Long-term assessment of right ventricular diastolic filling in patients with pulmonic valve stenosis successfully treated in childhood

Patients with severe pulmonic stenosis (PS) have right ventricular (RV) diastolic filling abnormalities detectable by tricuspid valve pulsed Doppler examination. To determine if these abnormalities persist long term after successful therapy of PS, 19 patients were examined 8 +/- 3 years after PS therapy. At the time of follow-up Doppler examination, the PS gradient was 15 +/- 8 mm Hg. From the tricuspid valve inflow Doppler study, the following measurements were obtained at peak inspiration: peak velocities at rapid filling (peak E) and during atrial contraction (peak A), ratio of peak E to peak A velocities, RV peak filling rate normalized for stroke volume, deceleration time, the fraction of filling in the first 0.33 of diastole as well as under the E and A waves, and the ratio of E to A area. Data from PS follow-up patients were compared with our previously reported data from 12 age-related control subjects and 14 untreated patients with PS. Patients with PS who were followed up had higher peak E velocity (0.75 +/- 0.14 vs 0.59 +/- 0.21 m/s), lower peak A velocity (0.47 +/- 0.09 vs 0.64 +/- 0.28 m/s), higher E/A velocity ratio (1.65 +/- 0.33 vs 1.11 +/- 0.52), higher 0.33 area fraction (0.52 +/- 0.08 vs 0.34 +/- 0.14), lower A area fraction (0.29 +/- 0.06 vs 0.45 +/- 0.21) and higher E/A area ratio (2.48 +/- 0.82 vs 1.73 +/- 1.05) than PS patients without treatment (p < 0.03). All Doppler indexes of the patients with PS who were followed up were the same as those of the control subjects except for the peak E velocity that was slightly higher (0.75 +/- 0.14 vs 0.63 +/- 0.11 m/s), the peak A velocity that was slightly higher (0.47 +/- 0.09 vs 0.38 +/- 0.09 m/s) and the E/A area ratio that was slightly lower (2.48 +/- 0.82 vs 3.50 +/- 1.25) (p < 0.03). Thus, at long-term follow-up, all RV diastolic filling indexes in successfully treated patients with PS improved compared with the untreated patients and approached values found in normal subjects. These data suggest that RV diastolic filling abnormalities in patients with PS are reversible over the long term and are therefore probably related to hypertrophy rather than fibrosis and scarring.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/29164/1/0000209.pd

Doppler assessment of pulmonary artery flow patterns and ventricular function after the Fontan operation

To assess the relation between ventricular systolic and diastolic function and pulmonary artery (PA) flow patterns after the Fontan operation, 15 postoperative patients were prospectively evaluated with echocardiography. Blood flow velocities in the PA were recorded with pulsed Doppler echocardiography. Ejection fraction was measured by 2-dimensional echocardiography using Simpson's rule. Indexes of diastolic function were measured from the systemic atrioventricular valve inflow Doppler and included peak E and A velocities, peak filling rate normalized for stroke volume, the fractions of filling in early and late diastole (E and A area fractions), and the E/A velocity and area ratios. Compared with 15 age-matched control subjects, the 15 patients who had undergone the Fontan procedure had decreased peak E velocity (0.65 +/- 0.20 vs 0.87 +/- 0.10 m/s), decreased E/A velocity ratio (1.29 +/- 0.23 vs 1.98 +/- 0.46), decreased normalized peak filling rate (6.09 +/- 0.90 vs 6.81 +/- 0.83 s-1), decreased E area fraction (0.63 +/- 0.09 vs 0.72 +/- 0.07), increased A area fraction (0.37 +/- 0.07 vs 0.24 +/- 0.06), and decreased E/A area ratio (1.77 +/- 0.45 vs 3.33 +/- 1.15) (p < 0.05). These diastolic filling abnormalities are consistent with impaired ventricular relaxation and decreased early diastolic transvalvular pressure gradient. PA Doppler recordings showed 2 distinct patterns of flow. Pattern I, observed in 9 patients, showed biphasic forward flow with peak velocities in mid to late systole and middiastole. Pattern II, observed in the remaining 6 patients, showed decreased systolic forward flow, a late systolic to early diastolic flow reversal, and delayed onset of diastolic forward flow. Compared with pattern I patients, pattern II patients had no significant differences in any of the Doppler indexes of diastolic function; however, pattern II patients had a significantly tower ejection fraction (43 +/- 9 vs 57 +/- 5%). Thus, many patients undergoing the Fontan procedure have impaired ventricular relaxation, but, in the presence of a normal ejection fraction, biphasic forward PA flow is maintained. With the development of decreased ejection fraction, atrial systolic filling pressures are likely increased, the ventricular suction effect is decreased, and PA flow is diminished or absent in systole and early diastole.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/29071/1/0000106.pd

Right ventricular outflow reconstruction with cryopreserved homografts in pediatric patients: Intermediate-term follow-up with serial echocardiographic assessment

AbstractObjectives. This study was performed to assess by echocardiography the intermediate-term outcome of cryopreserved homografts employed in pulmonary outflow reconstruction in children and to validate the reliability of Doppler echocardiography in their evaluation.Background. Cryopreserved homografts have become the most widely used pulmonary conduits. Previous reports have shown the occurrence of homograft regurgitation in the immediate postoperative period and the propensity of regurgitation to progress. Although Doppler echocardiography has been useful in assessing extracardiac valved conduit stenosis, its reliability in assessing a large series of cryopreserved homografts has not been documented.Methods. Echocardiograms of 41 patients (43 homografts) who underwent operations between December 1986 and October 1992 were retrospectively reviewed. The median age of patients at operation was 37.5 months (range 3 to 333), and the median duration of follow-up was 28.5 months (range 1 to 68). Homograft regurgitation was classified on a scale of 0 to 4+. Pressure gradients across the homografts measured in 23 catheterizations were correlated with corresponding echocardiographic gradients.Results. Regurgitation: Homograft regurgitation occurred in 100% of patients at follow-up. Progression of severity >2 grades occurred during follow-up in 35% and was associated with operation before age 18 months (p < 0.002) and stenosis progression (p < 0.05) but not with homograft type (aortic or pulmonary). These data predict that 50% of patients operated on before 18 months of age will have severe regurgitation by 15 months postoperatively compared with only 15% operated on after 18 months. Stenosis: At follow-up, 51% of homografts had a stenotic gradient ≥25 mm Hg predominantly at the distal anastomosis, and stenosis progression was related to young age at operation (<18 months, p < 0.005) and small conduit size (p < 0.01). Fifty percent of conduits implanted before age 18 months could be predicted to stenose by 21.8 months compared with only 5% of those implanted after age 18 months. The gradient measured from Doppler echocardiography correlated well with the catheterization gradient (r = 0.86).Conclusions. Cryopreserved homograft dysfunction is frequent and progressive. Young age at operation (<18 months) predicts more rapid deterioration. Doppler echocardiography is reliable in assessing the systolic gradients across homografts. Serial echocardiographic assessment in the follow-up of these patients accurately characterizes these problems

Echocardiographic detection of pericardiocentesis-induced subepicardial and intramyocardial hematoma

Pericardiocentesis has been widely used to relieve significant pericardial effusion and, in most cases, can be performed safely and without complications. We describe a rare complication of pericardiocentesis not previously reported in a pediatric patient. The crucial role of 2-dimensional echocardiography in the detection of this rare complication is illustrated.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/27750/1/0000143.pd

Pulsed Doppler assessment of left ventricular diastolic filling in children with left ventricular outflow obstruction before and after balloon angioplasty

To assess left ventricular (LV) diastolic filling in children with pressure overload hypertrophy, 12 patients with LV outflow obstruction (7 with aortic valve stenosis and 5 with aortic coarctation) and 12 healthy, age-matched control subjects were examined. Each child underwent M-mode echocardiography and pulsed Doppler examination of the LV inflow. The patients with LV outflow obstruction had cardiac catheterization and balloon angioplasty. Their echo/Doppler examinations were performed in the catheterization laboratory before and immediately after balloon angioplasty. From the M-mode echocardiogram, the LV cavity dimensions and wall thicknesses, LV mass and shortening fraction were measured. The following measurements were made from the Doppler recording: peak velocities at rapid ventricular filling (peak E) and during atrial contraction (peak A), ratio of peak E to peak A velocities, total area under the Doppler curve, percent of the total Doppler area occurring in the first one-third of diastole (0.33 area fraction), percent of the total area occurring under the E wave (E area fraction), percent of the total area occurring under the A wave (A area fraction) and the ratio of E area to A area.Before balloon angioplasty, the patients with LV outflow obstruction had higher peak E velocity (1.06 +/- 0.18 vs 0.88 +/- 0.11 m/s, p &lt; 0.01), higher peak A velocity (0.86 +/- 0.22 vs 0.47 +/- 0.08 m/s, p &lt; 0.01) and lower E/A velocity ratio (1.29 +/- 0.27 vs 1.93 +/- 0.34, p &lt; 0.01) than the normal subjects. In the patient group, 0.33 area fraction was significantly lower (0.38 +/- 0.07 vs 0.57 +/- 0.09, p &lt; 0.01) and A area fraction was significantly higher (0.44 +/- 0.14 vs 0.23 +/- 0.07, p &lt; 0.01) than in the normal subjects. Also, patients with LV outflow obstruction had greater LV wall thickness, smaller LV cavity dimensions and greater LV mass compared with normal subjects. In patients before and after balloon angioplasty, there was a significant decrease in LV outflow gradient (64 +/- 23 vs 33 +/- 22 mm Hg, p &lt; 0.01), but there was no change in any echo/Doppler measurement. Thus, children with LV outflow obstruction have abnormal LV early diastolic relaxation with a shift in filling toward late diastole. Immediately after successful relief of the systolic pressure overload, diastolic filling patterns are unchanged, suggesting that hypertrophy rather than afterload mismatch is the primary determinant of the impaired relaxation.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/28087/1/0000533.pd

Indoor blind navigator: A use case for self-guided tours in museums

© 2017 ACM. Notably valuable efforts have focused in helping people with special needs. In this work, we build upon the experience from the BlindHelper smartphone outdoor pedestrian navigation app and present Blind Nav , a system for indoor interactive autonomous navigation of blind and vision-impaired persons and groups (e.g. pupils) in museums. A pilot prototype is under development with the collaboration of the Lighthouse for the Blind of Greece. The paper describes the functionality of the application and evaluates candidate indoor location determination technologies, such as WLAN, Zigbee, and assistive tactile route indications combined with Bluetooth beacons and distance and direction change metering functionality, to come up with a reliable indoor positioning system adopting the latter solution