Miki Inoue

Pulsed wave Doppler tissue echocardiography assessment of the long axis function of the right and left ventricles during the early neonatal period

Objective: To assess the long axis function of both ventricles during the early neonatal period by using pulsed wave Doppler tissue (PWDT) echocardiography. Design: PWDT echocardiography was recorded from the lateral sites of the mitral and tricuspid annuluses and the tip of interventricular septum in 130 neonates within 24 hours after birth (day 0 group), in 135 neonates 1–7 days after birth (day 1–7 group), and in 131 healthy children (children group). Results: Peak systolic motion velocity (Sw) of the three ventricular walls positively correlated with the number of days after birth (p < 0.005). Compared with the children group, in neonates Sw in the right ventricle and peak early diastolic motion velocity (Ew) and peak atrial systolic motion velocity in the interventricular septum were lower than in the remaining two walls (p < 0.0005, p < 0.0001, and p< 0.0001, respectively). Although peak mitral and tricuspid flow velocities during early diastole (E) correlated with the number of hours after birth in the day 0 group, there was no significant change in the Ew of either ventricle. The E:Ew ratio of both ventricles was significantly higher in both neonate groups than in the children group (p < 0.001). The E:Ew ratio of the left ventricle was higher in the day 0 group than in the day 1–7 group (p < 0.005). Conclusions: The two ventricles differ in their normal PWDT echocardiographic values and in the parameter change after birth during the early neonatal period, which may reflect differences in ventricular adaptation after birth.

Myocardial Strain Imaging for Early Detection of Cardiac Involvement in Patients with Duchenne's Progressive Muscular Dystrophy

Objective: In patients with Duchennes progressive muscular dystrophy (DMD), myocardial fibrosis begins from the epicardial half of the left ventricular posterior wall. Myocardial strain imaging by tissue Doppler echocardiography is a new method for assessing regional myocardial function. We hypothesized that this method might be useful for the early detection of subclinical myocardial involvement in DMD patients. Methods: Myocardial radial strain of the left ventricle was measured in 25 DMD patients (age: 14.8 ± 3.1 years) with a normal left ventricular shortening fraction and 25 age‐matched healthy controls. Results: Peak systolic radial strain of the posterior wall in a short‐axis view of the left ventricle was significantly lower in DMD patients compared to control subjects (P < 0.0001). In the interventricular septum, peak systolic radial strain was not significantly different between the two groups. Receiver operating characteristic curve analysis differentiated DMD patients from control patients with 92% sensitivity and 92% specificity, when the cutoff value for systolic peak strain of the posterior wall was 61%. When radial strain was measured separately for the inner and outer halves of the posterior wall, a systolic negative strain was more frequently observed in the outer half than in the inner half of the posterior wall (6/25 vs. 0/25, P < 0.05). Conclusions: Myocardial strain imaging in DMD patients was characterized by decreased peak systolic strain of the posterior wall despite normal standard echocardiographic findings. Strain measurement might be useful for early detection of subtle regional myocardial dysfunction.

Assessment of systemic-pulmonary collateral arteries in children with cyanotic congenital heart disease using multidetector-row computed tomography: Comparison with conventional angiography

BACKGROUND The present study aimed to assess the feasibility of multidetector-row computed tomography (MDCT) for the evaluation of systemic-pulmonary collateral (SPC) arteries in children with congenital heart disease associated with reduced pulmonary blood flow. METHODS Forty-eight consecutive patients (mean age 9+/-5 months; range, 0-30 months) underwent MDCT angiography of the thorax with a 16-detector row scanner prior to cardiac catheterization and operation. Conventional angiographic findings were used as a gold standard for the detection of SPC vessels. Findings on CT angiograms, including CT scans, maximum intensity projections, and three-dimensional volume-rendered images, were used to evaluate depiction of SPC arteries. Quantification of measurements at the SPC artery diameter was evaluated independently on MDCT and conventional invasive angiography. RESULTS Among the 48 patients, 115 SPC arteries were identified with conventional angiography, and 94 SPC arteries were identified with MDCT. In 89 (77%) vessels, concordant findings were observed with both modalities, with adequate depiction in 53 vessels and suboptimal depiction in 36 vessels. In 26 (23%) vessels, MDCT was unable to identify SPC arteries. Further, CT angiography resulted in the false-positive identification of vessels in 5 cases. There was an excellent correlation between MDCT- and conventional angiography-based measurement of SPC vessel diameter (R(2)=0.83), although a systematic overestimation was observed with MDCT (bias 0.19+/-0.74 mm). CONCLUSIONS This study demonstrates that MDCT is a potentially useful tool, which may have implications for planning percutaneous interventions and surgical repair in the future.

Autonomic function in patients with Duchenne muscular dystrophy

Background:  Assessing autonomic function is important for patients with chronic heart failure, but the way that autonomic function changes in patients with Duchenne muscular dystrophy (DMD) and correlates with other clinical parameters during their young age is not clearly known.

Tracheal compression due to an elongated aortic arch in patients with congenital heart disease: evaluation using multidetector-row CT.

BackgroundThe airway can become obstructed as a result of compression by an elongated aortic arch.ObjectiveIn this study we evaluated tracheal compression using multidetector-row CT in patients with congenital heart disease and an elongated aortic arch.Materials and methodsThe trachea was measured at the level of the aortic arch in 205 children and young adults and then the severity of tracheal compression was determined by measuring the tracheal diameter ratio (short axis diameter/long axis diameter). Patients were divided as follows: group I (normal aortic arch; n=166), group II (transversely running aortic arch; n=22), and group III (elongated aortic arch; n=17). From the viewpoint of the relationship of the great arteries, group II had D-malposition, and group III had L-malposition.ResultsAge, height, weight and body surface area were significantly correlated with the short and long axis diameter in group I. There was a negative correlation between tracheal diameter ratio and the physical size parameters. The tracheal diameter ratio in group III was 0.50±0.13, which was significantly lower than in groups I and II (P<0.01 and 0.05, respectively).ConclusionEven apparently asymptomatic patients with an elongated aortic arch can have tracheal compression. An elongated aortic arch may be a useful predictor of tracheal compression.

Cell membrane stretch activates intermediate-conductance Ca2+-activated K+ channels in arterial smooth muscle cells.

The aim of this study is to determine the signal transduction of membrane stretch on intermediate-conductance Ca2+-activated K+ (IKca) channels in rat aorta smooth muscle cells using the patch-clamp technique. To stretch the cell membrane, both suction to the rear end of patch pipette and hypotonic shock were used. In cell-attached and inside-out patch configurations, the open probability of IKca channels increased when 20- to 45-mmHg suction was applied. Hyposmotic swelling efficiently increased IKca channel current. When the Ca2+-free solution was superfused, the activation of IKca current by the hyposmotic swelling was reduced. Furthermore, gadolinium (Gd3+) attenuated the activation of IKca channels induced by hyposmotic swelling, whereas nicardipine did not. In the experiments with Ca2+-free bath solution, pretreatment with GF109203X, a protein kinase C (PKC) inhibitor, completely abolished the stretch-induced activation of IKca currents. The stretch-induced activation of IKca channels was strongly inhibited by cytochalasin D, indicating a role for the F-actin in modulation of IKca channels by changes in cell stretching. These data suggest that cell membrane stretch activates IKca channels. In addition, the activation is associated with extracellular Ca2+ influx through stretch-activated nonselective cation channels, and is also modulated by the F-actin cytoskeleton and the activation of PKC.

Mitral annular plane systolic excursion/left ventricular length (MAPSE/L) as a simple index for assessing left ventricular longitudinal function in children

Assessment of longitudinal left ventricular (LV) function is important for early detection of cardiac dysfunction. Although mitral annular plane systolic excursion (MAPSE) obtained by M‐mode echocardiography offers a simple method for assessing longitudinal LV function, normal values of MAPSE for children change according to body size.

Minimum-intensity projection of multidetector-row computed tomography for assessment of pulmonary hypertension in children with congenital heart disease.

BACKGROUND The present study aimed to assess the feasibility of minimum-intensity projection (minIP) images for the evaluation of pulmonary hypertension (PH) in children with congenital heart disease (CHD). METHODS A total of 70 consecutive patients (mean age, 4.6 ± 4.4 years; range, 6 months-16 years) underwent multidetector-row computed tomography (MDCT) angiography of the thorax prior to cardiac catheterization and lung perfusion scintigraphy. Contiguous axial, coronal and sagittal minIP images of 5-mm thickness were reconstructed from the contrast-enhanced CT datasets. Two reviewers evaluated the images in consensus and qualitatively graded lung parenchyma attenuation as homogeneous (Class I), slightly heterogeneous lung attenuation that does not conform to the anatomic boundaries of the secondary pulmonary lobule (Class II), and mosaic pattern (Class III). MinIP attenuation grading results were then compared with those of perfusion scintigraphy. Furthermore, the relationships between the results of these modalities and mean pulmonary artery pressure (mPAP) and pulmonary vascular resistance (PVR) were evaluated. RESULTS In 51 (73%) patients, concordant findings were observed between the modalities, although minIP showed a higher grade for heterogeneous images than did scintigraphy. mPAP and PVR showed significant difference among the minIP attenuation classes (p<0.0001 for both). High-grade heterogeneous minIP images were associated with high mPAP, high PVR, presence of major aortopulmonary collateral artery, and chromosomal abnormality. CONCLUSION MinIP is a promising technique for depicting lung perfusion and can be used as superior alternative to scintigraphy in the evaluation of PH.

Rare venous connection causing severe hypoxia after Fontan operation

We describe a rare case of cyanosis following the Fontan operation with right-to-left shunting at the venous level, that is, an azygos venous to pulmonary venous connection. Few cases with partial anomalous pulmonary venous connection to azygos vein have been reported; however, there have been no reports describing the connection from azygos vein to pulmonary vein, which results in desaturation after Fontan operation. Multidetector-row computed tomography (MDCT) was a useful tool to depict this vascular malformation.

Mumps encephalitis with akinesia and mutism

Measles‐rubella‐mumps vaccination is routine in many countries, but the mumps vaccine remains voluntary and is not covered by insurance in Japan. A 5‐year‐old Japanese boy who had not received the mumps vaccine was affected by mumps parotitis. Several days later, he presented with various neurological abnormalities, including akinesia, mutism, dysphagia, and uncontrolled respiratory disorder. Mumps encephalitis was diagnosed. Despite steroid pulse and immunoglobulin treatment, the disease progressed. Magnetic resonance imaging showed necrotic changes in bilateral basal ganglia, midbrain, and hypothalamus. At 1 year follow up, he was bedridden and required enteral feeding through a gastric fistula and tracheostomy. Mumps vaccination should be made routine as soon as possible in Japan, because mumps encephalitis carries the risk of severe sequelae.