Search

We reviewed the long-term outcome of children with hypertrophic cardiomyopathy (HCM) based on the type.We reviewed the medical records of 100 patients (male 54 female 46) with HCM at our hospital between 1977 and 2015. The survival and cardiac event-free survival rates were calculated by the Kaplan-Meier method.The age at the time of the diagnosis ranged from 0 to 15 years with a median of 8 years. The number of patients with Noonan syndrome and hypertrophic obstructive cardiomyopathy (HOCM), idiopathic HCM (i-HCM), and secondary HCM (s-HCM) was 13, 13, 65, and 9 respectively. A dilated phase of HCM occurred in 24 patients. Nineteen (79 %) of the 24 patients died of heart failure, and two underwent a heart transplantation. Eight (33 %) of the 24 patients had s-HCM. The median age when a dilated phase occurred was 15 years old, and the median interval from the initial diagnosis to the dilated phase was 8 years. The median time from the diagnosis of a dilated phase to death was 1.6 years. Sudden death and implantable cardioverter defibrillator implantations occurred in 6 and 11 patients at around 15 years old, respectively. The 20-year survival rates were as follows: Noonan syndrome 84 %; HOCM 82 %; i-HCM 71 %; and s-HCM 17 %. Overall, the survival rates at 10, 20, and 30 years were 83 % (95 % confidence interval 73-89), 69 % (58-78), and 63 % (50-74), respectively. The overall cardiac event-free survival rates at 10, 20, and 30 years were 57 % (47-67), 39 % (31-50), and 32 % (21-44), respectively.The long-term outcome in children with HCM was poor, and the outcome of s-HCM was very poor. The occurrence of a dilated phase worsened the outcome in HCM patients. Sudden death and d-HCM often occurred at around 15 years old.

Background A stiffened, dilated ascending aorta may represent an important predictor of cardiovascular mortality, and has been reported in patients with congenital heart disease, including single ventricle. However, the serial conformational changes and determinants of reduced distensibility in ascending aorta have not been clarified. Methods This retrospective study investigated 115 postoperative Fontan survivors (median age at Fontan: 3.7 years). All patients underwent cardiac catheterization before and 1, 5, 10, and 15 years after the Fontan operation. We measured Z-scores for diameters and stiffness indexes (β) of the ascending aorta and descending aorta from angiograms. We also reviewed the clinical profiles, hemodynamic parameters, and exercise capacities of patients and compared them with results from 47 control subjects. Results Fontan survivors displayed significantly larger Z-score and β of the ascending aorta from before to 15 years after surgery than controls, whereas values for the descending aorta were comparable. Z-score for the ascending aorta was decreased, but β was elevated significantly according to the trend test. In multivariable analysis, β of the ascending aorta at 15 years after Fontan operation and its increasing trend were associated with older age at Fontan operation and elevated ventricular end-diastolic pressure. Reduced exercise capacity also correlated with stiffening of the ascending aorta. Conclusions Fontan survivors showed progressive stiffening and relatively slow growth of the dilated ascending aorta. Progressive stiffening of the ascending aorta may be coupled to diastolic dysfunction and reduced exercise capacity, suggesting the importance of lifelong management of subclinical Fontan pathophysiology.

Several studies have reported aortic dilation and increased stiffness of the ascending aorta in patients after repair of congenital heart disease (CHD), which may be a predominant cardiovascular risk. However, the clinical significance has not been described in detail. In this retrospective study, 175 repaired patients with complex CHD achieving biventricular circulation and age-matched 39 control subjects were reviewed (median age: 14.9 and 15.7 years, respectively). We measured the diameters of the ascending aorta and descending aorta from catheterization angiograms to yield Z-scores and stiffness indexes (β) using diameter fluctuations corresponding to pulsatile pressures. Clinical profile, peak oxygen uptake during the cardiopulmonary exercise test, and incidence of unscheduled hospitalization during follow-up was also reviewed. Compared with controls, patients with complex CHD, except for those with aortic coarctation, exhibited significant dilation and increased stiffness of the aortic root and ascending aorta, but not of the descending aorta. In this CHD population (n = 147, including 112 conotruncal anomalies), exercise capacities correlated independently with the diameter Z-score and stiffness index of the ascending aorta along with the history of repetitive thoracotomies, reduced forced vital capacity, and right ventricular hypertension. During a follow-up period (median 15.6 years), either dilation (Z-score >3.5) or increased stiffness (β >6.0) of the ascending aorta stratified morbidity, but no synergistic impact was detected. In conclusion, in repaired patients with complex CHD, a stiffened and dilated ascending aorta was frequently found, exerting significant adverse impacts on diminished exercise capacity and morbidity.

Background In Japan, the school screening program for heart disease (SS) has been performed since 1973. However, little has been reported on the electrocardiogram (ECG) changes and long-term prognosis in patients with hypertrophic cardiomyopathy (HCM) detected by the SS. Methods All 44 consecutive pediatric HCM patients (10.1 ± 3.0 years old), who had been originally consulted by the SS before the diagnosis of HCM from April 1981 to April 2017, were reviewed retrospectively. Results At the SS, all patients showed mild or no symptoms. All patients showed ECG abnormalities, and 75 % had a high proposed ECG risk score (≧6). However, 30 % of them had no echocardiogram finding of myocardial hypertrophy. During the follow-up period (14.8 ± 10.0 years), life-threatening events (LTE) occurred in 11 (25 %) patients, and the first LTE occurred during exercise in 8 (18 %). The estimated LTE and heart failure death-free survival rate at 10 years was 64.9 %. The LTE-free survival rate was lower in patients without than in those with myocardial hypertrophy at the SS. Conclusions The SS was useful in detecting patients with HCM with mild or no symptoms at the early stage. However, our study indicated that early detection of HCM is not associated with improvement in the prognosis of the patients. Further studies are needed.

Arterial switch operation (ASO) for dextro-transposition of the great arteries (d-TGA) has gradually replaced the atrial switch operation and has become the standard operation. To date, the outcomes of pregnant women with d-TGA after this new operation have not been investigated. In this study, we investigated the impact of ASO on pregnant outcomes and mid-term prognosis in women with d-TGA and compared with the atrial switch operation through the literature review.There were 20 pregnancies in 10 women with d-TGA after ASO and 6 resulted in abortion. Among 14 successful pregnancies in 10 women, 11 pregnancies achieved the term delivery and 3 pregnancies, including 1 twin pregnancy, resulted in preterm labor. Maternal cardiovascular events occurred in 4 (heart failure and arrhythmias in 3 and arrhythmia in 1), and all were controllable with medications. Risk factors for the peripartum cardiac events were older age at ASO and delivery, and higher concentration of brain natriuretic peptide (BNP) at first trimester (p0.05). In 7-60 month-follow-up after delivery, no case showed deterioration of functional class and systemic ventricular function. According to the literature review, women after ASO demonstrated a better prognosis than those after the atrial switch operation.The majority of women with d-TGA after ASO tolerated pregnancy and delivery well. The older age at ASO, an elderly pregnancy, and higher BNP levels at the first trimester were possibly risk factors of peripartum cardiovascular events among the group. The literature reviews and this study may indicate the advantage of systemic left ventricle compared with systemic right ventricle in long-term outcomes after delivery.

Elevated central venous pressure (CVP), low cardiac output, and mild hypoxia are common early and late after Fontan operations. However, the association of these characteristics with late mortality is unclear. We aimed to elucidate the hemodynamic determinants of mortality after Fontan operation.We evaluated early (group early; 0.5-5years postoperatively, n=387) and late (group late; ≥15years postoperatively, n=161) Fontan hemodynamics that included CVP (mm Hg), cardiac index (CI; L/min per mMortality was higher in group late than in group early (17 vs 11, P.0001). In both groups, higher CVP (hazard ratio [HR]1.46 and 1.38, respectively; P.001-.0001) and lower arterial blood oxygen saturation (HR 1.12, P.001 for both) were associated with increased mortality. Greater end-diastolic volume index (HR per 20: 1.73) and lower EF (HR per 10%: 3.38) were associated with increased mortality only in group early (P.0001 for both). In contrast, only in group late was higher CI associated with increased mortality (HR 2.50, 95% CI 1.30-4.55, P.01). Seven patients in group late with both high CVP (≥14) and CI (≥3.0) had the highest mortality (HR 18.1, 5.55-52.4, P.0001).Elevated CVP and low arterial blood oxygen saturation correlate with mortality in both early and late Fontan survivors. End-diastolic volume index and EF are associated with mortality only in the earlier cohort, whereas interestingly, elevated cardiac output is associated with increased mortality in the later cohort.

Background Fontan conversion from a classic Fontan operation such as atriopulmonary connection to total cavopulmonary connection with antiarrhythmia surgery is currently not indicated for patients without any late Fontan complications. Methods Thirty-two consecutive patients who underwent Fontan conversion between 1991 and 2012 were divided into 2 groups by the presence (group 1: n = 25, atrial tachyarrhythmia [AT] in 24 and protein-losing enteropathy in 4) or absence (group 2: n = 7) of late Fontan complications, and the surgical outcomes were retrospectively compared. During the study period, heart transplantation was not indicated for patients with failed Fontan circulation in Japan. Results The mean follow-up period was 6.2 ± 3.7 years in group 1 and 4.6 ± 3.8 years in group 2 ( p = 0.29). Overall survival rate at 10 years after conversion was 71% in group 1 and 100% in group 2 ( p = 0.12). Whereas preoperative AT and protein-losing enteropathy remained after conversion in 8 patients (33%) and all 4 patients (100%), respectively, in group 1, neither were observed in group 2. Cardiac catheter examinations presurgery (n = 32) at 1 year (n = 28), and at 5 years (n = 19) after the conversion showed that the cardiac index significantly and similarly improved in both groups after the conversion, and maintained for at least 5 years. Conclusions Cardiac output similarly improved after Fontan conversion in patients with or without late Fontan complications by elimination of venous blood congestion on Fontan pathways. Although long-term follow-up is mandatory, newly onset AT was not observed after prophylactic Fontan conversion.

Most of patients after the Fontan operation can reach their adulthood, however, the management strategy for this complex pathophysiology has not been yet established. In general, elevated central venous pressure (CVP) and low cardiac output (CO) due to impaired ventricular preload characterize the Fontan circulation and the ideal hemodynamics could be a combination of a lower CVP with a higher CO. Thus, preserved functional systemic ventricle with low pulmonary artery resistance is thought to be crucial for better long-term outcome. However, on the other hand, because of the unique hemodynamics, these patients have significantly higher incidence of complications, sequelae, and even mortality. The major complications are supraventricular arrhythmias, heart failure, and Fontan-related problems, including protein-losing enteropathy and pulmonary arteriovenous fistulae, both of which are refractory to the treatments, and most of these "Fontan inconveniences" increase as patients age. In addition, one of the recent emerging problems is Fontan-associated liver disease that includes liver cirrhosis and hepatocellular carcinoma. Furthermore, women with Fontan circulation also reach childbearing age and there have been increasing numbers of reports showing a high incidence of pregnancy-associated complications. All these problems may be a part of "Fontan inconveniences" because most of the current Fontan patients are still "young" i.e. in their twenties or thirties and it may be not surprising that more new Fontan-associated pathophysiology emerges as patients age. Recent evidence reminds us of the concept that adult Fontan pathophysiology is not just a cardiovascular disease, rather, a multiorgan disease with many interactions between cardiovascular and non-cardiovascular organs. Therefore, a multidisciplinary approach is mandatory to take care of and anticipate the better long-term outcome.

Right ventricle (RV) may determine heart failure (HF) severity in adults with congenital heart disease (ACHD). However, the association of RV properties with clinical profiles remains unclear.To clarify the associations of RV properties with biomarkers, exercise capacity, and unscheduled hospitalization (USH) in postoperative ACHD patients.We evaluated determinants of RV end-diastolic volume (EDVI, ml/m(2)) and pressure (EDP, mmHg) in 260 patients who were divided into 4 groups, i.e., those with RVEDVI100 and EDP≥10 (A, n=49, 19%), those with RVEDVI≥100 with EDP≥10 (B, n=22), those with RVEDVI100 and EDP10 (C, n=134), and those with RVEDVI≥100 and EDP10 (D, n=55). EDVI, EDP, and ejection fraction (EF, %) of the RV were independently associated with the corresponding value of the left ventricle (LV) (p0.0001 for all). Group A had a RV-EF of 53±8 and was defined HF with preserved RV-EF (RV-HFpEF). Younger age, lower platelet count, and elevated plasma γ-glutamyltransferase independently predicted the RV-HFpEF. When the presence of pulmonary hypertension and LV-HFpEF was included in the analysis, these two factors independently predicted the presence of RV-HFpEF (p0.05-0.001). On multivariate analysis, older age, number of surgeries, cardiac index, and RV systolic pressure independently determined peak oxygen uptake (PVO2, p0.05) and RV outflow reconstruction independently predicted USH. The RV-HFpEF group showed the lowest PVO2 and highest incidence of USH among the 4 groups (p0.05).Impaired RV characteristics, especially RV-HFpEF, with liver dysfunction and lower platelet count predicted lower exercise capacity with a poorer prognosis in postoperative ACHD patients.

Background The management of Eisenmenger syndrome (ES) has dramatically changed since the advent of disease-targeted therapy (DTT). However, guidelines for ES management, including DTT, have not been established. We aimed to clarify the current incidence, underlying disease, and management of ES in Japan, using a nationwide survey. Methods A written questionnaire was sent to members of the Japanese Society for Adult Congenital Heart Disease, through which information was obtained from 86 institutions. Results A total of 251 patients with ES (80.5% cases ≥ 20 years of age) were followed as of February 2012; DTT was performed in 124 (49.4%) patients. Unrepaired simple anatomy was reported as an underlying condition in 165 patients (65.7%). Among patients with ES, 55 (21.9%), 128 (51%), 53 (21.1%), and 12 (4.8%) were classified into functional classes I, II, III, and IV, respectively. DTT was routinely performed at 52 (60.5%) institutions, but there were variations in the DTT therapeutic strategy at these institutions. Combined therapy was more often used than monotherapy; an endothelin receptor antagonist was the most frequently prescribed medication. There were institutional differences regarding heart failure treatment and indications for anticoagulation. Digitalis and angiotensin-converting enzyme inhibitors or angiotensin II receptor blockers were widely used, but beta-blockers were infrequently used to manage heart failure. Conclusions This survey describes the current status, including prevalence and underlying disease, and variations in the practical management of ES in Japan. The results will help in the creation of future guidelines for ES management.

Most adults with congenital heart disease show high levels of natriuretic peptide (NP) when compared with normal controls. Levels of norepinephrine and NP were strongly related to outcome in studies that included many symptomatic patients, especially those with unrepaired congenital heart disease, Eisenmenger syndrome, and pulmonary hypertension. Limited data are available regarding serial assessment of biomarkers; such information could provide additional important information to help identify patients at risk, as demonstrated during patient follow-up and pregnancy.

The Fontan procedure is an open heart procedure performed in pediatric patients with a particular congenital cardiac anomaly known as a univentricular heart. The procedure is used to reroute the systemic venous blood from the inferior vena cava directly to the pulmonary artery. It improves patients' prognoses, but various late-phase extracardiac complications that manifest when patients reach adolescence have been recognized. These complications, pulmonary arteriovenous fistula and protein losing gastroenteropathy, for example, present significant challenges in the management of adults with Fontan circulation. Liver fibrosis is another possible late-phase complication and one of the most serious. Development of a neoplasm, usually a hepatocellular carcinoma, is sometimes reported. We encountered a young patient in whom Fontan circulation led to the development of a histologically unusual liver cancer that resembled the poorly differentiated hepatocellular carcinoma or the combined hepatocellular-cholangiocarcinoma with stem-cell features described in the latest WHO classification.

Background Abnormal cardiac autonomic nervous activity (CANA) is not uncommon in postoperative patients with congenital heart disease (CHD). Methods and results We attempted to clarify the prognostic value of the CANA variables in postoperative CHD patients and prospectively evaluated the CANA variables in 292 consecutive biventricular and 91 Fontan repair patients. The CANA variables included the heart rate variability, arterial baroreflex sensitivity (BRS), washout ratio of the myocardial metaiodobenzylguanidine scintigraphy, and plasma norepinephrine level. With a follow-up of 10 ± 2 years, 98 total events that required hospitalization, including 13 deaths and 48 unscheduled cardiac events (UCEs), occurred. In all the CHD patients, all the CANA indices predicted the total events and UCEs. Of those, the NE level (p = 0.0004) and BRS (p = 0.0373) predicted the mortality. In a multivariate analysis, the BRS was an independent CANA-predictor for the total events (p = 0.007). In the biventricular patients, the plasma NE level, heart rate variability, and BRS predicted the total events and UCEs and the BRS was the only independent CANA-predictor for the total events (p = 0.0329). In the Fontan patients, the plasma NE level was the only predictor for the UCEs (p = 0.0242) and no other CANA variables were independent predictors of the total events or UCEs. Conclusions All CANA variables, especially the BRS, were useful predictors for future clinical events in biventricular CHD patients, whereas no CANA variables, except for the plasma NE level, predicted future clinical events in the Fontan patients.

gradually increasing the number of medications and doses. Oral amiodarone was administered for atrial arrhythmia. Subsequently, her cardiothoracic ratio improved from 70% to 65%. We performed cardiac catheterization and an electrophysiology study (EPS) to evaluate hemodynamics and arrhythmogenic substrates before surgical treatment. In cardiac catheterization, right ventricular (RV) end-diastolic volume index improved, from 255 to 128 ml/m 2 after optimal medical treatment. EPS 1 An EPS was performed with the patient under general anesthesia. For this intervention, a 4-mm-tip 7-F quadripolar catheter (Navistar, Biosense-Webster, Diamond Bar, California) was used for mapping and ablation. A steerable multipolar circular mapping catheter (Lasso, BiosenseWebster) was placed at the junction between the left superior caval veins and the left side of the atrium to serve as a reference for mapping. First, we mapped the area around the common AV ring to determine the location of the AV node during continuous atrial pacing. Two separate His bundle electrograms were recorded at the dorsal and inferior portions of the common AV ring (Figure 1). We detected an anterior AV node based on recording at the dorsal site of the AV ring, while a posterior AV node was recorded at the inferior site of the AV ring. During atrial pacing, 2 different QRS complexes were observed dependent on the pacing rate (Figure 2A). These QRS complexes did not show preexcitation, but QRS duration was prolonged dependent on the pacing rate. Figure 2A indicates 3 types of QRS complexes: (a) was recorded at rest and with lead I positive; (b) was recorded during atrial pacing, which was relatively rapid as compared with that at rest; and (c) was recorded during transient mechanical conduction block of the anterior AV node via catheter manipulation. Thus, QRS complexes at rest represented a fusion beat between the anterior and posterior AV nodes. No ventriculoatrial conduction was seen during ventricular pacing, even with isoproterenol infusion. Next, we initiated AT using atrial burst stimulation. The QRS complexes during AT (atrial tachycardia) (AT cycle length 450

The influence of volume overload on ventricular performance has been previously investigated but primarily with respect to the duration of overload. The aim of the present study was to elucidate whether the magnitude of the preoperative volume overload, represented by the ventricular volume, has any effect on ventricular performance long after the Fontan operation in patients with tricuspid atresia. We evaluated consecutive changes in hemodynamic catheterization data obtained at 1, 5, and 10 years after primary Fontan repair. The variables were compared between patients with larger (n = 20) and smaller (n = 21) ventricles (preoperative end-diastolic volume [percentage of predicted] 262 ± 33%, maximum 320% vs 182 ± 22%, minimum 133%, respectively). In a subgroup of patients (n = 33) who underwent symptom-limited exercise at 10.7 ± 3.0 postoperative years, the peak oxygen uptake was measured, and the potential predictors were interrogated. The difference in ventricular contractility between the groups tended to increase with time, with those with a larger ventricle showing poorer contraction, irrespective of whether it was assessed in a load-dependent (ejection fraction) or load-independent (end-systolic elastance) manner. The differences in these variables reached statistical significance at 10 years (p = 0.028 and p = 0.032). Multivariate analysis indicated a larger ventricle was an independent risk factor of poorer aerobic capacity (p = 0.047). In conclusion, ventricular performance was less preserved in those with a larger ventricle, which might result in suboptimal aerobic capacity. Our findings suggest not only early unloading, but also avoidance of excessive volume overload is of importance to minimize the deleterious effect of volume overload on an inherently susceptible ventricle.

To evaluate the impact of systemic ventricular (SV) morphology on mechano-electrical interaction (MEI) and compare the results with clinical profiles in Fontan patients.Abnormal ventricular MEI causes systolic dysfunction of the right and left ventricles (RV, LV).We evaluated serial changes (up to 15 years post-Fontan operation) in QRS duration (QRS-d, ms), catheterization-based hemodynamics and SV performance in 77 patients and compared them with 36 referents.Preoperative QRS-d was wider in the Fontan patients (86+/-14 vs. 64+/-9, p0.001) and steadily increased for the next 15 years (107+/-25 vs. 85+/-9, p0.001). QRS-d was wider in non-LV type SV patients than those with LV morphology (p0.05) with a positive association with age at repair (p0.001). SV contractility (Ees) improved in the RV and LV groups (p0.05), during the next 10-year Ees, ventriculoarterial coupling (Ea/Ees) and ventricular efficiency (SW/PVA) were superior in the LV group. QRS-d and its long-term change correlated with the corresponding SV volume and change (p0.01), respectively, while the immediate postoperative volume reduction did not result in the QRS-d shortening. QRS-d correlated with Ees, Ea/Ees, SW/PVA, and peak oxygen uptake (VO(2)) (p0.001) and QRS-d was one of the main determinants of peak VO(2) (r=-0.48, p0.001).SV morphology-associated wide QRS-d compromises the MEI as well as energetic properties long-term after the Fontan operation, especially in non-LV type patients.

Central hypercapnic chemosensitivity (Chemo) influences the enhanced ventilatory and sympathetic responses in heart failure patients; however, its influence on these responses in Fontan patients is unknown.To measure Chemo and compare the results with rest and exercise ventilatory characteristics in Fontan patients.We measured Chemo (l/min/mmHg), hemodynamics, pulmonary function, cardiac autonomic nervous and neurohumoral activities and compared the results with the ventilatory response during exercise in 42 Fontan patients and 12 referents. Chemo did not differ significantly between the Fontan patients (1.5 +/- 0.9) and referents (1.3 +/- 0.4). However, a higher Chemo in addition to lower resting arterial oxygen saturation (SaO(2)) and higher dead space ventilation (Vd/Vt) independently determined a higher resting minute ventilation (VE) and, except for the Chemo, these factors also independently determined the higher resting ventilatory equivalent for carbon dioxide output (VE/VCO(2)) (p0.05-0.001). At peak exercise, the higher Chemo as well as the higher peak Vd/Vt and aerobic exercise capacity independently determined the higher peak VE and VE/VCO(2) (p0.01-0.001). Among cardiac autonomic and neurohumoral activities, only the higher plasma norepinephrine concentration was associated with higher Chemo in Fontan patients (r=0.40, p0.01) and age was correlated positively with Chemo in the high Chemo (or =2.1) Fontan patients (n=10).In addition to lower SaO(2) and higher Vd/Vt, an increased Chemo associated with sympathetic activation has a significant impact on accelerated rest and exercise ventilation in some Fontan patients, especially in adult patients.

Abnormal exercise-related heart rate (HR) dynamics, that is, blunted exercise HR response, lower peak HR, and delayed HR recovery after exercise, are associated with high morbidity and mortality in adults with acquired and congenital heart disease (CHD). However, the precise mechanisms underlying the abnormal HR dynamics remain unclear.The purpose of this study is to evaluate the precise contribution of cardiac autonomic nervous activity (CANA) and sinus node function on exercise-related HR dynamics in postoperative patients with CHD.We analyzed our previous data in 53 postoperative patients with CHD who had undergone pharmacologic evaluation, including intrinsic HR, and compared the results with HR dynamics.Intrinsic HR (84% +/- 11%) was lower than the expected value and independently correlated with resting HR (P.05). Univariate analysis demonstrated that all CANA indices significantly correlated with most HR dynamic parameters. On multivariate analysis, basal parasympathetic nervous activity significantly influenced all HR dynamics (P.05-.0001), except for peak HR, whereas postsynaptic beta sensitivity of the sinus node significantly influenced all HR dynamics (P.05-.001), except for early HR recovery. Resting plasma norepinephrine significantly correlated with all HR dynamics (P.05-.001), except for resting HR.Lower resting and peak HRs are independently associated with intrinsic sinus node dysfunction and abnormal sympathetic CANA, respectively. A blunted HR increase and delayed early HR recovery are independently associated with impaired sympathetic and parasympathetic CANAs with the greater influence on a blunted exercise HR increase.

Supraventricular tachycardia (SVT) is becoming of great concern for patients long after the Fontan operation and arterial blood pressure (BP) decreases during SVT may be associated with their morbidity and mortality.We investigated the BP during supraventricular pacing (SVP) to simulate SVT in these patients. We measured femoral venous pressure (FVP) and plasma norepinephrine (NE) during SVP at 150 and 180 per minute in 20 Fontan patients and recorded the initial BP fall, its recovery and steady-state BP.Wide QRS duration had a significant impact on a greater BP decline and increases in steady-state FVP and NE at 150 SVP. Changes in BP, FVP and NE were greater at 180 SVP and in adult patients. In addition to a greater impact of baseline BP and age on the initial BP drop and steady-state BP (p0.01); older age at Fontan repair, lower ventricular ejection fraction and heart rate variability were major determinants of greater BP fluctuation during 180 SVP (p0.05). Patients with a history of SVT (n=5) exhibited a greater initial BP drop and increase in FVP during 180 SVP (p0.01). The type of Fontan procedure had no influence on BP dynamics during SVP.In Fontan patients, wide QRS duration causes a greater hemodynamic fluctuation at slower SVT. Higher baseline BP and age, impaired ventricular function, late Fontan repair and a history of SVT were major determinants of hemodynamic deterioration during faster SVT.

Background Post-exercise heart rate (HR) and oxygen uptake (V˙O 2 ) recover more slowly in patients with the Fontan circulation, but little is known about the determinants of the delayed recovery. Purpose To evaluate the post-exercise cardiovascular dynamics and clinical profiles in these patients. Methods and results We studied 51 Fontan patients (14±4 years) (atriopulmonary connection, APC=18 and total cavopulmonary connection, TCPC=33) and compared the results with 34 patients after right ventricular outflow tract reconstruction (RVOTR) with identical exercise capacity and arterial baroreflex sensitivity (BRS) (15±4 years) and with 26 controls (14±4 years). There were no differences in post-exercise HR or V˙O 2 declines between the Fontan and RVOTR groups. Although the systolic blood pressure (SBP) decline was delayed in the RVOTR group ( p p 2 decline was determined by peak V˙O 2 , age and cardiac index ( p p p Conclusions In the Fontan group, post-exercise HR and V˙O 2 declines are markedly delayed and are determined by cardiac vagal nervous activity, exercise capacity and age, respectively. Despite identical impaired hemodynamics and exercise capacity, post-exercise SBP decline is greater in the Fontan group, especially after APC, than in the RVOTR patients.

To investigate the negative chronotropic response (NCR) to low-dose atropine in postoperative patients with congenital heart disease (CHD).Low-dose atropine causes a NCR through the central nervous system muscarinic receptor and is attenuated in adult heart failure patients. It has never been evaluated in CHD patients.NCR corrected for basal heart rate (HR) (minimal HR/basal HR=cNCR) was determined after low-dose atropine (3 microg/kg) administration in 124 postoperative CHD patients (97 biventricular repair and 27 Fontan patients) and 11 controls and was compared with the cardiac autonomic nervous and functional status.The cNCR in simple CHD (post atrial or ventricular septal defect closure), complex biventricular CHD, and Fontan patients were 0.92+/-0.04, 0.94+/-0.04 and 0.96+/-0.04, respectively, and higher than in controls (0.87+/-0.03, p0.001). In the complex CHD patients, higher cNCR was mainly associated with the lower pharmacologically determined cardiac parasympathetic nervous tone (PST), HR variability, high atrial natriuretic peptide, and lower right ventricular ejection fraction (p0.0001). In Fontan patients, the lower beta sensitivity of the sinus node and the PST mainly determined the higher cNCR (p0.01) and the cNCR did not correlate with either hemodynamics or exercise capacity.NCR is attenuated in proportion to the impaired cardiac parasympathetic nervous system and hemodynamics in postoperative complex biventricular CHD patients. In addition to PST, beta sensitivity of the sinus node significantly influences the NCR in Fontan patients.

Patients with pulmonary atresia and major aortopulmonary collateral arteries (MAPCAs) may be at risk for both ventilatory impairment and abnormal pulmonary circulation after definitive surgery. We measured the ventilatory response to exercise in 16 patients with MAPCAs after definitive surgery (group A) and compared the results with those in 16 patients with tetralogy of Fallot with pulmonary atresia and without MAPCAs after definitive operation (group B), with 24 patients with tetralogy of Fallot after one-stage repair without previous palliation (group C), and with 48 healthy subjects (group D). Pulmonary function and treadmill exercise tests were performed. Arterial blood gases were also analyzed and the dead space to tidal volume ratio calculated. In group A, the vital capacity, diffusion capacity, and peak oxygen uptake were lowest (p0.001), whereas the ventilatory equivalent for carbon dioxide was highest and its value at peak exercise correlated with age at time of surgery (r = 0.73, p0.002). The arterial oxygen tension decreased progressively in group A and its value at peak exercise inversely correlated with the mean pulmonary artery pressure in all patients (r = -0.75, p0.001). The arterial carbon dioxide tension decreased significantly at peak exercise in controls but showed no change in group A. The dead space to tidal volume ratio decreased during exercise in patients without MAPCAs and in controls but increased in group A, and the dead space to tidal volume ratio at peak exercise was inversely correlated with vital capacity in all patients (r = -0.77, p0.001). Diffusion capacity independently predicted arterial carbon dioxide tension and dead space ventilation during exercise. Marked restrictive ventilatory impairment with low diffusion capacity along with a pulmonary obstructive change contributed to the abnormal pulmonary gas exchange during exercise in group A. Earlier repair of MAPCAs may prevent the progression of the impaired ventilatory response to exercise in these patients.

The adsorption and catalytic properties of PdAu and PtC alloy surfaces were investigated under low pressure conditions, with the real surface composition being monitored using Auger electron spectroscopy. Flash desorption experiments on O2 and NO, and steady state kinetic experiments involving the reduction of these substances by H2 were performed on polycrystalline alloy surfaces. For the PdAu system, O2 desorption was promoted by gold, as shown by the shift of O2 desorption toward lower temperature and a linear decrease in the saturated amount of O2 adsorption with increase in gold content. For the PtCu system, O2 desorption was retarded by copper i.e. the O2 desorption temperature shifted upward with increase in copper content. In both the alloy systems, catalytic activities for the above reactions were significantly suppressed by the addition of gold or copper to the platinum group metals. The drop was more pronounced for NO reduction, suggesting that a larger ensemble of active platinum group metal atoms are necessary for NO dissociation.

Surface properties of supported palladium catalysts for NO decomposition were characterized using hydrogen adsorption, X-ray photoelectron spectroscopy (XPS), and temperature-programmed desorption and oxidation (TPD and IPO). Conversion of NO on Pd/MgO was proportional to the surface area of palladium. The interaction between palladium species and Mg2+ ions plays an important role in forming active sites for NO decomposition. Reduced palladium on MgO was not readily oxidized to PdO by oxygen even at high temperatures, in contrast to its behavior on SiO2. Oxygen adsorbed on reduced Pd/MgO desorbed at temperatures lower than those for bulk PdO/ MgO. It was concluded that NO decomposition on Pd/MgO catalysts proceeds mainly by a redox mechanism on partially reduced palladium species interacting with Mg2+

The performances of platinum-group metals, platinum, iridium, palladium, rhodium and ruthenium supported on γ-alumina, as catalysts for the selective reduction of nitrogen oxides by hydrocarbons were investigated. Platinum and rhodium had high nitric oxide conversion activities both in model mixtures and in real diesel exhaust gases, especially at relatively low temperatures between 200 and 350°C. It was confirmed that the platinum-rhodium and platinum catalysts have higher activity and durability than a catalyst composed of copper supported on ZSM-5 under real diesel exhaust conditions. The platinum-containing catalysts, however, produced more nitrous oxide than nitrogen. It is expected that platinum-group metal catalysts will be able to be used for practical purposes if once their selectivity toward nitrogen is improved.

A robotic experiment on lunar materials in the context of lunar base and lunar resources utilization is designed. A mobile robotic laboratory is sent to the lunar surface by an H-2 rocket to perform exploration for resources and experimental processing/handling of the surface materials.

Direct decomposition of nitric oxide to nitrogen and oxygen was investigated on supported palladium catalysts at 550-750°C. It was found that nitric oxide decomposition activities of Pd/MgAl2O4, Pd/MgO, Pd/Mg2Si3,O8 and Pd/MgZrO3, all of which included Mg2+ ions as the constituent of the oxides, were higher than those of Pd/γ-Al2O3, Pt/γ-Al2O3, and Cu/ZSM-5 in this temperature range. Furthermore, Mg2+ ions doped in Pd/γ-Al2O3 enhanced the catalytic activity. These results led us to conclude that Mg2+ ions on palladium catalysts play an important role in enhancing the decomposition activity.

The influence of the addition of sulphur and phosphorus on the activity of finely divided molybdenum-based catalysts formed in situ was investigated with regard to the hydrotreatment of Morichal crude oil (Venezuela). Reactions were carried out using a batch reactor at 470°C. The catalyst precursors used were molybdenum naphthenate, cobalt octylate and di-2-ethylhexyl phosphate. An increase in elemental sulphur addition led to increased catalytic activity, especially in the presence of phosphorus. It was found that the hydrogen sulphide that was generated from elemental sulphur can accelerate the decomposition of the precursors at temperatures below 240°C during the period of heating of the reactor. It was suggested that hydrogen sulphide is essential for the catalyst species to be sufficiently sulphided and activated without suffering possible coke poisoning. Phosphorus increased the hydrodesulphurization activity in amounts up to ca. 15·10 −4 mol P per 70 g of feed, but further addition decreased the activity. The optimum level was unchanged irrespective of the molybdenum concentrations employed. In addition, the vanadium removal improved remarkably with increase in the amount of phosphorus added. It is concluded that phosphorus interacted strongly with the vanadium compounds in the feed and prevented the catalyst species from being deactivated by the deposition of vanadium.

Thin-layer chromatography with flame ionization detection has been applied to the analysis of organic extracts of diesel exhaust particulates. Non-volatile organics whose boiling points are higher than ca. 300 degrees C can be analyzed, with a detection limit of ca. 0.03 micrograms and a relative standard deviation of ca. 10%. The organic extracts are separated into aliphatics , aromatics and polars by the development procedure with n-hexane, and the polars can be separated further by using toluene as the solvent. Some examples of application are presented.

Emission characteristics of a single cylinder diesel engine with a swirl chamber were investigated. Specific fuel consumption, exhaust gas temperature, specific mass emissions of CO, total hydrocarbon (THC), nitrogen oxides (NO x ), and particulates were measured. In addition, contents of carbon, hydrogen, CH 2 Cl 2 soluble fraction (SOF), aliphatic hydrocarbons, polar organics, benzo(a)pyrene (B(a)P), and low temperature combustion fraction in the particulates, and the burnout temperature of the particulates were analyzed. All these results were represented as contour maps on a speed-torque plane. The emission of CO and the particulates increased steeply near the maximum speed and torque investigated, whereas the NO x emission was almost independent of speed, increasing as the torque decreased. Content of hydrogen, SOF, aliphatic hydrocarbons, and low temperature combustion fraction showed similar patterns, having the maximum value at 1500 rpm at 1 4 load and decreasing toward 2500 rpm at full load. Burnout temperature of the particulate matter ranged from 673 to 707°C and correlated with the carbon content.

Clean-up procedures were developed for a method for determining the amount of polycyclic aromatic hydrocarbons (PAHs) in diesel exhaust particulate matter and in diesel fuel oils using reversed-phase high-performance liquid chromatography (HPLC). They were based mainly on the elimination of insoluble matter and aliphatic compounds that affect the performance of HPLC, from the dichloromethane extracts of particulate matter or from oils, with the aid of a disposable preparation column containing reversed-phase packings (Sep-Pak C18). Using these procedures, it is possible to detect 1 ng of benzo(a)pyrene in 30 mg of particulate matter with more than a 97% recovery or 0.5 ng in 50 μl of oil with 91% recovery. Examples of analyses are given for particulate matter emitted from a diesel test engine and for diesel fuel oils, such as gas oil, residual oil and coal-liquefied oil.