José M. González Rebollo

Use of Irbesartan to Maintain Sinus Rhythm in Patients With Long-Lasting Persistent Atrial Fibrillation A Prospective and Randomized Study

Background—Data from studies of angiotensin-converting enzyme inhibitors provide evidence that the renin-angiotensin-aldosterone system plays a role as a mediator of atrial remodeling in atrial fibrillation. The present study has evaluated the effect of treatment with the angiotensin I type 1 receptor blocker irbesartan on maintaining sinus rhythm after conversion from persistent atrial fibrillation. Methods and Results—To be included in the present study, patients must have had an episode of persistent atrial fibrillation for >7 days. The patients were then randomized and scheduled for electrical cardioversion. Two groups of patients were compared: Group I was treated with amiodarone, and group II was treated with amiodarone plus irbesartan. The primary end point was the length of time to a first recurrence of atrial fibrillation. From a total of 186 patients assessed in the study, 154 were analyzed with the use of intention-to-treat analysis. Seventy-five patients were randomly allocated to group I and 79 to group II. After 2 months of follow-up in the intention-to-treat analysis, the group treated with irbesartan had fewer patients with recurrent atrial fibrillation (Kaplan-Meier analysis, 84.79% versus 63.16%, P =0.008). The Kaplan-Meier analysis of time to first recurrence during the follow-up period (median time, 254 days [range, 60 to 710]) also showed that patients treated with irbesartan had a greater probability of remaining free of atrial fibrillation (79.52% versus 55.91%, P =0.007). Conclusions—Patients treated with amiodarone plus irbesartan had a lower rate of recurrence of atrial fibrillation than did patients treated with amiodarone alone.

Use of Irbesartan to Maintain Sinus Rhythm in Patients With Long-Lasting Persistent Atrial Fibrillation

Background— Data from studies of angiotensin-converting enzyme inhibitors provide evidence that the renin-angiotensin-aldosterone system plays a role as a mediator of atrial remodeling in atrial fibrillation. The present study has evaluated the effect of treatment with the angiotensin I type 1 receptor blocker irbesartan on maintaining sinus rhythm after conversion from persistent atrial fibrillation. Methods and Results— To be included in the present study, patients must have had an episode of persistent atrial fibrillation for >7 days. The patients were then randomized and scheduled for electrical cardioversion. Two groups of patients were compared: Group I was treated with amiodarone, and group II was treated with amiodarone plus irbesartan. The primary end point was the length of time to a first recurrence of atrial fibrillation. From a total of 186 patients assessed in the study, 154 were analyzed with the use of intention-to-treat analysis. Seventy-five patients were randomly allocated to group I an...

The role of angiotensin receptor blockers and/or angiotensin converting enzyme inhibitors in the prevention of atrial fibrillation in patients with cardiovascular diseases: meta-analysis of randomized controlled clinical trials

The inhibition of the renin‐angiotensin system has demonstrated both experimental and clinical effects in preventing atrial fibrillation. However, there is still uncertainty about the role of these drugs in clinical practice. The objective of this review has been to assess the effects of angiotensin II type‐1 receptor blockers (ARBs) and/or angiotensin converting enzyme inhibitors (ACEIs) for preventing atrial fibrillation. We searched the Cochrane controlled Trials Register (Cochrane Library Issue 4, 2002), MEDLINE (January 1980 to November 2003), EMBASE (January 1980 to November 2003) and reference list of articles. We also contacted manufacturers and researchers in the field. Selection criteria: We conducted a meta–analysis of all randomized controlled clinical trials that compared ARBs and/or ACEIs with either placebo or conventional therapy in patients with either hypertension, heart failure, ischemic heart disease, or diabetes mellitus. The pooled outcome was the development of new onset atrial fibrillation. Two reviewers independently assessed trial quality and extracted data. In some cases, the study authors were contacted for additional information. Seven trials involving a total of 24,849 patients were included (11,328 randomized to active therapy and 13,521 to control). There was a significant statistical difference in the pooled development of atrial fibrillation between the treatment and control group. (OR, 0.57; 95% CI, 0.39 to 0.82); test for overall effect z = 2.98 P = 0.003). Treatment with ACEIs/ARBs markedly reduces the risk of development or recurrence of atrial fibrillation.

Biochemical markers and cardiac troponin I release after radiofrequency catheter ablation: Approach to size of necrosis

BACKGROUND We designed this study to determine the value of serum levels of several cardiac markers in patients who underwent radiofrequency ablation and to establish the utility of cardiac troponin I (cTnI). After radiofrequency ablation there is always a small localized endomyocardial necrosis. The volume of the necrosis may be estimated by the rise of several biochemical marker levels, classically creatinine kinase (CK) and CK-MB. cTnI is a newly available biochemical marker with a high cardiac specificity. METHODS AND RESULTS We analyzed the data from 51 patients who underwent radiofrequency ablation and from 16 control patients who underwent an electrophysiologic study without ablation. The levels of CK, CK-MB mass, cTnI, and myoglobin were compared with clinical findings, ST-T wave abnormalities, and the presence of arrhythmias. The study shows that there is a higher release of cTnI compared with the standard markers CK, CK-MB, and myoglobin. A pathologic value of cTnI was found in 92% of the patients of the ablation group. CK-MB had a lower sensitivity (63%). The area under the receiver operating characteristic curve for cTnI was 0.9375, significantly superior to the other biochemical markers (P <.05). We found a moderate level of correlation between the number of radiofrequency pulses and cardiac cTnI release (r = 0.69, P <.0001). CONCLUSIONS The serum level of cTnI detects the minor myocardial damage produced by radiofrequency ablation. This would be useful information to have in patients who might have the potential for other ischemic events. The other biochemical or ablation parameters usually reported, including the radiofrequency ablation parameters, have no good correlation with the size of the myocardial necrosis. Therefore we suggest that monitoring of cTnI is the best way to detect and quantify the size of myocardial necrosis created by radiofrequency ablation.

Fibrilación ventricular recurrente durante un proceso febril en un paciente con síndrome de Brugada

Se han descrito distintos desencadenantes de arritmias ventriculares en los pacientes con sindrome de Brugada, como la bradicardia nocturna, la ingestion de alcohol y el estres. Presentamos un caso de un paciente varon de 30 anos con fibrilacion ventricular recurrente desencadenada por un episodio de fiebre y sudacion intensa. En 1995 habia sido remitido para estudio tras sufrir una parada cardiorrespiratoria por fibrilacion ventricular. El electrocardiograma demostraba un patron clasico del sindrome de Brugada. Las exploraciones complementarias realizadas fueron normales. Se indico el implante de un desfibrilador automatico. Durante un seguimiento de 4 anos, el paciente permanecio asintomatico. En marzo de 1999, tras una infeccion de vias respiratorias altas, presento fiebre muy elevada. Durante la madrugada y acompanado de gran sudacion y sensacion distermica, recibio tres descargas del desfibrilador. La interrogacion posterior del dispositivo demostro cinco episodios de fibrilacion ventricular, dos de ellos no sostenidos, y los restantes resueltos con descargas del desfibrilador. La cinetica de los canales de sodio tiene una fuerte dependencia de la temperatura, siendo mas rapida la activacion e inactivacion de los canales a mayor temperatura. Es posible que esta dependencia de la temperatura pueda explicar el papel de esta en el desencadenamiento de arritmias ventriculares en nuestro paciente. Different situations have been involved in the origin of ventricular arrhythmic events in patients with the Brugada syndrome such as bradycardia, alcohol consumption and mental stress We present a 30 year old male with recurrent ventricular fibrillation due to a febrile illness with intense sweating. He had been previously studied at our Unit in 1995 because of an episode of resuscitated cardiac arrest due to ventricular fibrillation. The twelve-lead electrocardiogram showed the typical characteristics of a patient with the Brugada syndrome. Different invasive and non-invasive tests performed were normal. He received a defibrillator and had no recurrences during 4 years of follow up. In March,1999, after an upper respiratory tract infection he had high fever treated with paracetamol but at down he had sweating and chills, followed by 3 defibrillator shocks. Late interrogation showed 5 episodes of ventricular fibrillation, two of them non-sustained, and the rest adequately treated by the defibrillator. Activation and inactivation kinetics for early INa are twofold faster at higher temperature, and shift activation and steady-state inactivation. This may explain the role of the temperature as a trigger for ventricular arrhythmias in our patient.

Interferencias electromagnéticas entre los desfibriladores automáticos y los teléfonos móviles digitales y analógicos

Introduccion y objetivos La interferencia funcional de los marcapasos por la telefonia movil ha sido descrita con los sistemas analogicos y con mayor incidencia con los sistemas digitales, incluyendo inhibicion y estimulacion inadecuada. La influencia de ambos sistemas sobre el desfibrilador automatico no ha sido aun completamente estudiada. Pacientes y metodos Estudiamos la influencia de los telefonos moviles tanto de la red analogica como digital en pacientes con desfibrilador automatico: en un modelo in vivo en un total de 72 pacientes, 50 con telefono analogico y 22 con telefono digital e in vitro con un simulador de arritmias conectado al propio desfibrilador de forma directa e indirecta con las sondas en un medio salino de impedancia similar a la del medio corporal (300-350 Ohmios). Analizamos diferentes modelos de desfibriladores, en un test estandarizado disenado para lograr una gran sensibilidad del dispositivo con distintos modelos de telefonos moviles y diferente energia de transmision. Resultados Se documentaron interferencias en 14 pacientes, en 8 con telefonos analogicos y en 6 con telefono digital. En 11 de ellos, la interferencia se produjo exclusivamente en el canal del electrocardiograma de superficies obtenido desde el programador externo del desfibrilador. En 5 pacientes se constataron alteraciones en el canal de registro intracavitario, con perdida intermitente de telemetria (con el programador externo en conexion al desfibrilador). En el modelo experimental, tambien se observo la perdida ocasional de telemetria. Con el simulador de arritmias se introdujo un ritmo sinusal normal en el medio salino (y tambien en conexion directa) y fue sensado de forma correcta por el desfibrilador (sin interferencias). Posteriormente se introdujeron diferentes arritmias ventri ventriculares sostenidas, que fueron correctamente diagnosticadas por el generador (con y sin la presencia del telefono movil, situado en multiples posiciones). Se comprobo que la perdida de telemetria observada previamente no habia producido ninguna alteracion en el generador, ya que contenia los intervalos RR de cada episodio y los electrogramas almacenados de forma correcta. Por tanto, no se documentaron alteraciones reales de sobresensado, ni infrasensado en ningun desfibrilador in vivo ni in vitro. No se observaron terapias inapropiadas. El posible efecto iman de estos telefonos no se objetivo durante ninguna prueba, lo que hubiera podido inhibir la deteccion del episodio. Conclusiones a) no hemos observado en nuestra serie ninguna interferencia clinicamente significativa entre los desfibriladores y los telefonos moviles de la red analogica ni digital, tanto en el paciente portador como en el modelo experimental, ya que las alteraciones observadas correspondieron exclusivamente a la telemetria entre el generador y el programador, sin afectar a la funcion intrinseca del dispositivo; b) el modelo in vitro empleado nos permite asegurar el funcionamiento correcto del dispositivo en caso de presentar arritmias ventriculares simultaneamente al uso del telefono; c) por tanto, el uso de los telefonos moviles no se ha demostrado que sea perjudicial en estos pacientes, y d) sin embargo, pueden ser aconsejables algunas normas sencillas, como mantener una distancia superior a 15 cm entre el desfibrilador y el telefono movil.

Randomized Comparison of Efficacy of Cooled Tip Catheter Ablation of Atrial Flutter: Anatomic Versus Electrophysiological Complete Isthmus Block

MADRID, A.H., et al.: Randomized Comparison of Efficacy of Cooled Tip Catheter Ablation of Atrial Flutter: Anatomic Versus Electrophysiological Complete Isthmus Block. There is a subset of patients with failed ablation of the cavotricuspid isthmus (CTI) using standard catheters and with 10% of the patients having recurrences. The purpose of this study was to compare the cooled and standard ablation with regard to acute successful electrophysiological achievement of bidirectional isthmus block and the subacute anatomic characteristics of the lesions. This randomized, experimental study compares the effects of ablation on the isthmus using a cooled catheter with those of a standard ablation catheter in 16 pigs. In 12 animals, CTI block was achieved after ablation (8/8 cooled and 4/8 standard). In two animals, it was not possible to achieve complete isthmus block and two had persistent slow conduction (all four using the standard catheter). After 1 week, the animals were slaughtered. The size of the lesion was greater with the irrigated tip catheters. Transmural lesions were found in 14 animals. A complete line of anatomic isthmus block was not documented after the first line in six animals, four with the standard and two with the cooled catheter. A conduction block was never present across gaps ≥ 5 mm. In conclusion cooled catheters achieved a complete line of electrophysiological and anatomical block in a significantly higher percentage than the standard catheters.

Usefulness of Brain Natriuretic Peptide to Evaluate Patients With Heart Failure Treated With Cardiac Resynchronization

INTRODUCTION AND OBJECTIVES The aim of the present study was to document the evolution of the blood levels of brain natriuretic peptide (BNP) in patients with heart failure and their correlation with the clinical course after implantation of a biventricular pacemaker. PATIENTS AND METHOD Twenty-eight patients with heart failure associated to left bundle branch block and left ventricular systolic dysfunction were included in the study. In each patient we performed laboratory tests, chest X-ray, electrocardiogram and echocardiogram, and measured blood levels of BNP. RESULTS During follow-up (10 [6] months) functional capacity improved, decreasing from 3.3 (0.6) to 2.10 (0.4) (P=.03). The rate of hospitalizations for heart failure decreased from an average of 1.8 (0.7) (6 months before the procedure) to 0.8 (0.3) (6 months after the procedure; P=.04). The basal value of BNP decreased from 193 (98) pg/mL to 52 (14) at the end of the follow-up in the responder group (22 patients) and increased from 564 (380) to 650 (80) pg/mL in the nonresponder group (6 patients). Patients who responded showed significant clinical improvement and decreasing levels of BNP, which reached a plateau an average of 6 months after implantation. Multivariate logistic regression analysis identified lower levels of BNP, idiopathic dilated cardiomyopathy, and functional class as independent predictors of response to therapy. Age, QRS width and left ventricular ejection fraction were not predictors of response. CONCLUSIONS Brain natriuretic peptide concentrations allowed us to monitor, in an objective manner, the clinical course of patients with biventricular resynchronization therapy.

Estudio macro y microscópico de la arteria coronaria derecha tras ablación con catéter y radiofrecuencia del istmo cavotricuspídeo en un modelo experimental

Introduccion y objetivos La arteria coronaria derecha esta localizada en el surco auriculoventricular, justo por debajo de la zona de ablacion del fluter, el istmo cavotricuspideo. Hasta el momento, con el uso de cateteres estandar de radiofrecuencia no se han descrito complicaciones significativas, pero aproximadamente en un 10% de los pacientes no se consigue la ablacion. El uso de cateteres irrigados, al crear una lesion mas profunda, en teoria podria danar el arbol coronario. Metodos Analizamos el efecto de la ablacion del istmo cavotricuspideo con radiofrecuencia sobre la anatomia patologica del istmo y la arteria coronaria, empleando de forma aleatorizada 2 cateteres: uno de ellos estandar y uno irrigado. Realizamos ablacion del istmo cavotricuspideo en 16 animales (cerdos). No hubo problemas clinicos ni modificaciones del segmento ST durante la ablacion. El corazon fue explantado a la semana. Resultados El examen macroscopico demostro integridad anatomica de la arteria coronaria derecha rodeada de la grasa del surco auriculoventricular, a traves de todo el istmo. El analisis microscopico de la pared coronaria puso de manifiesto un infiltrado inflamatorio en la grasa epicardica, que alcanzo en 14 casos la adventicia de la arteria coronaria, sin producir necrosis. Este infiltrado se extendio focalmente a la muscular media en 2 casos, sin alcanzar el endotelio. Se observo necrosis en la pared de una vena epicardica en un caso, con su interior trombosado. Conclusiones A pesar de la proximidad de la arteria coronaria derecha a las lesiones del istmo, no hemos observado necrosis en ningun caso. Sin embargo, hemos apreciado signos inflamatorios que han alcanzado focalmente la capa media. La pared venosa es susceptible de lesion con radiofrecuencia. Esto podria ser explicado por el distinto flujo sanguineo en cada vaso.

Correlación anatomopatológica y bioquímica de las lesiones producidas por la radiofrecuencia con catéteres estándar e irrigados de 4 mm

Introduccion y objetivos No se conoce bien la influencia en el tamano de la lesion de los cateteres irrigados. Tampoco estan bien caracterizadas las posibles diferencias de los dos sistemas con circuito abierto y cerrado. Disenamos este estudio para comparar las lesiones de los cateteres irrigados, comparandolas con las producidas por cateteres estandar de 4 mm y evaluamos la correlacion anatomopatologica y la liberacion de marcadores bioquimicos, incluyendo la troponina cardiaca I en un modelo experimental. Metodos Este estudio se realizo en 20 cerdos, aplicando 1-8 pulsos de radiofrecuencia con energias de 15, 25 y 50 W, y duracion de 15-60 s. A los 7 dias, el animal fue sacrificado para estudio anatomopatologico. Resultados Se produjeron un total de 54 lesiones, 25 con cateteres estandar y 29 con irrigados. El volumen medio de las lesiones con cateteres estandar fue de 146 ± 110 ml y con irrigados de 856 ± 864 ml (p Conclusiones Las lesiones producidas con un cateter irrigado son superiores a las causadas por cateteres estandar. El valor pico de troponina postablacion tiene una buena correlacion con el tamano real de la necrosis.