bluuebunny/crossref_metadata_2025_split huggingface dataset:
Development of the pharyngeal arch system related to the pulmonary and bronchial vessels in the avian embryo. With a concept on systemic-pulmonary collateral artery formation.
Authors: DeRuiter M C , Gittenberger-de Groot A C , Poelmann R E , VanIperen L , Mentink M M 
Published: June 2012

BACKGROUND
The literature is ambiguous as to the question of the developmental background of systemic-pulmonary collateral arteries. These are found in combination with various congenital heart malformations such as pulmonary atresia. From a clinical point of view, it is of interest to know whether we are dealing with the persistence of transient embryological vessels such as ventral segmental arteries or parts of pharyngeal arch arteries or with the prenatal or postnatal recruitment of the bronchial vasculature that normally supplies the lung. This study of the embryology of the extrapulmonary and intrapulmonary vasculature aims at a better understanding of the variations in origin, course, branching pattern, and histology of collateral arteries.

METHODS AND RESULTS
Serial sections of quail embryos ranging between stage HH11 and stage HH28 were incubated with a monoclonal antibody (alpha MB1) against endothelial cells and their precursors. Additional series of chick embryos were injected with india ink to study the lumenized vascular patterns. A splanchnic plexus consisting of endothelial cells and precursors is present around the foregut before the lung buds develop. This plexus expands and gives rise to the pharyngeal arch arteries, the ventral pharyngeal veins, the pulmonary vessels, and the bronchial vessels, including the intrapulmonary vessel network. During two subsequent periods, the splanchnic plexus is transiently connected to the systemic arteries and veins. The bronchial arteries and veins develop in the second period from these transient vessels. The expansion and extension of the splanchnic plexus to many organs during the formation of the bronchial vessels explains the varying course and branching pattern of the bronchial vasculature.

CONCLUSIONS
These results show that we are not dealing with two or more individual vascular systems that contribute to the developing vessels of the lungs but with one vascular plexus that normally gives rise to the pulmonary and bronchial vasculature but has the potential to give rise to other systemic-pulmonary connections.
Analysis of coronary angioplasty practice in the United States with an insurance-claims data base.
Authors: Topol E J , Ellis S G , Cosgrove D M , Bates E R , Muller D W , Schork N J , Schork M A , Loop F D 
Published: June 2012

BACKGROUND
Coronary angioplasty is frequently performed in the United States, with more than 300,000 procedures in 1990. Despite the high rate of use of the procedure, there have been few studies addressing practice patterns.

METHODS AND RESULTS
From a private insurance claims data base of 5.4 million individuals, a total of 2,101 patients who underwent coronary angioplasty during 1988-1989 were identified. Using their 4,578 hospital admission records and 87,578 outpatient claim records, with an average follow-up of 332 +/- 182 days, we compared patients' outcomes and charges according to whether they had an exercise stress test before the procedure, by sex, by region of the country, and by whether the angioplasty was performed in an institution with a training program. Only 29% of the study cohort had exercise testing before angioplasty; patients in the West (p = 0.001), those undergoing multivessel angioplasty (p = 0.00001), and those whose procedures were performed at sites with training programs (p = 0.04) were more likely to have a screening test, whereas women (p = 0.008) and those with a recent myocardial infarction (p = 0.00001) were less likely to have a screening test. The average length of stay for patients without myocardial infarction as a primary diagnosis was 5.6 days, with a total hospital charge of $15,027. In follow-up, 15.1% had coronary artery bypass surgery and 15% had at least one additional angioplasty procedure; the average follow-up charges were $4,879. Charges varied according to sex, region of the country, and academic status of the angioplasty institution. Certain outcomes showed variation by region of the country and academic status of the angioplasty institution.

CONCLUSIONS
The relative lack of an objective definition of myocardial ischemia and the marked variability of use of procedures according to geographic region suggest the need for further implementation of established guidelines.
Dobutamine stress echocardiography for assessment of perioperative cardiac risk in patients undergoing major vascular surgery.
Authors: Poldermans D , Fioretti P M , Forster T , Thomson I R , Boersma E , el-Said E M , du Bois N A , Roelandt J R , van Urk H 
Published: June 2012

BACKGROUND
The purpose of this study was to determine the predictive value of dobutamine stress echocardiography for perioperative cardiac events in patients scheduled for elective major noncardiac vascular surgery.

METHODS AND RESULTS
Patients (n = 136; mean age, 68 years) unable to exercise underwent a dobutamine stress test before surgery (incremental dobutamine infusion [10-40 micrograms.kg-1.min-1] continued with atropine [0.25-1 mg i.v.] if necessary to achieve 85% of the age-predicted maximal heart rate without symptoms or signs of ischemia). The clinical risk profile was evaluated by Detsky's modification of Goldman's risk factor analysis. Echocardiographic images were evaluated by two observers blinded to the clinical data of the patients, and results of the test were not used for clinical decision making. Technically adequate images were obtained in 134 of 136 patients, one major complication occurred (ventricular fibrillation), and three tests were discontinued prematurely because of side effects. Finally, data from 131 patients were analyzed with univariate and multivariate methods. The dobutamine stress test was positive (new or worsened wall motion abnormality) in 35 of 131 patients. In the postoperative period, five patients died of myocardial infarction, nine patients had unstable angina, and one patient developed pulmonary edema. All patients with cardiac complications (15 patients) had a positive dobutamine stress test. No cardiac events occurred in patients with negative tests. Five patients with a technically inadequate or prematurely stopped test were operated on without complications. By multivariate analysis (logistic regression), only age > 70 years and new wall motion abnormalities during the dobutamine test were significant predictors of perioperative cardiac events.

CONCLUSIONS
Dobutamine stress echocardiography is a feasible, safe, and useful method for identifying patients at high or low risk of perioperative cardiac events. The test yields additional information, beyond that provided by clinical variables, in patients who are scheduled for major noncardiac vascular surgery.
Action potential alternans and irregular dynamics in quinidine-intoxicated ventricular muscle cells. Implications for ventricular proarrhythmia.
Authors: Karagueuzian H S , Khan S S , Hong K , Kobayashi Y , Denton T , Mandel W J , Diamond G A 
Published: June 2012

BACKGROUND
Cardiac cells display rate-dependent beat-to-beat variations in action-potential duration (APD), action potential amplitude (APA), and excitability during periodic stimulation. We hypothesized that quinidine causes a marked increase in the variability of APD, APA, and excitability of ventricular cells isolated from quinidine-toxic, arrhythmic ventricles.

METHODS AND RESULTS
Action potentials were recorded from right ventricular endocardial tissues (2 x 1 cm, < 2 mm thick) isolated from dogs in which ventricular tachycardia and ventricular fibrillation (VT/VF) were induced with intravenous quinidine (80-100 mg/kg) over a 5-hour period in vivo (n = 7). As the basic cycle length (BCL) of stimulation was progressively shortened, rate-dependent variations in APD and APA occurred. The initial dynamic change was alternans of APD and APA that could be either in or out of phase between two cells. The magnitude of alternans was a function of the BCL and the strength of the stimulation current. At critically short BCLs, irregular APD and APA behavior emerged in the quinidine-intoxicated cells. In control cells (n = 16) isolated from three nontreated dogs, APD and APA remained constant at all BCLs tested (2,000-300 msec). Quinidine increased the slope of the APD restitution curve compared with control. The observed quinidine APD restitution curve was fitted with a biexponential equation, and computer simulation using the fitted restitution curve reproduced the aperiodic APD seen in the quinidine toxic cells during periodic stimulation. Thus, the observed irregular APD behavior was predictable from the restitution curve.

CONCLUSIONS
Quinidine toxicity increases the temporal and spatial variability of APD and APA in the ventricle that may promote the initiation of reentrant VT/VF in vivo. The slope of the APD restitution curve provides a method to quantitate inhomogeneities in repolarization time and could be a useful marker for proarrhythmia.
Decreased proportion of type I myofibers in skeletal muscle of dogs with chronic heart failure.
Authors: Sabbah H N , Hansen-Smith F , Sharov V G , Kono T , Lesch M , Gengo P J , Steffen R P , Levine T B , Goldstein S 
Published: June 2012

BACKGROUND
Whether biochemical and histological abnormalities of skeletal muscle (SM) develop in patients with chronic heart failure (HF) remains controversial. In the present study, dogs with chronic HF were used to examine potential alterations of SM fiber type, fiber size, number of capillaries per fiber (C/F), beta-adrenergic receptor density (Bmax), and fiber ultrastructural integrity.

METHODS AND RESULTS
HF was produced in 17 dogs by sequential intracoronary microembolizations. Biopsies of the lateral head of the triceps muscle were used in all studies. Type I and type II fibers were differentiated by myofibrillar ATPase (pH 9.4 or 4.2). Bmax was assessed by radioligand binding and SM ultrastructure by transmission electron microscopy. Comparisons were made with biopsies obtained from nine control dogs. The percentage of SM type I fibers was reduced in HF dogs compared with control dogs (19 +/- 2% versus 32 +/- 5%) (p < 0.001), whereas the percentage of SM type II fibers was increased (81 +/- 2% versus 68 +/- 5%) (p < 0.001). The change in fiber type composition was not associated with a preferential atrophy or hypertrophy of either fiber type. There was no difference in SM Bmax (198.9 +/- 14.3 versus 186.8 +/- 17.3 fmol/mg protein) or in C/F (5.37 +/- 0.26 versus 5.84 +/- 0.21) between HF dogs and control dogs. No ultrastructural abnormalities were present in SM fibers of HF dogs.

CONCLUSIONS
In dogs with HF, there is a decrease in the relative composition of the slow-twitch type I SM fibers and an increase in fast-twitch type II fibers. The shift in fiber type composition is not associated with preferential atrophy of either fiber type or with a reduction in C/F, beta-adrenergic receptor density, or structural abnormalities of the myofibers.
Myocardial infarct size can be estimated from serial plasma myoglobin measurements within 4 hours of reperfusion.
Authors: Yamashita T , Abe S , Arima S , Nomoto K , Miyata M , Maruyama I , Toda H , Okino H , Atsuchi Y , Tahara M 
Published: June 2012

BACKGROUND
An early estimation of infarct size is useful for the appropriate early treatment of patients with acute myocardial infarction. We evaluated how early and how accurately infarct size could be estimated from serial plasma myoglobin (Mb) measurements in patients with successful reperfusion.

METHODS AND RESULTS
We measured plasma Mb and creatine kinase (CK) in 35 patients in whom reperfusion therapy was successfully performed. Blood samples were collected at 15-minute intervals for 2 hours after reperfusion, at 30-minute intervals for the subsequent 2 hours, and at 3-6-hour intervals until 52 hours after reperfusion. Plasma Mb was measured by a newly developed turbidimetric latex agglutination assay. Total Mb and CK release (sigma Mb, sigma CK) were calculated with a one-compartment model. The mean chord motion in the most hypokinetic 50% of the infarct-related artery territory was calculated from follow-up ventriculograms as an index of the severity of regional hypokinesis. There were significant correlations between sigma Mb and sigma CK (r = 0.89), between log sigma Mb and the severity of regional hypokinesis (r = -0.85), and between log sigma CK and the severity of regional hypokinesis (r = -0.74). The time required for the cumulative Mb release curves to reach a plateau was 64 +/- 28 minutes. An additional 53 +/- 14 minutes was required to calculate the disappearance rate constant of Mb, and 15 minutes was necessary for the assay. Therefore, the total time required for sigma Mb to be available was 132 +/- 40 minutes, significantly shorter than the time required for sigma CK, 24.3 +/- 9.1 hours (p < 0.001). The infarct size could be estimated from the sigma Mb in 34 of 35 patients within 4 hours of reperfusion.

CONCLUSIONS
Infarct size can be estimated accurately 4 hours after reperfusion by calculating the sigma Mb in patients with successful reperfusion.
Angiopeptin inhibits intimal hyperplasia after angioplasty in porcine coronary arteries.
Authors: Santoian E D , Schneider J E , Gravanis M B , Foegh M , Tarazona N , Cipolla G D , King S B 
Published: June 2012

BACKGROUND
Restenosis is mediated by uncontrolled neointimal growth at the site of coronary angioplasty. Angiopeptin is an octapeptide analogue of somatostatin that has been shown to decrease the experimental intimal hyperplasia associated with vascular injury in rats and rabbits. The study purpose was to determine if angiopeptin inhibits the development of intimal hyperplasia in normolipemic swine coronary arteries after overstretch-balloon injury.

METHODS AND RESULTS
Overstretch-balloon injury was performed in normolipemic swine coronary arteries using a 3.5-mm angioplasty balloon. Treated animals received angiopeptin (50 micrograms/kg) 1 hour before and at the time of balloon injury. Angiopeptin was administered at 100 (micrograms/kg)/day SQ in two divided doses for 14 days. Animals were killed at 14 and 28 days (2 weeks after cessation of angiopeptin) after balloon injury. Treatment animals were compared with control animals receiving balloon injury alone. Angiopeptin significantly limited the experimental intimal hyperplasia estimated by the maximal intimal thickness and residual lumen (lumen area/lumen area+intimal area) compared with controls.

CONCLUSIONS
Angiopeptin inhibits the development of intimal hyperplasia in swine coronary arteries after balloon injury. The beneficial effect was detectable 2 weeks after cessation of angiopeptin therapy.
Regional wall motion analysis predicts survival and functional outcome after subendocardial resection in patients with prior anterior myocardial infarction.
Authors: Nath S , Haines D E , Kron I L , Barber M J , DiMarco J P 
Published: June 2012

BACKGROUND
Subendocardial resection is an established surgical technique for the treatment of ventricular tachycardia associated with prior myocardial infarction. Preoperative factors predictive of survival and functional outcome after surgery have not been completely characterized. We hypothesized that a quantitative assessment of regional wall motion would be a sensitive predictor of both survival and functional outcome after subendocardial resection. This was retrospectively tested in a group of 80 patients with prior anterior myocardial infarction who had undergone subendocardial resection for sustained ventricular tachycardia at out institution.

METHODS AND RESULTS
Centerline chord motion analysis was used to derive a wall motion score from the preoperative contrast right anterior oblique ventriculogram. Multivariate analysis revealed wall motion score to be a significant independent predictor of both long-term survival (p < 0.01) and New York Heart Association (NYHA) functional class I or II status at 6 months (p < 0.01) and at 24 months (p < 0.001) after surgery. Patients with a wall motion score of > 16%, compared with patients with a wall motion score of < or = 16%, had a better 5-year actuarial survival (74% versus 45%, p = 0.02) and were more likely to be NYHA class I or II at 6 months (87% versus 58%, p < 0.01) and at 24 months (82% versus 34%, p < 0.0001) after subendocardial resection.

CONCLUSIONS
A wall motion score derived from centerline chord motion analysis is a sensitive predictor of survival and functional outcome after subendocardial resection. Patients with a wall motion score of > 16% have an excellent prognosis after subendocardial resection. In contrast, patients with a wall motion score of < or = 16% have a poorer outcome and should be considered candidates only if other forms of therapy have failed or are unavailable.
Demonstration of functional border zone with myocardial contrast echocardiography in human hearts. Simultaneous analysis of myocardial perfusion and wall motion abnormalities.
Authors: Nanto S , Masuyama T , Lim Y J , Hori M , Kodama K , Kamada T 
Published: June 2012

BACKGROUND
Although the presence of a functional border zone (FBZ), defined as the nonischemic but asynergic myocardium adjacent to the ischemic area, has been demonstrated in animal hearts, it is not known whether this zone exists in humans.

METHODS AND RESULTS
Myocardial contrast echocardiography (MCE) was performed before and during balloon inflation in the area of coronary stenosis by injecting contrast medium through the guiding catheter in 13 patients with effort angina who underwent successful coronary angioplasty. The area showing MCE defect during balloon inflation was determined with reference to the preangioplasty MCE and was regarded as an ischemic area. The size of the FBZ was assessed by measuring the length of the endocardium that showed asynergy in the echo-enhanced (nonischemic) area. The FBZ measured was 13 +/- 4 mm in the short-axis view (n = 5) and 16 +/- 9 mm in the long-axis view (n = 8).

CONCLUSIONS
Nonischemic contractile dysfunction exists even in human hearts. The presence of an FBZ may limit the use of wall motion analysis in assessing the risk or ischemic area in patients with myocardial infarction. MCE appears to be a unique technique for assessing the risk or ischemic area.
Bamiphylline improves exercise-induced myocardial ischemia through a novel mechanism of action.
Authors: Gaspardone A , Crea F , Iamele M , Tomai F , Versaci F , Pellegrino A , Chiariello L , Gioffré P A 
Published: June 2012

BACKGROUND
In patients with stable angina pectoris aminophylline, a nonselective antagonist of adenosine receptors, markedly improves exercise capacity. To establish the role played by A1 adenosine receptors in the anti-ischemic action of aminophylline, the effects of bamiphylline, a selective A1 antagonist, on exercise-induced ischemia were investigated in patients with stable angina pectoris.

METHODS AND RESULTS
In a single-blind, placebo-controlled, randomized cross-over trial in 18 patients, oral administration of 1200 mg bamiphylline increased both the time to 1-mm ST segment depression (from 524 +/- 177 to 664 +/- 192 seconds, P < .01) and the rate-pressure product at 1-mm ST segment depression (from 159 +/- 31 to 190 +/- 34 beats per minute per mm Hg/10(2) (P < .001). End-diastolic and end-systolic left ventricular volumes, left ventricular ejection fraction, and systolic septal and posterior wall thickening investigated by two-dimensional echocardiography in 12 of the 18 patients were not affected by oral administration of bamiphylline (124 +/- 22 versus 125 +/- 20 mL, P = NS; 49 +/- 12 versus 50 +/- 13 mL, P = NS; 60 +/- 8% versus 58 +/- 7%, P = NS; 35 +/- 6% versus 36 +/- 7%, P = NS; 32 +/- 6% versus 33 +/- 6%, P = NS, respectively). In 7 of the 18 patients, the intravenous infusion of bamiphylline (5 mg/kg in 15 minutes) during cardiac catheterization did not produce any significant change of heart rate (76 +/- 10 versus 75 +/- 13 beats per minute, P = NS), mean right atrial pressure (3.8 +/- 1.7 versus 3.7 +/- 1.7 mm Hg, P = NS), mean aortic pressure (102 +/- 12 versus 99 +/- 10 mm Hg, P = NS), or left ventricular end-diastolic pressure (14 +/- 3 versus 14 +/- 4 mm Hg, P = NS) compared with baseline. Furthermore, after intravenous infusion of bamiphylline, the diameter of seven proximal and distal normal segments and of seven stenotic segments were similar to those measured at baseline (3.1 +/- 0.5 versus 3.1 +/- 0.5 mm, P = NS; 1.6 +/- 0.2 versus 1.7 +/- 0.2 mm, P = NS; 1.6 +/- 0.5 versus 1.6 +/- 0.5 mm, P = NS, respectively).

CONCLUSIONS
In patients with stable angina pectoris, oral administration of bamiphylline improves exercise capacity. Its anti-ischemic action does not appear to be mediated by systemic hemodynamic effects or by stenosis dilation. Therefore, the improvement of myocardial ischemia caused by bamiphylline is probably due to redistribution of coronary blood flow toward the underperfused subendocardium. This novel anti-ischemic action would appear to be mediated by antagonism of A1 receptors.
A simplified, single-lead unipolar transvenous cardioversion-defibrillation system.
Authors: Bardy G H , Johnson G , Poole J E , Dolack G L , Kudenchuk P J , Kelso D , Mitchell R , Mehra R , Hofer B 
Published: June 2012

BACKGROUND
Transvenous implantable cardioverter-defibrillators provide significant advantages in the treatment of patients with life-threatening ventricular arrhythmias. However, present technology requires considerable electrophysiology expertise, multiple incisions, and long operative times for successful implementation.

METHODS AND RESULTS
In this study, we present a prototype of a new, easy-to-insert unipolar transvenous defibrillation system that has the reliability of epicardial defibrillation but the ease of pacemaker insertion. This system incorporates a single anodal right ventricular defibrillation electrode using a 65% tilt biphasic pulse delivered to a 108-cm2 surface area pulse generator titanium alloy shell as an active cathode placed in a left infraclavicular pocket. Testing of this system was performed before implantation of a standard nonthoracotomy-transvenous defibrillation system in 40 consecutive patients with a history of ventricular tachycardia or fibrillation. The simplified unipolar single-lead system resulted in a defibrillation threshold of 9.3 +/- 6.0 J with 37 of 40 patients (93%) having a defibrillation threshold of less than 20 J. Moreover, the unipolar defibrillation system was efficiently used requiring only 3.4 +/- 0.8 ventricular fibrillation inductions to measure the defibrillation threshold and 100 +/- 28 minutes to implement.

CONCLUSIONS
This new unipolar transvenous defibrillation system is as simple to insert as a pacemaker, requires few ventricular fibrillation inductions, demands less technical expertise, and provides defibrillation at energy levels comparable to that reported with epicardial lead systems. It should substantially reduce the morbidity, time, and cost of defibrillator implantation.