Increased atrial contraction contribution to left ventricular filling during early septic shock

To assess the atrial systolic function and the contribution of atrial contraction to left ventricular (LV) filling in septic shock patients as compared with healthy volunteers.

Twenty-seven septic patients evaluated during first 48 h of ICU admission and compared with 27 healthy volunteers. Left atrial (LA) contraction contribution to LV filling was calculated as the active emptying atrial volume/LV end-diastolic volume. Atrial systolic function was evaluated with the atrial kinetic force [LAKE = 0.5 × blood density × LVV_active × (peak A velocity)²] and atrial ejection force [LASF = 0.5 × blood density × mitral annulus area × (peak A velocity)²].

LV ejection fraction was lower in septic patients than in control group: 51 ± 14%vs 60 ± 6% (p < 0.01). Contribution of LA contraction to LV preload was greater in septic patients than in normal subjects (26.7 ± 11.3% vs 15.9 ± 5.9%, p < 0.001), even if adjusted for age (0.49 ± 0.19 vs 0.35 ± 0.13, p = 0.004). LAKE and LASF were also significantly larger in septic patients than in normal subjects (21.8 ± 9.1 vs 7.3 ± 3 kdynes·cm, p < 0.001; 16.1 ± 11.7 vs 9.8 ± 4.3 kdynes, p = 0.048, respectively), and remained unchanged during the next 48 h.

In septic shock patients, LA systolic function increased and greatly contributed to support LV filling. These results highlight the role of preserving atrial contraction on the hemodynamic resuscitation in early septic shock.