Echocardiographic features in patients with beta thalassemia/hemoglobin E: a combining effect of anemia and iron load

Hemoglobin concentration, iron parameters and cardiac status of 25 patients with beta thalassemia/hemoglobin E disease were measured. Two-dimensional echocardiography was employed to evaluate chamber size, ejection fraction and muscle fiber shortening. The seventeen patients who had a mean hemoglobin concentration of less than 7.7 g/dl were found to have significantly larger cardiac chambers and higher cardiac output than the patients with higher hemoglobin concentrations. A statistically significant difference in ejection fraction and per cent of fractional shortening of cardiac muscle fibers was not found. A comparison of subjects with ferritin concentrations above and below 1,500 micrograms/L showed no significant difference in chamber sizes, ejection fraction and in per cent fractional shortening. However, a comparison of 14 patients with transferrin saturation > or = 80 per cent with those less than 80 per cent showed a significant decrease in both ejection fraction and fiber fractional shortening in the more highly saturated subjects. By using stepwise multiple regression analysis, the hemoglobin level was shown to significantly determine cardiac enlargement, while ejection fraction and percentage fractional shortening were significantly associated with transferrin-iron saturation. Thus, anemia leads to chamber enlargement, while high transferrin iron saturation is associated with cardiac muscle dysfunction. The findings in the individual patient reflect the integration of these two effects.