Clinical study suggests that beta-blockers by decreasing heart rate together with an increase in stroke volume do not negatively affect cardiac output allowing an economization of cardiac work and oxygen consumption in patients with septic shock. Whether this hemodynamic profile leads to an amelioration of myocardial performance is still unclear. The objective of the present study is therefore to elucidate whether a reduction in heart rate with esmolol is associated to an improvement of cardiac efficiency in patients with septic shock who remained tachycardic after hemodynamic optimization.

After 24-36 hours of initial hemodynamic stabilization, 44 septic shock patients with heart rate > of 95 bpm and requiring norepinephrine to maintain mean arterial pressure (MAP) between 65 and 75 mmHg despite adequate volume resuscitation,will receive a continuous esmolol infusion to maintain heart rate between 94 and 80 bpm. Norepinephrine will be titrated to achieve a MAP between 65 and 75 mmHg. To investigate myocardial performance, we will simultaneously assess LV ejection fraction (LVEF), tricuspidal annular plane solid excursion (TAPSE) by echocardiography, the dP/dt MAX and the cardiac cycle efficiency (CCE) both estimated from the arterial pressure waveform. Finally we will analyze changes in static arterial elastance. Data will be obtained at baseline and after four hours once achieved the predefined heart rate threshold.

Inclusion Criteria:

• septic shock criteria
• presence of heart rate > 95 bpm.

Exclusion Criteria:

• Pregnancy
• age < 18

Septic shock patients with heart rate > of 95 bpm and requiring norepinephrine to maintain mean arterial pressure (MAP) between 65 and 75 mmHg after at least 24 hours of hemodynamic optimization.