Mavrogeni S, Giamouzis G, Papadopoulou E, Thomopoulou S, Dritsas A, Athanasopoulos G, Adreanides E, Vassiliadis I, Spargias K, Panagiotakos D, et al. A 6-month follow-up of intermittent levosimendan administration effect on systolic function, specific activity questionnaire, and arrhythmia in advanced heart failure. Journal of cardiac failure. 2007;13:556–559.