Left ventricular systolic dysfunction during septic shock: the role of loading conditions

Abstract

Purpose: The clinical significance of septic myocardial dysfunction is controversial, a fact that may be explained by the influence of loading conditions. Many indices may be useful to characterize cardiac function during septic shock, but their feasibility and physiological coherence in the clinical setting are unknown. Methods: Hemodynamic and echocardiographic data with tissue Doppler and speckle tracking were prospectively recorded on the first 3 days of human septic shock. Hypokinesia, normokinesia, and hyperkinesia were defined as a left ventricular ejection fraction (LVEF) of <45, 45–60, and >60%, respectively. Twelve hemodynamic indices exploring contractility and loading conditions were assessed and analyzed. Results: Two hundred and ninety-seven echocardiographies were performed in 132 patients. During the first 24 h (H1–24), 48 (36.4%) patients were hyperkinetic, 55 (41.7%) were normokinetic, and 29 (22.0%) patients were hypokinetic. Thirteen patients had a secondary hypokinesia absent at H1–24 but present at H25–48 or H49–72, for an overall incidence of 42 (31.8%) during the first 3 days. Despite a limited feasibility (<50%), global LV longitudinal peak systolic strain was impaired in a majority (>70%) of the patients assessed, including all those with depressed LVEF, and declined early in patients whose LVEF secondarily deteriorated. Most contractility indices were inversely correlated with afterload indices. Hyperkinetic patients exhibited the worst reduction in afterload indices. Hospital mortality was significantly higher in patients with LV hyperkinesia than in their counterparts: 30 (62.5%) vs. 35 (41.7%), p = 0.02. Conclusions: Speckle tracking-derived strain was reduced in the majority of patients with septic shock, revealing covert septic myocardial dysfunction, but had poor feasibility. We found an inverse correlation between most of the contractility and afterload indices. Precise evaluation of afterload is crucial for adequate interpretation of LV systolic function in this setting.