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This editorial refers to ‘Right bundle branch block: prevalence, risk factors, and outcome in the general population: results from the Copenhagen City Heart Study’, by B.E. Bussink et al. , doi:10.1093/eurheartj/ehs291 The right bundle branch is a long, thin, and discrete structure composed of high-velocity conduction Purkinje fibres. It is located in the right side of the interventricular septum and occupies a subendocardial position in its superior and inferior thirds and deeper in the middle third. There are no ramifications in most of its course, but it starts to branch as it reaches the base of the anterior papillary muscle. The appearance of a right bundle branch block (RBBB) alters the ventricular activation sequence, produces a QRS prolongation, and changes the orientation for R- and S-wave vectors, thus generating a typical electrocardiogram (ECG) pattern ( Figure 1 ). Figure 1 Right bundle branch block produces a change in the normal activation of the heart. The prevalence of RBBB in the general population is estimated at between 0.2% and 0.8%, and it clearly increases with age.1 It may be associated with different cardiac structural diseases such as ischaemic heart disease, myocarditis, hypertension, congenital heart disease, cor pulmonale, and pulmonary embolism. Its prognosis depends on the type and severity of the associated heart condition; for example, in patients with ischaemic heart disease the presence of RBBB is a well-established mortality predictor.2–4 The same is true for patients with heart failure where at least two different studies showed a worse prognosis for patients with RBBB hospitalized with this condition.5,6 Nevertheless, all previously published data suggest an excellent prognosis in patients free of heart …

The cardiac conduction system (CCS) is constituted by specialised myocardial cells responsible for the initiation of the cardiac impulse and its fast propagation throughout the myocardium, in a regular and orderly manner, causing the heart to contract efficiently and send blood to the great arteries. The CCS consists of the sinus node (discovered by Keith and Flack in 1906), which is the normal pacemaker of the heart, the internodal pathways, and the atrioventricular (AV) system including the atrioventricular node (described by Tawara in 1906), the bundle of His (described by Wilhelm His in 1893), and the ventricular branches (described by Purkinje in 1845).

To present the findings of the Spanish Implantable Cardioverter-defibrillator Registry for 2013 compiled by the Electrophysiology and Arrhythmias Section of the Spanish Society of Cardiology.Prospective data were voluntarily recorded on a data collection form and sent to the Spanish Society of Cardiology by each implantation team.Overall, 4772 device implantations were reported, representing 85% of the estimated total number of implantations. The reported implantation rate was 102 per million population and the estimated total implantation rate was 120 per million. The proportion of first implantations was 68.8%. Data were received from 154 hospitals (4 fewer than in 2012). Most implantable cardioverter-defibrillator recipients were men (83.3%). The mean age was 62.5 (13.4) years. Most patients had severe or moderate-to-severe ventricular dysfunction and were in New York Heart Association functional class II. The most frequent underlying cardiac condition was ischemic heart disease, followed by dilated cardiomyopathy. Indications for primary prevention accounted for 53.0% of first implantations, consolidating the decrease first observed in 2012. Overall, 79.8% of devices were implanted by cardiac electrophysiologists.The 2013 Spanish Implantable Cardioverter-defibrillator Registry includes information on 85% of the devices implanted in Spain. The total number of implantations increased compared with the previous 2 years. The percentage of implantations for primary prevention indications decreased compared with the previous year.

In this paper, we study the empirical relationship between credit funding sources and the financial vulnerability of the Colombian banking system. We propose a statistical model to measure and predict banking-fragility episodes associated with credit funding sources classified into retail deposits and wholesale funds. We compute the probability of financial fragility for both the aggregated banking system and the individual banks. Our approach performs a Bayesian averaging of estimated logit regression models with monthly balance sheet data between 1996 and 2013. The results show the increasing use of wholesale funding to support credit expansion is a potential source of financial fragility. Therefore, monitoring credit funding sources could provide an additional tool to warn against banking disruptions. Classification JEL: C11, C23, C52, C53, G01, G20, G21

Background —Different responses to entrainment have been reported in relation to the pacing site of a variety of tachycardias. However, transient entrainment of bundle-branch reentrant tachycardia (BBRT) has not been investigated systematically. Methods and Results —We attempted entrainment of 13 BBRTs in 9 patients by pacing first the right ventricle and then the right atrium. The initial pacing cycle length (CL) was 10 ms faster than the tachycardia CL. Subsequent pacing sequences were performed with 5- to 10-ms CL decrements until tachycardia termination or loss of postatropine 1:1 AV conduction. Both full ventricular-paced and AV-conducted QRS complex references were obtained during sinus rhythm pacing from the same sites and with similar CL as during entrainment. Transient entrainment was achieved by ventricular and atrial stimulation in 11 and 8 tachycardias, respectively. Constant fusion was always present during entrainment by ventricular stimulation. There was no change in the QRS complex (orthodromically concealed fusion) during entrainment by atrial stimulation in 6 of 6 tachycardias with left bundle-branch block morphology and in 1 of 2 tachycardias with right bundle-branch block morphology. Conclusions —BBRT, especially if it has a left bundle-branch block morphology, can be differentiated from other wide-QRS-complex tachycardia mechanisms through analysis of the ECGs recorded during tachycardia entrainment by atrial and ventricular stimulation. This diagnostic approach may be especially useful when it is difficult to record a stable or sufficiently sized His bundle electrogram or when spontaneous changes in the ventricular CL precede similar changes in the His bundle CL.

Introduccion y objetivos Recientemente se ha desarrollado la tecnica de MAZE como un procedimiento quirurgico efectivo para el tratamiento de la fibrilacion auricular refractaria al tratamiento medico. Este estudio trata de describir los riesgos y beneficios de realizar la tecnica de MAZE en aquellos enfermos con fibrilacion auricular que van a ser intervenidos de otra lesion cardiaca organica Material y metodos Desde noviembre de 1993, hemos realizado 10 intervenciones con la tecnica de MAZE, para el tratamiento de fibrilacion auricular refractaria. La indicacion para realizar la tecnica se establecio en 5 pacientes por existir un antecedente de embolismo sistemico bajo tratamiento anticoagulante, en dos casos por existir una contraindicacion absoluta para la anticoagulacion y en 5 casos por refractariedad al tratamiento antiarritmico. Dos pacientes presentaban mas de una indicacion. En todos los casos se realizo una cirugia acompanante, 5 reemplazos valvulares mitrales, una plastia mitral, otra tricuspide y tres cierres de comunicacion interauricular tipo ostium secundum. Resultados Inmediatamente tras la cirugia el ritmo auricular en 9 casos y de fibrilacion auricular en uno. Cuatro enfermos precisaron estimulacion auricular transitoria durante el postoperatorio. Una enferma requirio un marcapasos definitivo por bradicardia sinusal sintomatica. Durante los primeros 3 meses, 4 enfermos tuvieron episodios paroxisticos de fibrilacion o flutter auricular. De los diez pacientes uno fallecio subitamente un mes despues de la cirugia. Siete enfermos han completado el seguimiento a dos anos manteniendose en ritmo sinusal estable, con buena respuesta cronotropica y en grado funcional I, sin precisar ninguno de ellos tratamiento antiarritmico. Todos ellos tienen evidencia ecocardiografica de actividad mecanica en ambas auriculas, habiendose reducido el tamano de la auricula izquierda desde 5,3 ± 0,7 a 4,5 ± 0,7 cm (p Conclusiones La tecnica de MAZE es una buena alternativa en enfermos seleccionados con fibrilacion auricular refractaria a tratamiento medico o con antecedentes de embolismo sistemico. Sin embargo, no esta exenta de problemas que complican el manejo postoperatorio.

Introduccion y objetivos El campo electromagnetico generado por los telefonos moviles puede causar disfuncion de marcapasos. Aunque los desfibriladores implantables son tambien susceptibles a ese tipo de interferencia, se han realizado pocos estudios para evaluar ese riesgo y la compatibilidad con la tecnologia GSM no ha sido probada. El objetivo de este estudio es detectar interferencia in vivo entre telefonos moviles GSM y desfibriladores. Material y metodos La poblacion de estudio se compone de 30 pacientes portadores de 8 modelosdistintos de desfibriladores. Veintiseis tenian electrodos endocardicos y 4 epicardicos. Se evaluaron tres telefonos moviles GSM: Siemens S3 COM y Motorola 6200 en todos los casos y Ericsson GA 318 en uno. Las pruebas fueron realizadas bajo monitorizacion electrocardiografica continua. Las formas de terapia eran desactivadas y los parametros de sensibilidad aumentados al maximo valor permitido. Los telefonos se colocaron en contacto proximo con la carcasa y sobre el precordio, en dos angulos distintos. Se estudiaron tres situaciones: establecimiento de llamada, contacto durante 15 s y recepcion de llamada. Se repitio el protocolo durante estimulacion a frecuencias superiores a la basal para evaluar una posible inhibicion del modo de marcapasos. Resultados No se observaron casos de interferencia electromagnetica. Un paciente presento episodios espontaneos de taquicardia ventricular no sostenida durante las pruebas que fueron detectados por el desfibrilador. Conclusiones Los resultados sugieren que la interferencia electromagnetica por telefonos moviles GSM es una causa poco probable de disfuncion de los desfibriladores implantables.

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

La fibrilación auricular (FA), cuya frecuencia sigue aumentando en la población de nuestro entorno, es la arritmia sostenida más prevalente, llegando a afectar hasta al 10% de los pacientes de edad avanzada. Esta enfermedad duplica la mortalidad por cualquier causa y aumenta hasta en 5–6 veces el riesgo de ictus, que tiene la característica de ser especialmente grave. Los pilares fundamentales del tratamiento de la FA son la reversión a ritmo sinusal o el control de la frecuencia de respuesta ventricular y la prevención de los fenómenos tromboembólicos. Para este último objetivo los tratamientos que se han mostrado más efectivos son los anticoagulantes orales. Desde hace décadas, y hasta hace apenas unos pocos años, los únicos fármacos orales disponibles para este fin han sido los fármacos antivitamina K, representados en nuestro medio principalmente por el acenocumarol y, en menor grado, por la warfarina. Estos fármacos han demostrado reducir el desarrollo de ictus y la mortalidad comparados con placebo y con los antiagregantes, por lo cual han sido y siguen siendo el tratamiento estándar y el comparador para cualquier fármaco antitrombótico en los pacientes con FA. La variabilidad en su respuesta terapéutica, sus interacciones y su estrecha ventana terapéutica, que conlleva la necesidad de monitorizar frecuentemente la respuesta, han originado la búsqueda de nuevos fármacos que, al menos manteniendo sus ventajas, logren evitar alguno de sus inconvenientes. Actualmente disponemos de una serie de nuevos fármacos que cumplen estas premisas, si bien tienen el inconveniente de un mayor coste directo. La llegada de estos nuevos anticoagulantes orales (NACO) hace necesario conocerlos adecuadamente, alcanzar un consenso en cuanto a sus indicaciones de uso y realizar cambios en la gestión clínica de estos pacientes en los casos en los que se utilicen. En el presente artículo revisaremos las indicaciones y forma de uso de las diferentes opciones (clásicas y nuevas) de tratamiento antitrombótico en pacientes con FA, la situación de los pacientes anticoagulados en nuestro entorno, las características de los NACO, sus recomendaciones de uso y los retos a los que se ven sometidos los/as médicos de familia en relación con estos cambios.

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].

The Quartet quadripolar lead (St. Jude Medical Inc., St. Paul, MN, USA) offers 10 different left ventricle pacing configurations that may further influence hemodynamic parameters compared to traditional bipolar pacing configurations. The purpose of this study was to evaluate whether pacing from additional quadripolar lead vectors could enhance cardiac output (CO).For each patient, CO was measured in "no-pacing" and in all the 10 configurations available, within 7 days of implantation of the device. Tip-ring, tip-right ventricular coil (RVC), and ring-RVC vectors were considered as traditional vectors. The seven additional configurations available in the quadripolar lead were considered as nontraditional vectors. CO was measured by ECHO. The best configuration was defined as the one presenting the highest CO measurement within configurations, which have a capture threshold3 V and a safety margin between the capture and the phrenic nerve stimulation thresholds.Fifty-one standard cardiac resynchronization therapy patients were enrolled. The mean of each patient's best CO obtained with traditional vectors was higher than the baseline nonpaced CO (4.16 L/min vs 3.64 L/min). The mean of each patient's best CO, including all 10 available configurations, was also higher than the baseline nonpaced CO (4.33 L/min vs 3.64 L/min). In addition, the mean of each patient's best CO obtained with the best configuration available through a quadripolar lead was better than the mean of each patient's best CO obtained with a traditional configuration. In 53% of patients, the best CO was obtained with a nontraditional vector unique to the quadripolar lead.A quadripolar lead offers multiple additional pacing options to increase CO acutely compared to conventional bipolar leads.

Aim Current guidelines recommend atrioventricular junction (AVJ) ablation in patients with atrial fibrillation (AF) treated with cardiac resynchronization therapy (CRT). Our study compared the CRT response of patients in sinus rhythm (SR) vs. AF. Methods and results In this observational, prospective, multicentre study, patients were grouped by intrinsic rhythm. For the first 2 months, the negative chronotropic drug was optimized in the AF group. If ventricular pacing was ≤85%, AVJ ablation was recommended. Responders were defined as patients who survived without requiring heart transplant and had a ≥ 10% reduction in left ventricular end-systolic volume (LVESV) at 12 months after implantation. Of 202 patients included, 156 (77%) were in SR and 46 (23%) had AF. After drug optimization, only 13/46 (28%) of the AF patients required AVJ ablation (AF + AVJ). The percentage of responders was 83/156 (53%) for SR vs. 22/46 (48%) AF (P = 0.4). Among AF patients the response was 16/33 (48%) for AF with non-AVJ ablation vs. 6/13 (46%) AF + AVJ, P = 0.56. The LVESV decreased in all three groups: −30 ± 39 mL, −24 ± 43 mL, and −22 ± 36 mL, respectively (P = 0.75). Mortality was higher in patients with AF compared with SR: 10/46 (21%) vs. 9/156 (5.7%), log rank 10.6, P

■ PURPOSE: Efficient ways are needed to implement the secondary prevention (SP) of coronary heart disease. Because few studies have investigated Web-based SP programs, our aim was to determine the usefulness of a new Web-based telemonitoring system, connecting patients provided with self-measurement devices and care managers via mobile phone text messages, as a tool for SP. ■ METHODS: A single-blind, randomized controlled, clinical trial of 203 acute coronary syndrome (ACS) survivors, was conducted at a hospital in Madrid, Spain. All patients received lifestyle counseling and usual-care treatment. Patients in the telemonitoring group (TMG) sent, through mobile phones, weight, heart rate, and blood pressure (BP) weekly, and capillary plasma lipid profile and glucose monthly. A cardiologist accessed these data through a Web interface and sent recommendations via short message service. Main outcome measures were BP, body mass index (BMI), smoking status, low-density lipoprotein-cholesterol (LDL-c), and glycated hemoglobin A 1c (HbA 1c ). ■ RESULTS: At 12-month followup, TMG patients were more likely (RR � 1.4; 95% CI � 1.1-1.7) to experience improvement in cardiovascular risk factors profile than control patients (69.6% vs 50.5%, P � .010). More TMG patients achieved treatment goals for BP (62.1% vs 42.9%, P � .012) and HbA1c (86.4% vs 54.2%, P � .018), with no differences in smoking cessation or LDL-c. Body mass index was significantly lower in TMG (� 0.77 kg/m 2 vs � 0.29 kg/m 2 , P � .005). ■ CONCLUSIONS: A telemonitoring program, via mobile phone messages, appears to be useful for improving the risk profile in ACS survivors and can be an effective tool for secondary prevention, especially for overweight patients.

Implantable cardioverter-defibrillators (ICDs) reduce mortality by terminating ventricular arrhythmias (VAs), and it has become widely accepted that this is done by delivering shocks. From the initials of ICD therapy it is known that ICD shocks are associated with reduced quality of life. Most importantly, recent accumulated evidence indicates a clear association among shocks (appropriate and inappropriate) and increased risks of heart failure (HF) and death (Poole et al, 2008). Knowing that, one of our major objectives when dealing with an ICD patient has to be reducing shocks while keeping the certainty that all the VAs are adequately terminated. When trying to reduce shocks our focus should be dual, inappropriate and unnecessary therapies. Inappropriate shocks are generally defined as those not delivered for ventricular tachycardia (VT) or fibrillation (VF), and may be due to oversensing (double counting of right and left ventricular depolarization, T-wave oversensing, noise, etc) or to atrial arrhythmias with rapid ventricular conduction. Unnecessary shocks are those that could have been avoided using other means of terminating the VT, namely antitachycardia pacing, or allowing the VT to spontaneously finish, in case of non-sustained episodes, prolonging the number of intervals needed to detect and initiate therapy. Depending on the trial, only 3–35% of shocked episodes were sustained VT/VF that absolutely require a shock for termination. When considering the number of shocks delivered for SVT, T-wave oversensing (TWOS) and lead noise, primary prevention patients may experience more inappropriate shocks than shocks for VT/VF. This highlights the need for improved shock reduction strategies. During this chapter we will review the most recent developments and algorithms to avoid inappropriate and unnecessary shocks.

We appreciate the authors' careful review of our manuscript and prepared the following response to their comments. The first comment is that the SmartDelay Determined AV Optimization: A Comparison to Other AV Delay Methods Used in Cardiac Resynchronization Therapy (SMART-AV) trial was underpowered to detect the additional response to atrioventricular (AV) optimization. Importantly, the authors performed a post hoc power calculation, basing their calculations on the observed fixed-group response. These calculations do not have the same validity as prospective power calculations and must be interpreted with great caution.1 Second, the noninferiority margin of 15 mL for a left ventricular end-systolic volume difference from baseline to 6 months post–cardiac resynchronization therapy was …

Aims Previous experimental and clinical studies have consistently suggested that right ventricular (RV) apical pacing has important adverse effects. Ventricular pacing (VP), however, is required, and cannot be reduced in many patients with atrioventricular (AV) block. The PREVENT-HF study was an international randomized trial that explored differences in left ventricular (LV) remodelling during RV apical vs. biventricular (BIV) pacing in patients with AV block. Methods and Results Patients with an expected VP prevalence ≥80% were assigned to RV apical or BIV pacing. The primary endpoint was the change in LV end-diastolic volume (EDV) >12 months. Secondary endpoints were LV end-systolic volume (ESV), LV ejection fraction (EF), mitral regurgitation (MR), and a combination of heart failure (HF) events and cardiovascular hospitalizations. Overall, 108 patients were randomized (RV: 58; BIV: 50). Intention to treat and on-treatment analyses revealed no significant differences in any of the outcomes. Analysis of covariance (ANCOVA) difference for treatment according to randomization (in mL): LVEDV −3.92 (−18.71 to 10.85), P= 0.6; LVESV −1.38 (−12.07 to 9.31), P= 0.80; LVEF 2.47 (−3.00 to 7.94), P= 0.37. Analysis of covariance difference for the on-treatment analysis: LVEDV −4.90 (−20.02 to 10.22, PP= 0.52; LVESV −6.45 (−17.28 to 4.38), P= 0.24, LVEF 2.18 (−3.37 to 7.73), P= 0.44. Furthermore, secondary endpoints did not differ significantly. Conclusion This study did not demonstrate significant LV volume differences >12 months between RV apical and BIV pacing for AV block. Thus, BIV pacing cannot be recommended as a routine treatment for AV block in these patients. However, the results encourage and inform the design of subsequent larger trials with higher power for detecting small volume changes. ClinicalTrials.gov Identifier: NCT00170326.

Background One variable that may influence cardiac resynchronization therapy response is the programmed atrioventricular (AV) delay. The SmartDelay Determined AV Optimization: A Comparison to Other AV Delay Methods Used in Cardiac Resynchronization Therapy (SMART-AV) Trial prospectively randomized patients to a fixed empirical AV delay (120 milliseconds), echocardiographically optimized AV delay, or AV delay optimized with SmartDelay, an electrogram-based algorithm. Methods and Results A total of 1014 patients (68% men; mean age, 66±11 years; mean left ventricular ejection fraction, 25±7%) who met enrollment criteria received a cardiac resynchronization therapy defibrillator, and 980 patients were randomized in a 1:1:1 ratio. All patients were programmed (DDD-60 or DDDR-60) and evaluated after implantation and 3 and 6 months later. The primary end point was left ventricular end-systolic volume. Secondary end points included New York Heart Association class, quality-of-life score, 6-minute walk distance, left ventricular end-diastolic volume, and left ventricular ejection fraction. The medians (quartiles 1 and 3) for change in left ventricular end-systolic volume at 6 months for the SmartDelay, echocardiography, and fixed arms were −21 mL (−45 and 6 mL), −19 mL (−45 and 6 mL), and −15 mL (−41 and 6 mL), respectively. No difference in improvement in left ventricular end-systolic volume at 6 months was observed between the SmartDelay and echocardiography arms ( P =0.52) or the SmartDelay and fixed arms ( P =0.66). Secondary end points, including structural (left ventricular end-diastolic volume and left ventricular ejection fraction) and functional (6-minute walk, quality of life, and New York Heart Association classification) measures, were not significantly different between arms. Conclusions Neither SmartDelay nor echocardiography was superior to a fixed AV delay of 120 milliseconds. The routine use of AV optimization techniques assessed in this trial is not warranted. However, these data do not exclude possible utility in selected patients who do not respond to cardiac resynchronization therapy. Clinical Trial Registration URL: http://www.clinicaltrials.gov Unique identifier: NCT00677014.

Las reglas fiscales aumentan la credibilidad de la politica economica, permiten un manejo fiscal contraciclico y sostenible y contribuyen a la estabilidad y al crecimiento. El gobierno colombiano ha usado reglas fiscales para limitar el crecimiento del gasto y el endeudamiento de los entes territoriales y propiciar la transparencia y la responsabilidad fiscal. Pero el alcance de dichas reglas ha sido limitado. En este trabajo se propone y evalua una regla fiscal cuantitativa del 1% del PIB de superavit primario estructural para el gobierno central, para consolidar el ajuste de las finanzas publicas y blindar su manejo en el futuro. Si esa regla se acogiera este ano, se lograrian ahorros de por lo menos un 0,7% del PIB entre 2008 y 2011, con lo cual se reduciria el nivel de la deuda en 3 puntos del PIB al final del periodo.

The efficacy of cardiac resynchronization therapy (CRT) in patients with atrial fibrillation (AF) and the need for atrioventricular junction ablation in these patients is controversial. The aim of the study was to analyze CRT results in patients with permanent AF. A total of 470 consecutive patients who underwent CRT in 6 centers were included in this study. Of these patients, 126 (27%) had permanent AF. Patients were evaluated at baseline and 12 months. No difference was found in the magnitude of improvement experienced by patients with AF compared with those in sinus rhythm (SR) with respect to quality of life, distance in 6-minute walking test, and left ventricular reverse remodeling. Despite the beneficial effects of CRT, death from refractory heart failure at 12 months was higher in patients with AF (17 of 126; 13.5%) than those in SR (14/344; 4.1%; p

Introduction and objectives. Ectopic activity originating inside the pulmonary veins has been associated with paroxysmal atrial fibrillation in some patients. However, the roles played by the pulmonary veins and the posterior wall of the left atrium in maintaining atrial fibrillation are not well understood. Methods. Our aim was to determine whether there is a correlation between the refractory period of either the lateral wall of the right atrium, the lateral wall of the left atrium, the posterior wall of the left atrium, or the pulmonary veins, and the inducibility of atrial fibrillation in an experimental swine model. We assessed atrial fibrillation inducibility using programmed atrial stimulation before and after intravenous administration of a high dose of methacholine in 20 pigs. Results. Atrial fibrillation was induced in 17 out of the 20 pigs. Univariate analysis showed that there were negative correlations between all refractory periods and atrial fibrillation inducibility. A short refractory period was associated with greater inducibility. In the multivariate analysis, only the refractory periods of the posterior wall of the left atrium and the pulmonary veins were associated with inducibility. We also investigated the relationship between the local atrial fibrillation cycle length and refractory period; the only significant correlation was with the refractory period of the lateral wall of the right atrium (Pearson correlation coefficient 0.97). Conclusions. In an experimental swine model, the inducibility of atrial fibrillation was found to be associated with the refractory periods of both the pulmonary veins and the posterior wall of the left atrium.

Cardiac electrophysiology laboratories deal with a wide range of pathological conditions, diagnostic techniques, and treatments. Since a huge quantity of material has been published in recent months, this article will be limited to discussion of the most significant developments in the prognostic evaluation of arrhythmias, hereditary disease, syncope, atrial fibrillation, implantable cardioverter-defibrillators, cardiac resynchronization therapy, and catheter ablation. Even within these areas, discussion will be restricted to specific concrete topics and to a limited number of publications that were judged to have important implications for clinical practice. Our principal aim was to provide clinical cardiologists with an overview of the latest developments in cardiac electrophysiology.

Introduction and objectives. The effect of cardiac resynchronization therapy on antitachycardia pacing still has to be determined. Patients and method. A total of 490 heart failure patients with an indication for an implantable cardioverter-defibrillator participated in the VENTAK CHF/CONTAK CD study, a single-blind, randomized, placebo-controlled study. We compared antitachycardia pacing efficacy in patients with or without cardiac resynchronization therapy. Due to the device design, antitachycardia pacing was always given simultaneously via both left and right leads (i.e., biventricular antitachycardia pacing). Patients were randomized at the time of implantation, with the pacing mode being programmed accordingly one month later. Results. During follow-up, 32 patients received antitachycardia pacing: 15 with cardiac resynchronization therapy and 17 without. In the 15 patients receiving resynchronization, 221 episodes of tachycardia were treated by antitachycardia pacing. The sinus rhythm conversion rate was 90.5%. In patients not receiving resynchronization, there were 139 episodes of tachycardia and the sinus rhythm conversion rate was 69.1%. The sinus rhythm conversion rate in the cardiac resynchronization therapy group was significantly higher than that in the control group (P

About 30% of patients treated with cardiac resynchronization therapy (CRT) do not respond to treatment. The aim of this study was to identify clinical predictors of lack of improvement in patients receiving CRT. From 197 consecutive patients scheduled to receive CRT, 143 fulfilled the inclusion criteria. Mean age was 68 +/- 7 years and 79% were men. Heart failure was due to ischemic heart disease in 49 patients (34%). Mean QRS duration was 165 +/- 26 ms, and left ventricular ejection fraction was 27 +/- 7%. Nonresponder patients were defined as those who died of heart failure, underwent heart transplantation, or did not increase the distance walked in 6 minutes >10%. At 6-month follow-up, there were 28 nonresponders (20%). Among nonresponders, 2 patients received a heart transplantation and 9 patients died of heart failure. In logistic regression analysis, independent predictors of lack of response to CRT were ischemic heart disease (odds ratio [OR] 2.9, 95% confidence interval [CI] 1.2 to 7; p = 0.023), severe mitral regurgitation (OR 3.5, 95% CI 1.3 to 9; p = 0.014), and left ventricular end-diastolic diameter > or =75 mm (OR 3.1, 95% CI 1.1 to 8; p = 0.026). Patients with these 3 predictors had a probability response of 27%.

Aims The prevent-atrial fibrillation (AF) registry analyses the clinical relevance and usefulness of the four preventive pacing algorithms, available in a family of cardiac stimulators, to prevent atrial fibrillation. Methods and Results This study is a prospective, non-randomized, multicentre registry. Patients are eligible for the registry if they have sick sinus syndrome (SSS) with or without pre-existing atrial fibrillation. The preventive pacing algorithms were programmed for each patient on an individual basis using the diagnostic features of the devices. In the period from April 2000 to April 2001 a total of 68 patients (33 male, 35 female) has been included in the registry in 14 hospitals in Spain. Mean age was 72±12 years and the pacemaker indication was SSS in 15 patients (22%) and SSS with paroxysmal AF in 53 patients (78%). The median AF burden for the total group (n=32) was significantly reduced from 3.9 to 1.3% (67%, P =0.034, Wilcoxon signed rank test). The decrease in AF burden was accompanied by a non-significant decrease in the median number of episodes per day from 1.47 to 0.64 (a decrease of 56%). The average atrial pacing % was increased from 72 to 78%. Conclusions The prevent-AF registry demonstrated the usefulness of four preventive pacing algorithms in daily clinical practice. During the registry a significant reduction in AF burden and all other endpoints was observed. Dedicated diagnostics were key to adapting the optimal pacing therapy during follow-up.

The Ventak CHF/CONTAK CD Biventricular Pacing Study is a prospective randomized trial to examine the safety and efficacy of biventricular (BV) pacing in patients with standard indications for an ICD, symptomatic heart failure, a LVEFor = 0.35, and a QRSor = 120 ms. Patients underwent implantation of a BV pacing and sensing system with backup defibrillation capability, which includes a steroid-eluting coronary venous lead that is advanced into the coronary venous vasculature by over-the-wire techniques. LV pacing threshold, BV impedance, and BV R wave amplitude were measured in 58 consecutive patients. Using a percutaneous over-the-wire insertion technique, steroid-eluting coronary venous leads were associated with satisfactory mean LV pacing threshold, BV impedance, and BV R wave amplitude acutely up to 4 months after implantation. Pacing threshold stabilized 2 weeks after lead implantation and sensing threshold remained stable from the time of implant.

Biventricular (BV) pacing is under clinical investigation for the treatment of heart failure. Its impact on mortality is unknown. Patients with heart failure and ventricular tachyarrhythmias received an implantable cardioverter defibrillator with BV pacing capability. Patients were randomized 1:1 to BV pacing or no pacing, then crossed over to the alternate mode after 3 months. All-cause mortality was measured in each arm up to the point of crossover. Fifteen of 222 patients died between implant and crossover. Five patients died while programmed to BV pacing and 19 died while programmed to no pacing. Survival in the BV pacing arm was 93 +/- 4% versus 86 +/- 6% in the no pacing arm (P = 0.18). In a patient population with symptomatic heart failure and ventricular arrhythmias, BV pacing does not appear to be associated with excess mortality. Larger and longer studies will be needed to determine if BV pacing confers a survival benefit.

Brugada syndrome (BrS) is a life-threatening, inherited arrhythmogenic syndrome associated with autosomal dominant mutations in SCN5A, the gene encoding the cardiac Na+ channel alpha subunit (Nav1.5). The aim of this work was to characterize the functional alterations caused by a novel SCN5A mutation, I890T, and thus establish whether this mutation is associated with BrS. The mutation was identified by direct sequencing of SCN5A from the proband's DNA. Wild-type (WT) or I890T Nav1.5 channels were heterologously expressed in human embryonic kidney cells. Sodium currents were studied using standard whole cell patch-clamp protocols and immunodetection experiments were performed using an antibody against human Nav1.5 channel. A marked decrease in current density was observed in cells expressing the I890T channel (from -52.0±6.5 pA/pF, n = 15 to -35.9±3.4 pA/pF, n = 22, at -20 mV, WT and I890T, respectively). Moreover, a positive shift of the activation curve was identified (V1/2 = -32.0±0.3 mV, n = 18, and -27.3±0.3 mV, n = 22, WT and I890T, respectively). No changes between WT and I890T currents were observed in steady-state inactivation, time course of inactivation, slow inactivation or recovery from inactivation parameters. Cell surface protein biotinylation analyses confirmed that Nav1.5 channel membrane expression levels were similar in WT and I890T cells. In summary, our data reveal that the I890T mutation, located within the pore of Nav1.5, causes an evident loss-of-function of the channel. Thus, the BrS phenotype observed in the proband is most likely due to this mutation, This work was supported by Fundació Obra social ‘‘La Caixa’’, Centro Nacional de Investigaciones Cardiovasculares [CNIC-03-2008] and Instituto de Salud Carlos III [FIS- PI08/1800]

Permanent pacemaker implantation is required in a large number of transplantation patients principally because of sinus node dysfunction of the donor atrium. The most suitable mode of pacing in these cases is still subject to controversy. We describe one case of a single lead system of VDD stimulation and sensing of the recipient atrial signal in a 32-year-old patient with posttransplant symptomatic sinus node dysfunction. Physiological adaptation of rate was achieved with recovery of normal receptor sinus node function. (PACE 1996; 19:1522–1523).

Atrioesophageal fistula is one of the most serious complications of pulmonary vein (PV) isolation. We describe a technique to monitor esophageal position during this procedure. A 39-year-old patient with atrial fibrillation underwent pulmonary vein isolation under guidance of the EnSite NavXTM electroanatomic navigation system. To avert unintentional esophageal injury, a tetrapolar electrode for transesophageal stimulation was inserted by nasogastric access, advanced to a retroatrial position, and connected to the NavXTM system. The image shows a cranial view (A) and a posterior view (B), with the tetrapolar electrode (dark blue) within the esophagus between the 2 ablation lines around the right and left pulmonary veins, and at a distance from the roof line (red dots). The electrode used as reference is seen at the level of the interventricular septum. This technique allows continuous visualization of the esophageal position; hence, the operator can avoid application of radiofrequency in the vicinity of the IMAGE IN CARDIOLOGY

ResumenLa fibrilación auricular (FA), cuya frecuencia sigue aumentando en la población de nuestro entorno, es la arritmia sostenida más prevalente, llegando a afectar hasta al 10% de los pacientes de edad avanzada. Esta enfermedad duplica la mortalidad por cualquier causa y aumenta hasta en 5–6 veces el riesgo de ictus, que tiene la característica de ser especialmente grave. Los pilares fundamentales del tratamiento de la FA son la reversión a ritmo sinusal o el control de la frecuencia de respuesta ventricular y la prevención de los fenómenos tromboembólicos. Para este último objetivo los tratamientos que se han mostrado más efectivos son los anticoagulantes orales. Desde hace décadas, y hasta hace apenas unos pocos años, los únicos fármacos orales disponibles para este fin han sido los fármacos antivitamina K, representados en nuestro medio principalmente por el acenocumarol y, en menor grado, por la warfarina. Estos fármacos han demostrado reducir el desarrollo de ictus y la mortalidad comparados con placebo y con los antiagregantes, por lo cual han sido y siguen siendo el tratamiento estándar y el comparador para cualquier fármaco antitrombótico en los pacientes con FA. La variabilidad en su respuesta terapéutica, sus interacciones y su estrecha ventana terapéutica, que conlleva la necesidad de monitorizar frecuentemente la respuesta, han originado la búsqueda de nuevos fármacos que, al menos manteniendo sus ventajas, logren evitar alguno de sus inconvenientes. Actualmente disponemos de una serie de nuevos fármacos que cumplen estas premisas, si bien tienen el inconveniente de un mayor coste directo. La llegada de estos nuevos anticoagulantes orales (NACO) hace necesario conocerlos adecuadamente, alcanzar un consenso en cuanto a sus indicaciones de uso y realizar cambios en la gestión clínica de estos pacientes en los casos en los que se utilicen.En el presente artículo revisaremos las indicaciones y forma de uso de las diferentes opciones (clásicas y nuevas) de tratamiento antitrombótico en pacientes con FA, la situación de los pacientes anticoagulados en nuestro entorno, las características de los NACO, sus recomendaciones de uso y los retos a los que se ven sometidos los/as médicos de familia en relación con estos cambios.AbstractAtrial fibrillation (AF), is the most prevalent sustained arrhythmia in general population, affecting up to 10% in patients of advanced age. AF doubles overall mortality and increases up to 5–6 times the risk of stroke, which have the characteristic of being particularly harmfull. The basis of treatment on AF are the rhythm or rate control and the prevention of thromboembolism. For the latter purpose the treatments that have been most effective are oral acticoagulants. For decades and until just a few years ago, the only oral drugs available for this purpose have been the anti-vitamin K, mainly represented in our country by acenocoumarol and lesser extent by warfarin. These drugs have been shown to reduce strokes and mortality compared to placebo and with antiplatelet drugs, so have been and continue to be the standard treatment and the comparator for all antithrombotic drugs in patients with AF. The variability in the therapeutic response, their food and drugs interactions and their narrow therapeutic window that entail the need to frequently monitoring, has led to look for new drugs that, at least maintaining their advantages, where able to avoid some of the drawbacks.Currently we have a number of new drugs that meet these premises, although they have the disadvantage of a higher direct cost. The arrival of these new oral anticoagulants (NOAC) make necessary to know them well, reach a consensus for a correct use and to make changes in the clinical management of these patients when they are used.In this article we review the indications and way of use of the different options (classics and news) of antithrombotic therapy in patients with AF, the situation of anticoagulated patients in our country, the characteristics of the NOAC, its recommendations for use and the challenges to that are subjected family physicians regarding these changes.