Background/Objective: Levosimendan represents an alternative to other positive inotropic agents based on its different mechanisms of action and favorable electrophysiological properties. This study compared the effects of levosimendan and dobutamine on echocardiographic parameters in heart failure patients with acute decompensation necessitating positive inotropic support. Methods: Patients with acute decompensated heart failure were randomized to receive inotropic support with either levosimendan (n=25) or dobutamine (n=25). Treatment groups were compared in terms of echocardiography measurements including tissue Doppler examination findings, systolic time interval assessments and diastolic parameters. In addition, groups were compared for demographic features, clinical characteristics and laboratory findings. Results: Among tissue Doppler measurements, Sm-lateral and Sm-septal significantly increased after treatment in both groups. E/E’ lateral and E/E’ septal significantly decreased only in the levosimendan group. Among systolic time interval parameters, increasing in left ventricular ejection time and shortening in pre-ejection period are similar in both groups, however a significant decrease in QS2i was observed in the levosimendan group. Levosimendan treatment was associated with significant decreases in blood pressures along with a significant increase in ejection fraction. Dobutamine treatment on the other hand resulted in significant increases in blood pressure, heart rate and ejection fraction. Conclusions: Our findings suggest that levosimendan and dopamine treatments are associated with only marginal differences in echocardiographic parameters. This study suggests that both levosimendan and dobutamine are almost equally effective in systolic time intervals. However, levosimendan appears to have additional advantage over dobutamine in shortening QS2i, indicating a fairly strong positive inotropic effect. Keywords : decompensated heart failure, dobutamine, levosimendan, inotropic support, echocardiography, tissue doppler, systolic time intervals DOI : 10.7176/JSTR/5-3-07