Efficacy of a phosphodiesterase type 5 inhibitor on the pulmonary artery index and postoperative hemodynamics after a Fontan operation.

There have been no reports regarding the influence of a change in the pulmonary artery index before or after a Fontan operation. Moreover, the factors that might affect the change in the pulmonary artery index are unclear. This was a retrospective study, which included 94 patients who underwent a Fontan operation. We divided the patients into two groups according to the change in the pulmonary artery index before and after the Fontan operation: the increased pulmonary artery index group (n = 51) and decreased pulmonary artery index group (n = 43). The pulmonary artery index after the Fontan operation was significantly higher in the increased pulmonary artery index group than decreased pulmonary artery index group (p < 0.0001). The central venous pressure (p < 0.0001) and pulmonary vascular resistance (p = 0.007) were significantly lower in the increased pulmonary artery index group. The mixed venous oxygen saturation was significantly higher in the increased pulmonary artery index group (p < 0.0001). The pulmonary artery index was more increased in the patients who were administered a phosphodiesterase type 5 inhibitor than in those who were not (p = 0.03). The change in the pulmonary artery index reflected the hemodynamics after a Fontan operation during the short term. In that respect, phosphodiesterase type 5 inhibitors might be involved in the process.

Successful Ablation of a Biatrial Tachycardia from the Superior Vena Cava after a Senning Operation for Complete Transposition of the Great Arteries.

The Senning operation used to be widely performed for an intracardiac repair in a complete transposition of the great arteries. During the long-term follow-up, supraventricular tachycardia (SVT) is often observed because of the complex suture lines. The typical mechanism of a Senning-related SVT is cavo-tricuspid isthmus-dependent atrial flutter. On rare occasions, complex SVTs (e.g., biatrial tachycardia (BiAT)) whose diagnosis and treatment are challenging, may occur. We report a rare case of a BiAT following a Senning operation that was successfully ablated from the superior vena cava, and the local activation time histogram module (CARTO3 V7 module [Biosense Webster, Irvine, CA, USA]) was crucial for analyzing the complex circuit.

Ultrahigh density atrio-ventricular dual-chamber mapping as a next generation tool for ablation of accessory pathways.

INTRODUCTION: Detailed three-dimensional (3D) mapping has been useful for effective radiofrequency catheter ablation. The Rhythmia system can create atrio-ventricular dual-chamber mapping, which reveals the atrial and ventricular potentials all at once in the same map. The aim of this study was to investigate the utility of mapping the atrium and ventricle simultaneously with a high-density 3D mapping system for the ablation of accessory pathways (AP). METHODS: From July 2015 to August 2020, 111 patients underwent ablation of APs. Dual-chamber maps were created in 50 patients (median age 15 [10-54], 32 male [64.0%]), while 61 patients underwent radiofrequency (RF) ablation with conventional single-chamber 3D maps. The background characteristics and procedural details were compared between the dual-chamber mapping group and the conventional single-chamber mapping group. RESULTS: The number of RF applications (median [IQR]; 1.0 [1.0-3.0] vs. 3.0 [1.0-6.0], p = .0023), RF time (median [IQR], s; 9.2 [2.0-95.7] vs. 95.6 [4.1-248.7], p = .0107), and RF energy (median [IQR], J; 248.4 [58.7-3328.2] vs. 2867.6 [134.2-7728.4], p = .0115) were significantly lower in the dual-chamber group. The fluoroscopy time (median [IQR], min; 19.9 [14.2-26.1] vs. 26.5 [17.7-43.4], p = .0025) and fluoroscopy dose (median [IQR], mGy; 52.5 [31.3-146.0] vs. 119.0 [43.7-213.5], p = .0249) were also significantly lower in the dual-chamber than single-chamber mapping group. CONCLUSION: The dual-chamber mapping was useful for ablating accessory pathways and reducing the number of RF applications, total RF energy, and radiation exposure as compared with traditional mapping techniques.

Efficacy of a Subcutaneous Implantable Cardioverter Defibrillator in a Child with Early Repolarization Syndrome.

An early repolarization (ER) pattern or J waves are considered to be a benign finding observed in the healthy population, however, it has been pointed out that the ER pattern seen in the inferolateral leads could be an independent risk factor for fatal arrhythmias. We present a pediatric case in which early repolarization syndrome (ERS) was suspected due to the presence of ER or J waves in the inferior leads, which eventually disappeared after the administration of pilsicainide. During the follow-up period, several fatal ventricular arrhythmias were recorded after implantation of a subcutaneous implantable cardiac defibrillator (S-ICD). This report describes the efficacy of S-ICDs in a child with an ER pattern after aborted sudden cardiac death.

The Impact of the Pulmonary Artery Index and Aortopulmonary Collateral Artery Coil Embolization on Intractable Pleural Effusions After a Fontan Surgery.

An intractable pleural effusion is a common comorbidity of a Fontan operation, occasionally leading to undesirable outcomes. The preventive effect of aortopulmonary collateral (APC) coil embolization against a pleural effusion before a Fontan operation is still controversial.This is a retrospective single-center study; among 227 Fontan cases, 57 cases with complete MRI data were analyzed at first. Factors associated with the duration of pleural drainage (median: 6 (2-41) days) and that of postoperative hospital stay (median: 25 (14-91) days) were analyzed using a multiple regression analysis. The pulmonary artery index (PAI; Nakata index) was associated with both the pleural drainage duration (P < 0.05, r2 = 0.17) and postoperative hospital stay (P < 0.05, r2 = 0.10).Thereafter, all the 227 patients were classified into the following three groups: Group A (12 patients in whom the embolization was performed within 30 days before the Fontan surgery), Group B (131 patients in whom the embolization was performed more than 30 days before the Fontan surgery), and Group C (84 patients in whom the embolization was not performed). Patients in Group A were found to be associated with the shortest length of both periods (P < 0.05).Lower PAI values were related to a prolonged pleural drainage duration and postoperative hospital stay. APC coil embolizations may reduce the risk if they are performed shortly (less than 30 days) before the operation.

Elimination of arrhythmogenesis after subtotal resection of congenital cardiac fibroma: a case report.

Subtotal tumour resection is used to treat infants with congenital cardiac fibroma and medication-resistant ventricular arrhythmias; however, complete elimination of arrhythmogenic substrates has been unclear. A 4-month-old male infant with congenital cardiac fibroma and ventricular fibrillation underwent subtotal tumour resection and implantable cardioverter-defibrillator implantation. Five years later, angiography revealed impending compression of the left coronary artery. Elimination of the arrhythmogenic substrate was confirmed and the device was removed successfully.

Elimination of arrhythmogenesis after subtotal resection of congenital cardiac fibroma: a case report.

Subtotal tumour resection is used to treat infants with congenital cardiac fibroma and medication-resistant ventricular arrhythmias; however, complete elimination of arrhythmogenic substrates has been unclear. A 4-month-old male infant with congenital cardiac fibroma and ventricular fibrillation underwent subtotal tumour resection and implantable cardioverter-defibrillator implantation. Five years later, angiography revealed impending compression of the left coronary artery. Elimination of the arrhythmogenic substrate was confirmed and the device was removed successfully.

Phrenic nerve protection via packing of gauze into the pericardial space during ablation of cristal atrial tachycardia in a child.

The success of catheter ablation of focal atrial tachycardia is limited by possible collateral damage to the phrenic nerve. Protection of the phrenic nerve is required. Here we present a case of a 9-year-old girl having a history of an unsuccessful catheter ablation of a focal atrial tachycardia near the crista terminalis (because of proximity of the phrenic nerve) who underwent a successful ablation by means of a novel technique for phrenic nerve protection: packing of gauze into the pericardial space. This method is a viable approach for patients with a failed endocardial ablation due to the proximity of the phrenic nerve.

QT Dynamics During Exercise in Asymptomatic Children with Long QT Syndrome Type 3.

Sympathetic provocative testing is commonly used to detect the abnormal QT dynamics in long QT syndrome (LQTS) patients, particularly LQTS type 1 and type 2. However, little is known about LQTS type 3 (LQT3). We investigated QT dynamics during exercise testing in LQTS patients, particularly LQT3. This study included 37 subjects, comprising 16 genotyped LQTS patients and 21 unrelated healthy subjects without QT prolongation. LQTS patients were divided into LQT3 and non-LQT3 groups. During exercise tests using a modified Bruce protocol, 12-lead electrocardiogram monitoring was performed using a novel multifunctional electrocardiograph. QT intervals were automatically measured. The QT/heart rate (HR) relationship was visualized by plotting the beat-to-beat confluence of the recorded data. A linear regression analysis was performed to determine the QT/HR slope and intercept. Estimated QT intervals at HR 60 bpm (QT60) were calculated by the regression line formula. QT/HR slopes were steeper for each LQTS group than for the control group (P < 0.001). QT60 values demonstrated a moderate correlation with QT intervals at rest (P < 0.0001) for both groups. The corrected QT intervals (QTc) at 4 min of recovery after exercise were significantly longer in the non-LQT3 group than in the control group but were not different between the LQT3 and the control groups. Abnormal QT dynamics during exercise testing were observed in both LQT3 patients and other LQTS subtypes. This method may be useful for directing genetic testing in subjects with borderline prolonged QT intervals.

QT dynamics evaluated on fully automated QT measurement in children.

BACKGROUND: The association between QT interval and heart rate (HR), QT dynamics, has been reported to vary greatly between individuals. We investigated QT dynamics using fully automated QT interval measurement with a commercially available multifunctional electrocardiogram (ECG) recorder. METHODS: The study group included 17 otherwise healthy subjects (mean age, 12.7 years; 11 girls, 6 boys), who were undergoing exercise test for arrhythmia evaluation. The subjects had single premature ventricular contraction. RESULTS: Mean corrected QT interval (Fridericia) at rest was 412 ± 19 ms (male, 408 ± 20 ms; female, 414 ± 19 ms), manually measured with a digitizer, using the tangent method. We assessed QT interval/HR slope during the whole exercise test, the exercise phase, and the recovery from exercise phase; the slopes were calculated offline after excluding wide QRS complex and were -1.15 ± 0.26 (r(2) = 0.65), -1.18 ± 0.30 (r(2) = 0.62), and -1.11 ± 0.25 (r(2) = 0.70), respectively. Estimated QT interval at HR 60 beats/min (QT60) was calculated using the regression line formula and was 383 ± 24 ms, 387 ± 28 ms, and 375 ± 21 ms, respectively. QT60 of the total exercise test correlated with the corrected QT interval at rest (P = 0.04, r(2) = 0.25). CONCLUSIONS: Assessment of QT dynamics is feasible on fully automated QT interval measurement with this ECG recorder. Further studies are required in larger populations to confirm the accuracy and precision of QT measurement and QT dynamics using this new multifunctional ECG.

High prevalence of the SCN5A E1784K mutation in school children with long QT syndrome living on the Okinawa islands.

BACKGROUND: Genetic testing for long QT syndrome (LQTS) is now in clinical practice. We conducted molecular genetic analyses to definitively diagnose LQTS and to determine its subtypes for gene-specific treatment. We conducted a retrospective study to determine the characteristics of schoolchildren with LQTS living on the Okinawa Islands. METHODS AND RESULTS: The study population included children identified in a school-based electrocardiographic (ECG) screening program for cardiovascular diseases who were referred to Okinawa Children's Medical Center between 2007 and 2012; 23 children met the diagnostic criteria for LQTS. Of them, 17 were genotype-positive and 14 were found to harbor theSCN5AE1784K mutation exclusively among the LQTS genotype-positive children. The children were divided into genotype-positive and -negative groups. Clinical characteristics and ECG data were analyzed and compared. The median Schwartz score was 3. The median QT interval was 521 ms. CONCLUSIONS: The major finding is that the prevalent subtype of LQTS in Okinawa is discordant with other cohorts living in other regions of Japan or overseas. We cannot exclude the possibility of the presence of a specific founder mutation in this geographically clustered population, particularly considering that the hospital is the only tertiary heart center for children in Okinawa. However, this uniquely high prevalence of theSCN5AE1784K mutation serves as a compelling justification to conduct a larger study.

Novel Compound Heterozygous Variants in Trans-2,3-Enoyl-Coenzyme A Reductase-Like Gene Associated With Catecholaminergic Polymorphic Ventricular Tachycardia.

A 10-year-old female patient experienced syncope while swimming, and electrocardiography revealed polymorphic ventricular tachycardia, leading to a diagnosis of catecholaminergic polymorphic ventricular tachycardia. No pathogenic variant was identified in RYR2. Additional comprehensive genetic testing revealed novel compound heterozygous variants in trans-2,3-enoyl-coenzyme A reductase-like gene, which caused a recessive form of catecholaminergic polymorphic ventricular tachycardia.

Automated external defibrillator documented degeneration of pre-excited atrial fibrillation into ventricular fibrillation.

Wolff-Parkinson-White (WPW) syndrome can be the cause of syncope or sudden cardiac death, which results from ventricular fibrillation (VF) degenerated from rapid anterograde conduction of atrial fibrillation (AF) to the ventricles through the accessory pathway. We present a case of WPW syndrome in which recording the actual moment of onset of the degeneration of pre-excited AF into VF. This was fortuitous and also lucky for this patient.

Age-dependent contribution of intrinsic mechanisms to sinoatrial node function in humans.

Average beat interval (BI) and beat interval variability (BIV) are primarily determined by mutual entrainment between the autonomic-nervous system (ANS) and intrinsic mechanisms that govern sinoatrial node (SAN) cell function. While basal heart rate is not affected by age in humans, age-dependent reductions in intrinsic heart rate have been documented even in so-called healthy individuals. The relative contributions of the ANS and intrinsic mechanisms to age-dependent deterioration of SAN function in humans are not clear. We recorded ECG on patients (n = 16 < 21 years and n = 23 41-78 years) in the basal state and after ANS blockade (propranolol and atropine) in the presence of propofol and dexmedetomidine anesthesia. Average BI and BIV were analyzed. A set of BIV features were tested to designated the "signatures" of the ANS and intrinsic mechanisms and also the anesthesia "signature". In young patients, the intrinsic mechanisms and ANS mainly contributed to long- and short-term BIV, respectively. In adults, both ANS and intrinsic mechanisms contributed to short-term BIV, while the latter also contributed to long-term BIV. Furthermore, anesthesia affected ANS function in young patients and both mechanisms in adult. The work also showed that intrinsic mechanism features can be calculated from BIs, without intervention.

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.

A novel mechanism of sudden infant death syndrome during atrioventricular reentrant tachycardia: a case report.

Background: Although orthodromic atrioventricular reentrant tachycardia (AVRT) using retrograde conduction through an accessory pathway (AP) is a common manifestation of Wolff-Parkinson-White (WPW) syndrome, a rare yet critical consequence is sudden cardiac arrest in a few patients. This fatal event used to be reported as a result of rapid atrioventricular conduction of atrial fibrillation via an AP. Case summary: A 3-month-old infant with WPW syndrome had AVRT accompanied by global cardiac ischaemia, apparently caused by a rapid ventricular rate itself that degenerated into ventricular fibrillation during the AVRT. Discussion: Our case suggested that orthodromic AVRT may be sufficient to cause WPW-related sudden cardiac death (SCD) or sudden infant death syndrome via fatal ischaemia and ventricular arrhythmias even when the effective refractory period of an antegrade AP conduction is long or even when an antegrade AP is not present. It is possible that an AP ablation in those who have a history of a fast orthodromic AVRT would be useful to prevent SCD in addition to symptom control.

Truncus arteriosus with interrupted aortic arch in very low birth weight infants.

A neonate, born after 29 weeks and 2 days gestation (weight 1015 g), was diagnosed with truncus arteriosus and interrupted aortic arch. On postnatal day 30 (1378 g), we performed bilateral pulmonary artery banding. On postnatal day 107 (3024 g), we carried out aortic arch repair and a Rastelli-type procedure. During follow-up, branch pulmonary artery and ascending aortic stenosis was observed. At 15 months, surgical angioplasty of the ascending aorta and bilateral branch pulmonary arteries was undertaken using the Lecompte maneuver.