Comparison of cryoablation with 3D mapping versus conventional mapping for the treatment of atrioventricular re-entrant tachycardia and right-sided paraseptal accessory pathways.

UNLABELLED: Aim Transcatheter cryoablation is a well-established technique for the treatment of atrioventricular nodal re-entry tachycardia and atrioventricular re-entry tachycardia in children. Fluoroscopy or three-dimensional mapping systems can be used to perform the ablation procedure. The aim of this study was to compare the success rate of cryoablation procedures for the treatment of right septal accessory pathways and atrioventricular nodal re-entry circuits in children using conventional or three-dimensional mapping and to evaluate whether three-dimensional mapping was associated with reduced patient radiation dose compared with traditional mapping. METHODS: In 2013, 81 children underwent transcatheter cryoablation at our institution, using conventional mapping in 41 children - 32 atrioventricular nodal re-entry tachycardia and nine atrioventricular re-entry tachycardia - and three-dimensional mapping in 40 children - 24 atrioventricular nodal re-entry tachycardia and 16 atrioventricular re-entry tachycardia. RESULTS: Using conventional mapping, the overall success rate was 78.1 and 66.7% in patients with atrioventricular nodal re-entry tachycardia or atrioventricular re-entry tachycardia, respectively. Using three-dimensional mapping, the overall success rate was 91.6 and 75%, respectively (p=ns). The use of three-dimensional mapping was associated with a reduction in cumulative air kerma and cumulative air kerma-area product of 76.4 and 67.3%, respectively (p<0.05). CONCLUSIONS: The use of three-dimensional mapping compared with the conventional fluoroscopy-guided method for cryoablation of right septal accessory pathways and atrioventricular nodal re-entry circuits in children was associated with a significant reduction in patient radiation dose without an increase in success rate.

Preexcitación ventricular: los niños sintomáticos y asintomáticos tienen el mismo riesgo potencial de muerte cardíaca súbita

Objetivos: los niños y adolescentes con preexcitación ventricular (PV) tienen un mayor riesgo de muerte súbita cardíaca (MSC). Si bien la terapia antiarrítmica y la ablación por catéter son tratamientos temporales o definitivos bien establecidos para los pacientes con síndrome de Wolff-Parkinson-White (WPW), aún no hay acuerdo acerca del manejo óptimo de los niños con PV asintomática. Teniendo en cuenta las directrices y recomendaciones más recientes, el objetivo de este estudio fue determinar las características electrofisiológicas de los pacientes jóvenes con PV y síndrome de WPW, con el fin de valorar y comparar su riesgo potencial de MSC. Métodos y resultados: se realizó un estudio retrospectivo de 124 pacientes jóvenes consecutivos con PV (51 con síndrome de WPW y 73 asintomáticos) sometidos a un estudio electrofisiológico transesofágico. En condiciones basales se indujo una taquicardia por reentrada auriculoventricular (TRAV) en 13 pacientes con WPW vs 10 pacientes asintomáticos (25,5% vs 13,7%, p=NS). Se indujo fibrilación auricular (FA) en 13 pacientes con WPW vs 15 pacientes asintomáticos (25,5% vs 20,5%, p=NS). Se encontró un intervalo R-R preexcitado más corto (IRRPEC o SPERRI, por sus siglas en inglés) £ 250 ms durante la FA en cuatro pacientes con WPW vs seis pacientes asintomáticos (30,8% vs 40%, p=NS). Durante la infusión de isoproterenol o la prueba de esfuerzo, se indujo TRAV en 31 de 44 pacientes con WPW vs 33 de 69 pacientes asintomáticos (70,4% vs 47,8%, p=0,018). Se indujo fibrilación auricular en 12 de 44 pacientes con WPW vs 21 de 69 pacientes asintomáticos (27,3% vs 30,4%, p=NS). Se encontró un IRRPEC £ 210 ms en 6 de 12 pacientes con WPW vs 10 de 21 pacientes asintomáticos (50% vs 476%, p=NS). No se observó ninguna correlación estadísticamente significativa entre la ubicación de la vía accesoria y los síntomas, inducibilidad de TRAV/FA, o media de período refractario de la vía accesoria (PREVA)/IRRPEC. Conclusión: los niños y adolescentes con síndrome de WPW tienen una mayor tasa de inducibilidad de TRAV que los pacientes asintomáticos. Sin embargo, no se encontraron diferencias entre los dos grupos en cuanto a la vulnerabilidad auricular y a los parámetros relacionados con el riesgo de MSC.

Ventricular pre-excitation: symptomatic and asymptomatic children have the same potential risk of sudden cardiac death.

AIMS: Children and adolescents with ventricular pre-excitation (VPE) are at increased risk for sudden cardiac death (SCD). Although antiarrhythmic therapy and catheter ablation are well established temporary or definitive treatments for patients with Wolff-Parkinson-White (WPW) syndrome, the optimal management of children with asymptomatic VPE remains to be clearly defined. On the basis of the most recent guidelines and recommendations, the aim of this study was to determine the electrophysiological characteristics of young patients with VPE and WPW syndrome to assess and compare their potential risk of SCD. METHODS AND RESULTS: We retrospectively investigated 124 consecutive young patients with VPE (51 with WPW syndrome and 73 asymptomatic) who underwent transoesophageal electrophysiological study. At baseline, atrioventricular reentrant tachycardia (AVRT) was induced in 13 WPW vs. 10 asymptomatic patients (25.5 vs. 13.7%, P = NS). Atrial fibrillation (AF) was induced in 13 WPW vs. 15 asymptomatic patients (25.5 vs. 20.5%, P = NS). A shortest pre-excited R-R interval (SPERRI) ≤250 ms during AF was found in four WPW vs. six asymptomatic patients (30.8 vs. 40%, P = NS). During isoproterenol infusion or stress testing, AVRT was induced in 31 of 44 WPW vs. 33 of 69 asymptomatic patients (70.4 vs. 47.8%, P = 0.018). Atrial fibrillation was induced in 12 of 44 WPW vs. 21 of 69 asymptomatic patients (27.3 vs. 30.4%, P = NS). A SPERRI ≤ 210 ms was found in 6 of 12 WPW vs. 10 of 21 asymptomatic patients (50 vs. 47.6%, P = NS). No statistically significant correlation was observed between accessory pathway location and symptoms, AVRT/AF inducibility, or mean APERP/SPERRI values. CONCLUSION: Children and adolescents with WPW syndrome have a higher rate of AVRT inducibility than asymptomatic patients. However, no differences between the two groups were found in atrial vulnerability and parameters related to the risk of SCD.

Cryoablation of AVNRT in children and adolescents: early intervention leads to a better outcome.

INTRODUCTION: Currently, transcatheter cryoablation is a well-established technique for the treatment of atrioventricular nodal reentry tachycardia (AVNRT) in children. In the past decade, many studies have focused on identifying factors that may affect acute and long-term outcome, but none has been shown to be strongly predictive of treatment success. The aim of our study was to determine whether patient age and cryoablation method correlate with acute and long-term success. METHODS AND RESULTS: We retrospectively reviewed 202 consecutive patients (98 male, mean age 11.5 years; range: 4-20 years) who underwent cryoablation for AVNRT at our institution from October 2002 to August 2012. Patients were divided into 2 groups according to age: group A <12 years (n = 101) and group B ≥12 years (n = 101). A single lesion or linear lesion technique was employed. A total of 217 cryoablation procedures were performed: 106 (49%) in group A and 111 (51%) in group B. All patients were evaluated in our postoperative follow-up program. The overall recurrence rate was 10.9% (22/202). AVNRT recurrence was significantly lower in group A than in group B (4.95% vs 16.8%, P = 0.000). No significant differences in recurrence rate were observed between groups when using the single lesion versus linear lesion technique. There were no permanent cryoablation-related complications. CONCLUSION: Our findings show that cryoablation had no complications and a very good success rate. Type of cryolesion is not predictive of long-term success, whereas lower recurrence rate is achieved when cryoablation is performed at a younger age.

Cryoablation of right-sided accessory pathways in children: report of efficacy and safety after 10-year experience and follow-up.

AIMS: The aim of this study was to report the 10-year experience of our Institution in cryoablation of supraventricular tachycardia due to a right accessory pathway (AP). METHODS AND RESULTS: Seventy-one cryoablations of right AP were performed between July 2002 and October 2011 in our Institution in 66 patients (mean age 12 + 3 years, 56% males). Acute procedural success rate was 97%: 80% in patients with concealed AP and 100% in those with manifest AP (P < 0.05). Acute procedural success rate was not related to institutional experience. No permanent complication occurred. Sixteen patients had recurrences during the follow-up (18.6 ± 6.6 months; range 3-111), 13 within the first month of follow-up, 2 within the 6 months of follow-up, and 1 within 12 months of follow-up. Cox regression showed that sex, patient age, number of delivered cryo-bonus, and presence of manifest or concealed AP are not independent predictors of procedural success. Among the 16 patients with recurrences, in 10 a cryoablation redo was successful and with no further AP recurrences. The mean fluoroscopy time was 28.4 min (range 19.7-44.6) with a significant decrease (P = 0.033) in relation to the increase of the institutional experience. There were no permanent ablation-related complications. CONCLUSION: Cryoablation of right-sided AP is effective and very safe in children. Better results are achieved in manifest AP. The learning curve has a real impact in the attempt to reduce the fluoroscopy time.

Acute quadriplegic myopathy in a 16-month-old child.

We present a case of a 16-month old previously healthy child who was hospitalized because of an acute respiratory insufficiency most likely caused by a viral infection and who then developed a severe acute quadriplegic myopathy (AQM). Initial clinical symptoms were respiratory acidosis, dypnea, intense wheezing, and deterioration of the level of consciousness, which required orotracheal intubation and mechanical ventilation. We administered neuromuscular blocking agents, corticosteroids, and antibiotics. After 9 days the clinical picture improved. An attempt to wean from the ventilator failed. We diagnosed AQM. This paper discusses AQM and its clinical importance.