Electrophysiological Characteristics and Outcomes of Radiofrequency Catheter Ablation of Atrial Flutter in Children with or Without Congenital Heart Disease.

There are scarce studies on radiofrequency catheter ablation (RFCA) of atrial flutter (AFL) in the pediatric population. This study therefore aimed to investigate the clinical features and RFCA of AFL in children with or without congenital heart disease. Data from 72 consecutive children (44 males; mean age, 6.1 ± 3.8 [0.9-15.0] years; and mean weight, 23.6 ± 13.9 [8.1-72.0] kg) undergoing RFCA for AFL from 2009 to 2019 were retrospectively reviewed. Thirty-three patients had normal cardiac structure and 39 had congenital heart disease (CHD) of whom 29 had undergone surgical repair and developed AFL at a mean of 3.1 ± 2.5 years later. Fifty-nine patients (84%) presented with persistent AFL. Five patients (7%) had cardiac dysfunction with LVEF of 30-48%, which normalized after ablation. Overall, acute success rate of ablation was 99% and recurrence rate was 18% at 0.5-10 years of follow-up. No procedure-related complications were identified. All 33 patients with normal cardiac structure had cavotricuspid isthmus (CTI)-dependent AFL. Among patients who had undergone corrective surgery for CHD, 15 (52%) had CTI-dependent AFL, 4 (14%) had surgical incisional scar reentrant AFL and the remaining 10 (34%) had both CTI-dependent and scar reentrant AFL. Success rate (100% vs. 97%, P = 1.0000) and recurrence rate (21% vs. 16%, P = 0.7008) were similar between patients with and without CHD. Overall, sick sinus syndrome (SSS) was found in 42% (30/72) of patients with AFL, with an incidence of 39% (13/33) among patients with normal cardiac structure and 59% (17/29) among those who underwent surgery for congenital defects. Permanent pacemakers (PM) were implanted in 53% (16/30) of patients with SSS after ablation. RFCA therefore appeared efficacious and safe for treatment of pediatric AFL. The mechanisms underlying AFL after corrective surgery for CHD are complex, including CTI-dependent macro-reentrant, scar reentrant, or a combination of both. SSS is not rare among pediatric AFL cases, with approximately half of patients needing PM implantation.

Association between severity of cardiac dysfunction caused by ventricular pre-excitation-led dyssynchrony and cardiac function recovery after ablation in children.

OBJECTIVE: To investigate the association between the severity of cardiac dysfunction caused by ventricular pre-excitation-led dyssynchrony and cardiac function recovery time after catheter ablation and identify predictors of cardiac function recovery after ablation. METHODS AND RESULTS: A total of 49 children underwent successful ablation (median 2.92 years). This study included 23 patients with mild cardiac dysfunction (left ventricular ejection fraction [LVEF]: 45% ≤ LVEF ≤ 55%), 15 with moderate (30% ≤ LVEF < 45%), and 11 with severe (LVEF <30%). The time for mean LVEF reaching 55% was 0.75, 3, and more than 12 months, respectively. The mean LVEF of children with severe cardiac dysfunction aged ≤6 years normalized within 12 months of follow-up (63.00% ± 1.41%). Mean LVEF of those aged more than 6 years did not normalize at 12 months of follow-up (38.67% ± 10.97%). LVEF recovery time was significantly different between these two age groups (median 11 months vs >12 months, χ2 = 4.55; P = .04). Cox regression analysis showed that preablation smaller left ventricular diastolic diameter (LVDd) Z score and higher LVEF were predictors of cardiac dysfunction recovery time (hazard ratio [HR] = 0.91, 95% confidence interval [CI] = 0.82-0.99, P = .04; HR = 1.09, 95% CI = 1.03-1.15, P = .01). CONCLUSION: Patients with higher LVDd Z scores and lower LVEF tend to have slower improvement in cardiac function after ablation. Patients with LVEF less than 30% and aged more than 6 years need more than 12 months to fully recover, and some might not even completely recover. Early catheter ablation is suggested once ventricular pre-excitation-led cardiac dysfunction is suspected.

Molecular detection of Enterocytozoon bieneusi in farm-raised pigs in Hainan Province, China: infection rates, genotype distributions, and zoonotic potential.

Enterocytozoon bieneusi is a zoonotic fungal pathogen with a high degree of host diversity that can parasitize many animals, including humans. Pigs may play an important role in the epidemiology of E. bieneusi as reservoir hosts. Nevertheless, the genotypes of E. bieneusi in pigs in China remain poorly understood. The aim of this study was to determine the prevalence of E. bieneusi infection amongst pigs raised on farms from four cities of Hainan Province, using nested polymerase chain reaction (PCR) of the partial small subunit of the ribosomal RNA gene, and to identify genotypes of E. bieneusi isolates based on sequence analysis of the ribosomal internal transcribed spacer (ITS) region. Among 188 stool samples, E. bieneusi was detected in 46.8% (88/188). Eight genotypes including four known (EbpA, CS-4, MJ14, and CHG19) and four novel (HNP-I - HNP-IV) genotypes were identified. Using phylogenetic analysis, genotypes EbpA, CS4, CHG19, HNP-III, and HNP-IV were clustered into zoonotic Group 1, while the remaining three genotypes (MJ14, HNP-I, and HNP-II) clustered into Group 10. The high prevalence of zoonotic genotypes of E. bieneusi among pigs suggests that pig farming is a potential source of human infection. Additionally, this is the first identification of genotypes in Group 10 in pigs indicating unique epidemic features of E. bieneusi in pigs in Hainan Province, the southernmost part of China.

TITLE: Détection moléculaire d'Enterocytozoon bieneusi chez les porcs d'élevage dans la province de Hainan en Chine : taux d'infection, répartition des génotypes et potentiel zoonotique. ABSTRACT: Enterocytozoon bieneusi est un pathogène fongique zoonotique avec une grande diversité d'hôte qui peut parasiter de nombreux animaux, y compris les humains. Les porcs peuvent jouer un rôle important dans l'épidémiologie d'E. bieneusi en tant qu'hôtes réservoirs. Néanmoins, les génotypes d'E. bieneusi chez le porc en Chine restent mal connus. Le but de cette étude était de déterminer la prévalence de l'infection par E. bieneusi chez les porcs élevés dans des fermes de quatre villes de la province de Hainan, en utilisant la réaction en chaîne par polymérase emboîtée (PCR) de la petite sous-unité partielle du gène de l'ARN ribosomal et de identifier les génotypes des isolats d'E. bieneusi sur la base d'une analyse de séquence de la région des espaceurs internes transcrits ribosomiques (ITS). Sur 188 échantillons de selles, E. bieneusi a été détecté dans 46,8 % (88/188). Huit génotypes, dont quatre génotypes connus (EbpA, CS-4, MJ14 et CHG19) et quatre génotypes nouveaux (HNP-I à IV), ont été identifiés. Dans une analyse phylogénétique, les génotypes EbpA, CS4, CHG19, HNP-III et HNP-IV étaient regroupés dans le groupe zoonotique 1, tandis que les trois génotypes restants (MJ14, HNP-I et HNP-II) étaient regroupés dans le groupe 10. La prévalence élevée des génotypes zoonotiques d'E. bieneusi chez les porcs suggère que l'élevage porcin est une source potentielle d'infection humaine. De plus, il s'agit de la première identification de génotypes du groupe 10 chez les porcs, indiquant des caractéristiques épidémiques uniques d'E. bieneusi chez les porcs dans la province de Hainan, la partie la plus méridionale de la Chine.

Right Atrial Appendage Aneurysm Resection to Cure Aneurysm-Related Atrial Tachyarrhythmia.

Congenital right atrial appendage aneurysm (RAAA) is an extremely rare malformation that can coexist with atrial tachyarrhythmia. There is no consensus on treatment for this condition. This research aimed to investigate the clinical characteristics and efficacy of surgical resection to treat atrial tachyarrhythmia originating from RAAA in children. Four RAAA children diagnosed with atrial tachyarrhythmia at the age of 1-5.25 years weighing 8.3-17.1 kg were discussed in this retrospective study. Patients underwent various treatments, included electrocardiogram (ECG) and echocardiography, antiarrhythmic medication therapy, radiofrequency catheter ablation (RFCA), surgical resection of RAAA and pathological examinations. The results from these treatments along with clinical features of patients were analyzed. The incidence of RAAA in patients with atrial tachycardia originating from the right or left atrial appendages (RAA or LAA) was 7.3% (4/55). The prevalence of RAAA in the RAA was 12.5% (4/32). Atrial tachyarrhythmia was identified both prenatally (26 and 36 weeks of gestational age) and postnatally (1 and 4 months after birth), with two patients per group, respectively. The RAAAs condition in two patients with atrial tachycardia (AT), concomitant atrial flutter (AF) and atrial fibrillation (Af) was identified using echocardiogram. Although, RAAA in two patients with mono AT was unidentified in echocardiogram and failed to be identified in the procedure of RFCA, RAAA was confirmed during surgical resection of the RAA. Multiple pre-surgical antiarrhythmic medications combined therapy used to treat all four patients showed either no effect at all or was only partially effective. The original atrial tachyarrhythmia was successfully abolished after RAAA surgical resection in four patients. AT originating from new foci was established in two patients post-surgically. The conditions of these two patients were successfully reverted and normal sinus rhythm maintained in the application of antiarrhythmic medications. These results confirmed the efficacy of RAAA surgical resection. The pathology study showed cystic dilation in parts of the atrial cavity, fibrosis of the cyst wall, generalized fibrosis of atrial myocardium with myocardium atrophy and cystic dilation. RAAA is prone to misdiagnosis by echocardiogram. Atrial tachyarrhythmia in patients with RAAA is usually resistant to antiarrhythmic medication therapy and RFCA. Surgical resection of RAAA is a safe and effective option that is minimally invasive.

Effectiveness of Radiofrequency Catheter Ablation of Outflow Tract Ventricular Arrhythmias in Children and Adolescents.

Outflow tract ventricular arrhythmias (OTVAs) are common in children; however, experience is limited on their radiofrequency catheter ablation (RFCA). The purpose of this study was to assess the outcomes of mapping and ablation of pediatric OTVAs and to evaluate the role of ECG algorithms in distinguishing the origin of OTVAs. We compared retrospectively collected single-center data on 92 consecutive pediatric patients (58 male; age, 8.2 ± 2.9 [range 3.6-18] years) who underwent RFCA for OTVAs from 2009 to 2015. Two independent and blinded observers analyzed ECG data. Of these children, 69 (75 %) were of RVOT origin. RFCA was given up in 1 case, and the acute success rate was 92.3 % (84/91), the 1-year follow-up recurrence rate was 8.3 % (7/84) and the complications of the procedure were 2.2 % (2/92). And 3D versus 2D mapping-guided RFCA was associated with significantly (p < 0.05) higher acute success rate (96.1 % [49/51] vs. 87.5 % [35/40]), and lower X-ray exposure (742.5 ± 323.1 vs. 1432.3 ± 605.5 mGy cm2) and 1-year recurrence rate (4.1 % [2/49] vs. 14.3 % [5/35]). The positive predictive value of four types of ECG algorithms used in adults for LVOT origin was only 47.7-65.4 %. In these cases, four identified as RVOT origin and two identified as LVOT origin by ECG underwent successful ablation on the other side of outflow tract finally. And these six children who underwent successful RFCA in both sides of outflow tract had no follow-up recurrence. OTVAs in children originate mostly from RVOT. RFCA can be used for ablation of pediatric OTVAs effectively and safely. In some cases, successful RFCA should be ablated in both sides of outflow tract. ECG-based prediction of OTVA origin as used in adults is limited in children.

Efficacy and Safety of Radiofrequency Catheter Ablation of Tachyarrhythmias in 123 Children Under 3 Years of Age.

BACKGROUND: The risk-benefit ratio of radiofrequency catheter ablation (RFCA) in infants and toddlers remains controversial. Experience with RFCA in these patients is limited. This work is intended to describe the efficacy and safety of RFCA in children under 3 years of age with tachycardia complicated by drug resistance, drug intolerance, or tachycardia-induced cardiomyopathy. METHODS: We retrospectively reviewed data from 123 consecutive children under 3 years of age (mean, 2.3 ± 0.8 years; weight, 13.6 ± 2.8 kg) with tachycardia complicated by drug resistance, drug intolerance, or tachycardia-induced cardiomyopathy; the children underwent an electrophysiology study between 1994 and 2014 at our center. Fifteen children had congenital heart disease, and 27 children were under 1 year of age. Among the 109 children who underwent RFCA, acute success rate (no inducible arrhythmia before procedure completion), 2-year rate of symptomatic tachyarrhythmia recurrence, and complication rate were assessed. RESULTS: Among the 123 children studied, 76.4% had atrioventricular reentrant tachycardia, 5.7% had atrioventricular nodal reentrant tachycardia, 2.4% had focal atrial tachycardia, 6.5% had atrial flutter, and 4.1% had idiopathic left ventricular tachycardia. For RFCA, the acute success rate was 94.5%, and the 2-year recurrence rate was 6.8%, without any major complications. CONCLUSION: RFCA appears to be an effective and safe therapeutic option in selected small children with tachycardia resistant to conventional medical management, tachycardia complicated by drug intolerance, or tachycardia-induced cardiomyopathy.

Optimal noninvasive assessment of initial left ventricular dysfunction in children with ectopic atrial tachycardia.

UNLABELLED: Tissue Doppler imaging (TDI) can identify cardiac dysfunction in adults. This study is aimed to improve early identification of initial left ventricular (LV) dysfunction secondary to ectopic atrial tachycardia (EAT) in children by TDI. A total of 70 children with EAT were included in the present study. Cardiac function was evaluated by conventional echocardiography, TDI, and plasma N-terminal pro-brain natriuretic peptide (NT-proBNP). Doppler signals obtained from the mitral inflow and TDI of the mitral annulus were the average values of three consecutive heartbeats. Left ventricular ejection fraction (LVEF), peak early diastolic transmitral velocity (E), peak systolic mitral annulus velocity (S'), early diastolic mitral annular velocity (E'), the ratio E/E', and TDI-derived myocardial performance index (TDI-MPI) were compared between two groups of children with normal or elevated plasma NT-proBNP concentrations. Of the children, 18.6% demonstrated tachycardia-induced cardiomyopathy (TIC). Compared with LVEF, the TDI-MPI and E/E' showed better correlations with elevated plasma NT-proBNP. Addition of TDI-MPI and E/E' to LVEF provided increased information to detect elevated plasma NT-proBNP (91.67% sensitivity). CONCLUSIONS: TIC occurred in 18.6% of children with EAT. Initial LV dysfunction assessed by the TDI-MPI and E/E' is associated with elevated plasma NT-proBNP, even the LVEF is normal.

[Left atrial and ventricular epicardial dual chamber pacing through a left lateral thoracotomy to treat pediatric complete atrioventricular block].

OBJECTIVE: To investigate the feasibility, advantages and efficacy of implantation of left atrial and ventricular epicardial dual chamber pacemaker to treat pediatric complete atrioventricular block. METHOD: 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. RESULT: 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. CONCLUSION: 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.

[Inhaled iloprost during acute pulmonary vasodilator testing for preoperative assessment of surgical operability of congenital heart disease with severe pulmonary hypertension].

OBJECTIVE: 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). METHODS: 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. RESULTS: 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. CONCLUSIONS: 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.