Brain natriuretic peptide as a hormonal marker of ventricular diastolic dysfunction in children with Kawasaki disease.

Although an increased level of serum brain natriuretic peptide (BNP) has been reported in children in the acute phase of Kawasaki disease (KD), no precise relation was documented between the serum BNP level and left ventricular (LV) systolic function. We hypothesized that the increased BNP levels may be explained by diastolic abnormalities in those with KD. We prospectively studied 25 patients in the acute phase of KD. Patients with abnormal systolic function were excluded. Pediatric cardiologists making the assessment of LV diastolic function were blinded to the BNP levels. Doppler interrogation was applied to measure LV inflow velocities, which were transformed to z scores using control measurements obtained from 83 healthy subjects. In the patients, the BNP levels ranged from 2.0 to 450.0 pg/ml, with a mean of 54.0 +/- 102.8 pg/ml. Six patients with abnormal velocities (> 2 SD in z score) showed significantly higher levels of BNP (152 +/- 173 pg/ml) than those in the remaining patients (p < 0.01). The BNP levels correlated positively with diastolic atrial velocity in z score (r = 0.51, p < 0.05), and negatively with diastolic early velocity to atrial velocity ratio in z score (r = -0.75, p < 0.01). This study suggests that LV diastolic dysfunction may occur in some children in the acute phase of KD, causing an increased level of BNP.

Bidirectional cavopulmonary shunt with right ventricular outflow patency: the impact of pulsatility on pulmonary endothelial function.

OBJECTIVE: Although in vitro studies have suggested the importance of flow pulsatility in endothelial function, few reports have focused on pulmonary endothelial function under decreased pulsatile flow after a bidirectional cavopulmonary shunt with or without an additional pulmonary flow source. The purpose of the present study was to assess the pulmonary endothelial function after bidirectional cavopulmonary shunt. METHODS AND RESULTS: Pulmonary vasodilating response was evaluated in 10 patients 0.4 to 7.0 years (median 1.6 years) after bidirectional cavopulmonary shunt who were provided an additional flow source by retaining the pulmonary outflow tract and in 8 control subjects. Average pulmonary flow velocity was measured with a Doppler flow wire placed in the segmental lower lobe pulmonary artery during incremental infusion of acetylcholine (10(-8), 10(-7), 10(-6), and 10(-5) mol/L) and then of nitroglycerin (0.5 and 1.0 microg. kg(-1). min(-1)) after recovery. In the control subjects, a dose-dependent increase in flow velocity was observed in response to acetylcholine (maximum increase was 155% +/- 17% of baseline) and to nitroglycerin (maximum increase was 151% +/- 20% of baseline). In contrast, patients showed a significantly impaired response to acetylcholine (maximum increase was 124% +/- 17% of baseline; P <.01 vs control), whereas the response to nitroglycerin was preserved (138% +/- 12% of baseline; P =.09 vs control). In addition, the maximum response to acetylcholine correlated significantly with the pulmonary pulse pressure (r = 0.89, P <.01) and with the pulmonary flow pulsatility (r = 0.88, P <.01). CONCLUSIONS: These results clearly suggest that patients after bidirectional cavopulmonary shunt show pulmonary endothelial functional attenuation and, of more importance, that decreased pulsatility of cavopulmonary flow is mainly responsible for this endothelial abnormality.

Clinical features of isolated noncompaction of the ventricular myocardium: long-term clinical course, hemodynamic properties, and genetic background.

OBJECTIVES: A nationwide survey was conducted to clarify the clinical features of isolated noncompaction of the ventricular myocardium (INVM) in Japanese children in comparison with features previously described in patients with INVM. BACKGROUND: Isolated noncompaction of the ventricular myocardium is a rare disorder characterized by an excessively prominent trabecular meshwork. It is accompanied by depressed ventricular function, systemic embolism and ventricular arrhythmia. METHODS: A questionnaire specifically designed for this study was sent to 150 hospitals in Japan where a pediatric cardiology division exists. RESULTS: Twenty-seven patients were diagnosed by two-dimensional echocardiography, their ages ranging from one week to 15 years at presentation, with follow-up lasting as long as 17 years. The gross anatomical appearance and the extension of noncompacted myocardium predominantly at the apex observed on two-dimensional echocardiograms were similar to observations reported previously. Dissimilarities included a greater number of asymptomatic patients at initial presentation, a longer clinical course with gradually depressed left ventricular function, no systemic embolism, and rare ventricular tachycardia in the Japanese children. Cardiac catheterization disclosed normal left ventricular end-diastolic volume and increased left ventricular end-diastolic pressure in most cases, consistent with restrictive hemodynamics. A higher incidence of Wolff-Parkinson-White syndrome was found in the children, whereas left bundle branch block was rarer than reported in adults. Familial recurrence was high (44%) and included many women. CONCLUSIONS: In Japanese children, INVM can be found by screening examinations at asymptomatic stage, and it might have a longer dinical course with gradually depressed left ventricular function and restrictive hemodynamics. The pattern of familial recurrence we observed implies that INVM is a distinctive clinical entity with a heterogeneous genetic background.

Selectin on activated platelets enhances neutrophil endothelial adherence in myocardial reperfusion injury.

OBJECTIVES: The glycoprotein P-selectin is an adhesion molecule that is rapidly expressed on the surface of platelets and endothelium during the inflammatory process. P-selectin on endothelium has been reported to play an important role in reperfusion injury. However, little is known regarding P-selectin on platelets in contributing to the pathophysiology of myocardial reperfusion injury. In this study, we hypothesized that P-selectin on platelets may enhance neutrophil endothelial adherence and this may play a role in neutrophil-mediated reperfusion injury. METHODS: Endothelial cells, cardiomyocytes, platelets and neutrophils were isolated from adult rats. Endothelial cells and cardiomyocytes were cultivated in a co-culture system. After exposure to hypoxia and reoxygenation, neutrophil adherence and migration were examined. RESULTS: After exposure to 6 h of hypoxia, endothelial cells co-incubated with platelets showed significantly greater neutrophil adherence (63.1 +/- 4.0%) and migration (78.2 +/- 6.7%) than endothelial cells alone (adhesion: 44.2 +/- 2.8%, migration: 57.9 +/- 4.9%). These increases were significantly inhibited (adhesion: 42.1 +/- 3.5%, migration: 65.5 +/- 3.8%) by an anti-P-selectin monoclonal antibody. Moreover, the superoxide-anion production was significantly elevated when activated platelets were added to neutrophils. This enhanced production was also inhibited by anti-P-selectin antibody. CONCLUSION: The presence of activated platelets enhanced neutrophil adhesion and migration process after hypoxia reoxygenation. This process may occur following platelet-neutrophil interactions via P-selectin and subsequent neutrophil activation.

Regional left ventricular motion during early filling phase in patients with right ventricular pressure overload.

Global left ventricular (LV) diastolic function has been reported to be disturbed under conditions of right ventricular pressure overload (RVPO). However, from the standpoint of regional wall motion, only a little information related to the mechanism of LV diastolic dysfunction is available. Eight patients with RVPO and 7 healthy volunteers were investigated using tagged cine magnetic resonance imaging. Regional diastolic fraction (RDF) was determined in 4 segments (anterior, lateral, inferior, and septal) in the mid-ventricular short axis section and in 2 segments (septal and lateral) in the 4-chamber section. A heterogeneity index was obtained from the RDFs of the short axis section. In the RVPO group, in both short axis and 4-chamber sections, the RDF of the septal segment was depressed, and it showed an inverse correlation with the right-to-left ventricular systolic pressure (RV/LV) ratio (r = -0.74, p < 0.05) in the short axis section. In the 4-chamber section, the RDF was lower in the septal segment than in the lateral segment (p < 0.05). The heterogeneity index in the RVPO group was greater than that in the control group (p < 0.01). The index correlated positively with the RV/LV ratio (r = 0.77, p < 0.05). The altered regional diastolic motion results in increased heterogeneity in regional diastolic motion.

Regional ventricular systolic abnormalities caused by a rudimentary chamber in patients with univentricular hearts.

Previous studies have demonstrated that regional wall motion abnormalities are common in univentricular hearts; however, the mechanism of this abnormality and its relation to hemodynamics remain unclear. The aim of this study was to document and analyze the etiology of regional wall motion abnormality and its relation to hemodynamics in univentricular hearts. Sixteen patients (age 11+/-6 years) were examined. A tagged cine magnetic resonance imaging method that superimposes "tags" on myocardium was used to assess regional systolic motion. The tags were traced from end-diastole to end-systole, and the percent regional shortening fraction was calculated as the shortening ratio. The tags were positioned on 6 segments. Normal ranges for wall motion were established from 10 normal volunteers. An asynchrony index was calculated as the SD divided by the mean regional shortening fraction to quantify asynchronous regional motion. Hemodynamic parameters were also obtained by cardiac catheterization. In patients, regional shortening fraction was significantly lower in segments adjacent to the rudimentary chamber compared with normal values in both circumferential and longitudinal directions (p <0.05 and p <0.01, respectively). The asynchrony index was much greater in patients than in controls (62+/-25 vs 27+/-10, p <0.01). The index correlated with rudimentary chamber volume and the rudimentary/main chamber volume ratio (r = 0.58, r = 0.79, respectively). Furthermore, the index correlated with end-diastolic pressure (r = 0.82). The rudimentary chamber may play an important role in causing asynchronous regional motion, and this motion may contribute to ventricular diastolic dysfunction.

Left ventricular regional systolic motion in patients with right ventricular pressure overload.

Left ventricular regional systolic motion was investigated in patients with right ventricular pressure overload and 10 controls using tagged cine magnetic resonance imaging. The regional shortening fraction was determined in four segments (septal, lateral, inferior, and anterior) on the short-axis image. An asynchrony index, nonhomogeneity of regional shortening, was calculated. Septal shortening in these patients was depressed, and showed an inverse correlation with the right-to-left ventricular peak pressure ratio (r=-0.80, P<0.01). Lateral shortening was greater in the patients than in the controls (P<0.01). The asynchrony index was significantly greater in the patients than in the controls (P<0.01), and correlated with the right-to-left systolic pressure ratio (r=0.64, P=0.02) and the left ventricular end-diastolic pressure (r=0.79, P<0.01). The altered distribution of regional circumferential shortening results in an increased heterogeneity of regional systolic motion. These findings may have important implications for the assessment of ventricular function in patients with right ventricular pressure overload.

Quantitative, non-invasive assessment of ventricular septal defect shunt flow by measuring proximal isovelocity surface area on colour Doppler mapping.

OBJECTIVE: To determine whether the proximal isovelocity surface area (PISA) method could be applied to estimate the magnitude of ventricular septal defect (VSD) shunt flow. DESIGN: Prospective analysis of clinical, echocardiographic, and angiographic data. SETTING: University hospital. PATIENTS: 14 children with VSD. METHODS: Colour Doppler images of VSD shunt flow were obtained in parasternal long axis view, four chamber view or both, adjusted to provide the best imaging of flow. The VSD shunt flow rate and shunt volume were calculated as follows: shunt flow rate (SFR) = 2 pi r2 V/BSA in ml/s/m2; shunt volume = SFR x shunt duration time. The shunt volume, shunt fraction, and pulmonary to systemic flow ratio (Qp:Qs) were confirmed by cardiac catheterisation. RESULTS: There was a correlation between shunt variables determined by PISA and those by catheterisation, including shunt volume (r = 0.78, P = 0.001) and shunt fraction (r = 0.74, P = 0.003). Qp:Qs was also significantly correlated with SFR (r = 0.79, P = 0.0007). The SFR was significantly different between the four patients with Qp:Qs < 2.0 (mean (SD) 54 (33) ml/s/m2) and the 10 patients with Qp:Qs > 2.0 (186 (69) ml/s/m2) (P = 0.004). CONCLUSIONS: These data suggest that the PISA method is a reliable non-invasive investigation for the quantitative assessment of VSD shunt flow and provides important information for decisions regarding surgical repair.

Accelerated ventricular rhythm in the newborn.

Accelerated ventricular rhythm was observed in two newborn infants. Neither of them had any causative clinical symptoms for the ventricular arrhythmia. The arrhythmia disappeared when the infants were 18 days and 45 days old, respectively. Arrhythmia was noted in the fetal period, especially in case 1.