RESUMEN
AIMS: In the current literature, results of the low-voltage bridge (LVB) ablation strategy for the definitive treatment of atrioventricular nodal re-entry tachycardia (AVNRT) seem to be encouraging also in children. The aims of this study were (i) to prospectively evaluate the mid-term efficacy of LVB ablation in a very large cohort of children with AVNRT, and (ii) to identify electrophysiological factors associated with recurrence. METHODS AND RESULTS: One hundred and eighty-four children (42% male, mean age 13 ± 4 years) with AVNRT underwent transcatheter cryoablation guided by voltage mapping of the Koch's triangle. Acute procedural success was 99.2% in children showing AVNRT inducibility at the electrophysiological study. The overall recurrence rate was 2.7%. The presence of two LVBs, a longer fluoroscopy time and the presence of both typical and atypical AVNRT, were found to be significantly associated with an increased recurrence rate during mid-term follow-up. Conversely, there was no significant association between recurrences and patient's age, type of LVB, lesion length, number of cryolesions or catheter tip size. CONCLUSION: The LVB ablation strategy is very effective in AVNRT treatment in children. Recurrences are related to the complexity of the arrhythmogenic substrate.
Asunto(s)
Ablación por Catéter , Criocirugía , Taquicardia por Reentrada en el Nodo Atrioventricular , Adolescente , Niño , Estudios de Cohortes , Criocirugía/efectos adversos , Femenino , Humanos , Masculino , Recurrencia , Taquicardia por Reentrada en el Nodo Atrioventricular/diagnóstico , Taquicardia por Reentrada en el Nodo Atrioventricular/cirugía , Resultado del TratamientoRESUMEN
BACKGROUND: Recent evidence has shown that the presence of abnormal substrate can be demonstrated also among patients with "lone" AF. OBJECTIVES: Interatrial conduction slowing is likely to characterize patients with paroxysmal atrial fibrillation (AF) and it could be correlated to the left atrium area of prolonged local bipolar endocardial electrograms. METHODS: P-wave duration (PWD), amplified PWD and endocavitary interatrial conduction time (IACT), were analyzed in 60 patients; 30 undergoing de novo ablation for paroxysmal AF with normal atrial volumes and without any other cardiac disease and 30 of similar age undergoing electrophysiological study for atrioventricular nodal reentrant tachycardia or atrioventricular re- entrant tachycardia. In patients with AF, voltage maps and local bipolar electrograms (LBE) duration map were evaluated. RESULTS: Although PWD was <120â¯ms in 28 patients with AF and in 29 controls, patients with AF exhibited longer PWD, amplified-PWD and IACT. Although low-voltage areas (<0.5â¯mV) were not found in the study population, 28 of them demonstrated areas with LBE longer than 60â¯ms. These LBE were found mainly in the roof of the left atrium and their extension was correlated to IACT (Râ¯=â¯0.51, pâ¯=â¯0.004). IACT >135.5â¯ms identified the subjects who experienced AF with 90% sensitivity and 97% specificity. CONCLUSION: A subclinical interatrial conduction disturbance is demonstrable in subjects with paroxysmal AF and normal left atrial volume. IACT has a good correlation to the areas of abnormal LBE in the left atrium. IACT >135â¯ms identified subjects who have experienced AF.
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Fibrilación Atrial , Taquicardia por Reentrada en el Nodo Atrioventricular , Fibrilación Atrial/diagnóstico , Electrocardiografía , Atrios Cardíacos/diagnóstico por imagen , Sistema de Conducción Cardíaco , HumanosRESUMEN
Radiofrequency ablation (RFA) is the most widely used technique for the treatment of cardiac arrhythmias. A variety of factors, such as the electrode tip shape, the force exerted on the tissue by the catheter and the delivered power, combine to determine the temperature distribution, and as consequence, the lesion shape and size. In this context, being able to know the temperature reached in the myocardium during the RFA can be helpful for predicting the lesion dimensions to prevent the occurrence of undesired tissue damage. The catheters used so far in such procedures provide single-point temperature measurements within the probe (by means of embedded thermocouples or thermistors), so no information regarding the temperature changes occurring in myocardial tissues can be retrieved. The aim of this study was to assess the feasibility of fiber Bragg grating sensors (FBGs) to perform multi-point and millimetric-scale temperature measurements within myocardium subjected to RFA. The assessment has been performed on ex vivo porcine myocardium specimens undergoing RFA. Data show the feasibility of the proposed solution in providing spatial temperature distribution within the myocardial tissue during the entire RFA. These high-resolved measurements may allow reconstructing the temperature distribution in the tissue. This study lays the foundations for the implementation of 3D thermal maps to investigate how the supplied power, treatment time, force of contact and irrigation flow of the catheter influence the thermal effects within the tissue.
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Procedimientos Quirúrgicos Cardíacos , Ablación por Catéter , Corazón/fisiología , Ablación por Radiofrecuencia , Temperatura , Animales , Estudios de Factibilidad , Miocardio , PorcinosRESUMEN
Aims: Recently, voltage gradient mapping of Koch's triangle to find low-voltage connections, or 'voltage bridges', corresponding to the anatomic position of the slow pathway, has been introduced as a method to ablate atrioventricular nodal reentry tachycardia (AVNRT) in children. Thus, we aimed to assess the effectiveness of voltage mapping of Koch's triangle, combined with the search for the slow potential signal in 'low-voltage bridges', to guide cryoablation of AVNRT in children. Methods and results: From June 2015 to May 2016, 35 consecutive paediatric patients (mean age 12.1 ± 4.5 years) underwent 3D-guided cryoablation of AVNRT at our Institution. Fifteen children were enrolled as control group (mean age 14 ± 4 years). A voltage gradient mapping of Koch's triangle was obtained in all patients, showing low-voltage connections in all children with AVNRT but not in controls. Prior to performing cryoablation, we looked for the typical 'hump and spike' electrogram, generally considered to be representative of slow pathway potential within a low-voltage bridge. In all patients the 'hump and spike' electrogram was found inside bridges of low voltage. Focal or high-density linear lesions, extended or not, were delivered guided by low-voltage bridge visualization. Acute success rate was 100%, and no recurrence was reported at a mean follow-up of 8 ± 3 months. Conclusions: Voltage gradient mapping of Koch's triangle, combined with the search for the slow potential signal in low-voltage bridges, is effective in guiding cryoablation of AVNRT in paediatric patients, with a complete acute success rate and no AVNRT recurrences at mid-term follow-up.
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Nodo Atrioventricular/cirugía , Criocirugía , Técnicas Electrofisiológicas Cardíacas , Taquicardia por Reentrada en el Nodo Atrioventricular/cirugía , Potenciales de Acción , Adolescente , Adulto , Factores de Edad , Nodo Atrioventricular/fisiopatología , Estudios de Casos y Controles , Niño , Preescolar , Criocirugía/efectos adversos , Femenino , Frecuencia Cardíaca , Humanos , Masculino , Valor Predictivo de las Pruebas , Recurrencia , Taquicardia por Reentrada en el Nodo Atrioventricular/diagnóstico , Taquicardia por Reentrada en el Nodo Atrioventricular/fisiopatología , Factores de Tiempo , Resultado del Tratamiento , Adulto JovenRESUMEN
A 23-year-old athlete with symptomatic low burden premature ventricular contraction (PVC) with left bundle branch block morphology and inferior axis morphology was sent to our department for RV mapping and PVC ablation. Exit zone of the PVC was easily and clearly defined by the bipoles A3-A4 achieving optimal and detailed pacemapping (Panels A-C) near the His bundle (yellow dots). The spatial conformation and the smooth shape of the catheter would definitely help everyday procedures in the setting of low burden PVC/noninducible focal ventricular arrhythmia, especially when the focus is located very close to the conductive tissue.