bluuebunny/crossref_metadata_2025 huggingface dataset:
Technetium-99m stannous pyrophosphate imaging of experimental infective endocarditis.
Authors: Riba A L , Downs J , Thakur M L , Gottschalk A , Andriole V T , Zaret B L
Published: June 2012

Technetium-99m stannous pyrophosphate (99mTc-PYP) cardiac scintigraphy was performed in 15 rabbits with experimental Streptococcus sanguis aortic valve infective endocarditis. The animals were imaged five to seven days after the administration of bacteria, and in each case abnormal accumulation of the tracer was visualized in the region of the aortic valve. Three types of cardiac scintigraphic patterns were demonstrated: focal, multifocal and extensive, each correlating well with the anatomical extent of the lesion as defined by gross pathology. Tissue distribution studies demonstrated a 30 +/- 5.3 (mean +/- SEM) fold excess of radionuclide uptake in the infective endocarditis lesion compared with that of normal myocardium. Imaging of excised hearts from four animals showed an excellent correlation with in vivo imaging as well as gross pathology. Five animals with nonbacterial thrombotic aortic valve endocarditis demonstrated similar scintigraphic and tissue distribution results. In contrast, four normal animals failed to demonstrate abnormal 99mTc-PYP cardiac scintigrams or tissue uptake. This study demonstrates that 99mTc-PYP cardiac scintigraphy is a sensitive technique to detect experimental aortic valve endocarditis.
Hemodynamically significant primary anomalies of the coronary arteries. Angiographic aspects.
Authors: Levin D C , Fellows K E , Abrams H L
Published: June 2012

Hemodynamically significant primary anomalies of the coronary arteries are those which alter myocardial perfusion. There are four major types: coronary artery fistulae, origin of the left coronary artery from the pulmonary artery, congenital coronary stenosis or atresia, and origin of the left coronary artery from the right sinus of Valsalva, with subsequent passage of the vessel between the aorta and right ventricular infundibulum. The angiographic features of these lesions are discussed.
George Lyman Duff Memorial Lecture. Lifestyles, major risk factors, proof and public policy.
Authors: Stamler J
Published: June 2012

In this report major risk factors in coronary heart disease (CHD) are reviewed, with particular emphasis on the role of nutrition. International and national epidemiologic data indicate that reducing or eliminating certain risk factors (e.g., a diet high in cholesterol and saturated fats) may reduce the risk of premature CHD. Most trends indicate that many Americans are more concerned about diet for health reasons. Preventive measures for CHD are also discussed.
Coronary arterial spasm and Prinzmetal's variant form of angina induced by hyperventilation and Tris-buffer infusion.
Authors: Yasue H , Nagao M , Omote S , Takizawa A , Miwa K , Tanaka S
Published: June 2012

Vigorous hyperventilation was induced for five minutes immediately after a five-minute infusion of 100 ml of Tris-buffer (pH 10) in nine patients with Prinzmetal's variant angina. In eight of the patients, chest pain with ischemic changes in the electrocardiogram occurred during this procedure or within five minutes after it ended. Coronary arterial spasm appeared after the procedure and disappeared after the administration of nitroglycerin in all four patients in whom coronary cinearteriography was performed. This was evident both before and after the procedure and after sublingual administration of nitroglycerin (0.6 mg). The oral administration of 90 mg of diltiazem, a calcium antagonistic drug, two hours before, completely suppressed the attack induced by the procedure in all of the five patients who received this drug. We conclude that hyperventilation plus Tris-buffer infusion induces coronary arterial spasm and anginal attack in patients with Prinzmetal's variant angina and that diltiazem suppresses these reactions.
Early intraaortic balloon pumping for anterior myocardial infarction without shock.
Authors: Leinbach R C , Gold H K , Harper R W , Buckley M J , Austen W G
Published: June 2012

Eleven patients with anterior myocardial infarction less than six hours old underwent intraaortic balloon pumping (IABP) in an attempt to control injury. Direct hemodynamic measurements excluded shock. Response to therapy was judged individually by comparison to a one-hour pretreatment period. There was no parallel control group. Five patients responded with an 84% fall in ST elevation in one hour, with preservation of precordial R waves and good ventricular function. In contrast, six patients responded poorly, with a 40% fall in ST elevation in one hour, Q wave development and poorer residual left ventricular function. Coronary angiography demonstrated a significant correlation between response and presence or absence of complete left anterior descending coronary artery occlusion. Early use of IABP in anterior myocardial infarction may interrupt injury, though in this series only in cases with residual left anterior descending patency.
The effect of ischemia on thallium-201 clearance from the myocardium.
Authors: Gewirtz H , O'Keefe D D , Pohost G M , Strauss H W , McIlduff J B , Daggett W M
Published: June 2012

To determine the effect of ischemia on myocardial clearance of thallium-201 (201Tl), we studied 12 dogs with ischemia produced after the injection of Tl. Tl was given I.V. 10 minutes before left anterior descending (LAD) coronary artery ligation. 85Sr-microspheres (MS) were administered 5 minutes later, and control biopsies were obtained from the myocardium. The LAD was tied and repeat biopsies obtained from the ischemic zone (IZ) and normal zone (NZ) 15 minures and 2 hours later. 46Sc-MS were given just before the final giopsy. Tl activity in the IZ was not significantly different from that in the NZ either before LAD occlusion or 15 minutes and 2 hours later. Tl clearance at the end of 2 hours was not significantly different (27 +/- 5% vs 28 +/- 5%, IZ vs NZ respectively) between the two zones. The half-time of Tl clearance from both the IZ and NZ was calculated at 4.5 hours (consistent with previously reported normal values). This occurred despite a decrease in regional myocardial blood flow to 24 +/- 6% of control (P less than 0.01) in the IZ and an increase to 47 +/- 14% of control (P less than 0.01) in the NZ during the study. We conclude that myocardial ischemia does not alter the normal rate of Tl clearance from the myocardium.
Long-term preservation of ischemic myocardium in the dog by hyaluronidase.
Authors: Kloner R A , Braunwald E , Maroko P R
Published: June 2012

The administration of hyaluronidase is a promising intervention to protect the ischemic myocardium in man, but evidence of the extent to which it may reduce the ultimate size of an infarct is not well-defined. Hence, open chest, anesthetized dogs were randomized into 10 control dogs which received saline and eight treated dogs which received three doses of hyaluronidase (500 NF units/kg I.V.) at 15 minutes, 2 hours and 24 hours after occlusion of the left anterior descending coronary artery (CAO). Regional myocardial blood flow (RMBF) assessed by the microsphere technique was measured 12 minutes after CAO. The chest was then closed and the dogs were allowed to recover. Twenty-one days after CAO, the hearts were excised, divided into 1 cm thick slices and incubated in triphenyl tetrazolium chloride. Infarct size was then determined by planimetry. The left ventricular myocardium was divided into multiple samples for RMBF analysis. In control dogs 23.2 +/- 2% of the left ventricle was infarcted, compared to only 9 +/- 2.8% (P less than 0.001) in hyaluronidase-treated dogs. RMBF in noninfarcted myocardium directly adjacent to the infarct was similar to that in the normal zone remote from the infarct in the control dogs; however, in the hyaluronidase-treated dogs, blood flow in the myocardium adjacent to the infarct was significantly reduced to 68% of normal (P less than 0.01) in the outer myocardial wall and to 86% of normal (P less than 0.02) in the inner myocardial wall, which indicates that this tissue, at least in some part, was in jeopardy, but was salvaged by hyaluronidase. Epicardial electrocardiographic data showed that three weeks after CAO, Q waves were less frequent and smaller in hyaluronidase compared to untreated dogs. Preservation of the frequency and magnitude of R waves was greater in the hyaluronidase-treated group at three weeks. We conclude that hyaluronidase resulted in long-term preservation of the ischemic myocardium.
Clinical and electrophysiologic findings in patients with paroxysmal slowing of the sinus rate and apparent Mobitz type II atrioventricular block.
Authors: Massie B , Scheinman M M , Peters R , Desai J , Hirschfeld D , O'Young J
Published: June 2012

Over five years, 13 patients with episodic apparent type II atrioventricular (AV) block associated with sinus slowing were seen. This phenomenon occurred only transiently during an acute illness in eight patients (group I) but recurred chronically in five (groupII). For the group as a whole, the mean spontaneous cycle length was 42% longer during the period of AV block compared with periods of 1:1 AV conduction (800 +/- 116 msec to 1138 +/- 489 msec) (P less than 0.05). Electrophysiologic studies in four group I patients showed no abnormalities, whereas abnormalities in AV nodal conduction and refractoriness or provocation of intranodal Mobitz type II AV block (during carotid massage) were observed in three patients in group II and were totally abolished by atropine. In group I patients, apparent type II AV block was self-limited. In the chronic group, recurrent symptoms required insertion of permanent pacemakers in two patients. Simultaneous type II block and sinus slowing appeared to be related to the effects of increased vagal tone on both nodal structures. Intracardiac pacing is not indicated for patients with transient episodes associated with an acute illness, but may be required for symptomatic patients with recurrent episodes.
Effects of dietary and pharmacologic alteration of serum lipids on platelet survival time.
Authors: Steele P , Rainwater J
Published: June 2012

Platelet survival time (SURV) (autologous labelling with 51Chromium) was shortened (3 +/- 0.03 days; average t 1/2 +/- SEM; normal t 1/2 3.7 +/- 0.03 days) in 88 out of 128 (69%) men with coronary disease. In 35 out of 47 men with hyperprebetalipoproteinemia, SURV was shortened (3 +/- 0.09 days) (74%). Of 30 men with hyperbetalipoproteinemia, SURV was shortened (2.5 +/- 0.10 days) in 26 (87%). Of 51 men without hyperlipoproteinemia, SURV was normal (3.3 +/- 0.10 days) in 24 (47%). Dietary alteration of serum triglyceride was undertaken in 12 men with hyperprebetalipoproteinemia, and in eight a decrease of triglyceride of more than 75 mg% was achieved (324 +/- 21-219 +/- 18 mg%; P less than 0.001) with an increase of SURV (2.2 +/- 0.11-2.8 +/- 0.13 days; P less than 0.001). In four, serum triglyceride increased by more than 75 mg% (279 +/- 14-451 +/- 28 mg%) and SURV decreased (2.7 +/- 0.16-2.3 +/- 0.21 days). Cholestyramine (16 g g.d.) and diet decreased serum cholesterol (348 +/- 7.6-319 +/- 6.3 mg%; P less than 0.001) in 15 men with hyperbetalipoproteinemia and SURV increased (2.3 +/- 0.08-2.7 +/- 0.07 days; P less than 0.001). Results suggest that SURV is shortened in men with coronary disease, particularly in those with hyperlipoproteinemia, and that alteration of triglyceride and cholesterol are associated with alteration of SURV.
Catenoid shape of the interventricular septum: possible cause of idiopathic hypertrophic subaortic stenosis.
Authors: Hutchins G M , Bulkley B H
Published: June 2012

Previous studies have shown that asymmetric septal hypertrophy (ASH) may occur in embryonic and malformed hearts and that muscle cell disarray is found in myocardium that contracts isometrically. To account for the characteristic ASH and septal muscle fiber disarray of idiopathic hypertrophic subaortic stenosis (IHSS), we postulated that a catenoid shape of the septum, i.e., net zero curvature, would have the mechanics required to produce IHSS. Accordingly, hearts from eight autopsied patients with IHSS were studied for curvature and thickness of free walls and septum, and they were compared to similar measurements in 80 other hearts. In all eight hearts with IHSS the septum was concave to the left in the transverse plane but convex to the left in the apex-to-base plane. Such a catenoid configuration of the septum was not observed in any of the other 80 hearts. The distinctive shape of the septum in IHSS would account for isometric contraction, since adjacent fiber tracts with opposite curvatures would develop maximum tension but would not have motion. Fiber disarray and local hypertrophy would result from such isometric contraction. Since ventricular configuration is acquired early in cardiogenesis, IHSS might therefore result from a genetic or embryonic determination of a catenoid septum.
Effects of self-induced starvation on cardiac size and function in anorexia nervosa.
Authors: Gottdiener J S , Gross H A , Henry W L , Borer J S , Ebert M H
Published: June 2012

Cardiac size, function and rhythm were examined in 11 patients with anorexia nervosa. Mean left ventricular, left atrial and aortic dimensions on echocardiogram were below normal adult values at baseline. In addition to decreased cardiac dimensions--ventricular ectopy, relative hypotension, bradycardia and blunted heart rate--response to exercise were noted. Left ventricular systolic function, however, was unimpaired as indicated by normal echocardiographic fractional shortening, and by normal exercise augmentation of ejection fraction determined by radionuclide cineangiography. Eight of the patients responded to treatment with a mean weight gain of 32%. In these eight, cardiac dimensions increased toward normal: left ventricular dimension increased by 13%; left atrial dimension by 20%; aortic dimension by 15% and estimated left ventricular mass by 20%. We conclude that abnormalities of heart size and rhythm occur in patients with anorexia nervosa. However, cardiac dimensions, including left ventricular mass, may increase following nutritional rehabilitation, accompanied by an increase in heart rate and blood pressure.
Comparative systemic and regional hemodynamic effects of dopamine and dobutamine in patients with cardiomyopathic heart failure.
Authors: Leier C V , Heban P T , Huss P , Bush C A , Lewis R P
Published: June 2012

Thirteen patients with severe cardiac failure underwent a single crossover study of dopamine and dobutamine in order to compare the systemic and regional hemodynamic effects of the two drugs. The dose-response data demonstrated that dobutamine (2.5--10 microgram/kg/min) progressively and predictably increases cardiac output by increasing stroke volume, while simultaneously decreasing systemic and pulmonary vascular resistance and pulmonary capillary wedge pressure. There was no change in heart rate or premature ventricular contractions (PVCs)/min at this dose range. Dopamine (2--8 microgram/kg/min) increased the stroke volume and cardiac output at 4 microgram/kg/min. Dopamine at less than 4 microgram/kg/min provided little additional increase in cardiac output and increased the pulmonary wedge pressure and the number of PVCs/min. At greater than 6 microgram/kg/min, dopamine increased heart rate. During the 24-hour maintenance-dose infusion of each drug (dopamine 3.7--4, dobutamine 7.3--7.7 microgram/kg/min), only dobutamine maintained a significant increase of stroke volume, cardiac output, urine flow, urine sodium concentration, creatinine clearance and peripheral blood flow. Renal and hepatic blood flow were not signfiicantly altered by the maintenance dose of either drug. Systemic and regional hemodynamic data suggest that dobutamine has many advantages over dopamine when infused in patients with cardiac failure.
The effect of free fatty acids on myocardial oxygen consumption during atrial pacing and catecholamine infusion in man.
Authors: Simonsen S , Kjekshus J K
Published: June 2012

The effect of myocardial uptake of free fatty acids (FFAu) on myocardial oxygen consumption (MVO2) in relation to increased heart rate and inotropic stimulation was determined in patients with coronary artery disease. Submaximal atrial pacing and isoproterenol stimulation increased MVO2 by 66% and 142%, respectively, at similar heart rates. Inhibition of lipolysis with beta-pyridyl carbinol almost abolished FFAu and reduced MVO2 significantly. Increased heart rate contributed 47% and FFAu 50% of the raised MVO2 attributed to inotropic stimulation was 30%. Augmentation of FFAu by triglyceride/heparin infusion increased MVO2 significantly above control levels, both during pacing and isoproterenol infusion. We conclude that MVO2 is closely correlated to FFAu, catecholamines sensitize the heart to FFA, and increased FFAu account for a major part of the increased MVO2 during catecholamine stimulation. The importance of reducing heart rate and lipolysis to reduce myocardial oxygen requirements is emphasized.
Association between coronary heart disease and the C3F-gene in essential hypertension.
Authors: Kristensen B O , Petersen G B
Published: June 2012

The occurrence of the C3F allele was investigated in the following three groups: 69 consecutive referred patients with untreated essential hypertension, including borderline hypertension; 70 patients with established and treated essential hypertension, already attending the same outpatient clinic, and 62 age- and sex-matched normotensive healthy subjects without clinical signs of atherosclerosis or familial predisposition to hypertension. In the three groups the C3F allele was found in 38.2%, 29% and 20%, respectively. Among the treated hypertensive patients with C3F gene, 40% had coronary heart disease (CHD) compared to 6.1% among the C3F negative (P less than 0.005), and the relative risk of CHD among the treated hypertensive patients with this allele was found to be 10.2 (P less than 0.002). The C3F gene was present in 72.7% of the treated patients with CHD. In the untreated patients the occurrence of CHD was low, and no differences between C3F positive and negative patients could be demonstrated. No association of the C3F allele with familial predisposition to hypertension was found. This study provides further evidence of a positive association of the C3F allele with atherosclerosis, and it is concluded that this allele in a hypertensive patient might accelerate the atherosclerotic process, with subsequent premature development of vascular complications.
The clinical significance of bundle branch block complicating acute myocardial infarction. 2. Indications for temporary and permanent pacemaker insertion.
Authors: Hindman M C , Wagner G S , JaRo M , Atkins J M , Scheinman M M , DeSanctis R W , Hutter A H , Yeatman L , Rubenfire M , Pujura C , Rubin M , Morris J J
Published: June 2012

The indication for prophylactic temporary and permanent pacing during acute myocardial infarction (MI) complicated by bundle branch block is high risk of progression via a Type II pattern to second or third degree (high degree) AV block during hospitalization or follow-up. In this study, determinants of high degree AV block during hospitalization and sudden death or recurrent high degree block during the first year of follow-up were examined in 432 patients with MI and bundle branch block. Timing of onset of bundle branch block, the involved fascicles, and the PR interval were examined as determinants of risk of progression to high degree AV block during MI. At highest risk were 186 patients with blocks involving the right bundle and at least one fascicle of the left bundle which were not documented on prior electrocardiograms. Risk was similar with (38%) or without (31%) accompanying first degree AV block. Patients with transient high degree AV block during MI had a 28% incidence of sudden death or recurrent high degree block during the first year of follow-up. Patients not continuously paced had a higher incidence of sudden death or recurrent high degree block than patients continuously paced (65% vs 10%, P less than 0.001). Sudden death during follow-up also occurred in 13% of patients without high degree block during MI. A subgroup with 1) documented prior MI, 2) anterior or indeterminant acute MI, and 3) no symptoms of cardiac failure had a 35% risk of sudden death. The role of permanent pacing in this group is unknown. Thus, patients at high risk of high degree AV block should receive prophylactic temporary pacing. Patients who survive high degree block with MI should receive temporary and then permanent pacing. Patients without high degree AV block during MI who nervertheless have a high risk of sudden death may benefit from permanent pacing.
Left ventricular volume during maximal supine exercise: a study using metallic epicardial markers.
Authors: Caldwell J H , Stewart D K , Dodge H T , Frimer M , Kennedy J W
Published: June 2012

Changes in left ventricular (LV) volumes and ejection fraction between rest and maximal supine exercise were evaluated in 11 patients who had had four epicardial markers placed during coronary artery surgery. After calibrating marker distances with respect to volume (r = 0.92--0.99) over one cardiac cycle for each patient, regression equations were used to compute LV volume from marker measurements for beats before and during exercise. The response of the left ventricle to exercise and the extent of revascularization could not be predicted from resting LV volume or ejection fraction. Ten patients had normal resting end-diastolic volumes and eight had normal resting ejection fractions. With exercise, three had a rise in end-diastolic volume and four had a fall in ejection fraction. Graft patency was greater in the group with an unchanged or increased ejection fraction (86 vs 50%, P less than 0.05). Epicardial clip motion can be used to determine LV volumes and ejection fraction during supine maximal exercise in man. The revascularized ventricle with normal or nearly normal performance in studies done at rest responds by decreasing end-diastolic and end-systolic volume and by increasing the ejection fraction. Increases in volumes or decreases in ejection fraction reflect old myocardial damage from infarction, fibrosis or ischemia from incomplete revascularization.
In vivo validation of a thermodilution method to determine regional left ventricular blood flow in patients with coronary disease.
Authors: Pepine C J , Mehta J , Webster W W , Nichols W W
Published: June 2012

Several methods have been used to measure left ventricular regional blood flow in humans. However, limitations and lack of validation in patients are major problems. A continuous thermodilution technique to measure regional left ventricular blood flow in patients with coronary disease was validated in vivo. This technique permits simultaneous assessment of venous blood flow draining predominantly from the anterior wall and of the total left ventricular effluent. Thermodilution measurements with simultaneous electromagnetic flowmeter recordings from anterior descending vein grafts were compared in patients with occluded or subtotally occluded anterior descending coronary arteries. The thermodilution method yielded values for both absolute anterior regional blood flow and changes in anterior regional flow that compared closely to anterior descending bypass graft flow measured independently. The multithermistor technique may be useful in monitoring flow effects of regional coronary disease over time, as well as in studies of agents purported to alter regional blood flow.
Single and two-dimensional echocardiographic visualization of the effects of septal myectomy in idiopathic hypertrophic subaortic stenosis.
Authors: Schapira J N , Stemple D R , Martin R P , Rakowski H , Stinson E B , Popp R L
Published: June 2012

Although the postoperative hemodynamic and echocardiographic features of idiopathic hypertrophic subaortic stenosis have been studied, the expected consistent postoperative thinning of the interventricular septum has not been reported. In this study, the short-term effects of septal myectomy were evaluated in 16 patients. All patients were assessed with pre- and postoperative hemodynamic studies and M-mode echocardiograms, and six of the 16 patients had pre- and postoperative two-dimensional echocardiograms. The mean resting preoperative gradient of 74 mm Hg (range 10--190 mm Hg), which fell to a mean resting postoperative gradient of 8 mm Hg (range 0--25 mm Hg), was associated with decreased end-diastolic interventricular septal thickness at the midventricular level in 14 of 16 patients and at the subaortic level in 16 of 16 patients by M-mode echocardiography. The group also demonstrated changes in left ventricular outflow tract configuration and dimension, mitral valve systolic anterior motion, mitral E-F0 slope and left ventricular percent fractional shortening by both M-mode and two-dimensional studies. In the two patients who did not show midventricular septal thinning on M-mode echocardiography, the two-dimensional echocardiograms revealed that the area of myectomy extended only through the subaortic region and not down to the midventricular septum. Thus, we have observed consistent postmyectomy septal thinning at both the midventricular and subaortic levels by M-mode echo. By defining the geometry of the septal myectomy in vivo with two-dimensional echocardiography, we can better interpret M-mode studies and identify factors that influence echocardiographic visualization of the region of myectomy.
Echocardiographic features of constrictive pericarditis.
Authors: Voelkel A G , Pietro D A , Folland E D , Fisher M L , Parisi A F
Published: June 2012

The most characteristic echocardiographic features of 12 patients with constrictive pericarditis were compared with the findings in 10 normal volunteers. Left ventricular posterior wall (LVPW) "flatness" was quantified by measuring the diastolic change in distance from the crystal artifact to the LVPW endocardium. In 11 of 12 patients the net diastolic LVPW endocardial movement was less than 1 mm. In 10 normal volunteers LVPW endocardium moved posteriorly in diastole from 1.5 to 4 mm (mean 2.2 +/- 0.8). Abnormal septal motion was present in five of 12 patients with constriction. Pericardial thickness measured using standard damping techniques for both cnstriction and normal population did not distinguish the two groups. The "flattening" of the left ventricular endocardium as quantified above verifies earlier qualitative observations and was the most consistent finding in this series of patients with constrictive pericarditis.
Electrocardiographic precordial mapping in anterior myocardial infarction. The critical period for interventions as exemplified by methylprednisolone.
Authors: Selwyn A P , Fox K M , Welman E , Jonathan A , Shillingford J P
Published: June 2012

Serial 72-point precordial mapping of ECG has been recorded to describe the natural history of changes in the precordial areas of ST segment elevation and the development of Q waves in 51 patients with acute uncomplicated anterior myocardial infarction. Eight patients have been studied in the same way but received 25 mg/kg of methylprednisolone sodium succinate as a single intravenous injection within 6 hours from the onset of chest pain. There was a linear relationship between the stable precordial area of Q waves at 24 hours and the rapidly changing precordial areas of ST segment elevation at 2--3 hours, 5--6 hours and 12 hours after the onset of pain in the untreated patients. When methylprednisolone was given, the treated patients developed a smaller precordial area of Q waves at 24 hours than was predicted from the precordial area of ST elevation recorded before the drug was given. This study has introduced a technique that can provide a qualitative assessment of the relationship between ECG evidence of ischemia and infarction in each patient.
Impedance plethysmography: the relationship between venous filling and sensitivity and specificity for proximal vein thrombosis.
Authors: Hull R , Taylor D W , Hirsh J , Sackett D L , Powers P , Turpie A G , Walker I
Published: June 2012

We investigated the hypothesis that the diagnostic accuracy of impedance plethysmography (IPG) for thrombosis of the popliteal or more proximal veins increases with enhanced venous filling. Venous filling was increased by prolonging cuff occlusion and by sequential testing. IPG and vengography were performed on 169 legs with and 317 legs without proximal vein thrombosis. The sensitivity and specificity of IPG rose significantly with increased venous filling. Changes in venous filling were associated with corresponding changes in emptying in normal legs, but not those with proximal vein thrombosis, so that the regression lines relating venous filling and emptying in normal and abnormal legs diverged significantly (P less than 0.001). If the IPG sequence had been terminated after only a single 45 second occlusion time test, sensitivity would have deteriorated by 10% and specificity by 20%. These observations indicate that the accuracy of IPG can be significantly enhanced if optimal venous filling is obtained.
Arterial insufficiency of the hand evaluated by digital blood pressure and arteriographic findings.
Authors: Hirai M
Published: June 2012

In 80 hands with arterial occlusive disease, systolic blood pressure at the wrist and in all fingers was measured by photoelectric plethysmography. The correlation of such pressures with angiographic evidence of organic obstruction or the development of digital ischemic signs was studied. Digital blood pressure was normal in all 184 fingers in which there was at least one obstruction-free arterial path to and through the finger. Ischemic signs developed in only one. Of 203 fingers with occlusion in vessels in or leading to both sides of the finger, a decreased pressure was seen in 173 and a normal pressure in 30. Ischemic signs were observed in 132 of 173 fingers with a decreased pressure, and in two of 30 with a normal pressure. The clinical significance of measurement of digital blood pressure in arterial occlusive disease is discussed.
Cardiac manifestations of malignant hyperthermia susceptibility.
Authors: Huckell V F , Staniloff H M , Britt B A , Waxman M B , Morch J E
Published: June 2012

Malignant hyperthermia is a disease resulting from defective cellular membranes, usually presenting as drug-induced pyrexic crises. We describe four patients with life threatening ventricular arrhythmias or chest pain in the absence of pyrexic crises. Three presented with life threatening arrhythmias and the fourth with severe atypical chest pain. Two patients had a family history of multiple sudden deaths. Resting CKs were elevated in three patients while CK-MB was elevated in one. Resting ECGs were abnormal in three. Three patients had recurrent ventricular tachycardia, two had recurrent ventricular fibrillation and multiple cardiac arrests. Cardiac catheterization showed abnormal left ventricular wall motion in two and minimal mitral valve prolapse in one while all had normal coronary arteries. Thallium-201 myocardial imaging demonstrated large perfusion defects in the patient with electrocardiographic Q waves and normal coronary arteries. Myocardial involvement has been demonstrated by clinical, electrocardiographic, hemodynamic, angiographic and myocardial imaging abnormalities. Malignant arrhythmias occurred in these patients in the absence of pyrexic crises or drug admininstration. Abnormal calcium release in the myocardium, as documented in skeletal muscle membranes, may be a unifying concept for the various manifestations described.
Echocardiographic evaluation of intracardiac pacing catheters: M-mode and two-dimensional studies.
Authors: Reeves W C , Nanda N C , Barold S S
Published: June 2012

Thirty patients with right ventricular (RV) and 15 with coronary sinus (CS) pacing catheters were studied by M-mode echocardiography. RV catheters, detected in 23, appeared as linear echoes in the right ventricle during mitral valve recordings in 12, adjacent or superimposed on the tricuspid valve (TV) in 14, and immediately anterior to aortic root and pulmonary valve echoes in two with a redundant loop in RV outflow. In three with complete heart block, prominent systolic anterior movements of the TV occurred when atrial systole coincided with ventricular systole, probably due to catheter-induced TV "buckling" or exaggerated TV annular motion. Catheter echoes mimicked TV recordings in three, since its motion pattern was similar, although delayed and mimicked prolapsing right atrial myxomas in two because of multilayered complexes behind TV, while reverberations cluttering the left ventricle simulated structural echoes present in that cavity. CS catheters, detected in 14 as linear echoes in the area of atrial septum recorded behind the TV, showed typical small humps in late diastole/early systole. Cross-sectional echocardiography with a mechanical sector scanner demonstrated RV catheters at the RV apex in five of seven patients, while CS catheters were detected near the base of the atrial septum in three of five patients. Echocardiography has the potential to localize pacing catheters which are occasionally difficult radiologically or electrocardiographically. Failure to recognize catheter echo patterns may result in errors in echocardiographic interpretation.
Physiologic correlates of echocardiographic pulmonary valve motion in diastole.
Authors: Pocoski D J , Shah P M
Published: June 2012

It has been shown that the echographic motion of the posterior aortic wall in diastole is closely related to the underlying left atrial events, possibly due to the anatomical proximity of the two structures. We observed that the pulmonary artery shares a similar close anatomical relationship with the left atrium. The present study in 55 consecutive patients with adequate echocardiographic recordings of the aortic root and the pulmonary valve demonstrates that the diastolic waveforms of the pulmonary valve and the posterior aortic wall are nearly identical in early diastole. The pulmonary valve e-f slope correlated with the posterior aortic wall O-R slope (r = 0.95) and the S2-f interval (second heart sound to f on the pulmonary valve) correlated closely with the S2-R interval (second heart sound to R on the posterior aortic root) (r = 0.94)). No significant correlation was found between the pulmonary valve e-f slope and the pulmonary artery pressures. The presence and amplitude of the maximum "a dip," on the other hand, correlated with the presence of pulmonary hypertension, with some notable exceptions. In addition, the "a dip" on the pulmonary valve and the depth of the A wave on the posterior aortic wall were significantly correlated (r = 0.85). It appears that the "a dip" on the pulmonary valve is influenced by dual mechanisms: pressure differences between the pulmonary artery and the right ventricle in late diastole and the left atrial events. Thus, the early diastolic waveform of the pulmonary valve, like the posterior aortic wall waveform, may primarily reflect underlying left atrial events and is not a measure of pulmonary artery pressure. The late diastolic waveform "a dip" has a dual mechanism, related in part to the underlying left atrial events, and also reflecting the instantaneous pressure differences across the pulmonary valve following atrial systole.
Systolic time intervals in children: normal standards for clinical use.
Authors: Cantor A , Wanderman K L , Karolevitch T , Ovsyshcher I , Gueron M
Published: June 2012

Systolic time intervals were measured in 253 normal children, with careful attention to precise recording and measuring techniques, to derive regression equations which could be used as reliable standards for clinical assessment of left ventricular performance in this age group. Using stepwise regression analysis, a highly significant correlation was found for electromechanical systole (QS2) and for left ventricular ejection time (LVET) with heart rate alone in both males and females, and age was not found to be a relevant variable. Similarly, for the preejection period (PEP) in males, heart rate was the only relevant variable. PEP in females showed a small but significant influence of age in addition to heart rate; in practice, this small influence can be neglected. Regression equations relating each of the systolic time intervals to heart rate alone were therefore derived for clinical use. The PEP/LVET ratio was found to be only weakly correlated with heart rate in males and with age in females, and in practice can be considered to be independent of these variables. The mean value of the PEP/LVET ratio and its standard deviation (0.30 +/- 0.04) can therefore be used for all children. We found that satisfactory recording of systolic time intervals can be obtained with little difficulty in almost all children using the techniques described. The method is therefore practical for clinical use in children, as it is in adults, and the normal standards derived in this study can serve as a reliable basis for its application.
Early imaging of experimental myocardial infarction by intracoronary administraion of 131I-labelled anticardiac myosin (Fab')2 fragments.
Authors: Khaw B A , Gold H K , Leinbach R C , Fallon J T , Strauss W , Pohost G M , Haber E
Published: June 2012

We examined the feasibility of early imaging of myocardial infarcts by intracoronary injection of 131I-labelled cardiac myosin-specific antibody (Fab')2. The left anterior descending coronary artery was occluded for 5 hours by a balloon catheter introduced through the carotid artery in 12 dogs. The catheter was withdrawn and 1 mCi 201Tl was injected intravenously and 500 muCi of 131I antibody were injected into the main left coronary artery. Six of these animals demonstrated evidence of myocardial infarction by ECG and subsequent triphenyl-tetrazolium chloride staining, while the others did not. In each of the infarcted animals, in vivo scintograms one-half hour after injection of isotope showed uptake of 131I in the anteroapical region of the heart corresponding to the region of absent 201Tl uptake. This relationship was confirmed in the excised hearts and in heart slices. In slices, 131I uptake corresponded to regions that did not stain with triphenyltetrazolium chloride. In the six animals that did not show evidence for infarction after coronary occlusion, uptake of 131I was not demonstrated, either in vivo or in excised specimens. In four additional dogs subjected to the same procedure, 125I-labelled (Fab')2 from nonimmune IgG was injected simultaneously into the left main coronary artery with 131I-labelled canine myosin-specific antibody (Fab')2. The ratio of uptake between infarct center and normal tissue was 34.3 +/- 1.5 (mean+/-SEM) for the specific antibody fragment as contrasted to 6.6+/-0.4 for the nonimmune IgG fragment, indicating that intracoronary injection does not favor nonspecific sequestration of protein in regions of infarction. Thus, the intracoronary administration of myosin-specific antibody fragments leads to early and specific one-half hour imaging of myocardial infarcts.
Intraoperative recording of specialized atrioventricular conduction tissue electrograms in 47 patients.
Authors: Dick M , Norwood W I , Chipman C , Castaneda A R
Published: June 2012

Intraoperative mapping of the specialized atrioventricular conduction system was performed in 47 patients during cardiac surgery. Specialized conduction tissue electrograms were identified in 37, and atrioventricular conduction preserved in 92%. Specialized conduction tissue was identified in 27 patients with atrioventricular canal defect: complete heart block was avoided in 25. Conduction tissue was located in six of 12 patients with complex transpositions; atrioventricular conduction was preserved in all six. Other lesions in which the technique was useful were Ebstein's anomaly and single atrium. Limitations to the technique are 1) deep hypothermia and circulatory arrest; 2) interruption in atrioventricular conduction during mapping; 3) inadequate exposure and access to probable sites of conduction tissue; 4) variation of size and spatial relations of individual malformations; and 5) limited time for identification of unusually located conduction tissue. Indications for use of this technique include patients with both forms of atrioventricular canal, complex transpositions, atrioventricular discordance, single ventricle and single atrium.
Morphological development of the pulmonary vascular bed in experimental pulmonic stenosis.
Authors: Levin D L , Heymann M A , Rudolph A M
Published: June 2012

The main pulmonary trunk was banded in four fetal sheep at 63--69 days of gestation. The fetuses were killed after they had developed progressive pulmonary stenosis at 98, 123, 134 and 135 days of gestation. The right lung of each animal was perfused with glutaraldehyde and serial sections followed microscopically. The medial width/external diameter ratios for fifth generation resistance vessels were significantly less (0.13) than those from six normal control lungs (0.16, p less than 0.001). In addition, the number of resistance vessels per cm2 lung tissue in the lungs of the animals with experimental pulmonic stenosis was less than in normal controls. The altered in utero hemodynamics with severe pulmonic stenosis results in thin-walled pulmonary arterial vessels. This may be caused by an increased blood oxygen tension of the blood perfusing the pulmonary circulation via reversed flow through the ductus arteriosus, or altered pulmonary arterial pressure characteristics in the pulmonary vessels distal to the obstructed pulmonary trunk.
Diagnostic value of visualization of the right ventricle using thallium-201 myocardial imaging.
Authors: Khaja F , Alam M , Goldstein S , Anbe D T , Marks D S
Published: June 2012

The diagnostic significance of visualizing the right ventricle on thallium-201 myocardial perfusion scans (T-scan) at rest was studied in 53 patients. In 33 patients the right ventricle was visualized clearly on the T-scan (group A). Hemodynamic evidence of right ventricular hypertension with systolic pressure greater than or equal to 30 mmHg was present in 28 of 33 (85%) of these patients. Right ventricular volume overload with left-to-right shunt greater than 2:1 was present in three patients. Other tests were diagnostic for right ventricular enlargement and or pulmonary hypertension as follows: chest x-ray (58%), echocardiogram (36%) and electrocardiogram (15%). In an unselected group of 20 patients (group B) where resting T-scan did not show visualization of the right ventricle, the right ventricular systolic pressure was less than 30 mm Hg in all. The other noninvasive tests did not reveal presence of right ventricular hypertrophy or enlargement. T-scan appears to be a useful and sensitive test in detecting right ventricular pressure or volume overload compared with other noninvasive tests. This may be useful in detection of patients with right ventricular hypertrophy or enlargement secondary to pulmonary hypertension or other causes.
Influence of right ventricular hemodynamics on left ventricular diastolic pressure-volume relations in man.
Authors: Ludbrook P A , Byrne J D , McKnight R C
Published: June 2012

To clarify the mechanism of displacement of the left ventricular diastolic pressure-volume function with alteration of loading conditions, the effects of nitroglycerin on pressure-volume relations in 13 patients were compared with those of amyl nitrite in 13 other patients during cardiac catheterization. After nitroglycerin, average systemic mean arterial pressure declined by 15.1 mm Hg (17%) and left ventricular end-diastolic pressure by 9.4 mm Hg (49%); right ventricular systolic and end-diastolic pressures fell 11.6 mm Hg (36%) and 5 mm Hg (41%), respectively. In all patients diastolic pressure-volume curves were significantly displaced downward and leftward. After amyl nitrite, average systemic mean arterial pressure fell 20.1 mm Hg (22%), but left ventricular end-diastolic pressure and right ventricular systolic and end-diastolic pressures were not significantly reduced. No significant displacement of diastolic pressure-volume curves occurred. Both the rate constant of the exponentially fit diastolic pressure-volume curve, and the rate of diastolic isovolumic relaxation (T) were unchanged after each drug. Thus downward displacement of diastolic pressure-volume functions after nitroglycerin appears to be dependent more upon reduction of right ventricular filling dynamics than coronary perfusion pressures. More favorable effects upon left ventricular function may be associated with reduction of both left ventricular filling pressures and systemic impedance (reflecting both "preload" and "afterload") than of systemic arterial pressures ("afterload") alone.
Combined aortic valve replacement and myocardial revascularization: results in 220 patients.
Authors: Richardson J V , Kouchoukos N T , Wright J O , Karp R B
Published: June 2012

During a 7.5-year period ending in June 1977, 220 patients underwent combined aortic valve replacement and myocardial revascularization. Early (30-day) mortality was 5.4% (12 patients), and was significantly affected by the development of perioperative myocardial infarction. For 23 patients with electrocardiographic and enzymatic evidence for definite infarction, hospital mortality was 17%; for 66 patients with probable infarction mortality was 5%; and for 116 patients without evidence for infarction mortality was 3%. The difference in mortality between the definite and no infarction groups was significant (p less than 0.01). The incidence of perioperative infarction was influenced by the type of myocardial protection employed during the operative procedure. Definite infarction occurred in 24% of 41 patients who had mild (28-32 degrees C), intermittent hypothermic coronary perfusion, in 9% of 142 patients with hypothermic ischemic arrest (myocardial temperature 20 to 27 degrees C) and in none of 22 patients with hypothermic, potassium-induced cardioplegia (myocardial temperature 8--18 degrees C). The difference in the rate of infarction between the coronary perfusion and the two hypothermic ischemic arrest groups was significant (p less than 0.01). The mean duration of followup for 100% of the hospital survivors was 22.5 months. Cumulative survival was 88% at 1 year and 77% at 3 years. These figures do not differ significantly from those for patients without coronary artery disease having isolated aortic valve replacement in our institution, and are superior to those reported for patients with coronary and aortic valve disease undergoing only aortic valve replacement. We conclude that combined aortic valve replacement and myocardial revascularization should be performed in all patients in whom the lesions coexist. Hypothermic ischemic arrest, preferably in combination with potassium-induced cardioplegia, provides the most myocardial protection during operation.
The effects of ergonovine maleate on coronary arterial size.
Authors: Cipriano P R , Guthaner D F , Orlick A E , Ricci D R , Wexler L , Silverman J F
Published: June 2012

Changes in coronary arterial size due to ergonovine maleate are described and quantitated in 90 patients--18 with typical angina pectoris, 56 with atypical chest pain, nine with variant angina pectoris, and seven heart transplant (allograft) recipients. We observed two angiographic changes in the diameter of coronary arteries: 1) spasm, which was characterized by occlusion or marked (greater than 85%) focal or diffuse vessel narrowing, or 2) relatively mild and diffuse vessel narrowing, which was interpreted as the normal pharmacologic response to the drug. Serial bolus injections of 0.05 mg, 0.10 mg and 0.25 mg of ergonovine maleate produced diffuse narrowing of the diameter of coronary arteries of 10 +/- 1.5%, 16 +/- 1.4% and 20 +/- 1.3% (mean +/- SEM), respectively, in the 72 patients with anginal syndromes who did not develop coronary spasm. The degree of coronary arterial narrowing was the same in heart transplant recipients and in patients with normally innervated hearts who did not develop coronary spasm. We believe the normal pharmacologic response to ergonovine maleate was due to a direct vasoconstrictor action of the drug; this action was independent of neural control extrinsic to the heart.