Acute myocardial infarction following radiofrequency catheter ablation in a child: a case report on the mechanism of coronary artery occlusion assessed by cardiovascular imaging.

Background: Radiofrequency ablation is a common treatment for atrioventricular nodal re-entrant tachycardia, even in paediatric patients weighing ≥15 kg, where outcomes are similar to those in adults. However, reports of acute coronary artery occlusion after radiofrequency ablation for atrioventricular nodal re-entrant tachycardia are rare. Case summary: An 11-year-old girl with symptomatic atrioventricular nodal re-entrant tachycardia refractory to drug treatment underwent radiofrequency ablation. During the procedure, ST elevation was observed, and coronary angiography revealed occlusion of the right coronary artery at the segment 4 atrioventricular branch. Intravascular ultrasonography showed a narrowed lumen and an abnormal area of low echogenicity in the adjacent myocardium. After dilation with a 1.5 mm diameter balloon, blood flow was successfully restored. Follow-up coronary computed tomography angiography revealed residual stenosis in the right coronary artery at the segment 4 atrioventricular branch; however, blood flow to the distal occlusion was preserved. The patient was discharged without further complications. Discussion: To the best of our knowledge, this is the first report of coronary artery occlusion following radiofrequency ablation for atrioventricular nodal re-entrant tachycardia, evaluated using intravascular ultrasonography and coronary computed tomography angiography. Based on the imaging findings, direct thermal injury was considered the cause of occlusion.

Emergency pacing via the umbilical vein of a neonate with congenital complete atrioventricular block: a report of two cases.

We report two cases of successful emergency pacing via the umbilical vein in neonates with congenital complete atrioventricular block. The first patient, a neonate with normal cardiac anatomy, underwent emergency temporary pacing via the umbilical vein under echocardiographic guidance. The patient underwent permanent pacemaker implantation on postnatal day 4. The second patient, a neonate with heterotaxy syndrome, underwent emergency temporary pacing through the umbilical vein under fluoroscopic guidance. The patient underwent permanent pacemaker implantation on postnatal day 17.

Efficacy of SubcutAneous implantable cardioVErter-defibrillators in ≤18 year-old CHILDREN: SAVE-CHILDREN registry.

BACKGROUND: In adult patients, subcutaneous implantable cardioverter defibrillators (S-ICDs) have been reported to be non-inferior to transvenous ICDs with respect to the incidence of device-related complications and inappropriate shocks. Only a few reports have investigated the efficacy of S-ICDs in the pediatric field. This study aimed to investigate the utility and safety of S-ICDs in patients ≤18 years old. METHODS: This study was a multicenter, observational, retrospective study on S-ICD implantations. Patients <18 years old who underwent S-ICD implantations were enrolled. The detailed data on the device implantations and eligibility tests, incidence of appropriate- and inappropriate shocks, and follow-up data were assessed. RESULTS: A total of 62 patients were enrolled from 30 centers. The patients ranged in age from 3 to 18 (median 14 years old [IQR 11.0-16.0 years]). During a median follow up of 27 months (13.3-35.8), a total of 16 patients (26.2%) received appropriate shocks and 13 (21.3%) received inappropriate shocks. The common causes of the inappropriate shocks were sinus tachycardia (n = 4, 30.8%) and T-wave oversensing (n = 4, 30.8%). In spite of the physical growth, the number of suitable sensing vectors did not change during the follow up. No one had any lead fractures or device infections in the chronic phase. CONCLUSIONS: Our study suggested that S-ICDs can prevent sudden cardiac death in the pediatric population with a low incidence of lead complications or device infections. The number of suitable sensing vectors did not change during the patients' growth.

Control of Heart Rate in Infant and Child Tachyarrhythmia With Reduced Cardiac Function Using Landiolol (HEARTFUL)　- Results of a Prospective, Multicenter, Uncontrolled Clinical Study.

BACKGROUND: The prospective Control of HEART rate in inFant and child tachyarrhythmia with reduced cardiac function Using Landiolol (HEARTFUL) study investigated the effectiveness and safety of landiolol, a short-acting ß1 selective blocker, in children.Methods and Results: Twenty-five inpatients aged ≥3 months to <15 years who developed supraventricular tachyarrhythmias (atrial fibrillation, atrial flutter, supraventricular tachycardia, and inappropriate sinus tachycardia) were treated with landiolol. The primary endpoint, the percent of patients with a reduction in heart rate ≥20% from the initial rate of tachycardia, or termination of tachycardia at 2 h after starting landiolol, was achieved in 12/25 patients (48.0%; 95% CI 28.4-67.6), which exceeded the predetermined threshold (38.0%). At 2 h after starting landiolol administration, heart rate had decreased by ≥20% in 45.8% (11/24) and recovery to sinus rhythm was achieved in 40.0% (6/15) of the patients. Adverse reactions (ARs) occurred in 24.0% (6/25) of patients, and the study was discontinued in 4.0% (1/25) of the patients; however, none of these ARs were considered serious. The most common AR was hypotension (20.0% [5/25] of patients). CONCLUSIONS: The HEARTFUL study has demonstrated the efficacy of landiolol, by reducing heart rate or terminating tachycardia, in pediatric patients with supraventricular tachyarrhythmias. Although serious ARs and concerns were not identified in this study, physicians should be always cautious of circulatory collapse due to hypotension.

Novel pediatric granulomatosis with polyangiitis with a marked bloody pericardial effusion and bloody stool: a case report.

BACKGROUND: Granulomatosis with polyangiitis (GPA) is a syndrome of refractory vasculitis involving the upper respiratory tract, lungs, kidneys, and systemic small and medium-sized arteries that affects all age groups. No pediatric case with a bloody pericardial effusion resulting in cardiac tamponade and co-existing hematochezia has been reported. CASE PRESENTATION: A 14-year-old boy was referred for evaluation of prolonged fever, chest pain, and intermittent hematochezia. Diagnostic imaging showed a prominent pericardial effusion. Immediately after admission, his systolic blood pressure decreased. Emergent pericardiocentesis resulted in aspiration of a massive amount of bloody pericardial fluid. This was diagnosed as cardiac tamponade because his blood pressure recovered immediately after the drainage. The patient had an elevated serine proteinase 3-anti-neutrophil cytoplasmic antibody (PR3-ANCA) level on serological examination. Head MRI showed thickening of nasal and sinusoidal mucosa and a cystic mass in the left sphenoid sinus. After ruling out malignancy based on the cytology of the effusion, chest MRI, and gallium scintigraphy, total colonoscopy showed multiple irregular-shaped aphthae from the right transverse colon to the cecum on the contralateral side of the mesenteric attachments. Biopsy specimens of aphthous lesions confirmed necrotizing granulomatous inflammation. A diagnosis of GPA was made based on these findings, and oral prednisolone (PSL) and azathioprine were started. The hematochezia disappeared rapidly, and no recurrence of pericardial effusion was seen after PSL tapering was completed. The PR3-ANCA level decreased into the normal range immediately after the initial therapy. CONCLUSIONS: Pericarditis is a common cardiac complication of GPA, but there have been no reports of resultant cardiac tamponade. This is the first case of pediatric GPA with cardiac and gastrointestinal complications preceding the common symptoms such as respiratory or renal symptoms. A case of pediatric GPA with hematochezia is also extremely rare. In conclusion, serial measurement of ANCA levels is important in patients with persistent fever and bloody stool, such as in inflammatory bowel disease, to make the diagnosis of a vasculitic syndrome.

Deep insight into cardiac dysfunction in children and young adults with Wolff-Parkinson-White syndrome using speckle tracking imaging.

Although ventricular pre-excitation via accessory pathways (APs) causes cardiac dysfunction in children and young adults with Wolff-Parkinson-White (WPW) syndrome, the underlying cardiac dysfunction mechanisms are unclear. This study aimed to characterize cardiac dysfunction and clarify sensitive cardiac dysfunction indicators in WPW syndrome patients classified by the APs location with a layer-specific strain analysis. Twenty-four patients with WPW syndrome with a mean age of 14.1 years (6.9-21.6 years) (11 cases: type A with a left-sided AP [WA group], 13 cases: type B with a right-sided AP [WB group]), and 37 age-matched normal controls (N group) were examined. We measured the left ventricle (LV), base-, mid-, and apical-level of circumferential strain (CS), and longitudinal strain (LS) using a layer-specific strain with speckle tracking imaging. Dyssynchrony was also measured based on the timing of the radial strain at each segment. Peak endomyocardial base- and mid-level of CS was lower in both the WA and WB groups compared to the N group. Peak mid-myocardial and epimyocardial base-level of CS and peak mid-myocardial mid-level of CS were lower only in the WB group compared to the N group. Peak LS in all three layers was lower only in the WB group compared to the N group. There was a significant difference between the patient and normal groups for the dyssynchrony index only at the base-level, and there was no significant difference between the groups for LV ejection fraction (EF). Layer-specific strain decreased in more sites in the WB group despite the normal EF value. Layer-specific strains are sensitive indicators for the detection of the early stages of cardiac dysfunction.

Predictive markers and prenatal management of isolated fetal complete atrioventricular block: A retrospective review at a single institution.

AIM: The study was conducted to determine an effective method for identifying patients at high risk of developing isolated complete atrioventricular block (CAVB) and to review the efficacy of prenatal anti-inflammatory treatment. METHODS: Fourteen CAVB cases and 76 anti-Ro-positive cases without CAVB were included in the study. Anti-Ro/La titers by double immunodiffusion and the prevalence of anti-52 kDa/60 kDa-Ro/48 kDa-La by Western blotting were compared between anti-Ro-positive women with and without CAVB. Outcomes of anti-Ro-positive CAVB cases were compared based on active prenatal anti-inflammatory treatment (plasma exchange or transplacental betamethasone). We evaluated the outcomes of five pregnancies from three women who had an affected child and underwent prophylactic plasma exchange (PEX) during subsequent pregnancy. RESULTS: Ten out of 14 patients with CAVB were positive for anti-Ro. Anti-Ro titers were significantly higher in patients with CAVB (CAVB median 64; without CAVB median 16; P < 0.01). All cases with CAVB showed high titers of anti-Ro (≥ 32×), whereas only 42% of cases without CAVB showed high titers (≥ 32×) (P < 0.001). The survival rate at one year was 80% in anti-Ro-positive CAVB cases with active prenatal anti-inflammatory treatment, but only 40% in cases that did not receive treatment. Recurrence was not observed in cases treated with prophylactic PEX. CONCLUSIONS: An anti-Ro level of 32× could be the threshold value for CAVB development. Prenatal anti-inflammatory treatment in patients with CAVB and prophylactic PEX in patients who had an affected child may have the potential to improve pregnancy outcomes.

Management of congenital complete heart block in a low-birth-weight infant.

Pacemaker implantation in infants during the early postnatal period is difficult because of their small body size and susceptibility to infection. We describe the successful pacemaker implantation for complete heart block in an infant weighing 803 g.

Analysis of arterial function in adults with a history of Kawasaki disease.

BACKGROUND AND PURPOSE: It remains controversial whether Kawasaki disease (KD) is a risk factor for the early onset of atherosclerosis. The purpose of the present study was to assess endothelial function and arterial stiffness as markers of the early onset of atherosclerosis in adult patients with a history of KD. METHODS AND SUBJECTS: We compared 14 adult patients with a history of KD with 41 healthy controls. To assess arterial endothelial function, we measured the reactive hyperemia-peripheral arterial tonometry (RH-PAT) index and augmentation index adjusted to 75 bpm (AIx@75) using the Endo-PAT 2000 (Itamar Medical, Caesarea, Israel). In addition, we analyzed medical history, blood pressure, lifestyle habits, and atherosclerosis-related serum biochemical markers [asymmetric dimethylarginine, adiponectin, lipoprotein (a), cholesterols, atherogenic index of plasma]. RESULTS: There was no difference between the KD and control groups with regard to the RH-PAT index values (2.10 ± 0.43 and 1.84 ± 0.49, respectively; p=0.19). However, in the KD group, the RH-PAT index values were negatively correlated with the febrile period in the acute phase of disease (r(2)=0.458, p=0.048). In addition, the AIx@75 values were higher in KD patients compared to healthy controls (-7.69 ± 11.86% and -15.87 ± 8.72%, respectively; p=0.01). No significant differences existed between the KD and control groups with regard to the serum biomarkers of atherosclerosis. CONCLUSIONS: We speculate that endothelial dysfunction in former KD patients is affected by the febrile period of the acute phase, and antiplatelet drugs may improve endothelial function. The increased arterial stiffness of patients caused by post-inflammatory fibrotic changes in the arterial wall indicates that adults with a history of KD have an increased risk of developing atherosclerosis.

Improvement in non-tachycardia-induced cardiac failure after radiofrequency catheter ablation in a child with a right-sided accessory pathway.

A 6-year-old boy was referred for an evaluation of intolerance to physical activity at his elementary school. The patient had no episodes of palpitations. He was diagnosed as Wolff-Parkinson-White syndrome with a right-sided accessory pathway (AP) and dilated cardiomyopathy (DCM). Ventricular dyskinesis was detected mostly in the ventricular septum. Because the asynchronous septal motion caused by pre-excitation through a right-sided AP might deteriorate his cardiac function, he underwent an AP ablation, after which the asynchronous ventricular wall motion disappeared and the wall thickness improved. We suggest that an AP ablation may be the treatment of first priority in patients who have DCM-like dyskinesis even without sustained tachyarrhythmias.

Imbalance of peroxisome proliferator-activated receptor gamma and adiponectin predisposes Kawasaki disease patients to developing atherosclerosis.

BACKGROUND: It remains controversial whether Kawasaki disease (KD) is a risk factor for the onset of atherosclerosis. An imbalance of peroxisome proliferator-activated receptor γ (PPARγ) and adiponectin appears to play a role in the onset of atherosclerosis in adults, and we therefore examined PPARγ mRNA expression and adiponectin profiles in the peripheral white blood cells obtained from KD patients. METHODS: A total of 50 subjects were studied: nine patients with acute KD, 20 patients with convalescent KD, and 21 age-matched controls. The gene expression of PPARγ, monocyte chemoattractant protein-1, and CC chemokine receptor 2 present in the blood were quantified. The relative gene expression, adiponectin levels, and the three adiponectin isoforms were compared among the subjects. RESULTS: The abundance of PPARγ and CC chemokine receptor 2 mRNA was significantly increased in convalescent KD patients. The monocyte chemoattractant protein-1 level was also increased in convalescent KD patients. The level of high-molecular-weight adiponectin was significantly lower in convalescent patients compared to controls. The PPARγ transcription levels negatively correlated with apolipoprotein A-I levels in acute KD patients. CONCLUSIONS: The transcript abundance of PPARγ and low levels of high-molecular-weight adiponectin in KD patients may have important clinical implications on the development of premature atherosclerosis. Because the potential risk for developing atherosclerosis has not yet been verified, long-term observation is important, even in convalescent KD patients without coronary artery lesions.

Drug-eluting stents ameliorate pulmonary vein stenotic changes in pigs in vivo.

The outcome of stent implantation for pulmonary vein stenosis (PVS) in children remains poor. Several reports describe placing drug-eluting stents to treat PVS, but their effectiveness remains unknown. In this study, three bare-metal stents (BMSs) and three sirolimus-eluting stents (SESs) were implanted in 1-month-old pigs. The pigs were killed 8 weeks later to compare in-stent stenosis rates. The extent of neointimal thickness, as measured by injury score, was significantly less in the SES group than in the BMS group (injury score 1: BMS 0.351 + or - 0.033 vs SES 0.226 + or - 0.031 mm; P < 0.01; injury score 2: BMS 1.232 + or - 0.244 vs SES 0.609 + or - 0.208 mm; P < 0.01). The pathologic findings showed confluence of inflammatory cells around the stent wires in BMS-treated areas and granuloma formation. Granuloma formation was not seen with SES. The degree of in-stent stenosis was significantly reduced in the SES group, suggesting that the use of drug-eluting stents is an effective treatment for PVS. Because of the small sample size and the considerable variation in injury scores and balloon-to-vein ratios, future studies with larger samples are necessary.