Successful Pacemaker Setting Using Treadmill Exercise Test in a Child with Fontan Circulation.

The usefulness of a treadmill exercise test for determining optimal pacemaker settings remains unknown. An 8-year-old boy with Fontan circulation and a dual-chamber pacemaker for a rate-dependent advanced atrioventricular block suffered from dullness and poor school attendance. Although the pacemaker log showed an atrial tachycardia/fibrillation episode, treadmill exercise testing revealed sinus tachycardia, which converted to a 2:1 atrioventricular block. The pacemaker setting was optimized, with improvement in the patient's condition.Treadmill exercise testing helps optimize dual-chamber pacemaker settings in children with complex congenital heart disease involved in energy-consuming physical activities and having a wide working range in sinus rate.

Successful Percutaneous Thrombectomy of the Left Pulmonary Artery in a Neonate After a Patent Ductus Arteriosus Clipping.

We report a neonate with a successful percutaneous thrombectomy of a total thrombotic occlusion of the left pulmonary artery (LPA) after a surgical clipping for a patent ductus arteriosus (PDA). We suspected the compression of the LPA by the clipping and postoperative hemodynamic instability caused the LPA obstruction. After the surgical removal of the PDA clip and division of the PDA, we could safely retrieve the LPA thrombus with a non-hydrodynamic thrombectomy catheter for coronary arteries.

Steroid-Refractory Protein-Losing Enteropathy with Gastrointestinal Bleeding in a Patient with Fontan Circulation.

Protein-losing enteropathy (PLE) is one of the major complications after a Fontan operation. Some PLE patients suffer from concurrent gastrointestinal bleeding. An effective treatment regimen for such patients has not been established yet. Further, it remains unknown whether PLE and gastrointestinal bleeding coexist independently, or protein losing is associated with gastrointestinal bleeding. We report a 7-year-old steroid-refractory post-Fontan PLE case suggesting the latter pathogenesis together with a literature review.

Blood reservoir function in patients with Fontan circulation and asplenia syndrome.

Splanchnic circulation constitutes a major portion of the vasculature capacitance and plays an important role in maintaining blood perfusion. Because patients with asplenia syndrome lack this vascular bed as a blood reservoir, they may have a unique blood volume and distribution, which may be related to their vulnerability to the haemodynamic changes often observed in clinical practice. During cardiac catheterisation, the mean circulatory filling pressure was calculated with the Valsalva manoeuvre in 19 patients with Fontan circulation, including 5 patients with asplenia syndrome. We also measured the cardiac output index and circulatory blood volume by using a dye dilution technique. The blood volume and the mean circulatory filling pressure and the venous capacitance in patients with asplenia syndrome were similar to those in the remaining patients with Fontan circulation (85 ± 14 versus 77 ± 18 ml/kg, p = 0.43, 31 ± 8 versus 27 ± 5 mmHg, p = 0.19, 2.8 ± 0.6 versus 2.9 ± 0.9 ml/kg/mmHg, p = 0.86). Unexpectedly, our data indicated that patients with asplenia syndrome, who lack splanchnic capacitance circulation, have blood volume and venous capacitance comparable to those in patients with splanchnic circulation. These data suggest that (1) there is a blood reservoir other than the spleen even in patients with asplenia; (2) considering the large blood pool of the spleen, the presence of a symmetrical liver may represent the possible organ functioning as a blood reservoir in asplenia syndrome; and (3) if this is indeed the case, there may be a higher risk of hepatic congestion in patients with Fontan circulation with asplenia syndrome than in those without.

Case of Incomplete Kawasaki Disease with No Symptoms Except Fever Causing the Development of Coronary Aneurysm.

Incomplete Kawasaki disease (iKD), which does not satisfy the standard KD diagnostic criteria because the required number of principal symptoms is not met, sometimes causes coronary aneurysms. Here we report the case of a patient with iKD who presented with only one principal symptom that resulted in the development of coronary aneurysm, as evidenced by angiography.

Improvement in Dyssynchrony with Pharmacological Ablation of Right-Sided Accessory Pathway-Induced Cardiomyopathy in Infants.

Right-sided accessary pathways in patients with Wolff-Parkinson-White (WPW) syndrome may cause cardiac dyssynchrony and dilated cardiomyopathy, with a characteristic septal shape, irrespective of any supraventricular tachycardia episodes. We report on two infants (13 and 5 months), whose right-sided accessary pathway-induced dilated cardiomyopathy was successfully treated by flecainide for the first time. After the flecainide administration, an abnormal aneurysmal dilation of the basal interventricular septum was almost restored to normal, and the decreased ejection fraction recovered. Flecainide use may be an important therapeutic option for this entity to avoid catheter ablation during infancy.

Importance of dynamic central venous pressure in Fontan circulation.

We tested our hypotheses that central venous pressure (CVP) shows an excessive increase in response to volume overload in Fontan circulation according to the extent of the reduction in venous capacitance (Cv), and that the maximum CVP after volume loading is associated with hepatic congestion. Changes in CVP after angiography (volume loading) were examined in 40 patients with Fontan circulation and 29 controls with biventricular circulation. CVP significantly increased with angiography in both groups, but the changes were much more evident in the Fontan group than in controls (3.3 ± 2.0 vs. 0.9 ± 1.4 mmHg, p = 0.0003). Multivariate analysis demonstrated that reduced Cv was the only significant determinant of CVP increase, independent of the amount of injected contrast medium, blood volume, pulmonary resistance, and ventricular diastolic stiffness (p < 0.05). Importantly, the use of a venodilator was associated with increased Cv and the resultant suppression of CVP elevation with volume load. In addition, CVP levels both at baseline (p = 0.02) and after volume loading (p = 0.01) were weakly but significantly correlated with the plasma levels of γ-glutamyl transpeptidase, a marker of hepatic congestion; however, multivariate analysis revealed that the CVP level after volume loading was a more important determinant of hepatic congestion. The results of this study highlight the importance of assessing dynamic in addition to static CVP for a better understanding of Fontan circulation. The potential importance of Cv as a therapeutic target for improving Fontan physiology needs further elucidation.

First Pediatric Case of Infective Endocarditis Caused by Serratia Liquefaciens.

Infective endocarditis (IE) caused by Serratia liquefaciens has been reported in only 2 adults. We experienced the first pediatric (neonatal) case of IE caused by S. liquefaciens, with mitral valve vegetation 4 days after a palliative heart surgery. This report underscores the importance of treating for both gram-positive and gram-negative bacteria in IE cases until the blood cultures elucidate the details.

A 1-year-old boy with long pauses caused by paroxysmal atrioventricular block and sinus arrest: Vagal reflex and effect of pacing.

Paroxysmal atrioventricular block (PAVB) is rare in children. A 1-year-old boy presented with PAVB and sinus arrest that resulted in refractory life-threatening symptomatic long pauses. Continuous heart rate variability analysis with high time resolution (wavelet analysis) revealed an abrupt increase in parasympathetic activity just before a long pause, which indicated a vagal reflex. Although a pacemaker is not always effective because of a concomitant vasodepressive response in such cases, the complete stabilization after pacemaker implantation in this case supports the necessity and usefulness of pacemaker implantation in patients with reflex-induced highly symptomatic bradycardia.

Novel mechanisms for cerebral blood flow regulation in patients with congenital heart disease.

BACKGROUND: The mechanisms that regulate cerebral flow in patients after surgery for congenital heart diseases (CHDs) remain poorly understood. We tested our hypothesis that postoperative patients with CHD have disease- or hemodynamic-specific compensatory mechanisms for maintaining cerebral perfusion. METHODS: A total of 89 children with specific hemodynamics including Glenn (n = 14), Fontan (n = 19), repaired tetralogy of Fallot (n = 24), and control patients (n = 32) were enrolled. The resistance and blood flow distribution between the brain (Rc and CIc) and lower body (Rs and CIs) were calculated by measuring the hemodynamic changes resulting from inferior vena cava occlusion during cardiac catheterization. RESULTS: Despite considerable differences in cardiac index and superior vena cava pressure (SVCp), cerebral blood flow was preserved in all noncontrol groups, with a ratio between the vascular resistances in the cerebral and lower body circulation (Rc/Rs) that was significantly lower than that in controls. Interestingly, the reduced Rc/Rs of Glenn patients was mediated by the reduced Rc, whereas augmented Rs was conducive to the reduced Rc/Rs in the Fontan and tetralogy of Fallot groups. Multivariate analysis revealed that high SVCp was significantly associated with low Rc. Although low cardiac index was significantly associated with increased Rc and Rs, its impact was much greater on Rs than on Rc. CONCLUSIONS: Compensatory mechanisms for cerebral flow regulation occur according to hemodynamic abnormality type in postoperative patients with CHD. Because such a regulation mechanism implies cerebral circulation fragility, further investigations are needed to address the impacts of cerebral circulation properties on neurodevelopmental outcomes.

Prevalence, implication, and determinants of worsening renal function after surgery for congenital heart disease.

Accumulating data in adults indicate the prognostic importance of worsening renal function (WRF) during treatment of acute heart failure. Venous congestion appears to play a dominant role in WRF; however, data regarding WRF in children with congenital heart disease (CHD) are limited. The present study was conducted to elucidate the prevalence and characteristics of WRF after surgery for CHD in children. We also tested our hypothesis that, similar to adult heart failure, venous congestion is an important determinant of WRF independent of cardiac output in this population. Fifty-five consecutive pediatric patients who underwent cardiovascular surgery for CHD were studied (median age 0.7 years; range 3 days to 17 years). The degree of WRF was assessed by the difference between the maximum levels of postoperative serum creatinine (Cr) and preoperative serum Cr. There was a high prevalence of WRF in the present cohort: an increase in Cr level was observed in 47 patients (85 %) and a Cr increase ≥0.3 mg/dL was seen in 23 (42 %). Importantly, WRF was significantly associated with a worse clinical outcome of a longer stay in the intensive care unit and hospital (both p < 0.05), even after controlling for age and operative factors. In addition, multivariate regression analysis revealed that central venous pressure, rather than cardiac output, was an independent determinant of WRF. Postoperative management to relieve venous congestion may help ameliorate or prevent WRF and thereby improve outcomes in patients with CHD.

Mechanism of aortic root dilation and cardiovascular function in tetralogy of Fallot.

The aortic root dilation in tetralogy of Fallot (TOF) is a long-term clinical problem, because a severely dilated aorta can lead to aortic regurgitation, dissection, or rupture, which can be fatal, necessitating surgical intervention. The details of the mechanism of aortic root dilation, however, are unclear. We have shown that aortic stiffness is increased in patients with repaired TOF, and may mirror the histological abnormality of elastic fiber disruption and matrix expansion. This aortic stiffness is related closely to the aortic dilation, indicating that aortic stiffness may be a predictor of outcome of aortic dilation. Furthermore, the aortic volume overload is a very important determinant of aortic diameter in TOF patients before corrective surgery. In addition, a chromosomal abnormality and the transforming growth factor-ß signaling pathway, a major contributor to aortic dilation in Marfan syndrome, also affect this mechanism. In this way, aortic dilation in TOF patients is suggested to be a multifactorial disorder. The aim of this review was therefore to clarify the mechanism of aortic dilation in TOF, focusing on recent research findings. Studies linking histopathology, mechanical properties, molecular/cellular physiology, and clinical manifestations of aortic dilation facilitate appropriate treatment intervention and improvement of long-term prognosis of TOF.

Influence of Left Ventricular Stiffness on Hemodynamics in Patients With Untreated Atrial Septal Defects.

BACKGROUND: Although left ventricular (LV) stiffening with age is believed to increase left-to-right shunting in patients with atrial septal defects (ASD), clinical data have not confirmed this. We sought determinants of the pulmonary-to-systemic flow ratio (Qp/Qs) in patients with untreated ASD. METHODS AND RESULTS: We retrospectively studied 180 patients with ASD who underwent percutaneous ASD closure between 2007 and 2011. Qp/Qs and LV stiffness were measured before ASD closure.The median age of the subjects was 18 years, and 117 (65.0%) were female. The mean ASD size adjusted for square root of body surface area (BSA) was 14.4±4.2 mm/m, and the Qp/Qs was 2.28±0.74. Adjusted ASD size most strongly related to Qp/Qs (r=0.74, P<0.0001). Multivariate analysis revealed that LV stiffness was a significant predictor of Qp/Qs, independently of adjusted ASD size and vascular resistance (P=0.0015). Based on the multivariate model that accounts for the effects of LV stiffness and vascular resistance, the minimal adjusted diameter that can cause a Qp/Qs of 2.0 was predicted to be 7.3 mm/m. CONCLUSIONS: Qp/Qs in ASD can change significantly depending on LV stiffness, suggesting that it would increase with age. An ASD >7.3 mm/m in diameter has the potential to cause significant left-to-right shunting, and may require closure regardless of hemodynamic status at the time of assessment.

Oxygen supply to the fetal cerebral circulation in hypoplastic left heart syndrome: a simulation study based on the theoretical models of fetal circulation.

Hypoxia due to congenital heart diseases (CHDs) adversely affects brain development during the fetal period. Head circumference at birth is closely associated with neuropsychiatric development, and it is considerably smaller in newborns with hypoplastic left heart syndrome (HLHS) than in normal newborns. We performed simulation studies on newborns with CHD to evaluate the cerebral circulation during the fetal period. The oxygen saturation of cerebral blood flow in newborns with CHD was simulated according to a model for normal fetal circulation in late pregnancy. We compared the oxygen saturation of cerebral blood flow between newborns with tricuspid atresia (TA; a disease showing univentricular circulation and hypoplasia of the right ventricle), those with transposition of the great arteries (TGA; a disease showing abnormal mixing of arterial and venous blood), and those with HLHS. The oxygen saturation of cerebral blood flow in newborns with normal circulation was 75.7 %, whereas it was low (49.5 %) in both newborns with HLHS and those with TA. Although the oxygen level is affected by the blood flow through the foramen ovale, the oxygen saturation in newborns with TGA was even lower (43.2 %). These data, together with previous reports, suggest that the cerebral blood flow rate is decreased in newborns with HLHS, and the main cause was strongly suspected to be retrograde cerebral perfusion through a patent ductus arteriosus. This study provides important information about the neurodevelopmental prognosis of newborns with HLHS and suggests the need to identify strategies to resolve this unfavorable cerebral circulatory state in utero.

Aortic root dilatation and aortic stiffness in patients with single ventricular circulation.

BACKGROUND: This study tested the hypothesis that aortic stiffness is increased more in patients with single ventricular (SiV) circulation and dilated aorta than in those without aortic dilatation, and that aortic stiffness is an independent determinant of aortic dilatation in this type of patient. METHODS AND RESULTS: Pulse wave velocity (PWV) and aortic size were measured during catheterization in 56 consecutive patients with SiV circulation (aortic dilatation, n=31 [observed/expected aortic root diameter >1.5]; without aortic dilatation, n=25). PWV was found to be significantly higher in the dilatation group than in the non-dilatation group (483.6±10.3 vs. 394.0±8.9 cm/s, P<0.001) after controlling for age and aortic pressure, factors known to influence PWV (P<0.001, analysis of covariance). There was a strong positive correlation between aortic root diameter and PWV (P<0.001). Multivariate analysis adding aortic flow (index of aortic volume load) to independent variables in 25 pre-Glenn patients with directly calculated aortic flow volume showed that PWV was an independent determinant of aortic dilatation (P<0.001). CONCLUSIONS: In patients with SiV circulation and dilated aorta, aortic stiffness is increased and is an independent determinant of aortic dilatation. To improve prognosis of Fontan circulation, further studies on whether aortic stiffness modulation reduces the progression of aortic dilatation and resultant aortic regurgitation are warranted.

Primary anastomosing hemangioma as a preoperative diagnostic mimicker of retroperitoneal cavernous hemangioma: A case report.

Anastomosing hemangioma (AH) is rare and a newly recognized variant of capillary hemangioma that is mostly found in the genitourinary tract. Additionally, AH is sometimes difficult to diagnose without pathological specimens. It is difficult to diagnose preoperatively due to the lack of specific clinical and radiologic appearance. The present report describes the imaging features from a radiological perspective and outlines the clinicopathologic features and treatment options. A 67-year-old woman was referred to Dokkyo Medical University Saitama Medical Center (Koshigaya, Japan) for a retroperitoneal tumor that was identified at a medical checkup 4 years prior. The patient had no symptoms, no abnormal physical signs and no past medical or specific family history. Routine blood tests were all within the normal ranges. A nonenhanced CT scan showed a circular, homogenous, well-circumscribed retroperitoneal tumor that was ~32×23 mm in size, between the abdominal aorta and the inferior vena cava, and just below the left renal vein. On a contrast-enhanced multidetector CT scan, the tumor showed heterogeneous septal enhancement in the arterial phase and persistent enhancement in the portal phase. The tumor was diagnosed as a benign neurogenic tumor or a retroperitoneal cavernous hemangioma at the time, and the patient was intended to be followed up at the outpatient clinic. However, it gradually increased to a maximum diameter of 35 mm over 4 years. Finally, it was completely resected by open laparotomy and pathologically diagnosed as AH. Retroperitoneal hemangioma is extremely rare in adulthood and has been confirmed in only 1-3% of all retroperitoneal tumors. To the best of our knowledge, only 6 cases of para-aortic AH have been reported. The incidence of this variant is very low. However, AH may be included in the differential diagnosis when a slowly progressing heterogeneous mass appears in the para-aortic region that exhibits a CT-enhanced pattern similar to a typical cavernous hemangioma.

Migraine attacks after transcatheter closure of atrial septal defect.

OBJECTIVE: The purpose of our study was to evaluate the effect of atrial septal defect (ASD) closure on migraine headache attacks (MHA). METHODS: A total of 247 patients who underwent percutaneous ASD closure at our facilities were sent a structured questionnaire. We diagnosed MHA according to the criteria of the International Headache Society. RESULTS: A total of 207 patients were included in the study. New-onset MHA occurred in 23 patients and persisted in 15 at a mean follow-up of 45 months. Of the 29 patients who had MHA prior to ASD closure, 11 reported exacerbation of MHA, 11 reported no change and seven reported improvement within three months after ASD closure. Compared with the patients who had no MHA, patients with de novo MHA were younger and patients with MHA improvement tended to be older. Switching from aspirin to ticlopidine or clopidogrel rapidly aborted frequent MHA in nine patients who had severe symptoms after ASD closure. CONCLUSIONS: These results indicate that Amplatzer device implantation can act as a permanent trigger of MHA in not a few patients, and that age may be an important predictive factor of the influence of ASD closure on MHA.

Landiolol hydrochloride infusion for treatment of junctional ectopic tachycardia in post-operative paediatric patients with congenital heart defect.

AIMS: Junctional ectopic tachycardia (JET) after cardiopulmonary bypass surgery for congenital heart defects is often therapy-resistant and associated with high morbidity and mortality. Improvement of pharmacological therapy is needed. METHODS AND RESULTS: We retrospectively analysed the clinical data of four patients with congenital heart defects, who developed post-operative JET and were treated with landiolol hydrochloride, representing all such patients treated at our university. In two patients, landiolol was used after failure of response to anti-arrhythmic therapies, including thermal control, sedation, discontinuation of catecholamines, and pharmacological therapy with nifekalant and amiodarone. Landiolol was used as a first-line therapy in the other two patients. In all patients, landiolol, at a dose ranging from 1.0 to 10.0 µg/kg/min, achieved successful sinus conversion within 15 min. No adverse events, such as bradycardia, hypotension, or hypoglycaemia, were encountered in all four patients. CONCLUSION: Although limited to a small and heterogeneous group of patients, the results suggest that landiolol is a potentially useful therapeutic option for the well-known difficult condition of post-operative JET, and warrant further investigation in large-scale controlled studies.

Heart failure with preserved ejection fraction in children: hormonal imbalance between aldosterone and brain natriuretic peptide.

BACKGROUND: There is no information on heart failure (HF) with preserved ejection fraction (HFpEF, EF >50%) in children. METHODS AND RESULTS: Through a retrospective review of 3,907 pediatric patients with cardiovascular disease, we examined the characteristics of pediatric HFpEF over a 10-year period. We identified 18 patients with HFpEF (0.5%). They were predominantly young children (1.1±0.9 years, no sex preponderance), who had undergone surgery for congenital heart disease. They also had concentric hypertrophy and diastolic dysfunction with elevated blood pressure. Notably, HFpEF patients had more pronounced elevation of serum aldosterone but less pronounced elevation of plasma brain natriuretic peptide (BNP) than 22 systolic HF patients (SHF, EF ≤50%) (aldosterone: 1,375±1,200 vs. 511±563pg/ml, P<0.05, and BNP: 101±141 vs. 749±818pg/ml, P<0.005). Consequently, the aldosterone/BNP ratio was significantly higher in HFpEF (38±63) than in SHF (1.7±1.9, P<0.05), and an aldosterone/BNP ratio of 10.3 or higher best predicted HFpEF (area under the curve=0.89). The HF mortality rate was significantly lower in the HFpEF than in the SHF cases, and HF symptoms showed amelioration in 61% of patients during the follow-up period of 4.2±2.6 years. CONCLUSIONS: HFpEF does exist in children. A common pathophysiology underlies childhood and adult HFpEF despite considerable epidemiological and etiological differences. Future controlled studies are warranted to assess the cause-effect relationship between unique hormonal profiles and HFpEF.

Transient Recovery of Complete Atrioventricular Block Due to Maternal Anti-SS-A Antibody Through Antenatal Steroid Administration After 27 Weeks of Gestation.

Maternal anti-SS-A antibodies may cause complete atrioventricular block or myocardial damage in a fetus. Effective treatment for this has not been established. Although antenatal steroids may be a treatment option for anti-SS-A antibody-related myocarditis or atrioventricular block, a complete atrioventricular block is usually considered irreversible once established. Previous reports have indicated that, in cases where antenatal steroids were effective for atrioventricular block, they were administered earlier in the pregnancy. Here we present a case where maternal steroid administration initiated from 27 weeks, which is beyond the recommended optimal treatment period, was effective in altering a complete atrioventricular block to a grade I atrioventricular block.