126 LEFT VENTRICULAR CONTRACTION-RELAXATION SEQUENCES IN THALASSEMIA MAJOR

Abstract

Echo evaluation of patients (pts) with Thalassemia Major (TM) has shown thick left ventricular posterior walls (LVPW) and, terminally, decreased LV function. This study assessed utility of a relatively new echo technique for detecting possible early myopathy in asymptomatic children with TM hypertransfused since diagnosis. High quality LVPW echoes were recorded at chordal level on 26 pts with TM (mean age=11.4±1.0(SE)years) and 22 controls (mean age=11.6±0.9years). Incremental LVPW thickness at normalized times in contraction and relaxation were measured by computer. TM pts had thinner LVPW at all times in contraction and relaxation (p<.02); at 100% contraction time, LVPW was 8.7±0.32(SE) mm vs 11.7±55mm control (p<.001); at 100% relaxation time, LVPW= 4.3±.18mm vs 5.9±3.4mm control (p<.001). Contraction was linear in controls, but in TM it was faster, completing 63±1.5% total contraction by 50% systolic time (p<.01). Relaxation by 40% diastolic time was nearly total in controls but in TM, it was slower, completing only 82±1.7% of total (p<.005). In conclusion, contrary to older TM pts, hypertransfused children with TM do not have thick LVPW. Contraction in these children is more consistent with chronic anemia and increased LV volume; however, slower relaxation suggests early myopathic changes. This echo technique is sensitive for detection of early myopathy prior to cardiac symptoms and should be useful in assessing myocardial response to chelation therapy in transfusion-dependent anemias.

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