Color and pulsed Doppler studies of atrial flow dynamics in normals and adult patients with uncomplicated atrial septal defects

Abnormal cardiac inflow patterns during postnatal development in a mouse model of Holt-Oram syndrome

Tbx5(del/+) mice provide a model of human Holt-Oram syndrome. In this study, the cardiac functional phenotypes of this mouse model were investigated with 30-MHz ultrasound by comparing 12 Tbx5(del/+) mice with 12 wild-type littermates at 1, 2, 4, and 8 wk of age. Cardiac dimensions were measured with two-dimensional and M-mode imaging. The flow patterns in the left and right ventricular inflow channels were evaluated with Doppler flow sampling. Compared with wild-type littermates, Tbx5(del/+) mice showed significant changes in the mitral flow pattern, including decreased peak velocity of the left ventricular (LV) early filling wave (E wave), increased peak velocity of the late filling wave (A wave), and decreased or even reversed peak E-to-A ratio. The prolongation of LV isovolumic relaxation time was detected in Tbx5(del/+) neonates as early as 1 wk of age. In Tbx5(del/+) mice, LV wall thickness appeared normal but LV chamber dimension was significantly reduced. LV systolic function did not differ from that in wild-type littermates. In contrast, the Doppler flow spectrum in the enlarged tricuspid orifice of Tbx5(del/+) mice demonstrated increased peak velocities of both E and A waves and increased total time-velocity integral but unchanged peak E/A. In another 13 mice (7 Tbx5(del/+), 6 wild-type) at 2 wk of age, significant correlation was found between Tbx5 gene expression level in ventricular myocardium and LV filling parameters. In conclusion, the LV diastolic function of Tbx5(del/+) mice is significantly deteriorated, whereas the systolic function remains normal.

Scintigraphic diagnosis of a right to left shunt in end-stage lung disease

PURPOSE

The presence of a right to left shunt influences the surgical approach to lung transplantation in patients with end-stage pulmonary disease. The purposes of this study included comparing contemporaneous lung scintigraphy with cardiac catheterization in the detection of intracardiac shunts in patients with end-stage lung disease and the point prevalence of right to left shunting was determined in patients with several different types of end-stage lung disease.

METHODS

Hundred and twenty six patients with end-stage lung disease who were candidates for lung transplantation underwent perfusion images of the lungs with Tc-99m-labeled macro-aggregated albumin (MAA). Planar scans of the brain and the kidneys were performed contemporaneously. Statistical analyses included correlation ofthe clinical, laboratory and scintigraphic variables. Group means were compared with the students t-test (two-tailed P-value).

RESULTS

There were 21 patients with primary pulmonary hypertension (PPH), 72 with emphysematous lung disease (COPD), 22 with pulmonary fibrotic disease (PF) and 11 with congenital heart disease (CHD) leading to pulmonary hypertension. Only 13 patients (10.3%) were found to have a right to left shunt. Of these, 4 had PPH, 2 had PF, and 7 had CHD. No shunts were found in patients with emphysema. All the positive studies had abnormally increased activity in both the brain and the kidneys. However, there were 25 cases with renal activity and none of these patients had brain activity or clinical evidence of a shunt. Increased pulmonary artery pressure was associated with scintigraphic presence of a shunt. There were no cases of a right to left shunt with a mean pulmonary artery pressure less than 50 mm Hg. In the subset of patients with a pulmonary pressure greater than 50 mm Hg, approximately 40% of the patients had a right to a left shunt. There were no measurable differences in the spirometry results, right ventricular ejection fraction (RVEF) or left ventricular ejection fraction (LVEF) in the subgroup of patients with PPH and right to left shunt in comparison with patients with PPH but without a right to left shunt.

CONCLUSIONS

The findings indicate that images of the brain, but not the kidneys, are an effective way to diagnose extrapulmonary right to left shunts in patients with end-stage pulmonary disease. The problem of a right to left shunt is uncommon in patients with emphysematous lung disease and relatively common in patients with primary pulmonary hypertension.