Satoshi Hiraishi

Changes in left ventricular output from fetal to early neonatal life

Using pulsed Doppler and two-dimensionally directed M-mode echocardiographic techniques, we measured left ventricular (LV) output, stroke volume, heart rate, LV end-diastolic dimension (LVEDD), LV end-systolic dimension, and LV percent fractional shortening (%FS) in 34 normal term infants 12 to 24 hours before parturition and thereafter serially 1, 24, and 96 hours after birth. Stroke volume was calculated as the product of the aortic flow velocity integral and aortic valve area. There was a twofold increase in LV output 1 hour after birth (fetal 170 +/- 46 ml/min/kg vs 1 hour 327 +/- 66 ml/min/kg; p less than 0.01) which was associated with significant increases in stroke volume, %FS, and LVEDD (stroke volume 1.21 +/- 0.33 ml/kg vs 2.25 +/- 0.37 ml/kg; %FS 34.3% +/- 5.8% vs 37.7% +/- 5.4%; LVEDD 15.4 +/- 1.1 mm vs 17.7 +/- 1.4 mm). Heart rate did not change 1 hour after birth. During the subsequent hours after birth, LV output decreased significantly to a value of 245 +/- 56 ml/min/kg (p less than 0.01) at 24 hours, which did not change 96 hours after birth. There were significant declines in stroke volume, LVEDD, and heart rate 24 hours after birth (stroke volume 2.02 +/- 0.42 ml/kg; LVEDD 17.0 +/- 1.1 mm; heart rate 121 +/- 11 beats/min). The %FS remained unchanged within the first 96 hours of age. These results indicate that the major regulator of LV output immediately after birth is stroke volume and not heart rate. The increase in stroke volume is related to an increase in LV size and LV myocardial contractility. Our data provide a useful basis for the interpretation of abnormal LV function in the early neonatal period.

Clinical course of cardiovascular involvement in the mucocutaneous lymph node syndrome: Relation between clinical signs of carditis and development of coronary arterial aneurysm

Seventy-nine patients with mucocutaneous lymph node syndrome were evaluated prospectively by clinical examination, electrocardiography, chest radiography, M mode and two dimensional echocardiography and thallium-201 myocardial scanning. Serial changes were categorized according to the duration of illness: stage I (1 to 10 days), stage II (11 to 20 days), stage III (21 to 30 days), stage IV (31 to 60 days) and stage V (61 days to 40 months). The presence of myocarditis in stages I and II was suggested in 40 of 79 patients (50.6 percent) by electrocardiographic, echocardiographic, radiographic and clinical abnormalities. Myocarditis was accompanied by pericarditis in six patients and by both endocarditis and pericarditis in one patient. These signs of inflammation were resolved by stage III in all but three patients with electrocardiographic abnormalities. In the active stage, large coronary arterial lesions were suspected only because of an abnormal spherical echo-free space in the region of the coronary arteries on two dimensional echocardiograph as well as electrocardiographic evidence of deep Q waves in leads II, III and aVF. One or more coronary aneurysms developed in 11 patients, primarily in stage II; regression of the aneurysm was noted in 5 of these patients during stages III, IV and V. Aneurysm regression demonstrated by angiography did not correlate with echocardiographic changes in aneurysm size in one patient. Moreover, the occurrence of coronary aneurysm did not correlate with the presence of signs of carditis, because the frequency of carditis was the same in patients with and without aneurysm.

Incidence and natural course of trabecular ventricular septal defect: Two-dimensional echocardiography and color Doppler flow imaging study

This study was designed to determine the prevalence of trabecular ventricular septal defect (t-VSD) in neonates and to evaluate the effects of its location, morphologic features, and size on its natural course during infancy. One thousand twenty-eight term newborn infants were examined by color Doppler flow imaging with orthogonal ultrasonographic views. Ten girls and 11 boys (2.0%) were found to have t-VSD. The natural course of the defect was examined in 42 consecutive cases, consisting of this group of 21 neonates and another group of 21 neonates with t-VSD. The morphologic features of the defect within the trabecular septum were classified as one or two defects (36 cases) and as a mesh-like defect (six cases). Reduction in size began from the right ventricular side or from within the trabecular septum. Spontaneous closure occurred most commonly during the first 6 months of life and was observed in 32 cases (76%) by 12 months of age: the frequency of closure was not related to the morphologic features and the initial size of the defect, but apical defects tended to have higher persistent patency than did defects in other locations (p less than 0.05). We conclude that the frequency of t-VSD in neonates and the frequency of spontaneous closure during early infancy are higher than previously believed. This information is important for predicting the natural course of t-VSD and deciding on its proper management.

Noninvasive visualization of coronary arterial aneurysm in infants and young children with mucocutaneous lymph node syndrome with two dimensional echocardiography

Real time two dimensional echocardiographic studies of the main coronary arteries were performed in 30 normal subjects and 58 patients with the mucocutaneous lymph node syndrome. Four echocardiographic coronary arterial patterns were observed: linear, dilated, fusiform or spherical. In normal subjects the left main coronary artery generally had a linear pattern but had a dilated pattern in two patients. The right coronary artery could not be visualized clearly. In 7 of the 58 patients with the mucocutaneous lymph node syndrome, a portion of the left main coronary artery had a fusiform or spherical pattern, or both, and the stem of the right coronary artery also had a spherical pattern in 2 patients. In all five patients who had coronary angiography, the procedure confirmed an aneurysm in the left main coronary artery or its branching point and the stem of the left anterior descending coronary artery or the stem of the right coronary artery, or both. In three of the five patients, coronary arterial aneurysms were predicted before coronary angiography was performed. Thus, two dimensional echocardiography is a reliable noninvasive method for evaluating coronary arterial aneurysms in infants and young children.

Two-dimensional echocardiographic determinants of interventricular septal configurations in right or left ventricular overload

Configurations of interventricular septum (IVS) and left ventricle were evaluated in 60 normal subjects and in 68 patients with congenital heart disease using two-dimensional short axis cross-sectional echocardiography (2DE). Patients were divided into four groups; right ventricular (RV) pressure overload (n = 21), RV volume overload (n = 12), left ventricular (LV) pressure overload (n = 10), and LV volume overload (n = 25). The radii of curvature of the IVS (IVSr) and LV free wall (FWr) were calculated in end systole and end diastole. Measured IVSr was normalized by dividing IVSr by FWr (IVSr/FWr). End-systolic flattening of IVS was a specific finding in patients with RV pressure overload, since this pattern was not observed in other hemodynamic groups. Echocardiographic determinants of IVSr/FWr in end systole correlated well with RV peak systolic pressure/LV peak systolic pressure ratio (r = 0.878). There was also correlation between IVSr/FWr in end diastole and RV end-diastolic pressure/LV end-diastolic pressure ratio (r = 0.579). Thus, the evaluation of IVS configuration is a useful 2DE method of estimating relative RV systolic pressure in infants and children with congenital heart disease.

Hemodynamic Adaptations at Birth and Neonates Delivered Vaginally and by Cesarean Section

In order to assess the possible influence of differences in delivery mode on cardiovascular adaptation at birth, we measured left ventricular output and its regional distribution in the major organs sequentially using an echographic technique during the first 96 h of life. We studied 27 normal newborns, of whom 15 were delivered vaginally and 12 by cesarean section. We also measured umbilical arterial and venous catecholamine concentrations. The umbilical arterial epinephrine and norepinephrine concentrations in the infants delivered vaginally were significantly greater than those in the infants delivered by cesarean section (epinephrine 1,195 +/- 208 vs. 565 +/- 81 pg/ml, p < 0.05; norepinephrine 11,832 +/- 3,819 vs. 5,153 +/- 1,400 pg/ml, p < 0.05). The left ventricular output and its regional distribution showed a similar pattern in the two groups, and there were no significant differences between them. These results indicate that the capacity of infants delivered by cesarean section to tolerate cardiovascular changes during the early neonatal period is comparable to that in infants delivered vaginally, even though there are significant differences in the catecholamine surge between these groups.

Transthoracic Doppler assessment of coronary flow velocity reserve in children with Kawasaki disease: Comparison with coronary angiography and thallium-201 imaging

OBJECTIVESnThe purpose of this study was to determine the feasibility of coronary flow velocity reserve (CFVR) measurement by transthoracic Doppler echocardiography (TTDE) in children with Kawasaki disease (KD).nnnBACKGROUNDnDoppler-derived CFVR is a reliable marker predicting the presence of myocardial ischemia.nnnMETHODSnWe studied 49 patients (median age 11 years) with KD. The CFVR was calculated as the ratio of hyperemic to basal peak (peak CFVR) and mean (mean CFVR) diastolic flow velocities in the posterior descending coronary artery (PD) and left anterior descending coronary artery (LAD). The CFVR measurements by TTDE were compared with the results of coronary angiography, thallium-201 (Tl-201) single-photon emission computed tomography (SPECT), and intracoronary Doppler study.nnnRESULTSnThe CFVR measurements by TTDE were obtained in 92 (94%) of 98 vessels of the PD and LAD in 49 study patients. Both peak and mean CFVRs for 21 stenotic vessels were significantly smaller than those for 35 normal vessels and for 20 vessels with aneurysmal lesions (p < 0.0001). Peak and mean CFVR <2.0 predicted significant coronary stenosis, as determined by coronary angiography, with sensitivities and specificities of 89% and 96% and 89% and 97%, respectively. Also, both peak and mean CFVRs were correlated with reversible perfusion defects on Tl-201 SPECT (agreement 80%; kappa 0.4). The correlation between peak and mean CFVRs determined by the TTDE and intracoronary Doppler studies in 36 vessels of 23 patients were 0.76 and 0.80, respectively.nnnCONCLUSIONSnThe CFVR measured by TTDE predicts the presence of significant coronary stenosis of either the right coronary artery or LAD, as well as myocardial ischemia of these territories in children with KD.

Quantitative Assessment of Pulmonary Vascular Resistance and Reactivity in Children with Pulmonary Hypertension Due to Congenital Heart Disease Using a Noninvasive Method: New Doppler-Derived Indexes

We assessed the usefulness of transthoracic Doppler-derived indexes obtained in the proximal pulmonary artery (PA) branch for estimating pulmonary vascular resistance (PVR) in 45 children with congenital heart disease (CHD) and 23 normal control subjects. The acceleration time, inflection time (InT), deceleration index, and peak velocity, which were measured from the systolic PA flow velocity curve obtained at the sites of the main PA, and right and left PA, were compared with the PVR in patients with CHD. In addition, changes in either Doppler-derived indexes or PVR during 100% oxygen administration were compared in 22 patients showing a baseline PVR ≥4.6 U/m2 (high PVR). The heart-rate-corrected InT (InTc) values obtained in the left PA in the high PVR group were significantly lower than those in the main PA (4.7xa0±xa01.5 vs. 7.5xa0±xa03.0; pxa0<xa00.001). The InTc obtained from the left PA separated patients with high and low PVR (4.7xa0±xa01.4 vs. 9.9xa0±xa02.4; pxa0<xa00.001) and no significant differences in InTc were found between the low PVR and the control groups. An increase in InTc toxa0>6 during 100% oxygen administration for the high PVR group indicated good PA reactivity with a sensitivity of 93%, specificity of 100%, and agreement of 95% (κxa0=xa00.83). Moreover, this InTc index correlated inversely with PVR (rxa0=xa0–0.80). In conclusion, our method can noninvasively separate high and low PVR and assess the PA reactivity for high PVR in children with CHD.

Two-dimensional Doppler echocardiographic assessment of closure of the ductus arteriosus in normal newborn infants

To elucidate the mechanism involved in closure of the ductus arteriosus (DA), 50 normal full-term infants were examined with two-dimensional and pulsed Doppler echocardiography. The examinations were performed initially within 1 hour after delivery and serially for 3 days. The two-dimensionally derived long-axis plane of the DA disclosed a characteristic localized protrusion into its lumen in 30% of the subjects within 1 hour, in 80% by 4 hours, in 96% by 8 hours, and in all by 24 hours after birth. In 10 infants in whom the intraluminal protrusion did not appear within 4 hours after birth, none had any recognizable changes in the inner diameter or length of the DA during this initial period. The development of the intraluminal protrusion resulted in localized narrowing of the ductal lumen. Doppler echocardiography revealed a high-velocity jet within and downstream from the narrowed portion of the DA. Thereafter, ductal narrowing progressed along the entire length. The intraluminal protrusion may be early evidence of ductal changes leading to eventual functional and anatomic closure.

Effect of suture closure of coronary artery fistula on aneurysmal coronary artery and myocardial ischemia

This study indicates the importance of coronary angiography and myocardial scintigraphy on long-term follow-up of patients after surgery for coronary arterial fistula in view of the progression to coronary artery obstruction and myocardial ischemia.