bluuebunny/crossref_metadata_2025_split huggingface dataset:
Radiofrequency catheter ablation of accessory atrioventricular connections in 250 patients. Abbreviated therapeutic approach to Wolff-Parkinson-White syndrome.
Authors: Calkins H , Langberg J , Sousa J , el-Atassi R , Leon A , Kou W , Kalbfleisch S , Morady F 
Published: June 2012

BACKGROUND
The purpose of this study was to report the results and complications of radiofrequency catheter ablation of accessory atrioventricular (AV) connections by using an abbreviated approach aimed at minimizing the duration of the procedure.

METHODS AND RESULTS
Two hundred fifty consecutive patients with the Wolff-Parkinson-White syndrome or paroxysmal supraventricular tachycardia involving a concealed accessory AV connection underwent catheter ablation with the use of radiofrequency current. In 179 of the 250 patients, catheter ablation was performed at the time of an initial electrophysiology test. Two hundred thirty-five patients had one accessory AV connection and 15 patients had two or more. One hundred eighty-three accessory AV connections were manifest and 84 were concealed. One hundred sixty-one were were located in the free wall of the left ventricle, 47 were in the right free wall, 44 were posteroseptal, 10 were anteroseptal, and five were intermediate test, and the ablation procedure was recorded for each patient, as was the total duration of fluoroscopy. A follow-up electrophysiology test was performed 2-3 months after the ablation procedure. Ninety-four percent of patients had all accessory AV connections successfully ablated and remained free of symptomatic tachycardia during a mean follow-up of 10 +/- 4 months. Two hundred nineteen patients (88%) had all accessory AV connections ablated during the initial attempt at catheter ablation. Mean duration of the entire procedure was 134 +/- 75 minutes. Procedure duration was longest in patients with multiple accessory AV connections, shortest in patients with intermediate septal accessory AV connections, and similar in all other locations. A nonfatal complication occurred in nine patients (4%).

CONCLUSIONS
The results of this study indicate that catheter ablation of accessory AV connections with radiofrequency current can be performed safely and expeditiously in a majority of patients and confirm in a large series the feasibility of catheter ablation at the time of an initial diagnostic electrophysiology test. This abbreviated therapeutic approach avoids the need for electropharmacological testing, long-term antiarrhythmic drug therapy, and surgical therapy in the majority of patients with the Wolff-Parkinson-White syndrome or with symptomatic tachycardias involving accessory AV connections.
Randomized trial of subcutaneous low-molecular-weight heparin CY 216 (Fraxiparine) compared with intravenous unfractionated heparin in the curative treatment of submassive pulmonary embolism. A dose-ranging study.
Authors: Théry C , Simonneau G , Meyer G , Hélénon O , Bridey F , Armagnac C , d'Azemar P , Coquart J P 
Published: June 2012

BACKGROUND
We compared the efficacy and safety of different dosages of a low-molecular-weight heparin, CY 216 D (Fraxiparine), in the treatment of submassive pulmonary embolism with unfractionated heparin in a prospective, randomized, dose-finding study.

METHODS AND RESULTS
The primary outcome was the evolution of pulmonary vascular obstruction. We enrolled 101 patients. Four patient groups were formed: standard heparin by continuous intravenous infusion (group 1) and Fraxiparine subcutaneously 400, 600, and 900 anti-Xa Institute Choay units/kg, respectively (groups 2, 3, and 4). Inclusions were stopped prematurely in groups 3 and 4 because of the incidence of major bleedings. At day 8, the improvement of the pulmonary vascular obstruction and the major bleedings were similar in groups 1 and 2.

CONCLUSIONS
The Fraxiparine dosage of 400 anti-Xa Institute Choay units/kg is as effective and safe as unfractionated heparin in the treatment of submassive pulmonary embolism.
Development and determinants of dynamic obstruction to left ventricular outflow in young patients with hypertrophic cardiomyopathy.
Authors: Panza J A , Maris T J , Maron B J 
Published: June 2012

BACKGROUND
To study the development of dynamic subaortic obstruction in young patients with hypertrophic cardiomyopathy (HCM), serial echocardiograms were retrospectively analyzed in a group of 26 consecutive children with this disease who showed no evidence of dynamic outflow obstruction at their initial evaluation (age, 11 +/- 3 years).

METHODS AND RESULTS
After a follow-up of 3-12 years (mean, 7 +/- 3 years), seven of the 26 patients (27%) developed echocardiographic evidence of subaortic obstruction, i.e., marked systolic anterior motion (SAM) of the mitral valve with mitral-septal apposition and increased left ventricular outflow tract systolic velocities (3.8 +/- 0.3 m/sec; range, 3.1-4.5). Patients who developed SAM had smaller transverse dimension of the left ventricular outflow tract and more anteriorly displaced mitral valve when initially evaluated than did patients without development of SAM (outflow tract dimension, 19.1 +/- 4 versus 24.6 +/- 4 mm; mitral valve position index, 1.07 +/- 0.2 versus 0.73 +/- 0.3; each p less than 0.02). In patients with development of SAM, the already reduced outflow tract dimension decreased further during follow-up, and the mitral valve became even more anteriorly displaced within the left ventricular cavity. These developmental alterations in outflow tract size were associated with increases in left ventricular wall thickness, particularly of the basal anterior septum (11.0 +/- 8 mm; 72 +/- 33%) compared with control patients with HCM who did not develop SAM (3.0 +/- 3 mm; 17 +/- 10%; p less than 0.05).

CONCLUSIONS
Development of subaortic obstruction in young patients with HCM results from a process of dynamic remodeling of left ventricular geometry over several years and is characterized by progressive narrowing of the outflow tract with anterior displacement of the mitral valve and disproportionate thickening of the basal anterior ventricular septum.
Cardiac potential and potential gradient fields generated by single, combined, and sequential shocks during ventricular defibrillation.
Authors: Wharton J M , Wolf P D , Smith W M , Chen P S , Frazier D W , Yabe S , Danieley N , Ideker R E 
Published: June 2012

BACKGROUND
Potential gradient field determination may be a helpful means of describing the effects of defibrillation shocks; however, potential gradient field requirements for defibrillation with different electrode configurations have not been established.

METHODS AND RESULTS
To evaluate the field requirements for defibrillation, potential fields during defibrillation shocks and the following ventricular activations were recorded with 74 epicardial electrodes in 12 open-chest dogs with the use of a computerized mapping system. Shock electrodes (2.64 cm2) were attached to the lateral right atrium (R), lateral left ventricular base (L), and left ventricular apex (V). Four electrode configurations were tested: single shocks of 14-msec duration given to two single anode-single cathode configurations, R:V and L:V, and to one dual anode-single cathode configuration, (R+L):V; and sequential 7-msec shocks separated by 1 msec given to R:V and L:V (R:V----L:V). Defibrillation threshold (DFT) current was significantly lower for R:V----L:V than for the other configurations and markedly higher for L:V. Despite these differences, the minimum potential gradients measured at DFT were not significantly different (approximately 6-7 V/cm for each electrode configuration). Potential gradient fields generated by the electrode configurations were markedly uneven, with a 15-27-fold change from lowest to highest gradient, with the greatest decrease in gradient occurring near the shock electrodes. Although gradient fields varied with the electrode configuration, all configurations produced weak fields along the right ventricular base. Early sites of epicardial activation after all unsuccessful shocks occurred in areas in which the field was weak; 87% occurred at sites with gradients less than 15 V/cm. Ventricular tachycardia originating in high gradient areas near shock electrodes followed 11 of 67 successful shocks.

CONCLUSIONS
These data suggest that 1) defibrillation fields created by small epicardial electrodes are very uneven; 2) achievement of a certain minimum potential gradient over both ventricles is necessary for ventricular defibrillation; 3) the difference in shock strengths required to achieve this minimum gradient over both ventricles may explain the differences in DFTs for various electrode configurations; and 4) high gradient areas in the uneven fields can induce ectopic activation after successful shocks.
Cilazapril and early atherosclerotic changes after balloon injury of porcine carotid arteries.
Authors: Lam J Y , Lacoste L , Bourassa M G 
Published: June 2012

BACKGROUND
Cilazapril, a converting enzyme inhibitor, has been shown to significantly decrease the extent of intimal smooth muscle cell proliferation after arterial injury in a normotensive rat model.

METHODS AND RESULTS
To assess the influence of cilazapril on myofibrotic changes after balloon injury, control (n = 7) or cilazapril-treated (n = 9) (20 mg/kg b.i.d.) normal 3-month-old pigs underwent dilatation angioplasty of the right, and deendothelialization of the left common carotid artery. Carotid arteries isolated at 4 weeks were examined morphometrically with a computerized digitizer after in situ glutaraldehyde fixation. Both in the deendothelialized and dilated arteries, the surface area in square millimeters of the neointima and media were similar in the treated and control animals; therefore, the ratio of neointima to media was again not different. The neointimal changes included a combination of proliferative changes as well as organization of mural thrombus and were equally well distributed in the two groups of animals. At the time that the animals were killed, blood pressure (38.2 +/- 2.1 versus 56.8 +/- 4.8 mm Hg, p = 0.003) and plasma angiotensin converting enzyme activity (5.6 +/- 4.1 versus 182.3 +/- 70.4, p = 0.02) were lower in treated than in control pigs, but aortic media thrombogenicity (as assessed in an ex vivo perfusion flow chamber) and serum lipids were not different between groups.

CONCLUSIONS
In pigs, cilazapril did not alter the development of myofibrotic changes after mild or severe balloon injury despite plasma angiotensin converting enzyme activity inhibition.
Clinical experience with a tiered-therapy, multiprogrammable antiarrhythmia device.
Authors: Bardy G H , Troutman C , Poole J E , Kudenchuk P J , Dolack G L , Johnson G , Hofer B 
Published: June 2012

BACKGROUND
The purpose of this report is to describe our initial experience with a tiered-therapy, variable detection criteria, multiprogrammable antiarrhythmia device capable of antitachycardia pacing, cardioversion, and defibrillation in 50 cardiac arrest survivors.

METHODS AND RESULTS
An epicardial lead system was used in 35 patients. A transvenous lead system was used in 15 patients. The index arrhythmia leading to device implantation was ventricular fibrillation (VF) in 23 patients, ventricular tachycardia (VT) in 21 patients, and both VT and VF in six patients. Postoperatively, all 50 patients benefited from the additional functions available in the new device compared with a device capable only of high-energy termination of arrhythmias using a simple rate detection algorithm. Total patient survival over a mean follow-up period of 15 +/- 5 months was 96%, with no patient succumbing to sudden arrhythmic death, cardiac death, or surgical death. Nine patients (18%) avoided the need for a bradycardia pacemaker because of the device's backup bradycardia pacing function. A programmable tachycardia cycle length stability algorithm prevented inappropriate device intervention into atrial fibrillation in 11 patients (22%). Detection schema flexibility, antitachycardia pacing capabilities, and low-energy cardioversion options allowed the elimination or avoidance of antiarrhythmic drugs in 41 patients (82%). Device data storage facilitated troubleshooting and reprogramming of detection algorithms and therapeutic schema in all 50 patients. Finally, the ability to perform noninvasive programmed electrical stimulation obviated the need for invasive cardiac catheterization in 35 of 35 patients who required electrophysiological testing after device implantation.

CONCLUSIONS
These findings indicate that a multiprogrammable antiarrhythmia device can provide a substantial advance in the treatment of patients with disabling or life-threatening ventricular arrhythmias by minimizing the use of painful shocks, reducing the need for antiarrhythmic drugs, lowering the incidence of inappropriate shocks, facilitating electrophysiological evaluation, and obviating the need for dual-device therapy.
Retrograde nontransseptal balloon mitral valvuloplasty. Immediate results and long-term follow-up.
Authors: Stefanadis C , Stratos C , Pitsavos C , Kallikazaros I , Triposkiadis F , Trikas A , Vlachopoulos C , Gavaliatsis I , Toutouzas P 
Published: June 2012

BACKGROUND
Percutaneous retrograde nontransseptal balloon mitral valvuloplasty is a new technique developed in our institution for opening a stenotic mitral valve. This technique is based on a new, externally steerable cardiac catheter that enters the left atrium retrogradely via the left ventricle.

METHODS AND RESULTS
The technique was used in 86 consecutive patients (18 men and 68 women; mean age, 51 +/- 11 years). Dilatation of the stenotic mitral valve was achieved in 85 of the 86 patients. After the procedure, mitral valve area increased from 0.92 +/- 0.22 to 2.14 +/- 0.54 cm2 and transmitral gradient decreased from 16 +/- 6 to 5 +/- 2 mm Hg. Major complications, such as cardiac performation, embolic events, or death, were not encountered. Severe mitral regurgitation (greater than 2+) developed in three patients (3.5%). In two patients (2.4%), there was major injury of the femoral artery. The maintenance of the initial improvement was similar to that found in studies that used transseptal techniques. The restenosis rate during the 2-year follow-up was 15.4%.

CONCLUSIONS
The immediate and long-term findings of this study indicate that retrograde percutaneous nontransseptal balloon mitral valvuloplasty is an effective and safe procedure with an acceptable major complication rate. Moreover, this new technique has the advantage that it does not involve puncture and dilatation of the interatrial septum, although it may occasionally lead to arterial damage. Further studies will show whether it may really be considered as an alternative method or method of choice for percutaneous balloon mitral valvuloplasty.
Relation between recovery sequence estimated from body surface potentials and T wave shape in patients with negative T waves and normal subjects.
Authors: Yamaki M , Kubota I , Endo T , Hosoya Y , Ikeda K , Tomoike H 
Published: June 2012

BACKGROUND
Advances in analytical methods of the epicardial electrical potentials allowed us to demonstrate spatial distributions of local recovery. Because local recovery will be reflected in events on body surface ECG mapping, abnormalities in recovery sequence that may be responsible for the origin of negative T waves can be detected from body surface potentials.

METHODS AND RESULTS
Eighty-seven unipolar ECGs were recorded simultaneously from the entire thorax in patients having negative T waves on left anterior precordial leads and in normal subjects. These included 40 patients with anterior myocardial infarction (MI), 21 patients with left ventricular hypertrophy (LVH), and 44 male volunteers. We measured Tmax time, defined as the instant of maximal first derivative of the T wave as the index of local recovery (Wyatt's method). Parameters related to T wave potentials were positive T wave amplitude, negative T wave amplitude, and T integral. Significant correlations were observed between the Tmax time and each of the T wave potentials. The T wave potentials were dependent on Tmax times. In the anterior MI, the late Tmax times were located on the upper left anterior chest and early Tmax times on the lower right lateral chest. In the LVH, the area showing a delayed recovery was displaced in a left downward direction compared with anterior MI.

CONCLUSIONS
Body surface Tmax time distributions clearly separate two negative T wave groups, i.e., anterior MI and LVH. Appearance of the negative T waves correlates well with the presence of the area with delayed Tmax time on the spatial distribution.
Normal ultrasonic myocardial reflectivity in athletes with increased left ventricular mass. A tissue characterization study.
Authors: Lattanzi F , Di Bello V , Picano E , Caputo M T , Talarico L , Di Muro C , Landini L , Santoro G , Giusti C , Distante A 
Published: June 2012

BACKGROUND
Ultrasonic integrated backscatter of myocardial walls is directly related to the morphometrically evaluated collagen content. The integrated backscatter is also increased in hypertrophic cardiomyopathy, probably because of fiber disarray. The purpose of this study was to investigate myocardial tissue reflectivity in subjects with physiological hypertrophy caused by intense physical training and to assess the relation between the acoustic properties of myocardial tissue and left ventricular wall thickness assessed by conventional two-dimensional echocardiography.

METHODS AND RESULTS
Twenty-four young male athletes (14 professional cyclists and 10 weight lifters, all in full agonistic activity) were studied together with 10 normal age-matched controls with sedentary life. By means of a commercially available two-dimensional echocardiograph, standard measurements were obtained according to the recommendations of the American Society of Echocardiography. With a prototype implemented in our Institute, an on-line radiofrequency analysis of ultrasound signals was also performed to obtain quantitative operator-independent measurements of the integrated backscatter of the myocardial walls. The integrated values of the radiofrequency signal were normalized for the pericardial interface and expressed in percent integrated backscatter (%IB). Compared with control subjects, athletes showed greater thickness values of septum (controls, 9 +/- 1; cyclists, 14 +/- 2; weight lifters, 15 +/- 1 mm, mean +/- SD; p less than 0.01) and posterior wall (9 +/- 1, 12 +/- 2, and 12 +/- 1 mm, respectively; p less than 0.01) but similar values of %IB for both septum (23 +/- 4%, 21 +/- 7%, and 23 +/- 8%, p = NS) and posterior wall (10 +/- 2%, 9 +/- 2%, and 11 +/- 2%, p = NS). In athletes, no correlation was found between septal and posterior wall thickness and the corresponding regional myocardial reflectivity (r = 0.23, p = NS and r = 0.01, p = NS, respectively). Furthermore, we compared the quantitative ultrasonic data between two subsets of 10 athletes and 10 patients with hypertrophic cardiomyopathy and similar degrees of septal thickness (16 +/- 1 versus 17 +/- 1 mm, respectively, p = NS). Septal and posterior wall %IB results were significantly higher in patients with hypertrophic cardiomyopathy (53 +/- 13% and 36 +/- 9%, respectively) than in athletes (21 +/- 7% and 10 +/- 3%, respectively; p less than 0.01 for both).

CONCLUSIONS
We conclude that 1) endurance athletes show a normal pattern of quantitatively assessed ultrasonic backscatter despite of a marked left ventricular hypertrophy and 2) athletes and patients with hypertrophic cardiomyopathy and similar degrees of myocardial wall thickness can be differentiated on the basis of quantitative analysis of backscattered signal.
Gene expression and atrial natriuretic factor processing and secretion in cultured AT-1 cardiac myocytes.
Authors: Lanson N A , Glembotski C C , Steinhelper M E , Field L J , Claycomb W C 
Published: June 2012

BACKGROUND
Studies were carried out to characterize several biochemical features of cultured AT-1 cells.

METHODS AND RESULTS
These cells were obtained from a transplantable atrial cardiomyocyte tumor lineage. Reverse transcriptase-polymerase chain reaction-based analyses demonstrated that the pattern of gene expression of cultured AT-1 cells was similar to that of adult atrial myocytes. AT-1 cells expressed atrial natriuretic factor (ANF), alpha-cardiac myosin heavy chain, alpha-cardiac actin, and connexin43. Radioimmunoassays verified that the cells synthesized, stored, and secreted ANF. Through size-exclusion, reversed-phase, and carboxymethyl-ion-exchange high-performance liquid chromatography, it was shown that cultured AT-1 cells stored ANF as pro-ANF (ANF-[1-126]), which was cosecretionally processed quantitatively to ANF-(1-98) and the bioactive 28-amino-acid ANF-(99-126). In addition, cultured AT-1 cells secreted ANF at almost a sixfold greater rate in response to endothelin-1, a potent secretagogue of ANF. KCl, metenkephalinamide, isoproterenol, phenylephrine, and 12-O-tetradecanoyl-phorbol-13-acetate also stimulated ANF release.

CONCLUSIONS
These studies, in combination with previous findings, demonstrated that cultured AT-1 cells, while maintaining the ability to proliferate, have retained functional, biochemical, and ultrastructural features that are characteristic of adult atrial myocytes.
Direct effects of gemfibrozil on the fibrinolytic system. Diminution of synthesis of plasminogen activator inhibitor type 1.
Authors: Fujii S , Sobel B E 
Published: June 2012

BACKGROUND
Platelet-associated epidermal growth factor (EGF) and transforming growth factor-beta (TGF-beta) can augment synthesis of plasminogen activator inhibitor type 1 (PAI-1). Accordingly, exacerbation of atherogenesis may accompany release of platelet-associated growth factors (or mitogens) occurring in association with occult, repetitive thrombosis and thrombolysis. In the Helsinki primary prevention trial, gemfibrozil decreased coronary events but did so essentially only in initially hypertriglyceridemic subjects. Such subjects are known to exhibit high concentrations of PAI-1 in plasma.

METHODS AND RESULTS
To determine whether pharmacological concentrations of gemfibrozil directly affect PAI-1 synthesis, we characterized its effects on a human hepatoma cell line (Hep G2) in vitro. Gemfibrozil decreased basal PAI-1 secretion by 43% and attenuated the augmentation of PAI-1 synthesis over 24 hours induced by EGF and TGF-beta by 37% and 39% without altering overall protein synthesis. Furthermore, it blocked the EGF and TGF-beta-induced increases in PAI-1 mRNA over 6 hours by 65% and 60%. Increases in plasma PAI activity induced by infusion of purified growth factors or by autologous platelet lysates in rabbits were inhibited by gemfibrozil by more than 50%.

CONCLUSIONS
Beneficial effects of gemfibrozil in reducing coronary events in hypertriglyceridemic patients may depend, in part, on potentiation of fibrinolysis by direct diminution of synthesis of endogenous PAI-1.
Linkage analysis and long QT syndrome. Using genetics to study cardiovascular disease.
Authors: Keating M 
Published: June 2012

BACKGROUND
Recombinant DNA technologies have facilitated the development of a set of polymorphic DNA markers covering the human genome. General linkage analysis in families predisposed to inherited disease is now feasible. Linkage analysis can help identify a disease gene even when relatively little is known about the disorder.

METHODS AND RESULTS
Using this approach, we have identified linkage between a gene that causes the long QT syndrome and DNA markers on chromosome 11.

CONCLUSIONS
The identification of the chromosomal location of the long QT locus is the first step in defining the specific mutations that cause this disease.