Pronounced Improvement in Systolic and Diastolic Ventricular Long Axis Function After Treatment with Metoprolol

BACKGROUND: Although it is well known that left ventricular (LV) function improves after treatment with beta-blockers in heart failure, little attention has been paid to the effects on LV long axis (LAX) function. AIMS: To evaluate LV LAX function after treatment with metoprolol, and to assess whether LV LAX contractile reserve could predict future long-term improvement. METHODS: Twenty-four heart failure patients were randomised to metoprolol or placebo for 6 months, followed by 6 months of open treatment with metoprolol. Rest and dobutamine stress echocardiography (DSE) was performed before and after each treatment period. RESULTS: After treatment with metoprolol, LV LAX function improved significantly, systolic velocity from 29+/-8 to 32+/-15 mm/s, p<0.01 (metoprolol) vs. 28+/-7 to 28+/-11 mm/s, ns (placebo); atrioventricular plane fractional shortening (AVP-FS) from 5.4+/-2.1 to 7.4+/-2.7%, p<0.001 (metoprolol) vs. 5.9+/-2.1 to 5.8+/-2.9%, ns (placebo). The improvement in function was maintained during DSE. LV LAX contractile reserve could not predict treatment response; the treatment effect on LV LAX function was significantly greater than the contractile reserve at baseline. The relative improvement in LV LAX function after metoprolol was 38%, compared with a 20% improvement in LV ejection fraction (EF). CONCLUSION: A significant improvement in LV LAX function was observed after treatment with metoprolol. AVP-FS and systolic velocities increased significantly, and to a greater extent than LVEF.