Concepción Moro

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...

Lack of efficacy of atenolol for the prevention of neurally mediated syncope in a highly symptomatic population: a prospective, double-blind, randomized and placebo-controlled study.

OBJECTIVES This study was designed to evaluate the efficacy of atenolol for the long-term management of patients with vasovagal syncope. The primary hypothesis was that atenolol is not superior to placebo for the treatment of vasovagal syncope. BACKGROUND There is no definitive well-controlled analysis of the efficacy of beta-adrenergic blocking agents in patients with recurrent vasovagal syncope. METHODS This is a prospective, randomized, double-blind, placebo-controlled study. Fifty patients with recurrent vasovagal syncope were included (at least two episodes in the last year). A baseline tilt test was performed. Twenty patients (40%) had a positive tilt test. Intravenous atenolol prevented a second positive tilt in five patients. The patients were randomized to receive either atenolol or a placebo (26 patients atenolol 50 mg/day, 24 patients placebo). The follow-up procedure lasted one year. The primary end point of the study was the time to first recurrence of syncope. RESULTS In the intention-to-treat analysis, the group treated with atenolol had a similar number of patients with recurrent syncopal episodes as the placebo group. The Kaplan-Meier actuarial estimates of time to first syncopal recurrence showed that the probability of remaining free of syncope drops similarly in both groups and that there was no statistical difference between both curves (patients treated with atenolol vs. the placebo) with a log-rank test p value of 0.4517. CONCLUSIONS The recurrence of neurocardiogenic syncope in highly symptomatic patients treated with atenolol is similar to that of patients treated with placebo.

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.

Arritmias cardiacas en la mujer

El objetivo de esta revision fue analizar las diferencias electrofisiologicas entre sexos ya descritas, asi como la presentacion y el tratamiento clinico de las arritmias en las mujeres. La evidencia, segun los datos de los estudios publicados hasta el momento, nos muestra que las mujeres tienen una frecuencia cardiaca media superior, un intervalo QT mas largo, una menor duracion del complejo QRS, asi como un menor voltaje de este respecto a los varones. Asimismo, en las mujeres son mas frecuentes la enfermedad del nodulo sinusal, la taquicardia sinusal inapropiada, la taquicardia supraventricular intranodal, la taquicardia ventricular idiopatica del ventriculo derecho, y el sindrome QT largo congenito y adquirido; en cambio, en los varones, la prevalencia de las siguientes arritmias es mayor: bloqueo auriculoventricular, hipersensibilidad del seno carotideo, fibrilacion auricular, taquicardia supraventricular con via accesoria, sindrome de Wolff-Parkinson-White, taquicardia ventricular por reentrada, fibrilacion ventricular y muerte subita, asi como el sindrome de Brugada. Con respecto a los dispositivos, se observo que tanto los varones como las mujeres obtienen un beneficio similar con el marcapasos y el desfibrilador, y tampoco hubo diferencias en el porcentaje de buena respuesta a la resincronizacion entre ambos sexos, con una supervivencia similar; sin embargo, llama la atencion la escasa participacion femenina en los estudios de investigacion de todas las tecnicas terapeuticas, tanto la ablacion como la resincronizacion y el desfibrilador automatico implantable.

Cardiac Arrhythmias in Women

The aim of this study was to review published data on gender differences in cardiac electrophysiology and in the presentation and clinical treatment of arrhythmias. The evidence from studies published to date show that women have a higher mean resting heart rate, a longer QT interval, a shorter QRS duration, and a lower QRS voltage than men. Women have a higher prevalence of sick sinus syndrome, inappropriate sinus tachycardia, atrioventricular nodal reentry tachycardia, idiopathic right ventricular tachycardia, and arrhythmic events in the long-QT syndrome. In contrast, men have a higher prevalence of atrioventricular block, carotid sinus syndrome, atrial fibrillation, supraventricular tachycardia due to accessory pathways, Wolff-Parkinson-White syndrome, reentrant ventricular tachycardia, ventricular fibrillation and sudden death, and the Brugada syndrome. With regard to implantable devices, it has been reported that defibrillators offer similar benefits in men and women. Moreover, there is no gender difference in the percentage who respond well to resynchronization therapy: survival is similar in the two sexes. However, it should be noted that few women have participated in studies of all types of therapy, including catheter ablation, resynchronization therapy, and the use of implantable defibrillators.

A Prospective Multicenter Study on the Safety of a Pacemaker with Automatic Energy Control: Influence of the Electrical Factor on Chronic Stimulation Threshold.

The effectiveness and safety of a pacemaker with automatic control of capture was evaluated in 162 patients followed at 27 Spanish centers. The aim of our prospective, multicenter, and randomized trial was to determine the relationship between the voltage output of the pulse generator and the stimulation threshold. We randomized 162 patients (107 men, mean age 75 ± 12 years). We implanted a ventricular pacemaker model Regency SR+ or SC+ with Pacesetters low polarization bipolar leads Membrane E 1450. The patients were randomized to receive Autocapture or not; group I (81 patients) Autocapture On, pulse output automatically adjusted and group II (81 patients) Autocapture Off, fixed output parameters (3.9 V, 0.37 ms). We performed a 6‐month follow‐up measuring stimulation threshold by means of the VARIO test and Autocapture test, evoked response signal, and R wave signal. The mean R wave was 15.77 ± 3.5 mV at the end of the follow‐up for group I, and 14.91 ± 6.8 mV for group II (P = NS). The measured evoked response at the end of the follow‐up was 9.25 mV in Group I and 8.48 mVin Group II (P = NS). The stimulation threshold was not different between groups. The current density created with the voltage and pulse width used in this study (± 3.9 V and 0.37 ms) at the tip of this electrode during the maturation process had no influence on the development of the chronic detection and stimulation thresholds.

Resincronización cardíaca en la insuficiencia cardíaca: bases, métodos, indicaciones y resultados

98 La insuficiencia cardíaca es una de las enfermedades más prevalentes en los países desarrollados. El pronóstico de los pacientes con insuficiencia cardíaca avanzada es todavía malo, a pesar de que en las últimas décadas se han investigado nuevas terapias para mejorar la calidad de vida y la supervivencia de estos enfermos. Por otra parte, hasta el 30% de los pacientes con insuficiencia cardíaca avanzada presenta alteraciones de la conducción intraventricular, lo que condiciona una asincronía en la contractilidad normal del ventrículo que deteriorará la función cardíaca. Mediante la terapia de estimulación cardíaca con resincronización se puede conseguir una mayor sincronía en la contractilidad ventricular. Numerosos estudios han demostrado el beneficio que produce la terapia de estimulación biventricular en la mejora de los parámetros hemodinámicos, la calidad de vida, el test de los 6 min y la clase funcional en pacientes con insuficiencia cardíaca, disfunción sistólica ventricular y retraso de la conducción intraventricular. Algunos estudios han demostrado una mayor supervivencia en los pacientes tratados con resincronización y desfibrilador. Todavía quedan bastantes interrogantes por resolver sobre los efectos de la terapia de resincronización cardíaca, el lugar de estimulación y el tipo de dispositivo a implantar (desfibrilador o marcapasos).