Background:Previous studies have suggested that β1-receptor blockers benefit septic shock patients.This study aimed to determine whether β1-receptor blockers benefit tissue perfusion in sepsis and to identify parameters to reduce the risk of this drug in sepsis.Methods:Consecutive septic shock patients were recruited from the Intensive Care Unit of Peking Union Medical College Hospital within 48 h of diagnosis.All patients were hemodynamically stable and satisfactorily sedated with a heart rate (HR) ≥100 beats/min.Esmolol therapy achieved the target HR of 10-15％ lower than the baseline HR.Clinical and physiological data of patients were collected prospectively within 1 h prior to esmolol therapy and 2 h after achieving the targeted HR.Results:Sixty-three patients were recruited.After esmolol therapy,blood pressure was unaltered,whereas stroke volume (SV) was increased compared with before esmolol therapy (43.6 ± 22.7 vs.49.9 ± 23.7 ml,t =-2.3,P =0.047).Tissue perfusion,including lactate levels (1.4 ± 0.8 vs.1.1 ± 0.6 mmol/L,t =2.6,P =0.015) and the central venous-to-arterial carbon dioxide difference (5.6 ± 3.3 vs.4.3 ± 2.2 mmHg,t =2.6 P =0.016),was also significantly decreased after esmolol therapy.For patients with increased SV (n =42),cardiac efficiency improved,and esmolol therapy had a lower risk for a decrease in cardiac output (CO).Therefore,pretreatment cardiac systolic and diastolic parameters with (n =42)/without (n =21) an increase in SV were compared.Mitral lateral annular plane systolic excursion (MAPSElat) in patients with increased SV was significantly higher than that in those without increased SV (1.3 ± 0.3 vs.1.1 ± 0.2 cm,t =2.4,P=0.034).Conclusions:SV of septic shock patients is increased following esmolol therapy.Although CO is also decreased with HR,tissue perfusion is not worse.MAPSElat can be used to predict an increase in SV before esmolol use.