Successful ablation of premature ventricular contractions originating from the posterior-superior process of the left ventricle approaching from the right atrium in a 13-year-old male.

This is a case of a 13-year-old male with frequent premature ventricular contractions with QRS configurations of the left superior axis and left bundle branch block, which originated from the posterior-superior process of the left ventricle. Premature ventricular contractions were successfully eliminated by delivering radiofrequency energy to the inferior wall of the right atrium without causing either junctional rhythm or atrioventricular block. Ventricular arrhythmias originating from this site have been sporadically reported in adults; however, this is the first report in a child.

Valley Index as a Predictor of Prenatal Diagnosis of Total Anomalous Pulmonary Venous Connection.

INTRODUCTION: Total anomalous pulmonary venous connection (TAPVC) has a low prenatal diagnostic rate. Therefore, we investigated whether Doppler waveforms with a low pulsatility in the pulmonary veins can indicate fetal TAPVC. METHODS: This retrospective study included 16 fetuses with TAPVC, including 10 with complex congenital heart disease and 104 healthy fetuses that underwent fetal echocardiography. Pulmonary venous S and D wave flow velocities and the valley (representing the lowest velocity between the S and D waves) were measured. Valley indices I and II were then calculated as (velocity of valley/greater of the S and D wave velocities) and (velocity of valley/lesser of the S and D wave velocities), respectively. RESULTS: Supra/infracardiac TAPVC cases exhibited significantly greater valley indices than that of the healthy group. After adjusting for gestational age at fetal echocardiography, valley indices I (odds ratio [OR] 7.26, p < 0.01) and II (OR: 9.23, p < 0.01) were significant predictors of supra/infracardiac TAPVC. Furthermore, valley indices I and II exhibited a high area under the curve for detecting supra/infracardiac TAPVC, regardless of the presence of pulmonary venous obstruction. CONCLUSION: The valley index may be a useful tool for the detection of fetal TAPVC.

Antibody recognition of complement factor H reveals a flexible loop involved in atypical hemolytic uremic syndrome pathogenesis.

Atypical hemolytic uremic syndrome (aHUS) is a disease associated with dysregulation of the immune complement system, especially of the alternative pathway (AP). Complement factor H (CFH), consisting of 20 domains called complement control protein (CCP1-20), downregulates the AP as a cofactor for mediating C3 inactivation by complement factor I. However, anomalies related to CFH are known to cause excessive complement activation and cytotoxicity. In aHUS, mutations and the presence of anti-CFH autoantibodies (AAbs) have been reported as plausible causes of CFH dysfunction, and it is known that CFH-related aHUS carries a high probability of end-stage renal disease. Elucidating the detailed functions of CFH at the molecular level will help to understand aHUS pathogenesis. Herein, we used biophysical data to reveal that a heavy-chain antibody fragment, termed VHH4, recognized CFH with high affinity. Hemolytic assays also indicated that VHH4 disrupted the protective function of CFH on sheep erythrocytes. Furthermore, X-ray crystallography revealed that VHH4 recognized the Leu1181-Leu1189CCP20 loop, a known anti-CFH AAbs epitope. We next analyzed the dynamics of the C-terminal region of CFH and showed that the epitopes recognized by anti-CFH AAbs and VHH4 were the most flexible regions in CCP18-20. Finally, we conducted mutation analyses to elucidate the mechanism of VHH4 recognition of CFH and revealed that VHH4 inserts the Trp1183CCP20 residue of CFH into the pocket formed by the complementary determining region 3 loop. These results suggested that anti-CFH AAbs may adopt a similar molecular mechanism to recognize the flexible loop of Leu1181-Leu1189CCP20, leading to aHUS pathogenesis.

CFH-CFHR1 hybrid genes in two cases of atypical hemolytic uremic syndrome.

Atypical hemolytic uremic syndrome (aHUS) is a rare complement-mediated disease that manifests as the triad of thrombotic microangiopathy. We identified two aHUS patients with neither anti-complement factor H (CFH) antibodies nor causative variants of seven aHUS-related genes (CFH, CFI, CFB, C3, MCP, THBD, and DGKE); however, their plasma showed increased levels of hemolysis by hemolytic assay, which strongly suggests CFH-related abnormalities. Using a copy number variation (CNV) analysis of the CFH/CFHR gene cluster, we identified CFH-CFHR1 hybrid genes in these patients. We verified the absence of aHUS-related abnormal CNVs of the CFH gene in control genomes of 2036 individuals in the general population, which suggests that pathogenicity is related to these hybrid genes. Our study emphasizes that, for patients suspected of having aHUS, it is important to perform an integrated analysis based on a clinical examination, functional analysis, and detailed genetic investigation.

Calmodulinopathy in Japanese Children　- Their Cardiac Phenotypes Are Severe and Show Early Onset in Fetal Life and Infancy.

BACKGROUND: Cardiac calmodulinopathy, characterized by a life-threatening arrhythmia and sudden death in the young, is extremely rare and caused by genes encoding calmodulin, namely calmodulin 1 (CALM1), CALM2, and CALM3.Methods and Results: We screened 195 symptomatic children (age 0-12 years) who were suspected of inherited arrhythmias for 48 candidate genes, using a next-generation sequencer. Ten probands were identified as carrying variants in any of CALM1-3 (5%; median age 5 years), who were initially diagnosed with long QT syndrome (LQTS; n=5), catecholaminergic polymorphic ventricular tachycardia (CPVT; n=3), and overlap syndrome (n=2). Two probands harbored a CALM1 variant and 8 probands harbored 6 CALM2 variants. There were 4 clinical phenotypes: (1) documented lethal arrhythmic events (LAEs): 4 carriers of N98S in CALM1 or CALM2; (2) suspected LAEs: CALM2 p.D96G and D132G carriers experienced syncope and transient cardiopulmonary arrest under emotional stimulation; (3) critical cardiac complication: CALM2 p.D96V and p.E141K carriers showed severe cardiac dysfunction with QTc prolongation; and (4) neurological and developmental disorders: 2 carriers of CALM2 p.E46K showed cardiac phenotypes of CPVT. Beta-blocker therapy was effective in all cases except cardiac dysfunction, especially in combination with flecainide (CPVT-like phenotype) and mexiletine (LQTS-like). CONCLUSIONS: Calmodulinopathy patients presented severe cardiac features, and their onset of LAEs was earlier in life, requiring diagnosis and treatment at the earliest age possible.

Improvement of beta-cell function in conjunction with glycemic control after medical nutrition therapy in newly-diagnosed type 2 diabetes mellitus.

BACKGROUND: The current study aimed to reveal the correlation of beta-cell function and insulin sensitivity with glycemic control and weight control before and after medical nutrition therapy (MNT) in patients with newly-diagnosed type 2 diabetes mellitus. METHODS: We retrospectively analyzed consecutive 68 patients with newly-diagnosed type 2 diabetes mellitus who started MNT without antihyperglycemic medications and underwent a 75-g oral glucose tolerance test (OGTT) before and after the therapy. Beta-cell function was evaluated by the OGTT-derived disposition index, whereas insulin sensitivity was evaluated by Matsuda's insulin sensitivity index. RESULTS: After 4.0 ± 1.5 months of MNT, mean HbA1c and body mass index significantly decreased from 9.6 ± 1.8% to 7.2 ± 1.0% and from 26.9 ± 4.1 to 25.4 ± 3.7 kg/m2 (both P < 0.001), while the median disposition index and Matsuda's index significantly increased from 0.34 (0.20-0.68) to 0.88 (0.53-1.52) (P < 0.001) and from 4.70 (2.95-5.93) to 5.17 (3.48-6.89) (P = 0.003), respectively. The disposition index was significantly correlated with HbA1c levels both before and after MNT (r = -0.61 and -0.68; both P < 0.001). The magnitude of the correlation after MNT was not different from that before MNT (P = 0.42). Matsuda's index was correlated not with HbA1c levels but with body mass index, both before (r = 0.07 [P = 0.57] and r = -0.58 [P < 0.001]) and after MNT (r = -0.01 [P = 0.95] and r = -0.52 [P < 0.001]). CONCLUSIONS: Beta-cell function was improved in conjunction with glycemic control after MNT in patients with newly-diagnosed type 2 diabetes mellitus. Insulin sensitivity was linked with weight control rather than glycemic control.

Absent pulmonary valve with tricuspid atresia/stenosis: literature review with new three long-term cases.

Absent pulmonary valve (APV) syndrome with tricuspid atresia or tricuspid stenosis (TA/TS) is an extremely rare malformation recently reported as a variant of APV with intact ventricular septum (VS). The condition, however, has univentricular physiology and unique structural and clinical features. The purpose of this study was to update the current knowledge about this condition by describing long-term outcomes of three new cases and reviewing the available literatures. A systematic literature search was performed to collect clinical and anatomical data of APV with TA/TS. Institutional medical records were retrospectively reviewed to identify APV with TA/TS patients. In a total of 62 (59 reported and 3 new) cases, patent ductus arteriosus was present in 98% of APV patients with TA/TS. A large ventricular septal defect, dilatation of the pulmonary arteries, which is typically found in APV with tetralogy of Fallot, and respiratory distress at birth were rarely reported. Most of the recent cases were successfully managed by the Glenn or Fontan procedure. Coronary artery anomaly and ventricular arrhythmia were more frequently reported as the cause of death or severe neurological sequelae (9/16 and 3/8, respectively). Additional surgical intervention was required in the mid/long-term period in three cases due to left-ventricular outflow obstruction and in two due to aortic dilatation. The Fontan and Glenn procedures improved the survival in the last two decades. In addition to coronary artery anomaly and ventricular arrhythmia, left-ventricular outflow tract obstruction and aortic dilatation should be carefully monitored.

Agenesis of the venous duct with abnormal return of the umbilical vein into the superior vena cava: A case report.

INTRODUCTION: Agenesis of the venous duct is rare, with an incidence rate of .04%-.6%. Abnormal drainage of the umbilical vein (UV) to superior vena cava (SVC) is seen in .5% of agenesis of the venous duct cases. We present a case of agenesis of the venous duct with drainage of the UV into the SVC accompanied by tetralogy of Fallot. CASE PRESENTATION: The fetus was diagnosed with agenesis of the venous duct and tetralogy of Fallot at 29 gestational weeks. The UV directly returned to the SVC. Cardiomegaly and pericardial effusion were observed but did not deteriorate. The female infant was born at 40 gestational weeks. Contrast-enhanced computed tomography showed that the UV was occluded at its proximal aspect. No abnormality of the portal system was noted. The infant underwent intracardiac repair and was doing well at 16 months of age. DISCUSSION/CONCLUSION: Although the extrahepatic drainage type of agenesis of the venous duct is occasionally associated with heart failure and hydrops, severe hydrops was absent in this case. It was speculated that vascular resistance in the long pathway to the SVC restricted direct inflow from the UV. Portosystemic shunts and agenesis of the portal system are reported complications of agenesis of the venous duct. Prenatal agenesis of the venous duct diagnosis may be crucial for early postnatal diagnosis of these conditions.

Electrocardiographic features of arrhythmogenic right ventricular cardiomyopathy in school-aged children.

It can be difficult to distinguish children with early-stage arrhythmogenic right ventricular cardiomyopathy (ARVC) from those with benign premature ventricular contraction (PVC). We retrospectively evaluated six school-aged children with ARVC and compared with those of 20 with benign PVC. The median age at initial presentation was 11.4 and 10.2 years in ARVC and benign PVC, respectively. None of the ARVC patients fulfilled the diagnostic criteria of ARVC at initial presentation. At ARVC diagnosis, the treadmill exercise test and Holter monitoring showed provoked PVC during exercise and pleomorphic PVC in all ARVC cases, respectively. During the observation period, terminal activation duration (TAD) was prolonged in all ARVC patients. In addition, ΔTAD (5.5 [3-10] ms) were significantly longer than those with benign PVC (p < 0.001). A new notched S-wave in V1 appeared in four (67%) ARVC patients, who had myocardial abnormalities in the right ventricle, and in zero benign PVC. Our electrocardiographic findings, such as provoked PVC during exercise, pleomorphic PVC, prolonged TAD, and a new notched S-wave in V1 could contribute to the early detection of ARVC in school-aged children.

Nationwide survey of the coronavirus disease 2019 prevention and treatment systems for kidney disease patients: a study of Japanese Society of Nephrology-certified educational facilities.

BACKGROUND: There are no reports of a large-scale survey on the infection prevention measures against coronavirus disease 2019 (COVID-19) in nephrology facilities. This study investigated the facility-level nephrology practices adopted during the COVID-19 pandemic and their associated challenges. Additionally, the treatment patterns and outcomes of chronic kidney disease (CKD) patients with COVID-19 were reviewed. METHODS: We conducted a nationwide questionnaire survey of 704 educational facilities that were certified by the Japanese Society of Nephrology (JSN) from October 20, 2020 to November 16, 2020. The questionnaire reviewed the facility characteristics, infection prevention measures taken during routine nephrology practice, impact of COVID-19 on nephrology practice, experiences in managing CKD patients with COVID-19, and nosocomial transmission in the nephrology unit. RESULTS: Of the 347 facilities that responded, 95.1% checked outpatients' body temperatures and COVID-19 symptoms at their visits. To reduce face-to-face contact, 80% and 70% of the facilities lengthened the intervals between outpatient visits and introduced online/telephonic consultations, respectively. As a result, more than half of the hospitals experienced a decrease in the numbers of outpatients and inpatients (64% and 50%, respectively). During the study period, 347 facilities managed 479 CKD patients with COVID-19. Oxygen administration and mechanical ventilation were performed for 47.8% and 16.5% of the patients, respectively, with a 9.2% total mortality rate. CONCLUSION: This survey demonstrated that JSN-certified educational nephrology facilities adopted multiple measures to manage the COVID-19 pandemic; however, they faced several challenges. Sharing these experiences could standardize these approaches and prepare us better for the future.

Prenatally diagnosed left atrial appendage aneurysm with various postnatal imaging investigations: A case report.

A congenital left atrial appendage aneurysm (LAAA) is a rare cardiac malformation, that is, usually diagnosed in adulthood. It is rarely diagnosed prenatally. In most cases, surgical resection is recommended soon after the diagnosis has been made due to the risk of arrhythmia and thrombotic events. The present report describes a case of LAAA that was prenatally diagnosed and was asymptomatic postnatally. Imaging revealed the relation of the cardiac and airway structures around the LAAA in detail. The patient underwent surgical resection of the LAAA successfully at 7 months of age and is currently healthy at 5 years of age.

The role of anti-complement factor H antibodies in the development of atypical haemolytic uremic syndrome: a possible contribution to abnormality of platelet function.

Atypical haemolytic uremic syndrome (aHUS) is associated with complement system abnormality, such as production of complement factor H (CFH) autoantibodies. The growing evidence indicates complement overactivation on platelets is intimately involved in aHUS pathogenesis, besides endothelial injury. We here showed plasma from patients with anti-CFH antibodies induced aggregation of washed platelets, while purified anti-CFH antibodies suppressed aggregation. This suggested anti-CFH antibody itself suppressed thrombosis, while other plasma factor including complement factors could overactivate the platelets, leading to aggregation, which augmented the notion the state of complement activation influenced by anti-CFH antibodies is important in the aggregation of platelets in aHUS.

Evaluation of Biomechanically Corrected Intraocular Pressure Measurements in Keratoconus and Forme Fruste Keratoconus.

INTRODUCTION: Although biomechanically corrected intraocular pressure (bIOP) is available, the effectiveness of intraocular pressure (IOP) correction in keratoconus and forme fruste keratoconus (FFK) eyes has not been investigated. OBJECTIVE: Evaluation of bIOP measurements in eyes with keratoconus and FFK. METHODS: Forty-two eyes in 21 patients with keratoconus in one eye and FFK in the fellow eye were examined (KC/FFK group; mean age 24.62 ± 8.6 years; 16 males and 5 females). The control group consisted of 62 eyes in 31 unaffected subjects (mean age 26.26 ± 3.64 years; 15 males and 16 females). The bIOP was determined using a Scheimpflug-based tonometer (Corvis Scheimpflug Technology [Corvis ST®]) after measuring the IOP with a conventional non-contact tonometer (NIOP). The agreement between NIOP and bIOP values was examined using the Bland-Altman plot. The difference between NIOP and bIOP (bIOP correction amount) was compared between keratoconus and FFK eyes. RESULTS: In the control group, there were no significant differences between right and left eyes in both NIOP and bIOP values (p = 0.975 and p = 0.224, respectively). In the KC/FFK group, NIOP values were significantly lower in the keratoconus eyes (9.93 ± 1.96 mm Hg) than in the FFK eyes (12.23 ± 3.03 mm Hg; p = 0.0003). There was no significant difference in bIOP values between the right and left eyes of the KC/FFK group (p = 0.168). The bIOP correction amount was significantly increased in keratoconus eyes (3.58 ± 2.12 mm Hg) compared to in FFK eyes (1.80 ± 3.32 mm Hg; p = 0.011). CONCLUSIONS: For eyes with keratoconus and FFK, the bIOP method is effective to adjust IOP measurements based on corneal biomechanical properties.

Correction to: Clinical characteristics and genetic backgrounds of Japanese patients with atypical hemolytic uremic syndrome.

The original article can be found online.

Different daily glycemic profiles after switching from once-daily alogliptin plus twice-daily metformin to their once-daily fixed-dose combination in Japanese type 2 diabetic patients.

The aim of this study was to investigate whether daily glycemic profiles and treatment satisfaction would be changed after switching from once-daily 25-mg alogliptin plus twice-daily 250-mg metformin to the fixed-dose combination of 25-mg alogliptin and 500-mg metformin once daily in type 2 diabetic patients. Twenty adult Japanese type 2 diabetic patients in whom once-daily 25-mg alogliptin plus twice-daily 250-mg metformin were switched to the fixed-dose combination of 25-mg alogliptin and 500-mg metformin once daily participated. Before and one month after the switch, participants were asked to perform one day of seven-point self-monitoring of blood glucose (SMBG), to wear a sensor of flash glucose monitoring for up to 14 days, and to respond to a questionnaire for treatment satisfaction. As a result, the SMBG profiles were significantly changed after the switch (p = 0.021); blood glucose levels 2 hours after breakfast were significantly elevated (p = 0.022), whereas those 2 hours after lunch were significantly reduced (p = 0.036). The flash glucose monitoring also demonstrated a significant change of daily glucose profiles (p < 0.001). The risk of glucose levels <80 mg/dL were decreased from evening to morning, while the risk of glucose levels ≥140 mg/dL were increased. Mean 24-hour glucose values were increased by 5 mg/dL on average (p < 0.001). Treatment satisfaction was significantly improved after the switch (p < 0.001). In conclusion, daily glycemic profiles were significantly changed after switching from once-daily 25-mg alogliptin plus twice-daily 250-mg metformin to the once-daily fixed-dose combination in Japanese type 2 diabetic patients. Treatment satisfaction was significantly improved after the switch.

Functional splicing analysis in an infantile case of atypical hemolytic uremic syndrome caused by digenic mutations in C3 and MCP genes.

Pathogenic variants in specific complement-related genes lead to atypical hemolytic uremic syndrome (aHUS). Some reports have indicated that patients with digenic variants in these genes might present severer phenotypes. Upon detecting novel intronic variants, transcriptional analysis is necessary to prove pathogenicity; however, when intronic variants are located in intron 1 and, as a result, no transcript is produced, no appropriate method had been established to reveal the pathogenicity. Recently, the minigene assay was used to assess the pathogenicity of intronic variants. Here, we report an infantile case of aHUS caused by digenic mutations in two different complement-related genes, C3 and MCP. Targeted sequencing detected a known variant in C3 and a novel variant in the intron 1 splicing donor site of MCP. To assess the pathogenicity of this intronic variant, we conducted functional splicing assay using a minigene construct and quantitative PCR analysis of the MCP transcript, revealing the pathogenicity of the intronic variant. In conclusion, the minigene assay revealed the pathogenicity of the intron 1 splicing donor site variant for the first time. This case showed a severe phenotype of infantile-onset aHUS associated with digenic variants in two complement-related genes.

Physiological and pathophysiological role of reactive oxygen species and reactive nitrogen species in the kidney.

End-stage renal disease is a leading cause of morbidity and mortality worldwide. The prevalence of the disease and the number of patients who receive renal replacement therapy are expected to increase in the next decade. Accumulating evidence suggests that chronic hypoxia in the tubulointerstitium represents the final common pathway to end-stage renal failure, and that reactive oxygen species (ROS) and reactive nitrogen species (RNS) are the key players in kidney injury. However, ROS and RNS that exceed the physiological levels associated with the pathophysiology of most kidney diseases. The molecules that comprise ROS and RNS play an important role in regulating solute and water reabsorption in the kidney, which is vital for maintaining electrolyte homeostasis and the volume of extracellular fluid. This article reviews the physiological and pathophysiological role of ROS and RNS in normal kidney function and in various kidney diseases.

Clinical characteristics and genetic backgrounds of Japanese patients with atypical hemolytic uremic syndrome.

BACKGROUND: Atypical hemolytic uremic syndrome (aHUS) is caused by complement overactivation, and its presentation and prognosis differ according to the underlying molecular defects. The aim of this study was to characterize the genetic backgrounds of aHUS patients in Japan and to elucidate the associations between their genetic backgrounds, clinical findings, and outcomes. METHODS: We conducted a nationwide epidemiological survey of clinically diagnosed aHUS patients and examined 118 patients enrolled from 1998 to 2016 in Japan. We screened variants of seven genes related to complement and coagulation, as well as positivity for anti-CFH antibodies, and assessed clinical manifestations, laboratory findings, and clinical course. RESULTS: The most frequent genetic abnormalities were in C3 (31%) and the frequency of CFH variants was relatively low (10%) compared to Western countries. The predominant variant in this cohort was C3 p.I1157T (23%), which was related to favorable outcomes despite frequent relapses. A total of 72% of patients received plasma therapy, while 42% were treated with eculizumab. The prognosis of Japanese aHUS patients was relatively favorable, with a total mortality rate of 5.4% and a renal mortality rate of 15%. CONCLUSIONS: The common occurrence of genotype C3, especially the p.I1157T variant was the characteristic of the genetic backgrounds of Japanese aHUS patients that differed from those of Caucasian patients. In addition, the favorable prognosis of patients with the unique C3 p.I1157T variant indicates that understanding the clinical characteristics of individual gene alterations is important for predicting prognosis and determining therapeutic strategies in aHUS.

[Atypical hemolytic uremic syndrome in an elderly patient successfully treated with eculizumab].

Herein, we present an elderly onset case of aHUS successfully treated with eculizumab. An 80-year-old woman with severe anemia, thrombocytopenia, and acute renal dysfunction was admitted to our hospital. A laboratory test revealed steep elevation in the LDH level, and the peripheral blood smear showed erythrocyte fragmentations. Accordingly, we diagnosed thrombotic microangiopathy, and treatment with plasma exchange was immediately initiated. In addition, she required hemodialysis because of rapid impairment of the renal function. After excluding Shiga toxin-producing Escherichia coli infection and malignancy and confirming her ADMTS13 activity above 10%, we diagnosed aHUS, according to the Japanese diagnostic criteria for aHUS. Next, we initiated treatment with eculizumab. Her hematological findings improved 23 days after the starting of eculizumab. In addition, her renal function gradually recovered, and hemodialysis was discontinued. The genetic test for several complement regulatory genes tested negative. The onset of aHUS is reported in children or young adults and is rarely reported in elderly. However, our case suggests the importance of precisely diagnosing aHUS and initiating early administration of eculizumab for improving the outcome even in elderly patients.