Background Heart failure is the most common cause of mortality in β-thalassaemia major. However, the management of this disease, apart from chelation therapy, is largely empirical. Therefore, we decided to evaluate the effect of metoprolol succinate on patients with thalassaemia cardiomyopathy (TCM).

Materials and methods In this clinical trial, 45 patients with TCM were randomised to receive either metoprolol (n=26) or placebo (n=19). Echocardiography and a 6 min walk test were performed at baseline and repeated after 6 months and the values compared.

Results In the metoprolol group, left ventricular ejection fraction (LVEF) rose from 38.65% to 42.84% (p<0.001), while it decreased in the placebo group from 37.89% to 35.84% (p=0.01); the difference between the two groups was significant (p<0.001). Left ventricular (LV) mass in the metoprolol group decreased from 154.31 to 144.26 g (p=0.02), while in the placebo group it increased from 174.32 to 200.15 g (p=0.68); the difference between the two groups was significant (p<0.001). End systolic volume (ESV) decreased in the metoprolol group from 42.19 to 36.73 cm³ (p<0.001) but increased from 47.37 to 57.42 cm³ in the placebo group (p=0.144); the difference between the groups was significant (p<0.001). No differences in exercise capacity or pulmonary capillary wedge pressure were seen between the two groups (p=0.268 and p=0.535, respectively).

Conclusions Metoprolol succinate as a β-blocker may have the potential to significantly improve systolic function in patients with TCM and reverse LV remodelling to the same extent as in other types of cardiomyopathy.

Trial registration number NCT01863173.