbonate therapy was assessed by analysis of arterial blood and cerebrospinal fluid (CSF) in 20 dogs during cardiac arrest and CPR. Samples were taken in the control period and every 5 minutes post-arrest of 20 minutes. Group I received no post-arrest CPR. Arterial pH fell from 7.37 to 7.31 (P less than 0.01) and CSF pH from 7.34 to 6.94 (P less than 0.001). Arterial pCO2 rose from 39 to 65 mm Hg (P less than 0.005) and CSF pCO2 increased from 47 to 123 (P less than 0.02). With CPR alone (group II) arterial pH decreased from 7.39 to 7.19 (P less than 0.005), while arterial pCO2 and CSF pH and pCO2 were undhanged. CPR with bicarbonate therapy (mEq = weight in kg times 0.43 times 1.1 mEq/min of arrest) given every 5 minutes (group III), resulted in a rise in arterial pH from 7.41 to 7.81 (P less than 0.02). Excess bicarbonate administration during CPR may result in a marked dissociation between arterial and CSF pH as a consequence of rapid CO2 diffusion across the blood-brain barrier. Large ampounts of NaHCO3 given during CPR may contribute to post-CPR cerebral depresssion.
Postoperative changes in aortocoronary saphenous vein grafts revisited: angiographic studies at two weeks and at one year in two series of consecutive patients.
Authors: Campeau L , Crochet D , Lespérance J , Bourassa M G , Grondin C M
Published: June 2012

Comparison of aortocoronary saphenous vein graft status at two weeks and at one year was made in two series of patients. The early postoperative evaluation includes 122 patients of the first 138 operated in our institution (182 grafts) and 83 subjects from a second series of 100 patients operated after modifications of surgical techniques (184 grafts). The one-year follow-up study was obtained in 105 patients of the first series (154 grafts) and in 67 of the second (152 grafts). The patency rate at two weeks was not significantly different between the two groups: 86.3% vx. 91.8%. A marked decrease of steonses noted early at anastomotic sites was observed: 15% to 5.5% (P less than 0.025). The patency rate at one year improved from 67% to 85,5% (P less than 0.0005). Grafts having flows at operation of at least 50 ml/min had patency rates of 90% in both series. The patency in grafts with initial flows below 50 ml/min increased from 28% to 73% (P less than 0.005). The incidence of late localized graft stenoses greater than 40% decreased from 16.5% to 6% (P less than 0.025), and diffuse narrowing greater than 40% was found in only 12% of the patent grafts at one year in the second series as compared to 31% in the first (P less than 0.001). These improved results do not appear to have been influenced by selection favoring better distal run-off in grafted arteries nor by the introduction of sequential grafts to multiple coronary arteries in the second group. Modified surgical techniques may explain the improved results.
Volume ejected in early systole. A sensitive index of left ventricular performance in coronary artery disease.
Authors: Johnson L L , Ellis K , Schmidt D , Weiss M B , Cannon P J
Published: June 2012

Indices based on early systolic ejection rates are theoretically more sensitive to ventricular performance than indices based on the entire systolic ejection (SE) period (mean ejection phase indices-MEPI): mean systolic ejection rate (MSER), mean normalized systolic ejection rate (MNSER) and mean velocity of circumferential fiber shortening (MVcf). The volume ejected in early systole is an indicator of the early rate of ejection. Accordingly, ventricular volume changes were determined by ventriculographic analysis for each thrid of SE in ml/sec (SER), as normalized systolic ejection rate (NSER), and as percent of stroke volume (PSV). In ten normal controls all these indices were higher in the first third compared to the other thirds of SE. Seven patients with diffuse ventricular disease had depressed values in the first third of SE. Despite "normal ventriculograms and normal MEPI, eight patients with left anterior descending coronary artery stenoses (greater than 60%) also had definitely depressed ejection indices during first third of systole. Detailed wall motion analysis in this group showed anteroapical hypokinesis isolated to the first third of SE. These data show that indices based on early SER are more sensitive than MEPI (MVcf, MNSER) for detecting abnormalities in ventricular performance in coronary artery disease;
Abnormal regional metabolism and mechanical function in patients with ischemic heart diseases: improvement after successful regional revascularization by aortocoronary bypass.
Authors: Chatterjee K , Matloff J M , Swan H J , Ganz W , Kaushik V S , Magnusson P , Henis M M , Forrester J S
Published: June 2012

Left ventricular anterior wall metabolism was investigated concurrently with global myocardail metabolism by simultaneous preoperation sampling of anterior interventricular venous (AIV) and coronary sinus (CS) as well as arterial bloods in seven patients with severe obstructive lesions of the major coronary arteries, including left anterior descending. Postoperative study was performed two weeks to six months following successful aortocoronary artery bypass surgery. All grafts including the aorto-left anterior descending artery grafts were patent. Preoperatively in three of the seven patients, anterior wall lactate extraction (R%L) was negative at rest. The average R%L at rest (7 +/- 14%) was abnormal and was negative (-49 +/- 26%) at a maximum supraventricular pacing rate (MPR) of 137 +/- 4.6 beats/min. Postoperatively, not only was resting R%L (39 +/- 4;4%) normal but also it remained normal during atrial pacing (32 +/- 8.5%) even though the postoperative MPR (164 +/- 4.4 beats/min) was much higher than the preoperative MPR; Postoperatively AIV pO2 both at rest (21 +/- 1.1 mm Hg) and at MPR (22 +/- 1.3 mm Hg) and directly determined O2 saturations (resting: 34 +/- 3.0%; MPR:35 +/- 2.1%) tended to be higher than the preoperative values (AIV pO2, resting: 18 +/- 1.7; MPR: 19 +/- 1.7 mm Hg; AIV O2 saturation resting: 30 +/- 2.7; MPR: 33 +/- 3.3%), although only differences in pO2 were statistically significant. In five of the seven patients in whom the pre and postoperative left ventricular angiograms could be compared, systolic wall motion of the left ventricular anterior wall improved markedly postoperatively. Average global myocardial lactate extraction (G%L) preoperatively was normal (19 +/- 4.8%) at rest but was negative (-22 +/- 12%) at MPR. Postoperatively however, G%L both at rest (44 +/- 5.5%) and at MPR (34 +/- 7.9%) were normal. Coronary sinus pO2 and O2 saturation were also higher postoperatively compared to the preoperative values. Over-all left ventricular performance indicated by increase in ejection fraction also improved postoperatively. This improvement was not caused by increased coronary blood flow. Postoperative coronary sinus blood flow both at rest (114 +/- 19 ml/min) and at MPR (199 +/- 27 ml/min) however were less than the preoperative values (resting 136 +/- 24, MPR 261 +/- 40 ml/min), There was also no increase in global O2 delivery and O2 consumption despite higher heart rate and rate-pressure product achieved during postoperative pacing stress and the patients did not develop angina. These findings suggest that improved regional and global metabolism and mechanical functions observed postoperatively in these patients may be due to redistribution of blood flow to the ischemic and nonischemic myocardium following successful aortocoronary artery bypass surgery.
Hemodynamic and metabolic effects of sodium nitroprusside on the performance and metabolism of regional ischemic myocardium;.
Authors: Luz P L , Forrester J S , Wyatt H L , Tyberg J V , Chagrasulis R , Parmley W W , Swan H J
Published: June 2012

To assess the effects of sodium nitroprusside (5-10 mug/min) on total and regional cardiac performance, energetics, and lactate metabolism during acute ischemia, studies were performed in 21 open-chest dogs. For studies of regional function and metabolism, length gauges were sutured to the epicardial surface and an epicardial vein adjacent to the artery to be occluded was cannulated. Following occlusion of the left anterior descending coronary artery, cardiac output, mean arterial pressure, epicardial vein blood flow, and systolic shortening of the ischemic segment decreased significantly, In the blood samples from the ischemic zone, but not in those from the coronary sinus, lactate extraction shifted to production. In seven control dogs these alterations persisted throughout the experiment. In 14 animals treated with nitroprusside, cardiac output increased while peripheral resistance and mean arterial pressure decreased. Systolic shortening in the ischemic segment increased from 1.10 +/- 0.24 (SEM) to 1.77 +/- 0.30 mm (P less than 0.005). In eight dogs, regional venous outflow increased from 1.9 +/- 0.1 to 3.0 +/- 0.4 ml/min despite a slight reduction in mean arterial pressure. Concomitantly, regional negative lactate balance was reduced from -61.0 +/- 20.0 to -23.2 +/- 5.7% (P less than 0.05). These results indicate that nitroprusside significantly improves both total cardiac performance and the mechanical performance of regional ischemic myocardium. Moreover, this improvement in mechanical function occurred concomitantly with apparent increase in regional perfusion and reduction in lactate production, suggesting that nitroprusside simultaneously alleviates ischemia.
Short-term survival after acute myocardial infarction predicted by hemodynamic parameters.
Authors: Verdouw P D , Hagemeijer F , Dorp W G , Vrom A V , Hugenholtz P G
Published: June 2012

In the acute phase of myocardial infarction, short-term prediction of the likelihood of survival helps the physician choose the appropriate therapy for individual patients. Of 122 patients admitted to the coronary care unit of the Thoraxcenter, University Hospital, Rotterdam, with an acute myocardial infarction, 16 died from pump failure. In these and the 106 survivors, the predictive value of peripheral systolic (SP) and diastolic (DP) blood pressure, pulmonary capillary wedge pressure (PCW), mixed venous oxygen saturation (MVO2sat) in the pulmonary artery and heart rate (HR), both alone and in combination, was evaluated at the time of admission and 24 hours later. When, at admission, (DP X MVO2sat)/PCW exceeded 250%, 97/99 patients survived, whereas values below 250% were associated with death in 14/23. All other papameters, taken alone or in other combinations, showed less discriminatory power. Thb mean value of this index in survivors (549%) was statistically different (P less than 0.001) from the mean value in nonsurvivors (183%). Twenty-four hours later all survivors with admission values lower than 250% had an improved index. Of the 14 nonsurvivors with admission values lower than 250%, seven had already died, and in seven others the index had decreased still further; Linear discriminant analysis showed that (0.024 SP -- 0.217 PCW + 0.234 MVO2sat) was the most powerful prognostic index at the time of admission; its time course did not provide a more effective prediction of ultimate fatality than (DP XMVO2sat)/PCW. Determination of (DP X MVO2sat)/PCW in patients hospitalized for acute myocardial infarction provides a reliable prognosis for short-term patient survival. Its practical value in guiding patient management, more particularly for initiating mechanical circulatory assistance or for emergency surgery, must be further assessed.
The sequence of normal recovery of excitability in the dog heart.
Authors: Abildskov J A
Published: June 2012

The sequence with which 18 to 70 ventricular sites recovered excitability after normal excitation was determined in 15 dogs. At the epicardial level the recovery sequence was similar to that of normal activation. The sequence of excitation and recovery differed at the endocardium with some basal areas recovering excitability earlier than the apex despite later activation. Evidence of a normal epicardial to endocardial recovery sequence was also obtained. The findings are compatible with and provide a tentative explanation of some features of T waves in human body surface electrocardiograms.
Diagnosis of cardiac tamponade by echocardiography: changes in mitral valve motion and ventricular dimensions, with special reference to paradoxical pulse.
Authors: D'Cruz I A , Cohen H C , Prabhu R , Glick G
Published: June 2012

The echocardiographic findings in three patients who presented with pericardial effusion and cardiac tamponade are described. Cyclic respiratory changes affected the diastolic movement of the anterior mitral leaflet, viz., during inspiration its anterior excursion decreased in amplitude and the E-F slope diminished. This inspiratory alteration in mitral valve motion was accompanied by an increase in right ventricular dimensions and a reciprocal decrease in left ventricular dimensions. Pericardial paracentesis confirmed the presence of effusion and relieved cardiac tamponade in all the patients. Repeat echocardiography, performed in two of the patients immediately after the pericardial tap, showed that the E-F slope had become steeper and that phasic respiratory variations in the diastolic motion of the anterior mitral leaflet were no longer present. The compatibility of our observations with the theories which endeavor to explain the mechanism of the paradoxical pulse in pericardial effusion with cardiac tamponade is discussed. We suggest that the abnormalities in anterior mitral leaflet motion defined by echocardiography constitute a useful addition to the study of patients with suspected cardiac tamponade resulting from pericardial effusion.
The reliability of intermittent ECG sampling in arrhythmia detection.
Authors: Rydén L , Waldenström A , Homberg S
Published: June 2012

Although intermittent ECG sampling is a commonly used method for arrhythmia detection there are no controlled studies of its efficiency. In the present study a continuous ECG was recorded for three hours in 52 patients with ventricular tachyarrhythmias. All ECGs were interpreted minute to minute to get the true arrhythmia content. Intermittent ECG samples were simulated by analyzing the first two and first five minutes of every 15 minutes in the ECG material. Two minute long ECG samples were also used every 30 minutes. The 15 and 30 minute long periods were classified as containing arrhythmias or not according to the arrhythmia content of the samples. These findings were subsequently compared with the true arrhythmia content. The arrhythmia detection rate depends on the sampling time and true arrhythmia occurrence. The distribution of arrhythmias within the periods was also of importance. With a five minute long ECG sample about 80% of the intervals containing any type of ventricular tachyarrhythmia will be detected. This is reduced to about 50% when one minute long ECG strips are used. Infrequent types of VPCs such as R on T or ventricular tachycardia are very poorly detected also when sampling as much as one-third of the total time. The study also included a comparison between the results obtained from the clinical material and the results obtained by the use of computerized arrhythmia models. It is concluded that intermittent ECG sampling besides a low detection rate for infrequent arrhythmias and short ECG samples, also brings a risk of underestimating or overemphasizing the arrhythmia occurrence depending on a periodic type of arrhythmia distribution among the patients. These factors make intermittent ECG sampling an unsuitable method for evaluating antiarrhythmic drugs.