Eduardo Castellanos

Comparison of radiofrequency catheter ablation of drivers and circumferential pulmonary vein isolation in atrial fibrillation: a noninferiority randomized multicenter RADAR-AF trial.

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

Taquicardias paroxísticas supraventriculares y síndromes de preexcitación

Paroxysmal supraventricular tachycardias are fast and usually regular rhythms that require some structure above the bifurcation of the His bundle to be continued. The 3 most common types are atrial tachycardias, atrioventricular nodal reentrant tachycardias, and tachycardias mediated by an accessory pathway. The last two varieties are discussed in the present manuscript. Their prognosis is benign regarding life expectancy but typically they are symptomatic and chronically recurrent, producing a certain disability. They usually occur in people without structural heart disease. Pharmacologic therapy is possible, but given the high efficacy of catheter ablation, these procedures are frequently chosen. Ventricular preexcitation is due to the presence of an accessory pathway, usually atrioventricular. The clinical course can be asymptomatic, generating a characteristic electrocardiographic pattern, produce paroxysmal supraventricular tachycardias, or facilitate other types of arrhythmias. Very rarely, they can cause sudden cardiac death. The treatment of choice for symptomatic patients is catheter ablation of the accessory pathway. The therapeutic attitude towards asymptomatic preexcitation remains controversial.

First Postpacing Interval Variability During Right Ventricular Stimulation A Single Algorithm for the Differential Diagnosis of Regular Tachycardias

BACKGROUND Failure to differentiate supraventricular from ventricular arrhythmias is the most frequent cause of inappropriate implantable cardioverter-defibrillator therapies. Although a sudden-onset criterion is available to differentiate sustained monomorphic ventricular tachycardias (SMVTs) and sinus tachycardias (STs), SMVTs arising during ST and SMVTs gradually accelerating above the cutoff rate can remain undetected. Regular paroxysmal atrial tachycardias (ATs) also can be undetected by onset and stability algorithms. We hypothesized that the first postpacing interval (FPPI) variability after overdrive right ventricular pacing may differentiate SMVTs from STs and ATs. METHODS AND RESULTS FPPI variability was measured in 23 SMVTs (cycle length [CL] 366+/-50 ms [VT group]), 27 supraventricular tachycardias, 15 episodes of induced or simulated ATs (CL 376+/-29 ms [AT group]), and 12 exercise-related STs (CL 381+/-24 [ST group]). Sequences of trains of 5, 10, and 15 beats were delivered with a CL 40 ms shorter than the tachycardia CL. An FPPI absolute mean difference between consecutive trains of 5 and 10 beats (deltaFPPI) < or =25 ms identified all VTs (mean difference 5+/-7 ms). In the AT group, the deltaFPPI was >25 ms in all sequences (mean difference 129+/-60 ms, P<0.01). In the ST group, the deltaFPPI was >50 ms in all STs (mean difference 118+/-47 ms, P<0.01). CONCLUSIONS FPPI variability may differentiate SMVT from AT and ST. This criterion is potentially useful in implantable devices that use a single ventricular lead.

Loss of biventricular pacing due to T-wave oversensing

The benefits obtained with cardiac resynchronization therapy are directly related to the occurrence of continuous biventricular pacing. We report a case of intermittent loss of biventricular pacing due to ventricular oversensing that worsened the functional status of the patient.

Inducción de arritmias ventriculares por estimulación antibradicardia apropiada en pacientes portadores de desfibrilador automático

Introduccion y objetivos La induccion de arritmias ventriculares por estimulacion ventricular antibradicardia apropiada en pacientes portadores de desfibrilador automatico implantable es un tipo de proarritmia raramente descrito. El objetivo del estudio es evaluar la incidencia, caracteristicas y manejo de este tipo de episodios. Metodos Revisamos de manera retrospectiva los registros de seguimiento de 180 pacientes portadores de desfibrilador automatico implantable con capacidad de almacenamiento de electrogramas. Se analizaron los episodios de arritmia ventricular inducidos por marcapasos, definidos como aquellos que empiezan inmediatamente despues de un estimulo apropiado de marcapasos, en un paciente con ritmo propio habitual. Se evaluaron el numero de episodios por paciente, el tipo de arritmia inducida, el modo de inicio, la terapia administrada y la efectividad de las medidas adoptadas para corregir el problema. Resultados Se detectaron episodios de arritmia ventricular inducidos por estimulacion en 9 pacientes (5%). Siete de ellos recibieron terapia, que fue efectiva en todos los casos. El numero de episodios por paciente oscilo entre uno y 95 (138 taquicardias ventriculares y 20 taquicardias ventriculares polimorficas/fibrilaciones ventriculares) y se iniciaron por estimulacion ventricular tras una pausa postextrasistolica o durante fibrilacion auricular. Los cambios en la frecuencia de estimulacion resolvieron el problema en 3 de 6 pacientes y la disminucion del voltaje de estimulacion en 3 de 3 casos. En 4 pacientes se anulo la funcion de marcapasos. Conclusiones La induccion de arritmias ventriculares por terapia antibradicardia apropiada es relativamente frecuente en pacientes portadores de desfibrilador automatico implantable. Se puede corregir cambiando la frecuencia y/o la energia de estimulacion, aunque en algun caso puede ser necesario anular la funcion de marcapasos.

Repetitive pacemaker spike during the vulnerable period in a cardiac resynchronization therapy defibrillator

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Utilidad en la práctica clínica del tratamiento antiarrítmico tras cardioversión eléctrica en pacientes sin cardiopatía estructural

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Valor de la angiografía rotacional radiológica intraprocedimiento en la ablación de fibrilación auricular. Comparación con otras técnicas de imagen

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

Electrofisiología cardiaca y arritmias

particular care should be taken when dressing the wound and in ensuring that the system is stably fixed in the cervical region of the patient. On the other hand, the fact that it can be connected to a permanent pacemaker generator allows for programming of more physiologic pacing modes that help to maintain the patient in a stable clinical condition and allow the patient to walk about without clinical deterioration. Such advantages are particularly desirable in patients who are totally dependent on pacing and who require very prolonged temporary pacing. The small size of the generator is conducive to portability, and this in turn helps ensure that the patient can walk around and has greater mobility in general. As a precaution, the resterilized pacemaker generators that are used for this purpose, although only ever in contact with the skin of the patient, should come from patients without evidence of infection at the time of switching to minimize the possibility of infection. The greater cost of the active fixation electrode used compared to the usual temporary pacing electrodes is compensated by the fact that the patient does not require admission to hospital in a unit with facilities for close patient monitoring. This technique should be considered in patients who will require prolonged temporary pacing for any reason, particularly those who are pacing-dependent. Miguel A. Arias,* Alberto Puchol, Marta Pachón, Jesús Jiménez-López, and Luis Rodrı́guez-Padial

Comparison of Radiofrequency Catheter Ablation of Drivers and Circumferential Pulmonary Vein Isolation in Atrial Fibrillation

En este articulo se comentan algunos de los trabajos mas relevantes publicados durante el ultimo ano en el campo de las arritmias y la electrofisiologia cardiaca, debido a su importancia clinica y a las mejoras que implementan en el continuo desarrollo tecnologico de los procedimientos invasivos en electrofisiologia cardiaca.