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A B S T R A C T Introduction and objectives: Cardiac resynchronization therapy is associated with improved quality of life and reduced morbidity and mortality in patients with severe ventricular dysfunction and wide QRS. However, its role in the reduction of ventricular arrhythmias is more controversial. Methods: We compared the incidence of ventricular arrhythmias in patients who were undergoing cardiac resynchronization therapy with an implantable cardioverter-defibrillator in terms of the degree of echocardiographic response to resynchronization. Patients were classified in 3 subgroups; super- responders, responders, and nonresponders. Results: We included 196 patients who were followed up for a median 30.1 months (interquartile range, 18.0-55.1 months). We recorded the presence of ventricular arrhythmias in 37 patients (18.8%); 3 patients (5.9%) in the super-responder group had ventricular arrhythmias vs 14 (22.2%) among the responders and 20 (24.4%) in the group of nonresponders (P = .025). In multivariate analysis, the only independent predictors of the appearance of ventricular arrhythmias were secondary-prevention device implantation (odds ratio = 4.04; 95% confidence interval, 1.52-10.75; P = .005), absence of echocardiographic super-response (odds ratio = 3.81; 95% confidence interval, 1.04-13.93; P = 043), QRS >160 ms (odds ratio = 2.39; 95% confidence interval, 1.00-1.35; P = .049) and treatment with amiodarone (odds ratio = 2.47; 95% confidence interval, 1.03-5.91; P = .041).

La terapia de resincronización cardiaca se asocia a mejora de la calidad de vida y reducción de la morbimortalidad de los pacientes con disfunción ventricular grave y QRS ancho. Sobre su papel en la reducción de arritmias ventriculares, hay más discusión. Se comparó la incidencia de arritmias ventriculares en pacientes portadores de desfibrilador automático implantable con función de resincronización cardiaca, según el grado de respuesta ecocardiográfica a la resincronización. Se clasificó a los pacientes en tres subgrupos: superrespondedores, respondedores y no respondedores. Se incluyó a 196 pacientes seguidos durante una mediana de 30,1 [intervalo intercuartílico, 18,0-55,1] meses. Se documentó presencia de arritmias ventriculares en 37 pacientes (18,8%); 3 pacientes (5,9%) del grupo de superrespondedores presentaron arritmias ventriculares, en comparación con 14 (22,2%) del grupo de respondedores y 20 (24,4%) del grupo de no respondedores (p = 0,025). En el análisis multivariable, el implante del dispositivo en prevención secundaria (odds ratio = 4,04; intervalo de confianza del 95%, 1,52-10,75; p = 0,005), la ausencia de superrespuesta ecocardiográfica (odds ratio = 3,81; intervalo de confianza del 95%, 1,04-13,93; p = 0,043), un QRS > 160 ms (odds ratio = 2,39; intervalo de confianza del 95%, 1,00-1,35; p = 0,049) y el tratamiento con amiodarona (odds ratio = 2,47; intervalo de confianza del 95%, 1,03-5,91; p = 0,041) fueron los únicos predictores independientes de aparición de arritmias ventriculares. Los pacientes superrespondedores a la terapia de resincronización cardiaca presentan una disminución significativa en la incidencia de arritmias ventriculares respecto a los demás pacientes. Pese a ello, los episodios arrítmicos no llegan a desaparecer por completo en este subgrupo. Cardiac resynchronization therapy is associated with improved quality of life and reduced morbidity and mortality in patients with severe ventricular dysfunction and wide QRS. However, its role in the reduction of ventricular arrhythmias is more controversial. We compared the incidence of ventricular arrhythmias in patients who were undergoing cardiac resynchronization therapy with an implantable cardioverter-defibrillator in terms of the degree of echocardiographic response to resynchronization. Patients were classified in 3 subgroups; super-responders, responders, and nonresponders. We included 196 patients who were followed up for a median 30.1 months [interquartile range, 18.0-55.1 months]. We recorded the presence of ventricular arrhythmias in 37 patients (18.8%); 3 patients (5.9%) in the super-responder group had ventricular arrhythmias vs 14 (22.2%) among the responders and 20 (24.4%) in the group of nonresponders (P = .025). In multivariate analysis, the only independent predictors of the appearance of ventricular arrhythmias were secondary–prevention device implantation (odds ratio = 4.04; 95% confidence interval, 1.52-10.75; P = .005), absence of echocardiographic super-response (odds ratio = 3.81; 95% confidence interval, 1.04-13.93; P = 043), QRS >160 ms (odds ratio = 2.39; 95% confidence interval, 1.00-1.35; P = .049) and treatment with amiodarone (odds ratio = 2.47; 95% confidence interval, 1.03-5.91; P = .041). The patients classified as super-responders to cardiac resynchronization therapy had a significant reduction in incidence of ventricular arrhythmias by comparison with the other patients. Despite this, arrhythmic episodes do not completely disappear in this subgroup. Sin financiación 3.792 JCR (2014) Q2. 33/123 Cardiac and cardiovascular systems UEM

Electrical defibrillation is the only effective therapy for cardiac arrest caused by ventricular fibrillation (VF) [1, 2] or pulseless ventricular tachycardia (VT). Scientific evidence to sup‐ port early defibrillation is overwhelming [3-5], being delay from collapse to delivery of the first shock the single most important determinant of survival [6, 7]. If defibrillation is deliv‐ ered promptly, survival rates as high as 75% have been reported [8, 9]. The chance of a fa‐ vourable outcome decline at a rate of about 10% for each minute cardiac defibrillation is delayed [3, 10].

This paper presents a computationally efficient numerical solution scheme to solve transient heat conduction problems using the boundary element method (BEM) without volume discretization. Traditionally, a transient solution using BEM is very computer intensive due to the excessive numerical integration requirements at each time increment. In the present work a numerical solution scheme based on the separation of time and space integrals in the boundary integral equation through the use of an appropriate series expansion of the integrand (incomplete gamma function) is presented. The space integrals are evaluated only once in the beginning and within each time increment the additional integrals are obtained from the previously evaluated space integrals by a simple calculation. Three‐dimensional applications are provided to compare the proposed strategy with that used traditionally. The CPU requirements are reduced substantially. The solution scheme presented allows for dynamically changing the time step size as the solution evolves. This feature is not practical in the traditional schemes based on boundary discretization only.

This paper presents an improved solution of three-dimensional plasticity problems using the boundary element method (BEM). The BEM formulation for plasticity requires volume as well as boundary discretizations. An initial stress formulation is used to satisfy the material non-linearity. Conventionally, the plastic field in the volume element (or cell) is interpolated based on the value of plastic stress at the nodes of the cell. In this paper, the distribution of the plastic field in the cell is based on a number of points interior to the cell. The plastic field is described using regression interpolation polynomials through these interior points. The constitutive relation is satisfied at each interior point. The number of points can be varied in each cell, thus allowing for adaptive volume cells. The plastic stresses are computed at the interior points only, therefore, the need for surface stress computation (which uses numerical derivatives at the surface) is completely eliminated. Three-dimensional applications are used to compare the present regression interpolation procedure with the conventional method for elasto-plasticity problems. In all variations of the applications studied regression interpolation based on interior points provided superior results to those determined via the conventional nodal interpolation method.

Computer-aided engineering tools are routinely used to simulate forging and heat-treatment operations and to perform thermal and stress analyses. This review gives a few examples of the current uses of process modeling tools and outlines some developing capabilities and near-term applications.

QRS width is a well known prognostic factor in ICD patients, however there is less information regarding bundle branch block morphology. Umbrella is a Spanish multicenter, prospective, observational registry sponsored by Medtronic including ICD patients from 39 centers followed by CareLink System. To analyze the influence of QRS width and morphology of bundle branch block in ventricular tachycardia (VT) or fibrillation (VF) recurrences, we studied patients from 27 participating centers followed between 1/04/2007 and 01/07/2012. Results: We included 568 patients (age 63.8±14, EF 33.1±9.4, QRS width 109±27ms), 77 (13.6%) of them with left bundle branch block (LBBB), and 49 (8.6%) with right bundle branch block (RBBB), and followed them during 23.3±18 months. LBBB was associated with more episodes of VT/VF, more shocks related to VT/VF and the occurrence of more than 3 episodes of VT/VF during follow-up (Table 1). Neither ejection fraction nor RBBB had any significant association to shocks or arrhythmia incidence. Width of QRS complex was only associated with a higher number of shocks (109±29 vs 120±25, p=0.002) and more than 3 episodes of VT/VF (109±29 vs 120±27, p=0.003) during follow-up. View this table: Table 1 Conclusion: Patients with LBBB had significantly more arrhythmic events compared to patients without LBBB. In our study EF and RBBB do not have prognostic relevance. QRS width has limited value. Further studies are needed to contrast these findings.

By simulating the flow of metal in forging, engineers can eliminate defects and undesirable flow patterns. Localized deformation heating of the forging can be predicted and avoided, with a resulting improvement of quality.