Résumé
PURPOSE: To examine the cardiac function, incidence and natural history of cardiac hypertrophy (CH) and the association of side effects with CH after pulse dexamethasone therapy in infants with bronchopulmonary dysplasia. METHODS: Twelve infants, gestational age 28.6+/-1.6(26-31)weeks, birth weight 1243+/-186 (1010- 1620)g, received a pulse course of dexamethasone, starting at 0.5mg/kg/d for three days and readministered ten days thereafter at a median of 19 days of age. Serial echocardiographic measurement of septal thickness(ST), left ventricular(LV) posterior wall thickness(PWT), LV diameter(LVD), LV length(LVL), LV mass, ejection fraction(EF) and acceleration time to right ventricular ejection time ratio(AT/RVET) were taken before, and 4, 11 days after starting dexamethasone. For infants diagnosed as CH, echocardiography was performed weekly until the parameters were normalized. Side effects of dexamethasone such as leukocytosis, hypertension, hyperglycemia and insulin therapy were recorded and compared. RESULTS: CH occurred in 5 of 12 infants(47%). ST, PWD, and AT/RVET increased significantly at 4 days and 11 days after starting dexamethasone than baseline. LVD decreased significantly at 4 days and 11 days after the administration of dexamethasone than before. Other parameter such as LVL, LV mass and EF were not changed and the evidence of left ventricular outflow obstruction was not observed. The incidence of hyperglycemia and insulin therapy were higher in CH group than in no CH group(p<0.05). Five infants with CH recovered until five weeks after starting dexamethasone on serial echocardiography, CONCLUSION: Infants receiving a pulse course of dexamethasone developed evidence of septal hypertrophy, thickened left ventricular wall and impaired filling of left ventricle immediately after starting dexamethasone but always resolved within five weeks Serial echocardiography is not probably routinely required in preterm infants with bronchopulmonary dysplasia receiving pulse dexamethasone therapy.