Right ventricular volumes and function in thalassemia major patients in the absence of myocardial iron overload

Aim: We aimed to define reference ranges for right ventricular (RV) volumes, ejection fraction (EF) in thalassemia major patients (TM) without myocardial iron overload. Methods and results: RV volumes, EF and mass were measured in 80 TM patients who had no myocardial iron overload (myocardial T2* > 20 ms by cardiovascular magnetic resonance). All patients were receiving deferoxamine chelation and none had evidence of pulmonary hypertension or other cardiovascular comorbidity. Forty age and sex matched healthy non-anemic volunteers acted as controls. The mean RV EF was higher in TM patients than controls (males 66.2 +/- 4.1% vs 61.6 +/- 6%, p = 0.0009; females 66.3 +/- 5.1% vs 62.6 +/- 6.4%, p = 0.017), which yielded a raised lower threshold of normality for RV EF in TM patients (males 58.0% vs 50.0% and females 56.4% vs 50.1%). RV end-diastolic volume index was higher in male TM patients (mean 98.1 +/- 17.3 mL vs 88.4 +/- 11.2 mL/m(2), p = 0.027), with a higher upper limit (132 vs 110 mL/m(2)) but this difference was of borderline significance for females (mean 86.5 +/- 13.6 mL vs 80.3 +/- 12.8 mL/m(2), p = 0.09, with upper limit of 113 vs 105 mL/m(2)). The cardiac index was raised in TM patients (males 4.8 +/- 1.0 L/min vs 3.4 +/- 0.7 L/min, p < 0.0001; females 4.5 +/- 0.8 L/min vs 3.2 +/- 0.8 L/min, p < 0.0001). No differences in RV mass index were identified. Conclusion: The normal ranges for functional RV parameters in TM patients with no evidence of myocardial iron overload differ from healthy non-anemic controls. The new reference RV ranges are important for determining the functional effects of myocardial iron overload in TM patients.