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We have read with interest the article by Herman et al1 describing the prospective outcome of patients with unexplained cardiac arrest (UCA). Certainly, it seems that a high incidence of adverse events occurs in a short-period follow-up. We agree that an implantable cardioverter defibrillator (ICD) is mandatory irrespective of achieving a final diagnosis. The poorer prognosis in patients with structural abnormalities respect to those with primary electric disorders is an interesting finding and might be because of a high efficacy of medical treatment for some cardiac channelopathies. However, some other considerations need to be addressed. It is somewhat surprising that the same incidence of …

Resumen Introduccion La ablacion transcateter constituye una alternativa terapeutica potencialmente curativa para diferentes taquiarritmias en la edad pediatrica. Objetivo Evaluar los resultados de la ablacion transcateter en pacientes menores de 16 anos. Metodos y resultados Entre febrero de 2000 y febrero 2010 se trataron 76 ninos con edad media de 11,38 ± 4 anos y peso medio de 48,8 ± 21 kg. El 92,9% no tenian cardiopatia estructural y el 54% habian recibido tratamiento con farmacos antiarritmicos. Los sustratos mas frecuentes tratados fueron las vias accesorias en 57 (67%) y la taquicardia intranodal en 23 (27%). En la mayoria (94%) la energia empleada fue la radiofrecuencia, en 4 la crioablacion y en uno ambas. El tiempo medio de escopia fue de 26,5 ± 24 min. El exito inmediato se consiguio en 68 ninos (89,4%), siendo necesario en 7 un segundo procedimiento, y en uno un tercer procedimiento. Hubo dos complicaciones, bloqueo de rama derecha transitorio y derrame pericardico. Tras un seguimiento medio de 37,6 ± 29 meses ha habido dos recurrencias y una complicacion tardia. Conclusiones En nuestra experiencia la ablacion transcateter en ninos es un procedimiento seguro y efectivo.

Resumen Introduccion y objetivos Los electrodos de desfibrilacion Sprint Fidelis presentan riesgo de disfuncion precoz. La mayor parte de las series en la literatura provienen de un solo centro. Describimos la experiencia clinica en nueve centros espanoles. Metodos Se analizaron los datos clinicos, del implante y el seguimiento de todos los pacientes con un electrodo Sprint Fidelis, describiendo los casos problema, calculando la supervivencia del electrodo a medio plazo e identificando posibles predictores de disfuncion. Resultados Se incluyo un total de 378 electrodos en 376 pacientes (el 85,7% varones), con una media de edad de 64,9 ± 13,6 anos. El 59,8% se implanto en pacientes con cardiopatia isquemica. La fraccion de eyeccion ventricular izquierda era 33,4% ± 14,5%. En el 74,8% de los casos se implanto por puncion subclavia izquierda. Tras un seguimiento medio de 30,9 ± 14 meses, 16 pacientes presentaron disfuncion del electrodo; la supervivencia a 36 meses fue del 96,1%. En 11 electrodos ocurrio una disfuncion aislada del sistema de sensado/estimulacion; en 3, del sistema de alta energia, y en 2, de ambos. Una mejor funcion ventricular se asocio con una mayor probabilidad de fractura del electrodo (el 42,4% ± 16% frente al 33% ± 14,3%; p = 0,011); tres centros presentaron una tasa de fracturas superior al 10% y los seis restantes, inferior al 5%. Conclusiones En esta serie multicentrica de 378 electrodos, la supervivencia estimada a 3 anos resulto mayor que en series previas, con un perfil de presentacion clinica similar de las disfunciones. La fraccion de eyeccion ventricular izquierda y el centro implantador fueron variables asociadas a la presencia de disfuncion.

Introduction and objectives Sprint Fidelis defibrillation leads are prone to early failure. Most of the reported series come from a single institution. This paper describes the clinical experience in nine Spanish hospitals. Methods Clinical, implant, and follow-up data of all patients with a Sprint Fidelis lead were analyzed. All cases of lead failure were identified, medium-term lead survival was calculated, and possible predictors for lead failure were determined. Results In total, 378 leads in 376 patients were studied. The mean age (male 85.7%) was 64.9 ± 13.6 years. The majority of patients (59.8%) had ischemic heart disease. Mean left ventricular ejection fraction was 33.4% ± 14.5%. Left subclavian vein puncture was used in 74.8%. During a mean follow-up of 30.9 ± 14 months, 16 lead failures have occurred, with a lead survival of 96.1% at 36 months after implantation. Eleven of 16 lead failures were caused by failure of pace/sense conductors, 3 by defects in the high-voltage conductor, and 2 by defects in both types of conductors. A less depressed left ventricular ejection fraction was associated with an increased probability of lead failure (42.4% ± 16% vs. 33% ± 14.3%; P = .011). Three hospitals presented a rate of lead failure higher than 10%; the rate was less than 5% in the remaining 6 hospitals. Conclusions In this multicenter series of 378 leads, the 3-year estimated survival was higher than that reported in prior series. Clinical presentation of lead failures was similar to that reported previously. Left ventricular ejection fraction and hospital of implantation were variables associated to lead failure.

Congenital long QT syndrome is mainly caused by mutations in the KCNQ1, KCNH2 and SCN5A genes. The aim of this study was to investigate the prevalence of mutations in these three genes in patients with long QT syndrome or idiopathic ventricular fibrillation seen at our center. The study included nine patients with long QT syndrome and four with idiopathic ventricular fibrillation. The first-degree relatives of genotype-positive probands were also investigated. Missense mutations were found in seven patients with long QT syndrome and two with idiopathic ventricular fibrillation. Overall, 71.4% of mutations were in KCNH2 and 28.6% were in SCN5A. No mutations in KCNQ1 were found. Only two mutations had been previously observed. Mutations were also found in six of the 19 relatives studied. In conclusion, our initial experience shows that genetic testing had a high sensitivity for diagnosing long QT syndrome. Mutations were found most frequently in the KCNH2 gene.

ObjectiveThis study aims to evaluate the influence of myocardial scar after premature ventricular complexes (PVC) ablation in patients with left ventricular (LV) dysfunction.Methods70 consecutive patients (58±11 years, 58 (83%) men, 23% (18–32) mean PVC burden) with LV dysfunction and frequent PVCs submitted for ablation were included. A late gadolinium enhancement cardiac magnetic resonance (LGE-CMR) was performed prior to the ablation and a quantitative and qualitative analysis of the scar was done.ResultsLeft ventricular ejection fraction progressively improved from 34.3%±9% at baseline to 44.4%±12% at 12 months (pConclusionsPresence of myocardial scar modulates, but does not preclude, the probability of response to PVC ablation in patients with LV dysfunction.

Introduccion y objetivos. Conocer en la practica clinica el uso de antiarritmicos tras cardioversion electrica en pacientes sin cardiopatia y su repercusion en el mantenimiento del ritmo sinusal. Metodos. Se realizo un seguimiento a un ano de 528 pacientes con fibrilacion auricular persistente sin cardiopatia significativa tras una cardioversion electrica efectiva en 96 hospitales espanoles, con controles clinicos 1, 3, 6 y 12 meses despues. Se analizo el uso y la utilidad de los farmacos antiarritmicos en la prevencion de recurrencias de fibrilacion auricular persistente. Resultados. Se trato al alta con farmacos antiarritmicos al 80% de los pacientes, y el mas utilizado fue la amiodarona. Ningun factor clinico se relaciono con un mayor uso de antiarritmicos. El 37% de los pacientes siguio en ritmo sinusal en todos los controles. En el control a los 12 meses, se mantuvo el tratamiento antiarritmico al 59% de los pacientes que seguian en ritmo sinusal. En el analisis multivariable de la regresion de Cox, el peso (hazard ratio [HR] por cada kilo = 1,01; p = 0,04) y la ausencia de tratamiento antiarritmico (HR = 1,59; p = 0,001) fueron factores independientes relacionados con la recurrencia de fibrilacion auricular persistente. La amiodarona tendia a ser superior a los otros antiarritmicos. Conclusiones. En la practica clinica habitual, tras una cardioversion electrica efectiva, la gran mayoria de los pacientes sin cardiopatia estructural recibe farmacos antiarritmicos, especialmente amiodarona, que es el principal factor relacionado con el mantenimiento del ritmo sinusal 1 ano mas tarde.

Introduction and objectives The aim was to investigate the clinical practice of using antiarrhythmic drugs after electrical cardioversion in patients without structural heart disease and their effect on the maintenance of sinus rhythm. Methods In total, 528 patients with persistent atrial fibrillation but without significant structural heart disease who underwent successful electrical cardioversion at 96 Spanish hospitals were followed up for 1 year. Patients were assessed at 1, 3, 6, and 12 months. The use and effectiveness of antiarrhythmic drugs for preventing the recurrence of persistent atrial fibrillation was evaluated. Results Some 80% of patients were receiving antiarrhythmic drugs at discharge, most frequently amiodarone. No specific clinical factor was associated with greater use of antiarrhythmics. Overall, 37% of patients were in sinus rhythm at all follow-up assessments. At the 1-year assessment, 59% of patients who remained in sinus rhythm were still taking antiarrhythmic drugs. Multivariate Cox regression analysis identified weight (hazard ratio [HR]=1.01 per kg; P =.04) and no antiarrhythmic treatment (HR=1.59; P =.001) as being independently associated with the recurrence of persistent atrial fibrillation. Amiodarone tended to be better than other antiarrhythmic drugs. Conclusions In routine clinical practice, the large majority of patients without structural heart disease received antiarrhythmic drugs, most frequently amiodarone, after successful electrical cardioversion. Drug use was the principal factor associated with the maintenance of sinus rhythm at 1 year.

Los pacientes portadores de desfibrilador automatico implantable precisan un seguimiento ambulatorio periodico en el que se evaluen todos los parametros y se revisen los eventuales episodios arritmicos. Este seguimiento permitira modificar o no la programacion antitaquicardia y antibradicardia en funcion de las terapias liberadas por el dispositivo. Se ha establecido que una periodicidad entre 3 y 6 meses es suficiente para detectar eventos potencialmente graves. Durante el seguimiento los pacientes pueden presentar arritmias cardiacas que deberan ser tratadas con farmacos o mediante ablacion con cateter. La tolerancia clinica de las arritmias y la historia de sincope previo al implante son dos de los principales factores a la hora de restringir o no la conduccion de vehiculos. Los conductores profesionales no podran seguir ejerciendo su profesion. Los fallos de fabricacion, con consecuencias potencialmente letales, no son predecibles; el fabricante tiene la obligacion de notificar su presentacion.

Aims To describe atrial fibrillation (AF) management in member countries of the European Society of Cardiology (ESC) and to verify cardiology practices against guidelines. Methods and results Among 182 hospitals in 35 countries, 5333 ambulant and hospitalized AF patients were enrolled, in 2003 and 2004. AF was primary or secondary diagnosis, and was confirmed on ECG in the preceding 12 months. Clinical type of AF was reported to be first detected in 978, paroxysmal in 1517, persistent in 1167, and permanent in 1547 patients. Concomitant diseases were present in 90% of all patients, causing risk factors for stroke to be also highly prevalent (86%). As many as 69% of patients were symptomatic at the time of the survey; among asymptomatic patients, 54% were previously experienced symptoms. Oral anticoagulation was prescribed in 67 and 49% of eligible and ineligible patients, respectively. A rhythm control strategy was applied in 67% of currently symptomatic patients and in 44% of patients who never experienced symptoms. Conclusion This survey provides a unique snapshot of current AF management in ESC member countries. Discordance between guidelines and practice was found regarding several issues on stroke prevention and antiarrhythmic therapy.

La disfuncion ventricular izquierda ocasionada por arritmias ventriculares es una entidad poco conocida. Para contribuir a su difusion presentamos los casos de 5 pacientes en los que se pudo establecer de forma inequivoca la conexion arritmia-disfuncion ventricular. Todos tenian arritmias ventriculares monomorficas repetitivas y disfuncion ventricular izquierda (fraccion de eyeccion ≤ 40% y dimension telediastolica ≥55 mm). En el estudio electrofisiologico se detecto un foco arritmogenico intraventricular localizado en el ventriculo derecho en 2 casos, en el ventriculo izquierdo en otros 2 y en el seno de Valsalva izquierdo en el quinto; en todos fue suprimido mediante ablacion con cateter. A los 7 ± 2 meses postablacion se observo una gran mejoria de la funcion sistolica y el remodelado ventricular izquierdo (fraccion de eyeccion ≥50% y dimension telediastolica ≤51 mm en los 5 enfermos), sin recurrencia de la arritmia durante el seguimiento (10-69 meses). Estos hallazgos confirman que las arritmias ventriculares repetitivas pueden causar disfuncion ventricular, reversible tras ablacion con radiofrecuencia.

Left ventricular systolic dysfunction related to ventricular arrhythmias is a relatively poorly understood entity. To increase our knowledge base, we describe 5 patients in whom the link between ventricular dysfunction and ventricular arrhythmia was unequivocally established. All patients had repetitive monomorphic ventricular arrhythmias and left ventricular systolic dysfunction (ejection fraction ≤40% and end-diastolic size ≥55 mm). The arrhythmogenic source was identified by electrophysiological study (right ventricle in 2 patients, left ventricle in 2, and left sinus of Valsalva in one), and was eliminated in all patients by radiofrequency catheter ablation. At 7±2 months post-ablation, large improvements were seen in left ventricular function and remodeling (ejection fraction ≥50% and end-diastolic size ≤51 mm in all cases), with no recurrence of arrhythmia during followup (10-69 months). This finding confirms that recurring ventricular arrhythmias can induce left ventricular dysfunction which may be reversible after ablation.

The purpose of this study was to determine whether administration of adenosine 5'-triphosphate (ATP; 20-40 mg) after successful ablation of accessory pathway (AP) with manifest preexcitation is useful for detecting residual conduction and predicting early recurrences.The reported incidence of recurrence of AP conduction after an initially successful procedure is 5% to 10%. Little information on the variables related to early recurrence has been reported.We prospectively used 108 ATP tests on 100 consecutive patients (66 men, mean age 36 +/- 15 years) with manifest preexcitation. Five minutes after successful ablation, intravenous boluses of ATP at increasing doses were injected until the target effect of second- or third-degree AV block or AP conduction was observed.The effect of ATP was AV block (negative test) in 82 cases (76%), conduction over previously ablated AP (positive test) in 9 cases (8.3%), and no achievement of target effect (nondiagnostic test) in 17 cases (15.7%). Thirteen early recurrences were observed in 12 patients. In all 9 (100%) patients with positive ATP test and in 4 (4.9%) of the 82 patients with negative ATP test, conduction over the AP recurred (relative risk 20; 95% confidence interval 8-53; P.000001). The diagnostic accuracy of the test (analyzing the target effect) was 95%, sensitivity 69%, specificity 100%, and positive and negative predictive values 100% and 95%, respectively.ATP administration after successful ablation of APs has a high predictive value for early recurrence and may help optimize the duration of the ablation procedure.

Atrial fibrillation (AF) is the most prevalent arrhythmia in hospital emergency departments and is a serious disease associated with a twofold increase in morbidity and a high mortality rate. However, the management of AF in this scenario is variable and frequently inadequate. This is probably a consequence of the diverse clinical aspects and therapeutic options to consider in the management of patients with AF. Therefore, implementation of specific, coordinated management strategies by the different care providers involved is needed to improve the quality of care and optimize the use of human and material resources. This document presents the guidelines recommended by the Spanish Society of Cardiology (SEC) and the Spanish Society of Emergency Medicine (SEMES) for the management of AF in hospital emergency departments. These guidelines are based on published scientific evidence and are applicable to most emergency departments in Spain. Specific management strategies are proposed for the conversion and maintenance of sinus rhythm, heart rate control during AF, prophylaxis for thrombi and emboli, and hospital admission and discharge protocols.

Unexplained cardiac arrest (UCA) can be caused by low-penetrance genetic disorders. The aim of this cross-sectional study is to assess the usefulness of a new diagnostic protocol: Thirty-five patients were recruited from 9 Spanish centers. Electrocardiogram, echocardiogram, and coronary catheterization were used to rule out electrical or structural heart disease in all subjects. Patients underwent pharmacologic tests with epinephrine and flecainide, followed by assessment of family members using electrocardiogram and echocardiogram, and next-generation genetic sequencing to analyze 126 genes if all the other test results were negative. A firm diagnosis of channelopathy required phenotypic proof of the condition in unmasking tests, the presence of a pathogenic variant consistent with the phenotype observed, and/or co-segregation of the mutation found in a family member's phenotype. A firm diagnosis was made in 18 cases. The diagnoses were 7 Brugada syndrome, 5 catecholaminergic polymorphic ventricular tachycardia, 3 long QT syndrome, 2 early repolarization syndrome, and 1 short QT syndrome. Pharmacologic testing was the most frequent method of diagnosis. In 5 cases, the diagnosis was made based on positive genetic testing without phenotypic alterations. In conclusion, this sequential diagnostic protocol allows diagnoses to be made in approximately half of the UCA cases. These diagnoses are low clinical penetrance channelopathies. If interpreted carefully, genetic tests can be a useful tool for diagnosing UCA without a phenotype. (C) 2015 Elsevier Inc. All rights reserved.

Background — In patients with syncope and structural heart disease, syncope is suspected to be attributable to a primary cardiac arrhythmia, but little is known of its mechanism when electrophysiologic study is unremarkable. Methods and Results — We applied an implantable loop recorder in 35 patients with overt heart disease at risk of ventricular arrhythmia, because these were patients with previous myocardial infarction or cardiomyopathy with depressed ejection fraction or nonsustained ventricular tachycardia in whom an electrophysiologic study was unremarkable. During a follow-up of 3 to 15 months, syncope recurred in 6 patients (17%) after a mean of 6±5 months; in 3 patients, the mechanism of syncope was bradycardia with long pauses (sudden-onset AV block in 2 cases and sinus arrest in 1 case); in 1 patient, there was stable sinus tachycardia; and in 2 patients, who had chronic atrial fibrillation, there was an increase in ventricular rate. A total of 23 episodes of presyncope were documented in 8 patients (23%): no rhythm variation or mild tachycardia in 12 cases, paroxysmal atrial fibrillation or atrial tachycardia in 10 cases, and sustained ventricular tachycardia in 1 case. No patient died during the study period nor suffered from injury attributable to syncopal relapse. Conclusions — The patients with unexplained syncope, structural heart disease, and negative electrophysiologic study had a favorable medium-term outcome with no case of death and a low recurrence rate of syncope without related injury. The mechanism of syncope was heterogeneous, and ventricular tachyarrhythmia was unlikely.

Introduction and objectives. We report the results of the first Catheter Ablation Registry of the Arrhythmia Working Group of the Andalusian Society of Cardiology (AWGASC) for 2000. Methods. The register includes information about the ablation procedures performed in 2000, which was collected retrospectively and submitted voluntarily by four out of six cardiac electrophysiology laboratories of the AWGASC. A total of 424 patients (mean age 45 ± 18 years; 50% men) were included. Twelve patients underwent two different ablation procedures, bringing the total number of procedures to 436. The overall success rate (based on current criteria), success rate by procedure, in-hospital mortality, and major complications are reported. Results. The type and distribution of the ablation procedures were atrioventricular nodal re-entry tachycardia ablation, 34%; accessory pathway ablation, 39%; ventricular tachycardia ablation, 8%; atrial tachycardia ablation, 3%; atrioventricular junctional ablation, 9%, and cavo-tricuspid isthmus ablation, 9%. The overall success rate was 94% (range 97.8% to 87.4% in different laboratories), rate of major complications 1.1% (range 0% to 3.7%), and overall mortality 0.23% (1 patient). Conclusions. These findings summarize the indications and results of catheter ablation procedures performed in 2000 at four cardiac electrophysiology laboratories in Andalusia. This is the first multicenter registry in Spain.

Introduction and objectives. Little information is available on the evolution of pediatric patients with vasovagal syncope. We therefore aimed to assess the medium-term clinical outcome of children evaluated by tilt testing for syncope of unknown origin. Patients and method. Fifty-one children under 17 years of age who had undergone tilt testing were identified from a data base and studied prospectively. Kaplan-Meier and Cox regression analyses were performed to estimate syncope-free survival, its predictors, and the relative risks of several patient subgroups. Results. Forty-seven (92%) of the children were followed for a mean 21 ± 9 months. The rate of recurrence of syncope was considerably lower than that estimated during history taking before the tilt test (19% vs 47%; p < 0.01). Although the low rate made it difficult to identify predictors, several potential predictors emerged from the multivariate analysis. Only the history of more than one syncope before the tilt test (vs. isolated syncope) was found to have independent predictive value (p = 0.04). The cumulative probability of recurrence projected for a period of 38 months was 66.2% (SEM = 16.5%) for children with more than one syncope before testing vs. 0% for those who had experienced only one. No other events occurred. Conclusions. The medium-term prognosis seems to be good for children with vasovagal syncope of unknown origin, given the low rate of recurrence, regardless of the results of tilt testing. The only predictor of recurrent syncope was pretest history, such that children with only one syncope before testing experience no recurrence and those with one or more episodes are estimated to have an increasingly higher likelihood of recurrence. These data may be useful for the recommending tilt testing and for planning therapy for children with vasovagal syncope.

Empiric circumferential pulmonary vein isolation (CPVI) has become the therapy of choice for drug-refractory atrial fibrillation (AF). Although results are suboptimal, it is unknown whether mechanistically-based strategies targeting AF drivers are superior.This study sought to determine the efficacy and safety of localized high-frequency source ablation (HFSA) compared with CPVI in patients with drug-refractory AF.This prospective, multicenter, single-blinded study of 232 patients (age 53 ± 10 years, 186 males) randomized those with paroxysmal AF (n = 115) to CPVI or HFSA-only (noninferiority design) and those with persistent AF (n = 117) to CPVI or a combined ablation approach (CPVI + HFSA, superiority design). The primary endpoint was freedom from AF at 6 months post-first ablation procedure. Secondary endpoints included freedom from atrial tachyarrhythmias (AT) at 6 and 12 months, periprocedural complications, overall adverse events, and quality of life.In paroxysmal AF, HFSA failed to achieve noninferiority at 6 months after a single procedure but, after redo procedures, was noninferior to CPVI at 12 months for freedom from AF and AF/AT. Serious adverse events were significantly reduced in the HFSA group versus CPVI patients (p = 0.02). In persistent AF, there were no significant differences between treatment groups for primary and secondary endpoints, but CPVI + HFSA trended toward more serious adverse events.In paroxysmal AF, HFSA failed to achieve noninferiority at 6 months but was noninferior to CPVI at 1 year in achieving freedom of AF/AT and a lower incidence of severe adverse events. In persistent AF, CPVI + HFSA offered no incremental value. (Radiofrequency Ablation of Drivers of Atrial Fibrillation [RADAR-AF]; NCT00674401).

Study objectives: To evaluate the benefit of sinus rhythm (SR) restoration in patients with chronic controlled atrial fibrillation (AF) and left ventricular systolic dysfunction (LVSD). Design: Prospective case-control study on the short-term outcome (6 to 9 months) of clinical and echocardiographic variables following attempted cardioversion. Setting: Outpatient clinic of a university hospital. Patients: Fifteen men and 5 women, ranging in age from 40 to 76 years, who had chronic controlled (mean [6 SD] ventricular rate, 82 6 10 beats/min) AF and left ventricular fractional shortening (LVFS) of < 28% at baseline. Control was provided by retrospective paired echocardiographic examinations of six AF patients, plus the study cases with potentially unsuccessful cardioversion or early recurrence of AF. Interventions: Attempt to restore SR with amiodarone or electrical countershock. Measurements and results: Conversion was attained in 17 patients, but AF recurred early in 4 patients, 3 of whom had proven ischemic LVSD. In the 13 patients with sustained SR, LVFS increased from 20 6 4% to 31 6 6% (p < 0.0001). In contrast, no changes were detected in the control group (n 5 13). This improvement was paralleled by decreases in left ventricular (LV) end-diastolic dimension (from 55 6 7t o 516 6 mm; p 5 0.014), LV mass (from 181 6 28 to 159 6 37 g; p 5 0.015), and left atrial diameter (from 45 6 9m m to 426 7; p 5 0.003). A marked decrease in heart rate (from 82 6 9t o 646 5 beats/min; p < 0.0001) and a reduction in New York Heart Association functional class (from 2.3 6 0.9 to 1.2 6 0.4; p 5 0.0007) also were observed in patients with sustained SR but not among subjects in the control group. Conclusions: Even when adequate control of the ventricular rate has been achieved, the LV function of patients with chronic AF greatly improves after restoration and maintenance of SR. (CHEST 2001; 120:132‐138) dysfunction Abbreviations: ACE 5 angiotensin-converting enzyme; AF 5 atrial fibrillation; LA 5 left atrium; LV 5 left ventricle, ventricular; LVEDD 5 left ventricular end-diastolic dimension; LVFS 5 left ventricular fractional shortening; LVM 5 left ventricular mass; LVS 5 left ventricular systolic; LVSD 5 left ventricular systolic dysfunction; SR 5 sinus rhythm

La evolucion, tanto cualitativa como cuantitativa, experimentada por la electrofisiologia en los ultimos anos ha llevado a la necesidad de crear unidades especificas dedicadas al manejo de los pacientes con arritmias cardiacas. En estas guias se consideran las necesidades materiales y humanas minimas con las que debe contar una unidad de arritmias.

El traumatismo mecanico de las vias accesorias es un fenomeno infrecuente que habitualmente es producido con el cateter de ablacion y resulta en un bloqueo de la conduccion de caracter casi siempre transitorio. Presentamos el caso clinico de un paciente afectado de sindrome de Wolff-Parkinson-White por via accesoria medioseptal, con crisis de taquicardia frecuentes no controladas con medicacion, lo que motivo la realizacion de estudio electrofisiologico. Durante el estudio previo a la ablacion, coincidiendo con la manipulacion del cateter de His (tetrapolar de 5 French), se produjo un traumatismo mecanico de la via accesoria, no recuperando la conduccion durante el seguimiento a medio plazo (28 meses). Este caso excepcional abunda en la complejidad de la toma de decisiones cuando de forma inadvertida se produce el traumatismo de una via accesoria.

Introduccion y objetivos. Se sabe poco acerca de las diferencias entre ninos y adultos en lo que respecta a los resultados del test de basculacion. El objetivo de este estudio es investigar las posibles diferencias en cuanto a: a) el perfil clinico y las circunstancias del sincope espontaneo; b) el rendimiento global del test, y c) el tipo de respuesta positiva obtenida. Material y metodos. Hemos estudiado a 31 ninos y 123 adultos con sincope de origen desconocido. Cuando el test basal (basculacion a 70o durante 30 min) resulto negativo, se repitio bajo perfusion de isoprenalina a dosis bajas. Resultados. No se encontraron diferencias ni en el perfil clinico, excepto en lo que respecta a la ocurrencia de traumatismo severo mas comun en los adultos (el 25% frente al 3% en los ninos; p Conclusiones. En nuestra serie, y con el protocolo de mesa basculante empleado, los ninos, a diferencia de los adultos, raramente presentan un resultado positivo en la basculacion bajo infusion de isoprenalina, siendo su tasa de respuestas cardioinhibidoras, por otra parte, mucho mayor que la de los adultos.

Aims To evaluate the efficacy and safety of a single loading oral dose of propafenone in the interruption of recent-onset atrial fibrillation. Methods After a complete medical history, physical examination, 12-lead ECG, chest X-ray, and routine biochemical laboratory testing, 55 consecutive patients with recent-onset atrial fibrillation were randomized double-blind in the emergency department for the administration of either a single oral dose (450 to 750 mg) of propafenone (29 cases) or a placebo (26 cases). After the 24-h observation period, comprehensive echocardiographic examination was performed. Results The groups were homogeneous as regards biological, clinical and echocardiographic characteristics. Two hours after treatment, 12 patients (41%) on propafenone but only two (8%) on placebo had converted to sinus rhythm ( P =0·005). This striking difference was maintained 6 h after treatment (65 vs 31%; P =0·015) but lessened at 12 h (69% vs 42%; P =0·060) and was insignificant at the end of the 24-h treatment period (79% vs 73%; P =0·752). Apart from hypotension, transient in three cases and sustained in one whose later echocardiographic examination demonstrated left systolic ventricular dysfunction, propafenone was well tolerated. Conclusions Although there is no significant difference in the rates of conversion 24 h after treatment, propafenone works faster than placebo in achieving sinus rhythm. This rapid action of oral propafenone can be useful to solve quickly the clinical problems of a high proportion of patients arriving at the emergency department with acute atrial fibrillation.

Introduccion y objetivos La utilidad de la evaluacionangiografica rutinaria de la arteria mamariaesta discutida. Este estudio pretende revaluarel problema mediante un somero analisis coste/beneficio. Metodos Fueron estudiados 121 pacientes consecutivos,receptores potenciales de un injerto de arteriamamaria interna izquierda por tener una estenosissignificativa del tronco comun izquierdo y/ode la arteria descendente anterior. El sondaje de laarteria se intento con el mismo cateter Judkins derechoutilizado en la coronariografia, empleandosesolo un cateter especifico en caso de fracaso. Semidio el tiempo transcurrido hasta la consecucionde una angiografia adecuada y se estudio la anatomiay calibre de la mamaria, comparando este ultimocon el de la arteria descendente anterior. Resultados Se consiguio una optima contrastacionde la mamaria en 119 casos (98,3%), teniendoque utilizarse un cateter especifico en solo 3 casos.El tiempo medio de consecucion fue de 170 s (rango8-900 s) y no se detecto ninguna complicacioninherente al procedimiento. Se encontraron hallazgosde potencial interes quirurgico en 15 casos(12%): ramas toracicas precoces de calibre significativo(10), oclusion, estenosis o calibre insuficientede la mamaria (3), oclusion o estenosis proximalde la arteria subclavia (2). Conclusiones La relacion entre el coste del procedimientoy la informacion obtenida en el mismocreemos que es favorable para aconsejar su realizacion,puesto que los hallazgos de potencial interes,aunque poco frecuentes, pueden ser importantes ala hora de establecer la estrategia quirurgica. Ademas,se consigue en un tiempo excepcionalmentecorto y sin coste adicional.

Introduccion y objetivos Con la senal de Dopplercontinuo de la curva de regurgitacion mitral sepuede obtener un indice, ΔP/Δt, que correlacionaestrechamente con la dP/dt. Este estudio evalua lafactibilidad del calculo, reproducibilidad y relaciondel indice con la fraccion de eyeccion y diversos parametrosecocardiograficos convencionales. Material y metodos Se estudiaron 110 pacientescon insuficiencia mitral dignosticada por Dopplercolor. El ΔP/Δt se obtuvo dividiendo la diferenciade presion entre dos puntos conocidos de la curvade insuficiencia mitral por Doppler continuo (–1 y–3 m/s, es decir, 32 mmHg segun el teorema simplificadode Bernouilli) por el intervalo de tiempo (s)que los separaba. La fraccion de eyeccion fue determinadaen 70 pacientes por metodos no ecocardiograficos(ventriculografia isotopica en 52 y radiologicade contraste en 18). En 49 de ellos sehallo tambien la fraccion de eyeccion medianteecocardiografia. Resultados Fue factible la medicion en 91 casosy se encontro una variabilidad intra e interobservadordel 5 y del 7%, respectivamente. La correlacionentre el ΔP/Δt y la fraccion de eyeccion fue significativapero debil (r = 0,59; p Conclusiones Elevada factibilidad cuando existeregurgitacion mitral, adecuada reproducibilidad yalta precision para identificar la disfuncion sistolicadel ventriculo izquierdo, son caracteristicas quehacen util al ΔP/Δt en la practica diagnostica ecocardiografica.

Electroanatomical mapping systems have reduced the amount of fluoroscopy required to ablate the cavotricuspid isthmus. The aims of this study are to evaluate the feasibility and safety of a zero-fluoroscopy approach to cavotricuspid isthmus catheter ablation using the Carto®3 system (Biosense Webster, Diamond Bar, CA, USA) and to compare the results of this approach with those of the zero-fluoroscopy approach using the Ensite-NavX™ system (St. Jude Medical, St. Paul, MN, USA).Twenty consecutive procedures guided by the Carto®3 system (Group A) were compared with two case-control groups matched from 146 procedures guided with the Ensite-NavX™ system. Group B consisted of 20 matched procedures from the first 50 procedures performed in the electrophysiology unit, and Group C consisted of 20 matched procedures from the last 50 procedures. Acute success (bidirectional block), complications, and recurrences were analyzed. The procedure times were also compared.There were no differences in the rates of acute success (95%, 100%, and 100%, respectively), complications (0%, 5%, and 0%), and recurrences (5.2%, 0%, and 5%) in the three groups. A zero-fluoroscopy approach was attempted in all procedures, and electroanatomical mapping made it possible to successfully avoid fluoroscopy in 90% of the procedures in Group A, 85% in B, and 95% in C. The total procedure time was shorter in Group C. The fluoroscopy and radiofrequency times were not different.A zero-fluoroscopy approach to cavotricuspid isthmus catheter ablation using the Carto®3 system is feasible in most procedures. This approach has similar results to the zero-fluoroscopy approach using the Ensite-NavX™ system.

Journal Article; INTRODUCTION We functionally analyzed a frameshift mutation in the SCN5A gene encoding cardiac Na(+) channels (Nav1.5) found in a proband with repeated episodes of ventricular fibrillation who presented bradycardia and paroxysmal atrial fibrillation. Seven relatives also carry the mutation and showed a Brugada syndrome with an incomplete and variable expression. The mutation (p.D1816VfsX7) resulted in a severe truncation (201 residues) of the Nav1.5 C-terminus. METHODS AND RESULTS Wild-type (WT) and mutated Nav1.5 channels together with hNavβ1 were expressed in CHO cells and currents were recorded at room temperature using the whole-cell patch-clamp. Expression of p.D1816VfsX7 alone resulted in a marked reduction (≈90%) in peak Na(+) current density compared with WT channels. Peak current density generated by p.D1816VfsX7+WT was ≈50% of that generated by WT channels. p.D1816VfsX7 positively shifted activation and inactivation curves, leading to a significant reduction of the window current. The mutation accelerated current activation and reactivation kinetics and increased the fraction of channels developing slow inactivation with prolonged depolarizations. However, late INa was not modified by the mutation. p.D1816VfsX7 produced a marked reduction of channel trafficking toward the membrane that was not restored by decreasing incubation temperature during cell culture or by incubation with 300 μM mexiletine and 5 mM 4-phenylbutirate. CONCLUSION Despite a severe truncation of the C-terminus, the resulting mutated channels generate currents, albeit with reduced amplitude and altered biophysical properties, confirming the key role of the C-terminal domain in the expression and function of the cardiac Na(+) channel. Yes

In the present review 6 lines of evidence will be discussed that suggest a prognostic significance for ventricular arrhythmias in patients with systemic hypertension and left ventricular hypertrophy: (1) in patients with systemic hypertension there is a statistical relation between asymptomatic ventricular arrhythmias and left ventricular hypertrophy; (2) in nonhypertensive left ventricular hypertrophy the prognostic value of ventricular arrhythmias is well known; (3) left ventricular hypertrophy is related to sudden death in patients with systemic hypertension; (4) it is generally acknowledged that ventricular arrhythmias are a frequent cause of sudden death; (5) there is experimental evidence to support the arrhythmic risk of left ventricular hypertrophy; and (6) it has been recently demonstrated that ventricular arrhythmias influence mortality in patients with left ventricular hypertrophy secondary to systemic hypertension. However, whether asymptomatic ventricular arrhythmias are specific markers for more severe sustained arrhythmias, or just markers for a more severe stage of the disease, remains to be determined.

First-line endoepicardial ventricular tachycardia (VT) ablation has been proposed for patients with arrhythmogenic cardiomyopathy (AC). This study reports procedural safety, outcomes, and predictors of recurrence.Forty-one consecutive patients [12 with left ventricle (LV) involvement, 7 left-dominant] underwent first-line endoepicardial VT substrate ablation. Standard bipolar and unipolar thresholds were used to define low-voltage areas (LVA). Arrhythmogenic substrate area (ASA) was defined as the area containing electrograms with delayed components. Implantable cardioverter defibrillator interrogations were evaluated for VT recurrence. Epicardial LVA was larger in all cases (102.5 ± 78.6 vs. 19.3 ± 24.4 cm2; P0.001). Consistent with an epicardium-to-endocardium arrhythmogenic substrate progression pattern, epicardial ASA (epi-ASA) was negatively correlated with bipolar endocardial LVA (r = -0.368; P= 0.035) and with endocardial bipolar/unipolar-LVA (Bi/Uni-LVA) ratio (r= -0.38; P= 0.037). A Bi/Uni-LVA ratio0.23 predicted an epi-ASA ≤10 cm2 (100% sensitivity, 84% specificity). Patients showing an epi-ASA10 cm2 required less epicardial (8.4 ± 5.8 vs. 25.3 ± 16; P= 0.045) and more endocardial (16.5 ± 8.6 vs. 7.5 ± 8.2; P= 0.047) radiofrequency applications. One patient with epi-ASA10 cm2 died of cardiac tamponade after epicardial puncture. Acute success (no VT inducibility after procedure) was achieved in 36 patients (90%). After 32.2 ± 21.8 months, 11 (26.8%) patients had VT recurrences. Left-dominant AC was associated with an increased risk of recurrence (HR = 3.41 [1.1-11.2], P= 0.044; log-rank P= 0.021).First-line endoepicardial VT substrate ablation achieves good long-term results in AC. Left-dominant AC is associated with an increased risk of recurrence. The Bi/Uni-LVA ratio identifies patients with limited epicardial arrhythmogenic substrate in whom the indication of epicardial approach should be more cautiously assessed.

We studied by means of probability analysis the role of exercise ECG in identifying coronary restenosis. A total of 213 patients were independently evaluated by clinical history, conventional assessment of the exercise ECG ('yes or no' statement), D score (a discriminant function derived from exercise ECG), and coronariography, 5.4 +/- 2.8 months after successful coronary angioplasty. The initial probability of restenosis (30%), that is, the prevalence of the condition, was radically changed by the result of clinical history (77% for patients with angina vs. 17% for those without angina). By contrast, ECG binary assessment, due to its low accuracy (70% vs 82% of clinical history, P0.005), was unable to significantly change the established probabilities after symptomatic evaluation. Finally, D score, which greatly enhanced specificity (92% vs. 76% of bivariate assessment, P0.0001), proved to be useful in changing the probability (from 32% to 76% or to 25%) of patients (n = 34) with a discordant result (no angina/positive exercise ECG). When this stepwise approach was tested in 46 new patients, predicted and observed probabilities were actually very similar. We conclude that exercise ECG has a very limited role in identifying coronary restenosis if positive responses are not adjusted with a weighted score which takes into account other exercise derived factors.

Introduction and objectives Cardiac channelopathies are genetic alterations that can cause sudden death. Long QT syndrome and Brugada syndrome are 2 such conditions. Both are diagnosed according to previously published criteria. Our objective was to determine the sensitivity of these criteria in a consecutive series of patients carrying the mutations that cause them. Methods We enrolled 15 families and 31 causal mutation carriers with a high pathogenic probability of having long QT syndrome and Brugada syndrome. We conducted clinical and electrocardiographic studies to analyze the extent to which these patients fulfilled the diagnostic criteria. Statistical analysis was with SPSS 17.0. Results Some 48.3% of the subjects met the criteria indicating a high probability of long QT syndrome or Brugada syndrome. Among those with the mutation for long QT syndrome, only 10 out of 21 had a Schwartz index score≥4. Both the median Schwartz score and the cQT interval were lower in relatives than in probands. Of those with the mutation for Brugada syndrome, 60% failed to meet current diagnostic criteria, which were more frequently fulfilled in relatives. Pharmacological tests with epinephrine and flecainide helped establish the diagnosis in 2 mutation carriers with negative phenotype. Conclusions Current diagnostic criteria for long QT syndrome and Brugada syndrome had low sensitivity in our sample of genetic carriers. Genetic tests supported by pharmacological tests can increase diagnostic sensitivity, especially in asymptomatic relatives.

Cavotricuspid Isthmus Ablation Without Fluoroscopy. Introduction and Objectives: The use of intracardiac navigation systems has enabled a significant reduction of the radiation dose in the majority of ablation procedures. The purpose of this study is to evaluate the feasibility and safety of cavotricuspid isthmus ablation without the use of fluoroscopy as a first-line treatment. Methods and Results: An observational study without a control group in patients referred for treatment of common atrial flutter. In all of the procedures, Ensite-NavX™ was the only guidance system used to visualize the catheters. One or two diagnostic catheters and a cooled-tip ablation catheter were used in each procedure. Bidirectional cavotricuspid isthmus block was considered to indicate a successful procedure. Eighty-three ablation procedures were performed in 80 patients (82.5% men, 61 ± 10 years of age). The procedure was repeated in 3 patients (3.75%) due to flutter recurrence. Success was obtained in 98.8% of the procedures; in 1 patient it was necessary to implant a pacemaker for sinus node dysfunction and 4 patients experienced minor complications. In 75 procedures (90.4%), fluoroscopy was not required. Visualization of the diagnostic catheters was the most common reason for using fluoroscopy. The time required to perform the ablation procedure was similar to that published in other series. Conclusions: Cavotricuspid isthmus ablation using a nonfluoroscopic thre-dimensional (3D) navigation system is effective and safe. (J Cardiovasc Electrophysiol, Vol. 22, pp. 656-662, June 2011)

Congenital long QT syndrome is mainly caused by mutations in the KCNQ1, KCNH2 and SCN5A genes. The aim of this study was to investigate the prevalence of mutations in these three genes in patients with long QT syndrome or idiopathic ventricular fibrillation seen at our center. The study included nine patients with long QT syndrome and four with idiopathic ventricular fibrillation. The first-degree relatives of genotype-positive probands were also investigated. Missense mutations were found in seven patients with long QT syndrome and two with idiopathic ventricular fibrillation. Overall, 71.4% of mutations were in KCNH2 and 28.6% were in SCN5A. No mutations were found in KCNQ1. Only two mutations had been previously observed. Mutations were also found in six of the 19 relatives studied. In conclusion, our initial experience shows that genetic testing had a high sensitivity for diagnosing long QT syndrome. Mutations were found most frequently in the KCNH2 gene.