[The effect of levosimendan and dobutamine treatment on QT dispersion in patients with decompensated heart failure: a prospective study].

Objective: We investigated the effect of intravenous levosimendan on QT dispersion compared with intravenous dobutamine in patients with acute decompensated heart failure.

Methods: This prospective cohort study included 38 patients who were admitted with acute decompensated heart failure (New York Heart Association functional class III-IV). Twenty-five patients (11 men, 14 women; mean age 70.5 ± 11.13 years) were treated with levosimendan infusion and 13 patients (5 men, 8 women; mean age 71.08 ± 6.86 years) were treated with dobutamine infusion. Intravenous levosimendan was administered with an initial bolus dose of 12 μg/kg for 10 min, followed by a continuous infusion of 0.1 μg/kg/min for 1 hour and 0.1 μg/kg/min 23 hours. Intravenous dobutamine was administered with a continuous dose of 10 μg/kg /min for 24 hours. Transthoracic echocardiography was performed and electrocardiograms were obtained before and after drug infusions. QTc dispersion was defined as the difference between the maximum and the minimum QT intervals and the value was corrected for heart rate. Chi-square test, Wilcoxon test and Mann-Whitney U tests were used for data analysis.

Results: No significant differences were found before and after treatment of both levosimendan and dobutamine with respect to minimum QT intervals, maximum QT and QT dispersions. (Pretreatment and 24th hour values of levosimendan group were; 0.43 ± 0.04 s, 0.44 ± 0.04s; 0.49 ± 0.05s, 0.50 ± 0.05s; 0.06 ± 0.03s, 0.06 ± 0.03s; in dobutamine group values are - 0.39 ± 0.05 s, 0.41 ± 0.05s; 0.45 ± 0.05s, 0.48 ± 0.05s; 0.06 ± 0.04s, 0.06 ± 0.04s, respectively) (p>0.05). No side effects related to drugs were seen during follow-up in all two treatment groups.

Conclusion: Our results suggest that, therapeutic doses of levosimendan infusion do not have a significant effect on QT parameters - the predictors of arrhythmias-, in patients with decompensated heart failure when compared with dobutamine infusion.