Successful transcatheter ablation of fascicular potential in pediatric patients with left posterior fascicular tachycardia / 中华儿科杂志

<p><b>OBJECTIVE</b>To simplify the methods of transcatheter mapping and ablation in the pediatric patients with left posterior fascicular tachycardia.</p><p><b>METHOD</b>While in sinus rhythm, the fascicular potential can be mapped at the posterior septal region (1 - 2 cm below inferior margin of orifice of coronary sinus vein), which display a biphasic wave before ventricular wave, and exist equipotential lines between them. When the fascicular potential occurs 20 ms later than the bundle of His' potential, radiofrequency was applied. Before applying radiofrequency, catheter position must be observed using double angle viewing (LAO 45°RAO 30°), and it should be made sure that the catheter is not at His' bundle. If the electrocardiogram displays left posterior fascicular block, the correct region is identified and ablation can continue for 60 s. Electrocardiogram monitoring should continue for 24 - 48 hours after operation, and notice abnormal repolarization after termination of ventricular tachycardia. Aspirin [2 - 3 mg/(kg·d)] was used for 3 months, and antiarrhythmic drug was discontinued. Surface electrocardiogram, chest X-ray and ultrasound cardiography were rechecked 1 d after operation. Follow-up was made at 1 month and 3 months post-discharge. Recheck was made half-yearly or follow-up was done by phone from then on.</p><p><b>RESULT</b>Fifteen pediatric patients were ablated successfully, and their electrocardiograms all displayed left posterior fascicular block after ablation. None of the patients had recurrences during the 3 to 12 months follow-up period. In one case, the electrocardiogram did not change after applying radiofrequency ablation and the ventricular tachycardia remained; however, on second attempt after remapping, the electrocardiogram did change. The radiofrequency lasted for 90 seconds and ablation was successful. This case had no recurrences at 6 months follow-up.</p><p><b>CONCLUSION</b>Transcatheter ablation of the fascicular potential in pediatric patients with left posterior fascicular tachycardia can simplify mapping, reduce operative difficulty and produce a distinct endpoint for ablation.</p>

Radiofrequency catheter ablation of arrhythmias in pediatric patients guided by three-dimensional mapping system / 中华儿科杂志

<p><b>OBJECTIVE</b>To explore safety, indications and advantages of mapping and ablation of arrhythmia in children guided by Carto and Ensite system.</p><p><b>METHODS</b>Guided by Carto system, radiofrequency catheter ablation (RFCA) was performed on 8 pediatric patients with tachycardia whose mean age was (6.2 + or - 1.7) years, mean weight was (18.0 + or - 2.0) kg. Guided by Ensite system, RFCA was performed on 10 pediatric patients with arrhythmia, 8 of them were ablated guided by Ensite Array system: 6 cases with premature ventricular contractions (PVCs), 2 cases with right atrial tachycardia, their mean age was (11.3 + or - 1.2) years, and mean weight (40.0 + or - 5.0) kg. The other two cases with W-P-W syndrome were ablated guided by Ensite Navx system.</p><p><b>RESULT</b>Guided by Carto system, 8 cases were successfully mapped and ablated: 6 cases had incision atrial tachycardia, 1 case had left atrial tachycardia and 1 case had right atrial tachycardia. In 1 case with incision atrial tachycardia the condition recurred after 3 months, and was ablated again successfully. Guided by Ensite Array system, 6 cases with PVCs (in 2 originating from the right ventricular inflow tract and in 4 originating from the right ventricular outflow tract) and 2 cases with right atrial tachycardia were successfully mapped and ablated, PVCs of the first 6 cases were reduced from (32 333 + or - 4509) 24 h to (0-4)/24 h after ablation. In 1 case with automatic atrial tachycardia, mapping could not be done by Ensite Array system, because P wave could not be identified from T wave. Single bolus of adenosine 20 mg was given within 30 s to let ventricles stop for 2 s (cardio-ventricular pacing standby) until T wave vanished, mapping and ablation were operated again successfully, but another atrial tachycardia occurred 1 day later. Guided by Ensite Navx system, 2 cases with W-P-W syndrome were successfully ablated, operation under X-rays lasted for 8 and 10 min. In none of the 9 patients the disease recurred after follow-up for 6 months.</p><p><b>CONCLUSION</b>Carto system is suitable for mapping and ablation in pediatric patients with continuous tachycardia, especially with incision atrial tachycardia; Ensite Array system fits children older than 10 years with right heart discontinuous arrhythmia; and Ensite NavX system can set up model and display endocardial anatomic structure quickly. Compared with two-dimensional mapping system, the three-dimensional mapping system (Carto and Ensite) can display the origin of arrhythmia and activation sequence clearly, decrease difficulty of operation efficiently and diminish operation time under X-ray.</p>

Applying interventional treatment for the atrial septal defect in 165 children under five years of age / 中华儿科杂志

<p><b>OBJECTIVE</b>To study the clinical technology of transcatheter closure of secundum atrial septal defects (ASD) with Amplatzer device in younger and lower body weight children.</p><p><b>METHODS</b>The transcatheter closure of ASD using Amplatzer septal occluder (ASO) was performed in 165 children under 5 years of age (75 boys and 90 girls) with secundum ASD from Aug 1998 to May 2004. The age of the cases ranged from 2 to 5 (mean 3.7 +/- 1.1) years. The body weight ranged from 9 to 18 (mean 12.6 +/- 2.3) kg. The ratio of pulmonary circulation quantity to the systemic circulation quantity (Qp/Qs) was 3.2 +/- 1.9. All the patients underwent clinical examination, X-ray, electrocardiography (ECG) and echocardiography (Echo) for diagnosis of secundum ASD. The transthoracic echocardiography (TTE) was used to detect and measure the defect of the patients and even trans-esophageal echocardiography (TEE) had to be used when it was necessary. With Echo and X-ray guidance, the measuring balloon was used in the body and outside the body to determine the balloon-stretch diameters of ASD, and proper occluders were selected accordingly for the patients for interventional treatment of ASD.</p><p><b>RESULTS</b>The devices were implanted successfully in 163 (98.8%) cases. One failure occurred in a case in whom the device moved into the left atrium after release, and the other failure was that the position of the device was uncertain because of temporary unavailability of a special transducer for TEE. Surgical operations were performed for these two cases. The stretch diameter of ASD was from (8 - 30) mm, (mean 18.3 +/- 5.1) mm. The size of device was selected according to the stretch diameter of ASD. The diameter of the occluders selected was from (8 - 30), (mean 18.6 +/- 5) mm in this series. The occlusion procedure was monitored by fluoroscopy and TTE and in 5 cases (3%) by TEE. The diameter of right ventricle was improved within 2 days after occlusion from (mean 16.4 +/- 4.9) mm to (mean 12.6 +/- 3.8) mm, (p < 0.01). One hundred and forty seven cases belonged to the simple secundum ASD(89%). Thirteen cases who were complicated with other cardiac deformity were treated successfully with different interventional procedure. Six cases had multiple openings and three of these cases had tumour-like changes of the atrial septum which were closed completely just by one occluder. In only one case small quantity of residual shunt remains. No other severe complication was found in this group. About 100 cases (60%) had large ASD, so the procedure was more difficult in those cases.</p><p><b>CONCLUSION</b>The clinical effectiveness of treatment of ASD in children under 5 years of age with Amplatzer occluders was satisfactory and therefore this therapeutic procedure is feasible for this age group of patients. Nevertheless, we do not recommend to use the technique for infants and children under 2 years of age. Strict selection of indications and proper size of occluder and good cardiologic and surgical settings are among the basic factors for successful interventional occlusion of ASD in young children.</p>

Radiofrequency catheter ablation of septum originated tachycardia in children / 中华儿科杂志

<p><b>OBJECTIVE</b>The study was undertaken to analyze retrospectively the results of radiofrequency catheter ablation (RFCA) on septum originated tachycardia in children with arrhythmia. The 98 children were all treated with RFCA on septum originated tachycardia in which the ablation sites were located near the bundle of His.</p><p><b>METHODS</b>Fifty female and forty-eight male cases were included in this analysis. They were at the age of 8.1 +/- 2.3 years and their body weight was (28 +/- 9) kg. The arrhythmia they suffered from consisted of atrioventricular nodal reentry tachycardia (AVNRT) (n = 62), atrioventricular reentry tachycardia (AVRT) on septum (n = 25), atria Itachycardia on Koch areas (n = 3) and left ventricular tachycardia (ILVT) on the septum (n = 8). Swartz SRO long sheath was used on the right site ablation. Titration of capacity and degreed time of increase were used in the ablation.</p><p><b>RESULTS</b>Radiofrequency ablation was successful in all cases. Eleven cases had relapse after the procedure. They accepted RFCA again and then the treatment succeeded. One case of AVRT at the posterior septum experienced complete atrioventricular block (AVB) during ablation. Two weeks later this case was implanted with permanent pacemaker.</p><p><b>CONCLUSIONS</b>The septal site is narrow and small in children. Atrioventricular node is tender. If the above facts were neglected, it was very likely to cause AVB, especially in children accepting the procedures of electrophysiologic study an RFCA on the septal site. Attention should be paid to the followings during such procedures: ablation in the sinus rhythm; ablation following the principle, titration of capacity and degreed time of increase; ablation at the right site long sheath; thermo-ablation catheter application and ablation on the two sides of septum in the posterior septum ablation procedure. The end-point of ablation in children should be the elimination of tachycardia and the delta wave, disassociation of VA or passing through bundle of His at pacing in the ventricle, disappearance of jumping conduction or no echo or one echo but without AVNRT after infusion of isoprenaline and stimulation procedure. Avoiding bundle of His injury is important during the procedure of ablation in children.</p>

Ablation of postoperative "incisional" reentrant atrial tachycardia and flutter in children using the CARTO system / 中华儿科杂志

<p><b>OBJECTIVE</b>In children with congenital heart diseases who have undergone surgical interventions, postoperative arrhythmias frequently complicate the clinical course. "Incisional" atrial tachycardia or flutter is one of the most common forms of postoperative arrhythmias in these patients and can lead to significant morbidity and even mortality. The aim of this study was to investigate how to use antiarrhythmic drugs and the CARTO system to treat these cases.</p><p><b>METHODS</b>There were 12 patients with "incisional" atrial tachycardia or flutter complicating surgery for congenital heart diseases in this study (3 patients with correction of tetrology of Fallot, 3 with atrial septal defect repair, 2 with ventricular septal defect repair, 1 with switch, 1 with repair of Ebstein's anomaly, 1 with total anomalous pulmonary venous drainage, and 1 with atrial septal closure with the Amplatzer septal occlusion). Patients whose body weight was less than 10 kg or those who did not wish to accept ablation were treated with antiarrhythmic drugs, including digitoxin, propranolol, metoprolol and cordarone. CARTO system was used to map 6 patients whose body weight was more than 10 kg and who agreed with accepting ablation for atrial tachycardia and flutter. Radio-frequency ablation was performed in these 6 cases including two cases of "incisional" atrial tachycardia and 4 of atrial flutter.</p><p><b>RESULTS</b>(1) The antiarrhythmic drug was successful in 6 patients with "incisional" atrial tachycardia. (2) Six patients including 2 children with "incisional" atrial tachycardia and 4 children with atrial flutter were successfully ablated. But one case of "incisional" atrial tachycardia relapsed after 3 months of ablation. This case, however, was successfully ablated again later. No further relapse was observed during the 2 - 24 months of follow-up.</p><p><b>CONCLUSION</b>Ablation of "incisional" atrial tachycardia and flutter is the first choice to treat the patients whose body weight is more than 10 kg and those who agree with accepting ablation by CARTO system. Drug therapy of "incisional" atrial tachycardia and flutter is palliative and it is the only selection to treat the patients whose body weight is less than 10 kg or those who do not wish to accept ablation procedure.</p>