[Atrial fibrillation. Monitoring of rhythm versus monitoring of ventricular response]. / Fibrilación auricular. Control del ritmo frente a control de la respuesta ventricular.

Atrial fibrillation is the most frequent supraventricular arrhythmia. The goals for the treatment of this arrhythmia are symptom control and reducing cardiovascular morbidity and mortality. In elderly patients with no symptoms we must indicate therapy based on rate control. On the other side, in young patients without heart disease, those very symptomatic or if atrial fibrillation causes a significant hemodynamic and functional deterioration we must try, at least initially, a strategy of maintaining sinus rhythm. In the future, we hope that the development of new anti-arrhythmic drugs safer and more effective, and refining catheter ablation will lead to increased therapeutic efficacy in patients with atrial fibrillation.

Fibrilación auricular. Control del ritmo frente a control de la respuesta ventricular / Atrial fibrillation. Monitoring of rhythm versus monitoring of ventricular response

fibrilación auricular es la arritmia supraventricular más frecuente. Los objetivos que nos hemos de plantear en el tratamiento de esta arritmia son el control de los síntomas y la reducción de la morbimortalidad cardiovascular. En pacientes de edad avanzada con escasa sintomatología debemos indicar una terapia de control de frecuencia. Por otro lado, en aquellos pacientes jóvenes sin cardiopatía, aquellos muy sintomáticos o en los que la fibrilación auricular ocasione un importante deterioro hemodinámico y funcional hemos de intentar, al menos inicialmente, una estrategia de mantenimiento del ritmo sinusal. En el futuro esperamos que el desarrollo de nuevos fármacos antiarrítmicos más seguros y eficaces y el perfeccionamiento de las estrategias de ablación con catéter permitan incrementar la eficacia terapéutica en nuestros pacientes con fibrilación auricular (AU)

Atrial fibrillation is the most frequent supraventricular arrhythmia. The goals for the treatment of this arrhythmia are symptom control and reducing cardiovascular morbidity and mortality. In elderly patients with no symptoms we must indicate therapy based on rate control. On the other side, in young patients without heart disease, those very symptomatic or if atrial fibrillation causes a significant hemodynamic and functional deterioration we must try, at least initially, a strategy of maintaining sinus rhythm. In the future, we hope that the development of new anti-arrhythmic drugs safer and more effective, and refining catheter ablation will lead to increased therapeutic efficacy in patients with atrial fibrillation (AU)

[Systemic embolism after reversion to sinusal rhythm of persistent atrial flutter]. / Embolismo sistémico tras reversión a ritmo sinusal del aleteo auricular persistente.

BACKGROUND: The incidence of embolism in atrial flutter has been underestimated in the routine clinical practice. PATIENTS AND METHODS: In this study the incidence of thromboembolic events after restoration of sinus rhythm (by catheter ablation or cardioversion) was compared in two groups of consecutive patients, with a different anticoagulation protocol. A total of 169 patients were evaluated. A first retrospective analysis of 79 non anticoagulated patients (group I). A second prospective group of 90 patients who were treated with an anticoagulation protocol (group II) similar to that for patients with atrial fibrillation. All had typical atrial flutter of at least one month's duration before the procedure. RESULTS: The mean age of patients in group I was 61 12 years and the mean left ventricular ejection fraction was 57 6%. Patients in group II had a mean age of 61 10 years and the mean left ventricular ejection fraction was 56 9%. No differences were observed regarding prevalence of structural cardiopathy, arterial hypertension, diabetes mellitus, left ventricular dysfunction, atrial size or atrial fibrillation between the two groups of patients. Four patients in the retrospective analysis (5%) had an embolic event associated with the procedure, compared with 0 (0%) in the group of patients treated with the anticoagulation protocol. The efficient anticoagulation was associated with a lower risk of thromboembolic events (p < 0.05). CONCLUSIONS: The incidence of embolic events after reversion to sinusal rhythm of persistent atrial flutter can be decreased. These patients should follow the same recommendations of anticoagulation that apply for patients with persistent atrial fibrillation that are going to be reverted to sinus rhythm.

Embolismo sistémico tras reversión a ritmo sinusaldel aleteo auricular persistente / Systemic embolism after reversion to sinusal rhythm of persistent atrial flutter

Pacientes y métodos. En este estudio se compara la incidencia de eventos tromboembólicos después de restaurar el ritmo sinusal (por ablación con catéter o cardioversión) en dos grupos consecutivos de pacientes con un protocolo de anticoagulación diferente. Se evaluaron 169 pacientes. Un primer análisis retrospectivo de 79 pacientes no anticoagulados (grupo I). Un segundo grupo prospectivo de 90 pacientes se trató con un protocolo de anticoagulación (grupo II) similar al de los pacientes con fibrilación auricular. Todos presentaban aleteo auricular típico de al menos un mes de duración antes del procedimiento. Resultados. Grupo I: la edad media fue 61ñ12 años y la fracción de eyección ventricular izquierda media de 57 ñ 6 por ciento. Grupo II: tuvo una edad media 61 ñ 10 años y fracción de eyección ventricular izquierda media de 56 ñ 9 por ciento. No hubo ninguna diferencia en la prevalencia de cardiopatía estructural, hipertensión arterial, diabetes mellitus, disfunción ventricular izquierda, tamaño auricular o fibrilación auricular entre los dos grupos de pacientes. Cuatro pacientes del análisis retrospectivo (5 por ciento) presentaron un episodio embólico asociado con el procedimiento, comparado con 0 (0 por ciento) de los pacientes tratados con un protocolo de anticoagulación. La anticoagulación eficaz se asoció con un menor riesgo de tromboembolismo (p < 0,05). Conclusiones. Es posible reducir la incidencia de eventos embólicos después de la reversión a ritmo sinusal del aleteo auricular persistente. Estos pacientes deben seguir las mismas recomendaciones de anticoagulación que los pacientes con fibrilación auricular persistente que van a ser revertidos a ritmo sinusal (AU)

[Evaluation of the anatomopathological characteristics and the safety of radiofrequency lesions at the atrial level with two different systems of irrigated tip catheters on an experimental level]. / Estudio de las características anatomopatológicas y la seguridad de las lesiones producidas en la aurícula con dos diferentes sistemas de catéteres de punta irrigada en un modelo experimental.

INTRODUCTION AND OBJECTIVES: We performed this study to evaluate the security and efficacy in the lesions produced on the atrial wall by different irrigated catheters in an experimental model. We evaluated the anatomopathologic characteristics of the lesions produced by two different systems of irrigated tip catheters, with opened or closed circuit. METHODS: This study was performed in 16 pigs applying 60 sec radiofrequency pulses with three different energy levels (15, 25 y 50 Watts). Two different systems of radiofrequency ablation irrigated catheters were used, opened and closed. We used 4 pigs in which we performed ablation with a standard catheter as a control group. Under fluoroscopic guidance, catheters were placed on the high and low right atrial lateral wall, where lesions were produced. After 7 days, animals were sacrificed for anatomopathological study. RESULTS: A total of 27 lesions were performed with irrigated catheters (11 closed circuit and 16 opened) and 6 with standard catheters in the control group. We did not find significant differences in the lesion characteristics between the two different systems of irrigated tip catheter used, nevertheless lesions performed with the closed system were slightly greater. Th lesions produced with irrigated catheters were always superior in the control group. Transmurality in the free atrial wall is frequent with both systems. We did not see any perforation in the atrial wall. CONCLUSIONS: We did not find significant differences in the size of the lesions produced with the two systems of irrigated catheters used. These data from an experimental model can provide useful information for atrial tachycardia radiofrequency ablation procedures in humans.

[Anatomopathological and biochemical correlation of lesions produced by standard and irrigated 4 mm radiofrequency catheters]. / Correlación anatomopatológica y bioquímica de las lesiones producidas por la radiofrecuencia con catéteres estándar e irrigados de 4 mm.

INTRODUCTION AND OBJECTIVES: The influence on the size of radiofrequency lesions by cooling of the tip of the electrode remains unclear. Moreover, the possible effects of two different cooling systems, closed and open, have not been well differentiated. We designed this study to compare both systems of irrigated-tip catheters and the lesions produced with standard 4 mm catheters and also to evaluate the pathological and biochemical marker release correlation (cardiac troponin I) in an experimental model. METHODS: The study was performed in 20 pigs. Applying between 1-8 radiofrequency pulses, at a power of 15, 25 or 50 watts, for 15-60 seconds to each animal. After 7 days, the pigs were sacrificed for anatomopathological study. RESULTS: A total of 54 lesions were produced, 25 with standard catheters and 29 with irrigated catheters. The mean volume of the lesions produced with standard catheters was 146 +/- 110 microl and with irrigated-tip catheters 856 +/- 864 microl (p < 0.001). Peak values of cardiac troponin I were also higher for irrigated catheters (18 +/- 15 ng/ml) than for standard (6.5 +/- 3 ng/ml). The correlation between the size of the lesion and the levels of cardiac troponin I were 0.86 and 0.79 with the standard and irrigated-tip catheters, respectively. The incidence of cratering was higher with standard catheters (60%) than with irrigated (27%). CONCLUSIONS: The lesions produced with an irrigated catheter are greater than those observed with standard catheters. The mean peak value of postablation cardiac troponin demonstrate a good correlation with the real size of the necrosis.

[Recurrent ventricular fibrillation during a febrile illness in a patient with the Brugada syndrome]. / Fibrilación ventricular recurrente durante un proceso febril en un paciente con síndrome de Brugada.

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.

[The clinical practice guidelines of the Sociedad Española de Cardiología on the automatic implantable defibrillator]. / Guías de práctica clínica de la Sociedad Española de Cardiología sobre el desfibrilador automático implantable.

Since the first implantation in man in 1980 implantable cardioverter defibrillator technology has greatly improved and the number of devices implanted has increased considerably every year. Non thoracotomy lead systems and biphasic shocks are now the approach of choice, offering an almost 100% success rate. This document reviews the recommendations for qualification of personnel and for the centres implanting and carrying out follow-ups on defibrillators. The current indications for the implantation of implantable cardioverter defibrillator are also addressed.

[Electromagnetic interference between automatic defibrillators and digital and analog cellular telephones]. / Interferencias electromagnéticas entre los desfibriladores automáticos y los teléfonos móviles digitales y analógicos.

BACKGROUND AND OBJECTIVES: Functional pacemaker interference by mobile telephones has been described with analogical systems and with possible greater influence, digital systems, including inhibition and inadequate pacing. The influence of both system has not been extensively studied in patients with implantable cardioverter defibrillators (ICD). PATIENTS AND METHODS: We studied the influence of mobile phones, both digital and analogic network, on the performance of several models of defibrillators, in a standardised test set up designed to provide high sensitivity. The purpose of our study was to establish whether there are any influences on ICD functions, both in in vivo and in in vitro models. Several mobile phones, with different transmission powers, were moved towards the defibrillator and the electrode, under continuous documentation of defibrillator sensing and interrogation afterwards. The experimental model was performed with the aid of an arrhythmia simulator (Intersim) and demo-defibrillators. The tests were repeated both in and out of a solution of saline water with an impedance within normal human limits. RESULTS: Partial loss of telemetry was found in 14 patients, 8 with analogical phones and 6 with digital phones. Fourteen patients showed alterations only on the surface electrocardiogram channel and five on the intracavitary channel. The same results were reproduced in the in vitro model. However, the in vitro test allowed us to simulate multiple ventricular arrhythmias, and demonstrate the normal sensing and functioning of the defibrillator during a "spontaneous" arrhythmia. After testing, we demonstrate that no real oversensing/undersensing was documented in any device. There was no evidence of ICD reprogramming or pacing inhibition. In particular, no inadequate therapies were delivered. CONCLUSIONS: a) in our series, we have not demonstrated clinically significant electromagnetic interferences with mobile phones of digital or analogical networks: b) the in vitro model allowed us to conclude that even if a spontaneous arrhythmia appears, the function of the defibrillator is not altered; c) the use of mobile phones seems to be safe for defibrillator patients, and d) however, some basic rules, such as to maintain the phone at least 15 cm away from the defibrillator, are advised.

[Current indications for implantable automatic defibrillators]. / Indicaciones actuales del desfibrilador automático implantable.

Since the first implantation in man in 1980 implantable cardioverter defibrillator technology has greatly improved and the number of devices implanted has increased considerably in recent years. Non-thoracotomy lead systems and biphasic shocks are now the approach of choice, offering nearly a 100% success rate. This paper version reviews the current indications for the implantation of implantable cardioverter defibrillator and is an upgraded of an article previously published by the Arrhythmia's Section of the Spanish Society of Cardiology. Recommendations for qualification of centres implanting defibrillators and follow up are also addressed.

[The value of cardiac troponin I as diagnostic test in the study of chest pain]. / Valor de la troponina I cardíaca como prueba diagnóstica en el estudio del dolor torácico.

BACKGROUND AND OBJECTIVES: Cardiac troponin I is a highly sensitive and specific myocardial injury marker. We have analyzed the use of cardiac troponin I values in the diagnosis of coronary artery disease, in previously healthy patients who developed chest pain with inconclusive analytical and ECG diagnostic findings. PATIENTS, MATERIAL AND METHODS: A one year cross-sectional consecutive study was conducted, in a total of 37 patients with no previously known heart disease who were admitted to the coronary unit for suspected anginal chest pain with normal cardiac enzymes and ECG. Abnormal cardiac troponin I levels at admission were defined as > or = 0.4 ng/ml, and were compared with coronary angiography or exercise test results and related to the duration of pain and the time from the appearance of symptoms to blood extraction. RESULTS: Thirty-three of the 37 initially included patients were studied. Coronary artery disease was diagnosed in 22, 15 of whom had increased troponin I values, yielding a sensitivity of 68% (48%-84%) and a specificity of 82% (53%-97%). In the subgroup of patients with pain lasting > 30 min, sensitivity reached 85% (59%-97%) and specificity 83% (42%-99%). There were no significant differences between subgroups with different time delays from appearance of symptoms to blood extraction. CONCLUSIONS: Cardiac troponin I is very useful for the studying ischemic chest pain without a definitive diagnostic ECG nor biochemical data, resulting in a high sensitivity and specificity for myocardial ischemic injury detection. Its diagnostic value increases in cases of prolonged pain episodes.

Protective effects of acidic fibroblast growth factor against cardiac arrhythmias induced by ischemia and reperfusion in rats.

An in vivo study has been conducted to evaluate the effect of acidic fibroblast growth factor (aFGF) on cardiac arrhythmias which occur in transient myocardial ischemia followed by reperfusion. In a rat model of myocardial ischemia and reperfusion, cardiac arrhythmias were assessed during the first three minutes of reperfusion. Systemic administration of 2.6 micrograms aFGF just before coronary recirculation resulted in a significant reduction in incidence and severity of ventricular extra beats (VEBs), ventricular tachycardia (VT) and ventricular fibrillation (VF), compared with control rats (VT incidence: 30% vs 80%, VF incidence: 10% vs 40%; episodes of VT: 4.1 +/- 0.34 vs 8.8 +/- 0.95; episodes of VF: 4.8 +/- 0.32 vs 11.5 +/- 1.47). Our results suggest a novel role for FGFs as potential antiarrhythmic agents.

Cardiovascular toxicities related to the infusion of cryopreserved grafts: results of a controlled study.

To evaluate cardiovascular toxicities associated with the infusion of cryopreserved grafts, we prospectively monitored the infusions of 29 autologous bone marrow transplant (BMT) recipients. Fifteen allogeneic BMT recipients served as a control group. Cardiac rhythm was recorded continuously with the Holter technique from at least 2 h before the start of graft infusion until 24 h after completion. Blood pressure was closely monitored during the same period. Graft infusions were performed through a standard transfusion filter with breaks between aliquots. When the infusion had commenced, diuretics were given frequently (40 and 40% of allogeneic BMT and autologous BMT recipients, respectively) to avoid fluid overload. Non-cardiovascular clinical toxicities were observed more frequently in autologous BMT patients (41% vs 6%, p = 0.02) and no significant differences were seen between autograft and allograft recipients in any of the measured cardiovascular parameters. The heart rate decreased slightly in both groups but no patient in either group had a heart rate of < 60 b.p.m. or heart block. No significant changes in blood pressure were detected in either group. Ventricular ectopic beats/atrial ectopic beats ratio increased in the autologous BMT group after graft infusion (0.7 vs 0, p = 0.1). Time to engraftment did not differ significantly from other published series. Our results suggest that increasing infusion time of cryopreserved material and using a standard filter may reduce toxicities associated with the infusion of cryopreserved grafts. Early administration of diuretics may contribute to better control of blood pressure.

[Late potentials analysis in patients with malignant ventricular arrhythmia]. / Análise de potenciais tardios em pacientes com arritmias ventriculares malignas.

PURPOSE: To assess the relationship between late potentials and spontaneous ventricular arrhythmias, organic heart disease, inducibility of arrhythmias at electrophysiological study and ejection fraction. METHODS: The population is comprised by 52 patients (41 men, 11 women with mean age 50 +/- 16 years) with spontaneous clinically documented ventricular tachycardia or ventricular fibrillation. An electrophysiological study was performed with conventional programmed stimulation. Within a week of the test a study of late potentials was also performed. RESULTS: Late potentials were documented in 73% of the patients with ventricular tachycardia and only in 17% of the patients with ventricular fibrillation. Sixty-eight percent of the patients with ischemic cardiopathy presented late potentials and in these, ventricular tachycardia was inducible in 93%. Only one from a group of 7 patients with ventricular arrhythmias and no organic heart disease, presented late potentials. In patients with late potentials, 84% have inducible ventricular tachycardia, but only 26% of patients without late potentials have inducible ventricular tachycardia. The incidence of late potentials was inversely correlated with left ventricular ejection fraction. CONCLUSION: The presence of late potentials was more frequent in patients with ventricular tachycardia than in patients with ventricular fibrillation. The presence of late potentials has a sensibility of 81.5% and a specificity of 78% to detect patients with inducible ventricular tachycardia.

[The nonpharmacological treatment of tachyarrhythmias in 23 children and adolescents]. / Tratamiento no farmacológico de las taquiarritmias en 23 pacientes en edad infantil y juvenil.

We comment the results with non pharmacological treatment in 23 patients (mean age 11 +/- 4 years) with multiple episodes of palpitations, most of them required intravenous drugs for interrupting it. Twenty-eight procedures were performed, 17 catheter ablation and 11 surgical interventions. The energy source employed for fulguration until 1990 was DC and since 1991 radiofrequency. The best results with catheter ablation were obtained with accessory pathways. Interruption was achieved in all patients after a mean of 1.2 sessions per patient, but it was definitive in only 72%. Most of the patients (81%) remained asymptomatic without antiarrhythmic drugs. Nine patients with accessory pathways underwent surgery interruption, it was achieved in all; only one patient had arrhythmia recurrence, due to a second pathway in a different localization. We could not ablate a ectopic atrial tachycardia, that underwent surgery. There was only one indication for surgery in a patient with ventricular tachycardia. Catheter ablation does not present technical problem in children and teenagers, different from adults. The presented results lead us to suppose that the indications for non pharmacological treatment in the young will become more common.