Improvement of left ventricular relaxation as assessed by tissue Doppler imaging in fluid-responsive critically ill septic patients

Left ventricular (LV) diastolic function is often impaired in critically ill septic patients. The peak velocity of the mitral annulus early wave during diastole (E'), measured by Doppler echocardiography, is a major tool to evaluate LV relaxation, the ATP-dependent part of diastole. The authors hypothesized that if volume expansion (VE) is followed by an increase in stroke volume (SV) ("adequate" VE), LV relaxation and consequently E' may be increased. This was a prospective study in which 83 mechanically ventilated septic patients with circulatory failure were enrolled. Doppler echocardiography was performed before and after the infusion of 500 ml of saline over 20 min. Patients were then classified into two groups according to their response to VE: responders (R) were those in whom SV increased by at least 15 %; all others were considered to be non-responders (NR). SV, mitral flow early wave velocity (E), E' and the E/E' ratio were measured before and after VE. VE-induced variations (a dagger) in all parameters were compared in R and NR. Patients with an E' < 0.12 m/s were considered to have LV diastolic dysfunction. Fifty-nine patients (71 %) were R and 24 (29 %) were NR. Fifty-six percent of R patients and 58 % of NR patients had LV diastolic dysfunction. For patients with LV diastolic dysfunction (n = 47), a dagger E' was significantly higher in the R group (29 +/- A 5 vs. 5 +/- A 8 %; p = 0.01) whilst a dagger E/E' was higher in the NR group (35 +/- A 9 vs. 2 +/- A 6 %; p = 0.02). E' maximal velocity increased with adequate VE, suggesting an improvement of LV relaxation with the correction of hypovolaemia in patients with septic shock.