Alteraciones electrocardiográficas periictales en pacientes pediátricos con epilepsia. Un estudio prospectivo / Peri-ictal electrocardiographic alterations in paediatric epilepsy patients. A prospective study

INTRODUCCIÓN: Las crisis epilépticas pueden asociarse a alteraciones del ritmo cardíaco periictales e incluso a muerte súbita (SUDEP). Existen escasos estudios pediátricos al respecto. OBJETIVO: Determinar las alteraciones del ritmo cardíaco en pacientes pediátricos con epilepsia estudiados con videoelectroencefalograma (video-EEG). MÉTODOS: Estudio prospectivo, observacional, en pacientes menores de 18 años ingresados para video-EEG en el Hospital Clínico Red de Salud UC-Christus, Santiago, Chile. Se realizó una evaluación neurológica y cardiológica, electrocardiograma (ECG) y Holter ECG simultáneo al video-EEG. RESULTADOS: Se estudió a 25 pacientes, 12 con epilepsias refractarias, 23/25 focales y 20 en tratamiento con politerapia. Se registraron 768 horas de video-EEG, incluyendo 281 crisis epilépticas en 15 pacientes: 157 clínicas y 103 generalizadas. No hubo arritmias graves; sólo alteraciones inespecíficas o probablemente benignas, principalmente bloqueo incompleto de la rama derecha en 11 pacientes, más frecuente en las epilepsias refractarias (p < 0,036). La variación de la frecuencia cardíaca ocurrió principalmente en crisis > 30 segundos. Ningún paciente ha presentado SUDEP. CONCLUSIONES: Éste es el primer estudio prospectivo, con una nueva técnica, usando simultáneamente video-EEG y Holter ECG en pediatría. Pese al alto número de crisis y pacientes refractarios, no encontramos alteraciones graves del ritmo cardíaco, en concordancia con la evaluación clínica. El bloqueo de la rama derecha se considera un hallazgo cardiológico no patológico, pero tuvo una alta prevalencia en nuestra muestra, comparada con la población normal, especialmente en la epilepsia refractaria. Dado que la SUDEP es un evento grave en la epilepsia, es importante ahondar más en este tipo de estudios para evaluar medidas preventivas

INTRODUCTION: Epileptic seizures can be associated with peri-ictal heart rhythm disorders and even sudden death (SUDEP). Few paediatric studies have been conducted on the subject. AIM: To determine heart rhythm disorders in paediatric patients with epilepsy who were studied with video-electroencephalogram (video-EEG). METHODS: Prospective, observational study in patients under 18 years of age admitted for video-EEG at the Hospital Clínico Red de Salud UC-Christus, Santiago, Chile. A neurological and cardiological evaluation and electrocardiogram (ECG) were performed, in addition to a Holter ECG simultaneously with the video-EEG. RESULTS: Twenty-five patients were studied, 12 with refractory epilepsies, 23/25 focal and 20 on polytherapy. Altogether 768 hours of video-EEG were recorded, including 281 seizures in 15 patients: 157 clinical and 103 generalised. There were no serious arrhythmias, only non-specific or probably benign disorders, mainly incomplete right bundle branch block in 11 patients, which were more frequent in refractory epilepsies (p < 0.036). Heart rate variation occurred mainly in seizures >30 seconds. No patient presented SUDEP. CONCLUSIONS: This is the first prospective study, with a new technique, using video-EEG and Holter ECG simultaneously in paediatrics. Despite the high number of seizures and refractory patients, we found no serious heart rhythm disorders, consistent with the clinical evaluation. Right bundle branch block is considered a non-pathological cardiological finding, but was highly prevalent in our sample compared to the normal population, especially in refractory epilepsy. Given that this is a serious event in epilepsy, it is important to further investigate such studies to assess preventive measures

Síndrome de hipoplasia de corazón izquierdo: experiencia de 10 años de un programa de etapificación quirúrgica / Hypoplastic left heart syndrome: 10 year experience with staged surgical management

Resumen El síndrome de hipoplasia de corazón izquierdo (SHCI) es una cardiopatía congénita con letalidad superior al 95%. La etapificación quirúrgica es la principal vía de tratamiento, y se inicia con la operación de Norwood; la sobrevida a largo plazo de los pacientes tratados es desconocida en nuestro medio. Objetivos 1) Revisar nuestra experiencia en el manejo de todos los pacientes con SHCI evaluados entre enero 2000 y junio 2010. 2) Identificar factores de riesgo de mortalidad quirúrgica. Pacientes y método Estudio retrospectivo de una única institución con una cohorte de pacientes con SHCI. Se revisan antecedentes clínicos, quirúrgicos, y registros de seguimiento. Resultados Se evaluaron 76 pacientes con SHCI; 9/76 tenían comunicación interauricular (CIA) restrictiva, y 8/76, aorta ascendente de < 2 mm; 65/76 fueron tratados: 77% tuvieron operación de Norwood con conducto entre ventrículo derecho y ramas pulmonares como fuente de flujo pulmonar, 17% Norwood con shunt de Blalock-Taussig, y 6% otra cirugía. La mortalidad en la primera etapa quirúrgica fue del 23%, y en operación de Norwood, del 21,3%. En el período 2000-2005 la mortalidad en la primera etapa quirúrgica fue del 36%, y entre 2005-2010, del 15% (p = 0,05). La sobrevida global fue del 64% a un año y del 57% a 5 años. Por análisis multivariado fueron factores de riesgo para mortalidad la presencia de aorta ascendente diminuta y CIA restrictiva. Conclusiones Nuestros resultados inmediatos y a largo plazo en la etapificación quirúrgica de SHCI son similares a la experiencia de grandes centros. Hay una mejoría en mortalidad operatoria en la segunda mitad de la serie. Se identifican factores de riesgo de mortalidad.

Abstract Hypoplastic left heart syndrome (HLHS) is a lethal congenital heart disease in 95% of non-treated patients. Surgical staging is the main form of treatment, consisting of a 3-stage approach, beginning with the Norwood operation. Long term survival of treated patients is unknown in our country. Objectives 1) To review our experience in the management of all patients seen with HLHS between January 2000 and June 2012. 2) Identify risk factors for mortality. Patients and method Retrospective analysis of a single institution experience with a cohort of patients with HLHS. Clinical, surgical, and follow-up records were reviewed. Results Of the 76 patients with HLHS, 9 had a restrictive atrial septal defect (ASD), and 8 had an ascending aorta ≤ 2 mm. Of the 65 out of 76 patients that were treated, 77% had a Norwood operation with pulmonary blood flow supplied by a right ventricle to pulmonary artery conduit, 17% had a Norwood with a Blalock-Taussig shunt, and 6% other surgical procedure. Surgical mortality at the first stage was 23%, and for Norwood operation 21.3%. For the period between 2000-2005, surgical mortality at the first stage was 36%, and between 2005-2010, 15% (P = .05). Actuarial survival was 64% at one year, and 57% at 5 years. Using a multivariate analysis, a restrictive ASD and a diminutive aorta were high risk factors for mortality. Conclusions Our immediate and long term outcome for staged surgical management of HLHS is similar to that reported by large centres. There is an improvement in surgical mortality in the second half of our experience. Risk factors for mortality are also identified.

Well-Being and Agency in Parents of Children With Congenital Heart Disease: A Survey in Chile.

BACKGROUND: Parents of children having congenital heart diseases (CHDs) develop symptoms of depression, distress, anxiety, and hopelessness more frequently than parents of healthy children. Associated with the described symptoms, parents may experience a lack of control and disempowerment, which decreases the parent's agency, a construct from development studies, and which may have negative consequences on adherence to treatment. The primary aim of this study was to assess the effect of medical treatment on well-being and agency in parents of children having CHDs, in Chile, and to compare it with reference values. METHODS: Forty parents of children having CHDs (before surgery and before hospital discharge) and 115 parents of healthy children were surveyed. The following scales were applied to this population: the General Health Questionnaire, the Basic Psychological Needs Scales, the Self-Determination Scale, the Beck Hopelessness Scale, and a socioeconomic survey. RESULTS: Children's surgery decreased parents' hopelessness (3.13 ± 0.35 and 2.18 ± 0.40, P = .04), and no significant differences were found in the remaining scales. Parents of children with CHDs scored significantly worse than parents of healthy children on the General Health Questionnaire (13.82 ± 1.03 and 9.21 ± 0.64, P = .001). This difference was not found using the others scales. CONCLUSION: Children's surgery has a positive effect on parent's hopelessness, but it does not have any impact on their well-being nor agency. Parents of children with CHD have a decreased well-being compared to parents of healthy children but have a similar level of agency. Socioeconomic level and gender may influence this association.

[Hypoplastic left heart syndrome: 10 year experience with staged surgical management]. / Síndrome de hipoplasia de corazón izquierdo: experiencia de 10 años de un programa de etapificación quirúrgica.

UNLABELLED: Hypoplastic left heart syndrome (HLHS) is a lethal congenital heart disease in 95% of non-treated patients. Surgical staging is the main form of treatment, consisting of a 3-stage approach, beginning with the Norwood operation. Long term survival of treated patients is unknown in our country. OBJECTIVES: 1) To review our experience in the management of all patients seen with HLHS between January 2000 and June 2012. 2) Identify risk factors for mortality. PATIENTS AND METHOD: Retrospective analysis of a single institution experience with a cohort of patients with HLHS. Clinical, surgical, and follow-up records were reviewed. RESULTS: Of the 76 patients with HLHS, 9 had a restrictive atrial septal defect (ASD), and 8 had an ascending aorta ≤2mm. Of the 65 out of 76 patients that were treated, 77% had a Norwood operation with pulmonary blood flow supplied by a right ventricle to pulmonary artery conduit, 17% had a Norwood with a Blalock-Taussig shunt, and 6% other surgical procedure. Surgical mortality at the first stage was 23%, and for Norwood operation 21.3%. For the period between 2000-2005, surgical mortality at the first stage was 36%, and between 2005-2010, 15% (P=.05). Actuarial survival was 64% at one year, and 57% at 5years. Using a multivariate analysis, a restrictive ASD and a diminutive aorta were high risk factors for mortality. CONCLUSIONS: Our immediate and long term outcome for staged surgical management of HLHS is similar to that reported by large centres. There is an improvement in surgical mortality in the second half of our experience. Risk factors for mortality are also identified.

Tormenta eléctrica en síndrome de Brugada tratada exitosamente con infusión de isoproterenol / Electrical storm in Brugada syndrome successfully treated with isoproterenol. Report of a case

We report a 22-year-old male who experienced several episodes of syncope within a timeframe of few hours. In the emergency room, multiple ventricular fibrillation episodes where documented along with a type 1 Brugada ECG pattern. Isoproterenol in continuous infusion was started, normalizing the ECG and avoiding further arrhythmia recurrences. The patient was implanted with an automated defibrillator and discharged 3 days after admission.

Terapia de resincronización en pacientes con insuficiencia cardiaca: experiencia acumulada de 10 años / Cardiac resynchronization therapy in patients with heart failure: A 10-year experience

Background: Multiple randomized trials support the clinical benefits of cardiac resynchronization therapy (CRT) in patients with heart failure (HF) and ventricular dyssynchrony. Since the year 2000 this therapy has been increasingly used in Chile. Aim: To describe the clinical characteristics and follow-up of HF patients undergoing CRT in a single Chilean university hospital during the last 10 years. Patients and Methods: All patients undergoing CRT between 2000 and 2010 in our university hospital were included. Clinical and echocardiographic data were extracted from medical records and mortality causes were obtained from the National Identification Service. Results: A total of 252 patients underwent CRT during the study period. Seventy five percent were in New York Heart Associatin (NYHA) functional class III and mean ejection fraction was 29 ± 10%. Complete left bundle branch block was present in 55% and 20% had permanent atrial fibrillation (AF). Mean survival was 86% at 1 year and 82% of patients in NYHA class III-IV improved at least one functional class. Survival was poorer in patients with ischemic etiology (hazard ratio (HR) 1.48), functional class IV (HR 2.2), right bundle branch block (RBBB) (HR 3.1) and AF (HR 3.4). No survival differences were observed between patients with and without an implanted cardiodefibrillator. Conclusions: This series show good clinical outcomes, comparable to those reported in randomized trials. Predictors of worse survival included an ischemic etiology, functional class IV, RBBB and AF. Patients with a defibrillator had no better survival, which could be relevant in countries with limited health care resources.

[Electrical storm in Brugada syndrome successfully treated with isoproterenol. Report of a case]. / Tormenta eléctrica en síndrome de Brugada tratada exitosamente con infusión de isoproterenol.

We report a 22-year-old male who experienced several episodes of syncope within a timeframe of few hours. In the emergency room, multiple ventricular fibrillation episodes where documented along with a type 1 Brugada ECG pattern. Isoproterenol in continuous infusion was started, normalizing the ECG and avoiding further arrhythmia recurrences. The patient was implanted with an automated defibrillator and discharged 3 days after admission.

[Cardiac resynchronization therapy in patients with heart failure: a 10-year experience]. / Terapia de resincronización en pacientes con insuficiencia cardiaca: experiencia acumulada de 10 años.

BACKGROUND: Multiple randomized trials support the clinical benefits of cardiac resynchronization therapy (CRT) in patients with heart failure (HF) and ventricular dyssynchrony. Since the year 2000 this therapy has been increasingly used in Chile. AIM: To describe the clinical characteristics and follow-up of HF patients undergoing CRT in a single Chilean university hospital during the last 10 years. PATIENTS AND METHODS: All patients undergoing CRT between 2000 and 2010 in our university hospital were included. Clinical and echocardiographic data were extracted from medical records and mortality causes were obtained from the National Identification Service. RESULTS: A total of 252 patients underwent CRT during the study period. Seventy five percent were in New York Heart Associatin (NYHA) functional class III and mean ejection fraction was 29 ± 10%. Complete left bundle branch block was present in 55% and 20% had permanent atrial fibrillation (AF). Mean survival was 86% at 1 year and 82% of patients in NYHA class III-IV improved at least one functional class. Survival was poorer in patients with ischemic etiology (hazard ratio (HR) 1.48), functional class IV (HR 2.2), right bundle branch block (RBBB) (HR 3.1) and AF (HR 3.4). No survival differences were observed between patients with and without an implanted cardiodefibrillator. CONCLUSIONS: This series show good clinical outcomes, comparable to those reported in randomized trials. Predictors of worse survival included an ischemic etiology, functional class IV, RBBB and AF. Patients with a defibrillator had no better survival, which could be relevant in countries with limited health care resources.

Resultados inmediatos y alejados del switch arterial en pacientes condextrotransposición de grandes arterias: experiencia de 20 años / Early and late results of the switch operation for d-transposition of the great vessels. clinical experience in 108 patients operated on between 1992 and 2012

Objetivos: Comunicar los resultados de la operación de switch arterial en pacientes portadores de dextro Transposición de Grandes Arterias (D-TGA) y evaluar su evolución en el tiempo. Pacientes y Método: Estudio retrospectivo de pacientes sometidos a switch arterial entre mayo de 1992 y noviembre de 2012. Se comparó período 1 (1992 a 2002) con período 2 (2003 a 2012). Se definió D-TGA simple aquella sin lesiones asociadas y D-TGA compleja aquella con asociación de comunicación interventricular o coartación aórtica. Resultados: Un total de 108 pacientes componen la serie, 44 en el período 1 y 64 en el período 2, sin diferencias demográficas y anatómicas entre ambos períodos. Setenta tenían D-TGA simple y 38 D-TGA compleja. La mortalidad operatoria en el período 1 fue 33% versus 8,4 por ciento en el período 2 (p< 0.025); hubo tendencia a mayor mortalidad en pacientes con anatomía coronaria compleja. Se observó una disminución del riesgo relativo de mortalidad de 68,7 por ciento en el período 2. El 28,7 por ciento presentaron complicaciones postoperatorias, sin diferencias entre ambos períodos. Un paciente falleció en forma alejada. La mediana de seguimiento fue de 60 meses y la supervivencia de 84,25 por ciento a 10 y 20 años. Se realizaron 16 re intervenciones, principalmente plastías percutáneas de ramas pulmonares. La mayoría de los pacientes se mantenían asintomáticos. La mortalidad operatoria de los últimos 5 años fue 2,6 por ciento. Conclusiones: La mortalidad operatoria ha disminuido significativamente a lo largo de 20 años; persiste un mayor riesgo en ciertos patrones de anatomía coronaria. La supervivencia alejada y libre de reintervenciones es muy favorable.

Aim: to report the results of the arterial Switch operation in patients with D-transposition of the great vessels (D-TGA) and to evaluate their late course. Patients and Methods: A retrospective review of the clinical data on patients consecutively operated on for D-TGA using the switch procedure. Results obtained in patients operated on between 1992 and 2002 (Period 1) were compared to those obtained in patients undergoing their operation between 2013 and 2012. Patients with D-TGA and no complications were compared to those who had interventricular septal defect or aortic coarctation associated their TGA. Results: 44 patients belonged in Period 1 and 64 in Period 2 (total 108). Demographic and anatomical characteristics were similar in both periods. Simple D-TGA was present in 70 patients and complex D-TGA in 38. Operative mortality was higher in Period 1 compared to Period 2 (33 per cent vs. 8.4 percent, p<0.025). A higher, albeit not statiscally significant mortality was observed in patients with complex as opposed to simple D-TGA. A 68.7 per cent relative reduction mortality risk was observed in Period 2. Complications developed in 28.7 per cent of patients, with no difference between periods. Only 1 patient died during late follow up. Median follow up was 60 months and survival rate was 84.3 percent at 10 y 20 years. Sixteen patients required re-intervention, mainly to perform percutaneous plastic procedures on pulmonary artery branches. Most patients had an asymptomatic course during follow up. Surgical mortality for the last 5 years was 2.6 percent. Conclusion: surgical mortality for the arterial switch operation in patients with D-TGA has significantly decreased along a 20 year period. An increased surgical risk persists for patients with certain forms of coronary artery anomalies. Late survival free of re-intervention was the rule in these patients.

[Twiddler syndrome: report of one case]. / Síndrome de Twiddler: una causa infrecuente de disfunción de marcapaso definitivo. Caso clínico.

We report a 26 year old patient who had a single chamber pacemaker implantation one year before. During a routine pre-operative evaluation, pacemaker dysfunction was demonstrated due to sensing and pacing failure, associated to left pectoral muscle rhythmic contraction. Chest X-ray confirmed Twiddler syndrome, in which twisting or rotation of the device inside the pocket results in lead dislodgement and device malfunction.

Cardiac resynchronization therapy (and multisite pacing) in pediatrics and congenital heart disease: five years experience in a single institution.

INTRODUCTION: Clinical evidence supports the use of cardiac resynchronization therapy (CRT) in adults with heart failure, but experience in pediatrics and congenital heart disease (CHD) is limited in terms of patient numbers and follow-up. We sought to determine the functional assessment and clinical outcomes in pediatric and CHD CRT patients followed uniformly at one institution. METHODS: Retrospective review of 60 consecutive patients who underwent CRT between 2002 and 2007. RESULTS: At implantation, median age was 15.0 years (5 months to 47 years). Overall, 46 patients had CHD (77%) and 14 had dilated cardiomyopathy. Prior to CRT, 92% were on heart failure treatment drugs and 55% had pacemakers. Median follow-up time was 0.7 years (1 day-5.3 years). Median QRS width decreased from 149 to 120 ms (P < 0.001). Median ejection fraction (EF) increased from 36% to 42% (P < 0.001) and improvement was particularly evident in the group with CHD. Of note, 8 of 13 patients with single ventricle morphology had a "strong CRT response," defined as either an improvement of 2-3 ordinal points in NYHA classification and/or increased ventricular function by >or= 10 EF units. Overall, an improvement in functional status was observed in 39 of 45 patients (87%) with sufficient follow-up data. CONCLUSIONS: Children and CHD patients treated with CRT have acute improvement in ventricular function, but implantation may require individualized planning and unconventional approaches. Future important goals include preimplant determination of CRT responders in pediatric and CHD patients, optimizing lead placement and programing, as well as long-term CRT device management issues.

How revealing are insertable loop recorders in pediatrics?

INTRODUCTION: An insertable loop recorder (ILR) in patients with infrequent syncope or palpitations may be useful to decide management strategies, including clinical observation, medical therapy, pacemaker, or implantable cardioverter defibrillator (ICD). We sought to determine the diagnostic utility of the Reveal ILR (Medtronic, Inc., Minneapolis, MN, USA) in pediatric patients. METHODS: Retrospective review of clinical data, indications, findings, and therapeutic decision in 27 consecutive patients who underwent ILR implantation from 1998-2007. RESULTS: The median age was 14.8 years (2-25 years). Indications were syncope in 24 patients and recurrent palpitations in three. Overall, eight patients had structural heart disease (six congenital heart disease, one hypertrophic cardiomyopathy, one Kawasaki), five had previous documented ventricular arrhythmias with negative evaluation including electrophysiology study, and three patients had QT prolongation. Tilt testing was performed in 10 patients, of which five had neurocardiogenic syncope but recurrent episodes despite medical therapy. After median three months (1-20 months), 17 patients presented with symptoms and the ILR memory was analyzed in 16 (no episode stored in one due to full device memory), showing asystole or transient atrioventricular (AV) block (2), sinus bradycardia (6), or normal sinus rhythm (8). Among asymptomatic patients, 3/10 had intermittent AV block or long pauses, automatically detected and stored by the ILR. In 19 of 20 patients, ILR was diagnostic (95%) and five subsequently underwent pacemaker implantation, while seven patients remained asymptomatic without ILR events. Notably, no life-threatening events were detected. The ILR was explanted in 22 patients after a median of 22 months, two due to pocket infection, 12 for battery depletion and eight after clear documentation of nonmalignant arrhythmia. CONCLUSIONS: The ILR in pediatrics is a useful adjunct to other diagnostic studies. Patient selection is critical as the ILR should not be utilized for malignant arrhythmias. A diagnosis is attained in the majority of symptomatic patients, predominantly bradyarrhythmias including pauses and intermittent AV block.

Mejoría de la función ventricular sistólica en pacientes pediátricos y/o portadores de cardiopatías congénitas sometidos a resincronización cardíaca / Cardiac resynchronization therapy is associated with improved systolic ventricular function in pediatrics and congenital heart disease

Antecedentes: Diversas publicaciones han validado el uso terapéutico de resincronización cardíaca en adultos portadores de insuficiencia cardíaca, pero la experiencia en pacientes pediátricos y en pacientes portadores de cardiopatías congénitas es limitada. Objetivo: Determinar los resultados de resincronización cardíaca en pacientes pediátricos y/o portadores de cardiopatías congénitas.Método: Revisión retrospectiva de los antecedentes clínicos, ecocardiogramas y electrocardiogramas en 40 pacientes consecutivos con disfunción ventricular, tratados con resincronización cardíaca entre septiembre 2002 y julio 2006 en el Children's Hospital Boston.Resultados: Al momento del implante la mediana de edad fue 16,4 años (4 meses-47años). Cinco pacientes teníancorazón estructuralmente normal, 33 eran portadores de cardiopatía congénita y 2 tenían diagnóstico de miocardiopatía. Dieciocho pacientes (45 por ciento) tenían marcapaso definitivo. La mediana de seguimiento fue 1,7 años (2 meses-4 años). Cinco pacientes no usan su sistema de estimulación biventricular. La función ventricular mejoró en 30/35 pacientes (85,7 por ciento). La fracción de eyección aumentó de 31,4 a 41,5 por ciento, principalmente como consecuencia de disminución del volumen ventricular izquierdo de fin de sístole, con mínima disminución del volumen ventricular izquierdo de fin de diástole. Cinco pacientes no respondieron y no se identificaron factores predictores de los no respondedores. Análisis por intención de tratar reflejamejoría en 30/40 pacientes (75 por ciento). Conclusión: La resincronización cardíaca produce mejoría de la función ventricular en un porcentaje significativo de unapoblación seleccionada de pacientes pediátricos y/o portadores de cardiopatías congénitas, predominantemente asociada con disminución del volumen ventricular izquierdo de fin de sístole. Estos hallazgos pueden tener importante relevancia en el tratamiento a largo plazo de este grupo de pacientes.

[Experience in the use of a new endocardial stimulation electrode]. / Experiencia en el uso de un nuevo catéter electrodo de estimulación endocavitaria: Seguimiento a un año.

BACKGROUND: Since February 2002, Flextend electrode catheters are used at the Cardiovascular Unit of the Catholic University Clinical Hospital. These transvenous catheters have an IS-1 connector, silicone coating, active fixation and retractile helix with dexamethasone acetate. AIM: To report early and one year results using Flextend catheters. MATERIAL AND METHODS: Retrospective analysis of all patients that received an implant of a Flextend catheter in the Unit. RESULTS: Forty one Flextend catheters were implanted in 24 patients, without acute displacement or clinical pericarditis. In 18 electrode catheters located in the right atrium the mean values for p wave, stimulation threshold and impedance at the moment of placement, were 2.9+/-1.4 mV, 0.8+/-0.4 V and 522+/-86 Ohms, respectively. The figures 24 hours after placement were 3.6+/-2.1 mV, 0.8+/-0.3 V and 612+/-69 Ohms, respectively. In 23 electrode catheters in the right ventricle, mean values at the moment of placement for R wave, stimulation threshold and impedance were 11.3+/-3.6 mV, 0.8+/-0.2 V and 756+/-108 Ohms, respectively. The figures 24 hours after placement were 3.6+/-2.1 mV, 0.8+/-0.3 V and 612+/-69 Ohms, respectively. In one patient, the stimulation threshold increased two months after placement and required a new intervention. CONCLUSIONS: Flextend catheters ca be placed successfully with a low rate of complications and stable function parameters on follow up.

[Permanent pacemaker implantation in patients with persistent left superior vena cava and absent right superior vena cava. Report of three cases]. / Implante de marcapaso definitivo en pacientes con vena cava superior izquierda persistente y ausencia de vena cava superior derecha. Caso clínico.

Persistent left superior vena cava and absent right superior vena cava is an uncommon anatomical association. This is a challenging situation for permanent pacemaker implantation. We report three patients with this anomaly and a permanent pacemaker successfully implanted through the left superior vena cava and coronary sinus, without acute or chronic complications.

[Radiofrequency ablation of ventricular tachycardia in a patient after surgery for Tetralogy of Fallot: case report]. / Fulguración con radiofrecuencia de taquicardia ventricular después de corrección quirúrgica de Tetralogía de Fallot: caso clínico.

Ventricular tachycardia is one of the most feared complications after surgical repair of Tetralogy of Fallot and it is associated with sudden death. We report a 26 years old female with a history of surgical repair of Tetralogy of Fallot at age of 4 year-old, who developed sustained ventricular tachycardia despite antiarrhythmic drugs. She was successfully treated with radiofrequency catheter ablation. Radiofrequency catheter ablation is a valid treatment for these patients.

[Chest pain and ST segment abnormalities in patients with accessory atrioventricular pathways. Report of three cases]. / Dolor torácico y alteración del segmento ST en pacientes con vías accesorias aurículo-ventriculares.

We report three patients with pre-excitation syndrome that resembled an acute coronary syndrome. A 65 years old woman, consulting in the emergency room for palpitations and retrosternal pain. EKG showed regular tachycardia and ST depression that reverted spontaneously after an episode of vomiting. A subsequent EKG demonstrated a pre-excitation syndrome and the accessory pathway was fulgurated. A 18 years old male presenting with tachycardia and chest pain elicited during exercise. An EKG showed a pre-excitation syndrome and ST segment elevation in V2 and V3. A coronary angiogram was normal. The accessory pathway successfully fulgurated. A 63 years old woman that presented tachycardia while exercising. She was subjected to an electrical cardioversion. An electrophysiological study showed an accessory pathway that was successfully fulgurated.

[Results of radiofrequency ablation of the inferior vena cava-tricuspid valve isthmus for atrial flutter]. / Flutter auricular: resultados inmediatos y alejados de la fulguración con radiofrecuencia del istmo cavo-tricuspídeo.

BACKGROUND: Radiofrequency ablation of the inferior vena cava-tricuspid valve isthmus relieves atrial flutter in 95% of cases. AIM: To evaluate the long term results of radiofrequency ablation of the inferior vena cava-tricuspid valve isthmus in atrial flutter. MATERIAL AND METHODS: Retrospective review of 86 patients with common atrial flutter, treated with radiofrequency ablation of the isthmus, while in sinus rhythm or flutter. Patients were contacted by telephone for a new clinical and electrocardiographic assessment, three to 40 months after the procedure. RESULTS: Of all the patients treated, five died and five were lost from follow up, thus 76 patients (mean age 56 years, 58 males) were contacted for reassessment. At the moment of the procedure, 51% had an underlying cardiac disease and 25% had high blood pressure. All referred palpitations, 25% had dyspnea, 84% were receiving antiarrhythmic drugs and 33% were on oral anticoagulants. Flutter was paroxystic in 83% and chronic in 17%. Fulguration was successful in all patients; one patient presented a high grade atrioventricular block as a complication of the procedure. At reassessment, 82% of patients were in sinus rhythm, 16% had atrial fibrillation and 2%, an atypical flutter. CONCLUSIONS: Radiofrequency fulguration is a safe and effective treatment of atrial flutter.

[Treatment of beneficiaries of the Chilean public health system with arrhythmias in a University Clinical Hospital]. / Experiencia de plan piloto para pacientes del FONASA portadores de arritmias atendidos en el Hospital Clínico de la Pontificia Universidad Católica de Chile.

BACKGROUND: The costs of medical care increase along with technological advances. Therefore, highly complex and expensive procedures should be performed in a limited number of institutions. AIM: To report the initial experience on electrophysiological studies performed to beneficiaries of a public health insurance system in Chile (FONASA). MATERIAL AND METHODS: An agreement was reached between the Electrophysiology Unit of the Clinical Hospital of the Catholic University and FONASA, to perform electrophysiological studies at a minimal cost, that only considered disposable materials and hospital stay. Thirty patients with supraventricular arrhythmias or ventricular arrhythmias without an associated cardiopathy, were attended using this agreement at the unit. RESULTS: In all treated patients, arrhythmias disappeared. Costs remained within the assigned budget, excepting occasional complementary tests. CONCLUSIONS: This pioneering experience demonstrated that it is possible that public health insurance systems can buy complex and expensive procedures to private hospitals.

[New surgical approach to device closure of multiple apical ventricular septal defects]. / Cierre perventricular de la comunicación interventricular múltiple con dispositivo Amplatzer.

We present an alternative technique for closing multiple ventricular septal defects difficult to access during surgery. A guidewire is advanced through the right ventricular free wall and through the main apical defect to the left ventricle, and this approach is used to place an Amplatzer device to occlude the ventricular septal defects. The procedure is performed in the beating heart, under intraoperative transesophageal echocardiographic guidance, and without extracorporeal circulation. It appears to be a simple and reproducible procedure with excellent short-term results.