Mitsuru Nakasato

Prediction of Peak Pulmonary Artery Pressure by Continuous-Wave Doppler Echocardiography in Infants and Children

SummaryContinuous-wave Doppler echocardiography was used to estimate peak pulmonary artery (PA) pressure in 104 infants and children, aged 4 days to 16 years, with normal hearts (control group) and 43, aged 29 days to 13 years, with various kinds of heart disease (patient group). The Doppler transducer was directed toward the right ventricular outflow tract and angled until the maximal velocity signal was reached. Doppler velocity time intervals were measured as follows: acceleration time (AT), from the onset to the peak of the velocity curve; and ejection time (ET), from the onset to the termination of the velocity curve. In the control group, AT corrected through dividing by the RR interval of the electrocardiogram (ATc), and AT/ET by dividing by the square root of the RR interval (AT/ETc), were independent of body surface area. In the patient group, peak PA pressure had a significant inverse correlation with both ATc (r=-0.78) and AT/ETc (r=-0.87). Thus, AT/ETc derived from continuous-wave Doppler echocardiography is a good quantitative predictor of peak PA pressure in infants and children.

Estimation of Right Ventricular Pressure in Children by Thallium-201 Myocardial Imaging Using Single-Photon Emission Computed Tomography

Thallium-201 myocardial imaging using single-photon emission computed tomography was performed to estimate right ventricular (RV) systolic pressure in 34 children (aged 4.1 to 16.1 years, mean 7.9 +/- 2.9). Acquisition of the images was performed using a semicircular arc of 180 degrees. On a short-axis slice, a line drawn perpendicular to the ventricular septum so as to cross the RV free wall showing maximum uptake was defined as the region of interest. Thallium-201 counts in regions of interest over both RV and left ventricular (LV) free walls were measured. The ratio of RV-to-LV peak thallium-201 counts was compared with RV peak systolic pressure and the ratio of RV-to-LV peak systolic pressure measured at cardiac catheterization. Both RV peak systolic pressure and the ratio of RV-to-LV peak systolic pressure correlated well with the ratio of RV-to-LV peak thallium-201 counts (r = 0.95 and 0.96, respectively). The ratio of RV-to-LV peak thallium-201 counts greater than or equal to 0.45 could predict RV pressure overloading with a sensitivity of 92%, and a specificity of 88%. Thus, the quantitative analysis of thallium-201 myocardial imaging using single-photon emission computed tomography permits the noninvasive and accurate estimation of RV systolic pressure in children.

Right and left ventricular function assessed by regional wall motion analysis in patients with tetralogy of Fallot

We studied pre- and postoperative regional right and left ventricular wall motion and global ejection fraction in 18 patients with tetralogy of Fallot who had successful repair, and compared these values to those of patients with a history of Kawasaki disease as controls. Right ventricular ejection fraction was significantly lower in the preoperative group (52 +/- 4%) than that in the control group (57 +/- 4%), and that in the postoperative state (49 +/- 4%) was significantly lower than those in the control and preoperative groups. Left ventricular ejection fraction was significantly lower in the preoperative group (56 +/- 7%) than that in the control group (61 +/- 5%), while that in the postoperative state (64 +/- 6%) was significantly higher than those in the control and preoperative groups. Regional ventricular wall motion analysis revealed that shortening fractions in the tricuspid valve region were reduced in the preoperative patients and were persistent even after successful repair; those in the right ventricular outflow tract region were decreased after the correction. Regional left ventricular wall motion showed that shortening fractions in the anterolateral region were improved after the correction. We conclude that right ventricular dysfunction was present in the preoperative patients with tetralogy of Fallot and was persistent even after total correction.

Contracted form of endocardial fibroelastosis in two siblings

two forms: dilated and contracted.1 The left ventricular cavity is enlarged in the dilated form, whereas it is normal or small in the contracted form. Several investigators have reported the dilated form of endocardial fibroelastosis occurring siblings.2,3 In contrast, to our knowledge, only one report of a familial occurrence of the contracted form has been previously published.4 We describe two siblings with the contracted form of endocardial fibroelastosis.

Balloon pulmonary valvuloplasty for pulmonary valve stenosis with atrial septal defect

We performed successful balloon pulmonary valvuloplasty (BPV) in 6 patients with pulmonary valve stenosis and atrial septal defect (ASD) accompanied by atrial left-to-right shunt without an increase of shunting immediately after BPV. It suggests that such patients should be treated by BPV initially and the need for ASD repair can be assessed during long-term follow-up.

Left and right ventricular volume characteristics in tetralogy of Fallot and their relationship to arterial oxygen saturation and age.

Left (LV) and right ventricular (RV) volume characteristics in 43 patients with tetralogy of Fallot (TOF) undergoing no prior surgical intervention, aged 3–50 months, were evaluated. The control group consisted of 45 patients with Kawasaki disease without cardiac lesions, aged 12–82 months. The TOF patients were divided into four groups: those having arterial oxygen saturation < 80% with an age at the time of study < 18 months (group 1a) or with that ≧ 18 months (group 1b), and those with arterial oxygen saturation ≧ 80% with an age < 18 months (group 2a) or with that ≧ 18 months (group 2b). The results were compared with those in control subjects. In group 1a, each of LV end‐diastolic volume (EDV), LV ejection fraction (EF), RVEDV and RVEF was reduced. In group 1b, LVEDV, LVEF and RVEF were decreased. In groups 2a and 2b, RVEF alone was depressed. From these results, the severity of hypoxemia was an important risk factor for ventricular dysfunctions. No influence of age on the volume characteristics was found. The investigations suggested that patients with TOF having an arterial oxygen saturation < 80% are probably candidates for early surgical intervention.

A new form of total anomalous pulmonary venous connection with double drainage

an uncommon congenital heart disease in which all of the pulmonary veins connect to the right atrium or one of its tributaries. It is conventionally classified by the site of drainage of the pulmonary venous blood flow: supracardiac, cardiac, infracardiac and mixed types.1 Recently, the double connection type of TAPVC in which all pulmonary veins drain to a confluence that drains into two different sites, usually into the coronary sinus and the left innominate vein, has been reported.2–4 We describe a new form of TAPVC with double connection and discuss the embryogenesis of this uncommon anomaly.

Percutaneous balloon aortoplasty for restenosis after extended aortic arch anastomosis for type B interrupted aortic arch.

A 4-month-old boy underwent a percutaneous balloon aortoplasty for restenosis after extended aortic arch anastomosis for type B interrupted aortic arch (IAA). Balloon aortoplasty resulted in a decrease in the peak systolic pressure gradient across the obstructive segment from 84 mmHg to 19 mmHg and in an increase in diameter from 2.5 mm to 4.3 mm. No complications related to the procedure were observed. We assume that balloon aortoplasty can be effective and safe for relieving postoperative aortic obstruction associated with IAA.

Balloon pulmonary valvuloplasty for double outlet right ventricle with valvular pulmonary stenosis

A male neonate presented with cyanosis. Echocardiograms showed a double outlet right ventricle, an absent outlet septum, a subaortic ventricular septal defect and valvular pulmonary stenosis. Balloon pulmonary valvuloplasty was performed at 19 days of age, resulting in an immediate increase of the systemic arterial oxygen saturation from 67 to 87%. As far as could be found, this is the first report of a patient with a double outlet right ventricle without the outlet septum who was clinically observed and underwent balloon pulmonary valvuloplasty.

Shortening Patterns of the Infundibulum in Valvular Pulmonary Stenosis Before and After Balloon Valvuloplasty

Abstract. We analyzed shortening patterns of the infundibulum in 11 patients with valvular pulmonary stenosis (PS) before and immediately after balloon valvuloplasty and at follow-up. The control group consisted of 32 patients with Kawasaki disease. The valvuloplasty was performed at the age of 5.8 ± 2.9 (mean ± SD) years and a satisfactory relief of obstruction was achieved in each. The follow-up study was done at 1.1 ± 0.2 years after the valvuloplasty. With the use of lateral projection of right ventriculograms, transverse diameters of the midinfundibulum were measured over one cardiac cycle from initiation of the pulmonary valve opening. Indices demonstrating shortening patterns of the infundibulum were as follows: time to the beginning of shortening (TBS), time to the shortest diameter (TSD), and shortening fraction (SF). TBS were prolonged before the valvuloplasty, whereas it was comparable with that in the control group, immediately after the procedure and at follow-up. TSD was increased before and immediately after the valvuloplasty, but it was normalized at follow-up. SF was increased at every observation. Thus, shortening patterns of the infundibulum in PS were characterized by increasing TBS, TSD, and SF. At short-term follow-up following the valvuloplasty, TBS and TSD were normalized, which could be a result of a successful relief of pulmonary obstruction. In contrast, SF remained elevated, which indicates that the musculature of the infundibulum remains hypertrophic up to 1 year after the valvuloplasty.