Objective: To summarize the clinical and electrophysiological characteristics of children with Wolff-Parkinson-White syndrome or ventricular pre-excitation. Methods: One hundred and seventy-nine consecutive children with Wolff-Parkinson-White syndrome or ventricular pre-excitation who were hospitalized at Beijing Anzhen Hospital Affiliated to Capital Medical University and planned to accept radiofrequency ablations were selected.Electrocardiogram and echocardiography were completed and detailed clinical data were collected before ablations.Anterograde refractory period of accessory pathways (ERPAPA) and retrograde ventriculoatrial conduction were measured during electrophysiology studies.The clinical and electrophysiological characteristics of these children were analyzed. Results: The ratio of left-sided to right-sided accessory pathways was 1.001.93(61 cases vs.118 cases). Six out of 61 patients with left-sided accessory pathways were verified by electrophysiology study.There was no statistical difference of P-R interval and QRS duration between patients with right-sided and left-sided accessory pathways(all P>0.05). Twelve patients were combined with congenital heart diseases.Fourteen patients with right-sided accessory pathways were of ventricular pre-excitation induced dilated cardiomyopathy.ERPAPA was measured successfully in 110 patients, ERPAPA less than 250 ms accounted for 32.7%(36/110 cases). Six children with two pathways were recognized.Antidromic atrioventricular reentrant tachycardia was induced in 3 children.One child had slow conduction pathway localized in right-sided septum. Conclusions Right-sided overt accessory pathways are more common in children with Wolff-Parkinson-White syndrome or ventricular pre-excitation.Organic heart diseases are not uncommon.Besides congenital heart disease, a small proportion of patients with right overt accessory pathways may develop ventricular pre-excitatory induced dilated cardiomyopathy resulting from ventricular wall dyskinesia.Most of the decremental retrograde ventriculoatrial conduction is the characteristic of ventricular muscles rather than the accessory pathways in nature.Two pathways are not uncommon in children with Wolff-Parkinson-White syndrome or ventricular pre-excitation.Before finishing radiofrequency ablation, the anterograde and retrograde function of the accessory pathway should be evaluated in detail again because it is easy to neglect the existence of another accessory pathway.

Objective: This study aimed to investigate the correlation between supraventricular tachycardia (SVT) and tachycardia-induced cardiomyopathy(TIC) in children and assess the risk factors for the development of TIC. Method: One hundred and eighty-three patients were recruited in four hospitals of Beijing diagnosed as SVT were divided into two groups depending on whether or not complicated with TIC. The age, gender, tachycardia type, ventricular rate during tachycardia, frequency of tachycardia episodes and duration of tachycardia were compared between the two groups and risk factors associated with TIC were analyzed. Statistical analyses were performed using t test, Mann-Whitney U and χ² test. Result: Totally 183 patients were included in this study (paroxysmal supraventricular tachycardia, PSVT, n=149; atrial tachycardia, AT, n=34). The incidence of TIC was 13.1%. There was significant difference regarding the incidence of TIC between children with AT and children with PSVT (26.5% vs. 10.1%, χ²=6.537, P=0.011). The percentage of AT in patients with TIC was significantly higher than patients without TIC (37.5% vs. 15.7%, χ²=6.537, P=0.011). Patients with TIC had a higher frequency of tachycardia episodes(2.5(1.0-4.8) beats/year vs 4.0(1.0-10.0) beats/year, Z=-2.223, P=0.026)and longer duration of tachycardia(11.0(1.1-36.0) h vs 2.5(1.0-12.0) h, Z=-2.154, P=0.031)compared with patients without TIC. Multivariate predictors of TIC was longer duration of tachycardia (OR=2.041, P=0.028). Conclusion TIC occurs in 13.1% of children with SVT. The incidence of TIC in children with AT is higher than in children with PSVT. Risk factor for the development of TIC is longer duration of tachycardia.

Objective: The study assessed the clinical characteristics and response to acute intravenous antiarrhythmic drug therapy of supraventricular tachycardia (SVT) in children. Methods: This was a multicenter prospective descriptive study including 257 children from First Hospital of Tsinghua University, Peking University First Hospital, Children's Hospital Affiliated to Capital Institute of Pediatrics and Beijing Anzhen Hospital who received intravenous antiarrhythmic drug therapy for SVT from July 2014 to February 2017. The clinical and tachycardia features, response to intravenous antiarrhythmic drug therapy of these children were characterized. Statistical analyses were performed using t test, Mann-Whitney U test, χ² test and H test. Results: The onset of SVT occurred at any age with a distribution with positive skewness, 57.6% (n=148) children<1 year, 17.5% (n=45) children1~<3 years, 10.5% (n=27) children 3~<6 years and 14.4% (n=37) children ≥ 6 years of age. The percentages of SVT types were 49.4% (n=127) for atrioventricular reentry tachycardia (AVRT), 4.3% (n=11) for atrioventricular nodal reentry tachycardia (AVNRT), 26.8% (n=69) for unclassified paroxysmal SVT and 19.5% (n=50) for atrial tachycardia (AT), respectively. Tachycardia-induced cardionyopathy (TIC) secondary to SVT developed in 30 of 225 (13.3%). Left ventricular ejection fraction (LVEF) of the 27 children attacked by TIC returned to normal after successful control of SVT (41.1%±6.3% vs. 60.3%±9.2%, t=-10.397, P=0.000). Complete termination of SVT by antiarrhythmic drugs was achieved in 164 of 257 (63.8%), partial termination rate was 18.7% (48 of 257) and failure to terminate rate was 17.5% (45 of 257). Propafenone (complete cardioversion in 98 (73.1%) of 134) and amiodarone (complete cardioversion in 23 (76.7%) of 30) showed better efficacy for SVT termination than adenosine (complete cardioversion in 26 (44.1%) 59) (χ²=20.524, P=0.000). Paroxysmal SVT had a higher termination rate on pharmacological therapy than AT (67.1% vs. 50.0%, χ²=6.337, P=0.042). Patients of different age groups had significantly different response to antiarrhythmic therapy (χ²=13.904, P=0.031). Children<1 year of age showed the least response to antiarrhythmic drug therapy with complete termination in 51 (55.4%) of 92. Adverse effects occurred in 9 patients (3.5%): Four patients had severe hypotensive shock using propafenone (n=3) and adenosine (n=1), and 3 patients had sinus arrest using adenosine. Conclusion Most (57.6%) children with SVT have their first clinical episode within 1 year of age, and AVRT is the most common type. TIC occurs in 13.3% of children with SVT. Intravenous antiarrhythmic drug therapy has a 63.8% complete termination rate for children with SVT and incidence of adverse effects is 3.5%. Propafenone and amiodarone are more effective for SVT termination in children than adenosine. Serious adverse effects may occur when using propafenone.

Objective:To observe and follow up the effect of transcatheter occlusion of the azygos/hemiazygos veins in patients with complex congenital heart diseases and venous stealing after bidirectional Glenn procedure, who had not meet the criteria of total cavopulmonary connection(TCPC) or corrective operation.Methods:This article analyzed retrospectively and followed up the effect of transcatheter occlusion of the azygos/hemiazygos vein in patients after bidirectional Glenn procedure hospitalized during February 2012 to September 2017.Results:Transcatheter occlusions of azygos veins were performed in 21 patients and left superior vena cava(LSVC) was occluded in one of patients meanwhile. Azygos veins and hemiazygos veins were both occluded in two patients. One patient had the hemiazygos vein occluded. Aortic-to-pulmonary collaterals were occluded in 6 patients in the meantime. Atrial septal defect occluders were applied in the transcatheter occlusions of azygos veins, hemiazygos veins and LSVC, except one patient with an azygos vein which was 5.5 mm in diameter. Saturation was increased from 0.78 to 0.85 through occlusion( P<0.05). The pressure of superior vena cava(SVC) did not elevate and the mean pressure of SVC was13.97mmHg and 14.22 mmHg before and after occlusion( P>0.05). No complications associated with interventional procedures occurred. There was no significant decrease in blood oxygen saturation. Facial and upper limb edema, varicose veins in the chest and abdominal wall, pleural effusion and peritoneal effusion did not happen during follow up of 2 years. Two patients underwent TCPC operation one year and five years after interventional occlusion separately. Conclusion:Transcatheter occlusion of azygos/hemiazygos vein or PLSVC was feasible in patients with complex congenital heart diseases and venous stealing after bidirectional Glenn procedure on the premise of choosing suitable indications. Suitable indications meant that the pressure of pulmonary artery and superior vena cava was less than 20 mmHg in the basal state, and the pressure of superior vena cava was also less than 20 mmHg before the release of the occluder. Occlusions may increase the oxygen saturation of patients, improve the quality of life, and even promote the development of pulmonary vascular bed, so as to achieve the indications of TCPC operation in some patients.

Objective: To explore the safety and effectiveness of left bundle branch area pacing (LBBAP) in children. Methods: Clinical data, pacing electrocardiogram and parameters of 6 patients (5 females and 1 male) who underwent permanent pacemaker implantation and LBBAP from January to June 2019 in the Department of Pediatric Cardiology of Anzhen Hospital were retrospectively analyzed. Results: The weight of the 6 patients aged between 9 and 14 years ranged from 26 to 48 kg. Five patients were diagnosed with third degree atrioventricular block, and 1 patient was diagnosed with cardiac dysfunction after right ventricular apical pacing. Cardiac function decreased in one patient and remained normal in the other five patients. Left ventricular end diastolic diameter (LVEDD) Z score was 1.85±0.65. V₁ lead showed changes like right bundle branch block in pacing electrocardiogram. No significant difference was found regarding QRS wave duration ((95±13) ms vs. (111±20) ms, t=-1.610, P>0.05) between preoperation and postoperation. Pacing threshold was (0.85±0.26) V. The sensing threshold was (15.0±4.3) mV and the impedance was (717±72) Ω. P potential was recorded in 3 cases. The earliest left ventricular local activation time was (56±5) ms and remained stable at different output voltages. Postoperative echocardiography revealed that the electrodes were located near the endocardium of the left ventricular septum. No complications such as myocardial perforation and electrode dislocation occurred during follow-up. The pacing threshold, sensing threshold and impedance were (0.60±0.09)V, (16.1±3.9)mV, (662±78)Ω respectively at 3 months after operation. The patient with low left ventricular ejection fraction (LVEF) recovered to normal on the 3 rd day after LBBAP (45% vs. 57%). The LVEDD Z score decreased to (1.1±0.3) at 3 months after operation and was significantly lower than that before operation (t=2.38, P<0.05). Conclusions LBBAP in children can achieve narrow QRS pacing andphysiological pacing with stablepacing parameters. It can improve left ventricular enlargement caused by long-term bradycardia, and cardiac dysfunction and cardiac enlargement caused by long-term right ventricular apical pacing quickly and effectively.LBBAP is safe and feasible for older children in the near future. However, the long term potential risks of LBBAP need further observation and study.

OBJECTIVETo analyze the adverse effects of type B ventricular pre-excitation on ventricular wall motion and left ventricular function and its clinical characteristic.

METHODThe clinical, electrophysiological and echocardiographic characteristics of the 9 cases with type B ventricular pre-excitation before and after ablation seen between March 2011 and March 2013 were analyzed. The patients aged from 3 to 16 years. Five of them were female.

RESULTDyschronous left ventricular contraction was demonstrated by M-Mode echocardiography in all of the cases. The basal segments of the interventricular septum turned thin and moved in a manner similar to that of an aneurysm, with typical bulging during end-systole, which was observed in six cases. All patients received successful RFCAs. The locations of the accessory pathways (APs) were the right-sided anteroseptum (n = 2) and the free wall (n = 7). Their physical activities and growth improved greatly in the four cases with coexisting dilated cardiomyopathy (DCM). The echocardiographic data demonstrated that their LV contraction recovered to synchrony shortly after the ablation, LVEF recovered to normal and LVED decreased to almost normal gradually during the follow-up.

CONCLUSIONOvert right-sided APs may have adverse effects on ventricular wall motion and left ventricular function. They can even result in DCM. Dyssynchronous ventricular contraction induced by right-sided overt accessory pathway may be the vital mechanism. Such kinds of cases are indication for ablation with good prognosis.

Adolescent ; Cardiomyopathy, Dilated ; diagnostic imaging ; etiology ; physiopathology ; Catheter Ablation ; Child ; Child, Preschool ; Echocardiography ; Female ; Heart Ventricles ; physiopathology ; Humans ; Male ; Myocardial Contraction ; Ventricular Dysfunction, Left ; diagnostic imaging ; etiology ; physiopathology ; Wolff-Parkinson-White Syndrome ; complications ; physiopathology