Related factors of tachycardia-induced cardiomyopathy caused by atrial tachycardia in children / 中华实用儿科临床杂志

Objective To investigate the correlation between various types of atrial tachycardia (AT) and tachycardia-induced cardiomyopathy(TIC) in children and to assess the risk factors for the development of TIC.Methods Patients with AT were divided into 2 groups depending on whether complicated with TIC or not,defined as left ventricular ejection fraction(LVEF) ＜ 50％ on echocardiography.The presence of atrial rhythm in Holter monitoring,ventricular rate of AT,and the type of AT onset were compared between the 2 groups; the risk factors associated with TIC were also analyzed.Results Totally 72 patients were enrolled in this study.The incidence of TIC was 23.6％.The incidence of TIC in patients presenting incessant tachycardia was significantly higher than that of patients presenting paroxysmal tachycardia(53.6％ vs 4.5％,P ＜ 0.01).Patients with TIC had a higher mean atrial rhythm percent [(98 ± 5) ％ vs (37 ± 4) ％,P ＜ 0.001] and faster mean ventricular rate [(134.25 ± 19.24) beats/min vs (100.03 ± 18.83) beats/min,P ＜ 0.05] compared with those without TIC.After successful control of tachycardia,LVEF in patients with TIC gradually recovered within 6 to 75 days [(29.44 ± 21.62) days].Conclusions An incessant AT with higher percent of atrial rhythm and faster mean ventricular rate is more frequently complicated by cardiomyopathy.Recovery of TIC can be achieved after successful control of AT.Early intervention and treatment should be performed for those with high risk factors for the development of TIC.

Effect of radiofrequency catheter ablation for different types of tachyarrhythmias in 1000 children / 中华实用儿科临床杂志

Objective To investigate the success rate,factors associated with recurrence,safety and effect of age on results of radiofrequency catheter ablation(RFCA) for different types of tachyarrhythmias in children.Methods A thousand children diagnosed as tachyarrhythmias underwent electrophysiological study (EPS),with mean age (7.6 ±3.8) years old(0.33-16.50 years old).RFCA methods and results for different kinds of tachyarrhythmias along with recurrence and complications were analyzed.RFCA results for different age groups were compared.Results A thousand children underwent EPS.The number of atrioventricular reentrant tachycardia(AVRT) was 560 (56％),atrioventricular nodal reentrant tachycardia (AVNRT) was 210 (21％),ventricular tachycardia/ventricular premature contraction (VT/PVC) was 159 (15.9％),focal atrial tachycardia (FAT) was 49 (4.9％),and atrial flutter/incisional reentrant atrial tachycardia (AF/IRAT) was 22 (2.2％).Totally 958 children underwent RFCA,among whom success rate was 96.2％ and recurrence rate was 8.1％.EPS performed on recurred cases showed restoration of primary pathway/origin was 5.3％,while appearance of new pathway/origin was 2.8％.Five hundred and thirty-three AVRT cases underwent RFCA,among whom success rate was 98.0％,recurrence rate was 8.4％,restoration of primary pathway was 4.0％,and appearance of new pathway was 4.4％.Success rate of right anterior/mid septal pathway was relatively low (85.3 ％),but its rate of restoration of primary pathway was high (31.0％),as 205 cases of AVNRT underwent RFCA,among whom success rate was 100％,recurrence rate was 5.9％,and restoration of primary origin was 4.9％,while 22 cases of AF/IRAT underwent RFCA,among whom success rate was 95.5％ with no recurrence,46 cases of FAT underwent RFCA,in which success rate was 84.8％ ; success rates for two-dimensional mapping group and three-dimensional mapping combined with cool-tip ablation group were 62.5％ and 96.7％ respectively and the difference was significant (P ＜ 0.05),as 10 cases recurred in which 7 originated from atrial appendages,and these 7 cases were successfully cured by appendectomy,152 cases of VT/PVC underwent RFCA,in which success rate was 89.5％,recurrence rate was 6.6％,restoration of primary origin was 5.9％.There was no difference in success rate between different age groups.The gross success rates and success rates for different types of arrhythmias between early and late periods were not different,while recurrence rates for AVNRT and left anterior pathways in early periods were significantly higher than late periods(P ＜0.05).There were totally 8 cases with complications(0.84％),including 2 cases of complete atrioventricular block and 1 case of anesthetic accident which happened in early period.The other 5 were vascular complications,and there was no death.Conclusions RFCA can be safely used as frontline treatment to cure some kinds of tachyarrhythmias in children with high success rate and low recurrence rate.There is no difference in rates of success,recurrence and complication between younger and older children,while difficulty for procedure increased for the former so that caution should be made for selection of patients.Application of three-dimensional mapping for difficult arrhythmias can increase success rate for ablation.Proficient experience and skillful manipulation are the main factors to avoid complications.

Left atrial and ventricular epicardial dual chamber pacing through a left lateral thoracotomy to treat pediatric complete atrioventricular block / 中华儿科杂志

<p><b>OBJECTIVE</b>To investigate the feasibility, advantages and efficacy of implantation of left atrial and ventricular epicardial dual chamber pacemaker to treat pediatric complete atrioventricular block.</p><p><b>METHOD</b>Eleven children with median age 4.0 years (0.5-7.6 years) diagnosed as complete atrioventricular block resisting to drug therapy received implantations of left atrial and ventricular epicardial dual chamber pacemakers. Six were male and five female. Temporal or permanent right ventricular pacing was used for all of them before implantation of left atrial and ventricular epicardial dual chamber pacemakers. Three cases showed cardiac dysfunction. Left lateral thoracotomy was performed at 4th intercoastal space along anterior axillary line under general anesthesia, the pericardium was incised vertically anterior to the phrenic nerve, two pacing leads were individually located at left atrial appendage and left ventricular lateral wall. After all the parameters were detected to be satisfactory, a pouch was made at left abdomen under coastal margin. Dual chamber pacemaker was connected with pacing leads through subcutaneous tunnels. The sizes of heart chambers, cardiac functions, parameters of pacemaker, sensitivity, pacing status, PR interval and QRS interval were closely followed up post-operatively.</p><p><b>RESULT</b>Implantations of pacemakers were successful for all of the patients with no complications associated with operations. Preoperative electrocardiograms showed QRS interval (180 ± 33)ms under right ventricular pacing, it decreased to (140 ± 24)ms after implantation of left atrial and ventricular epicardial dual chamber pacemaker, significantly lower than right ventricular pacing (t = 8.8, P < 0.05) . Atrioventricular (AV) interval was set at 90 ms, PR interval (124 ± 4)ms. Echocardiograms performed within 2-3 days after implantation of left atrial and ventricular epicardial dual chamber pacemakers showed that for the 3 cases who were previously under right atrial and right ventricular dual chamber pacing presenting cardiac dysfunction, their left ventricular diastolic diameter (LVDd) decreased from (46.3 ± 12.5) (32.0-55.0) ms to (44.7 ± 12.0) (31.0-53.0) mm and left ventricular ejection fraction (LVEF) increased from 30% ± 15% (18%-47%) to 44% ± 18% (33%-65%). During 2-14 months' follow up, LVEF increased progressively which became significantly higher than before (65% ± 8% vs. 30% ± 15%, t = 5.6, P < 0.05) . Cardiac chamber sizes and left ventricular systolic function for the other 8 patients maintain normal during follow up. Pacing status and sensitivity were satisfactory for all these patients during follow up.</p><p><b>CONCLUSION</b>Implantation of left atrial and ventricular epicardial pacemaker might be considered for children diagnosed as complete atrioventricular block for whom endocardial pacemaker could not be implanted, due to its utmost protection for cardiac function with minimal injury and its ability to prevent or reverse pacemaker syndrome. Left atrial and left ventricular epicardium should be regarded as the first-choice and routine locations for epicardial pacing.</p>

Inhaled iloprost during acute pulmonary vasodilator testing for preoperative assessment of surgical operability of congenital heart disease with severe pulmonary hypertension / 中华外科杂志

<p><b>OBJECTIVE</b>To evaluate the efficacy of iloprost in acute vasodilatation test during cardiac catheterization and to explore a useful hemodynamic indication regarding operability in the patients with severe pulmonary hypertension (PH) related to congenital heart disease (CHD).</p><p><b>METHODS</b>The clinical data of 46 patients [mean age (12 ± 9) years] with severe PH related to CHD from June 2006 to December 2008 was retrospectively analyzed. All patients underwent standard right and left cardiac catheterization and a trial of inhaled iloprost test during cardiac catheterization. The mean pulmonary arterial pressure was (80 ± 13) mm Hg (1 mm Hg = 0.133 kPa) and pulmonary vascular resistance index was (17 ± 10) wood.m². A positive response to inhaled iloprost was defined as a decrease of at least 20% in pulmonary vascular resistance index (PVRI) without changes on systemic artery pressure. Patients with positive response to iloprost underwent cardiac surgical repair. The pulmonary artery pressure and PVRI was monitored by Swan-Ganz catheter postoperatively.</p><p><b>RESULTS</b>Of the 46 patients, 29 (63.1%) showed a positive response after iloprost inhalation, defined by a significant reduction in PVRI from (15 ± 6) wood.m(2) at baseline to (9 ± 4) wood.m² in response to iloprost inhalation therapy (P < 0.05). The ratio of pulmonary to systemic resistance (Rp/Rs) decreased from 0.7 ± 0.2 to 0.4 ± 0.2 (P < 0.05). Seventeen patients (36.9%) didn't respond to iloprost displayed only little changes in PVRI [from (21 ± 10) wood.m(2) to (19 ± 9) wood.m²] and Rp/Rs (from 1.0 ± 0.5 to 0.9 ± 0.5). Out of 29 positive patients, 21 (72%) underwent successful cardiac surgical repair with a reduction of mean pulmonary arterial pressure (mPAP) to an average of (27 ± 10) mm Hg after the operation. Only 2 patients out of the 17 patients from the negative group were referred to surgery. Their mPAP was greater than 45 mm Hg.</p><p><b>CONCLUSIONS</b>A significant reduction in pulmonary artery pressure after cardiac surgery was observed in patients with positive response to inhaled iloprost. Inhaled iloprost may be a valuable tool in the preoperative evaluation of patients with severe PH related to CHD.</p>