Acute and short-term hemodynamic effects of metoprolol in Eisenmenger syndrome: a preliminary observational study.

Background: Progressive heart failure and sudden cardiac death are the common causes of death in Eisenmenger syndrome. β-Bockers may be useful in Eisenmenger syndrome, but the safety and efficacy are not proven. The objective of the study was to evaluate the hemodynamic effects and safety of metoprolol in Eisenmenger syndrome.
Methods: Fifteen patients of Eisenmenger syndrome with a mean age of 22.6 (±8.9) years were studied. Hemodynamic parameters were measured at baseline, after 15 mg of intravenous metoprolol and 6 weeks after oral metoprolol (25 mg/d for 2 weeks and 50 mg/d for 4 weeks).
Results: Intravenous metoprolol was well tolerated, although there was a significant decrease in pulmonary and systemic blood flows. The calculated pulmonary vascular resistance index (23.3 ± 8.6 to 27.4 ± 10.6 Wood U, P = .005) and systemic vascular resistance index (34.9 ± 9.9 to 41.9 ± 13.5 Wood U, P = .005) increased significantly. After 6 weeks of oral metoprolol, the pulmonary artery mean pressure declined significantly (79.9 ± 12.9 to 73.4 ± 14.0 mm Hg, P = .04), which was associated with a slight decrease in mean aortic pressures as compared with baseline. The 6-minutes walk distance increased (401.2 ± 99.9 to 462.5 ± 81.7 m, P = .005).
Conclusions: Preliminary observations suggest that metoprolol is safe and well tolerated in selected patients with Eisenmenger syndrome. Acute hemodynamic worsening recovers in the short term, and the exercise capacity improves in most patients. Larger studies are warranted.
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