[Two-dimensional speckle tracking imaging in assessing the left ventricular systolic function and its dynamic changes...

To evaluate early and dynamic changes of the left ventricular systolic function of patients with septic shock by two-dimensional speckle tracking imaging (2D-STI), and to provide guidance for treatment and prognosis.

Fifty-eight septic shock patients admitted to intensive care unit (ICU) of Subei People's Hospital from January 2016 to April 2017 were enrolled. The septic shock patients were given early fluid resuscitation. The left ventricular end-diastolic volume (LVEDV), left ventricular end-systolic volume (LVESV), left ventricular ejection fraction (LVEF), early diastolic mitral flow velocity/early diastolic mitral annular peak velocity (E/Em) were obtained by conventional echocardiography, and the left ventricular global longitudinal strain (GLS), global circumferential strain (GCS), global radial strain (GRS) were obtained by 2D-STI before fluid resuscitation and 1, 3, 7, 14 days after fluid resuscitation. According to the 28-day survival, the septic shock patients were divided into survival group (38 cases) and death group (20 cases). Thirty normal subjects with age and sex matched were selected as control group.

(1) Compared with control group, heart rate (HR) and LVESV were increased [HR (bpm): 92.71±12.51 vs. 73.07±5.52, LVESV (mL): 42.50±7.89 vs. 38.73±4.23, both P < 0.05], while LVEF, GLS, GCS were decreased [LVEF: 0.57±0.06 vs. 0.61±0.03, GLS: (-17.72±1.35)% vs. (-22.07±1.95)%, GCS: (-17.08±1.49)% vs. (-22.98±1.97)%] in septic shock group (all P < 0.01). (2) Compared with the data before fluid resuscitation, heart rate was declined (bpm: 87.83±11.50 vs. 92.71±12.51, P < 0.01), while LVEDV and LVEF were increased [LVEDV (mL): 102.32±9.23 vs. 99.24±8.86, LVEF: 0.59±0.05 vs. 0.56±0.06] in patients of the septic shock after fluid resuscitation (all P < 0.01). (3) With the extension of treatment time, HR, LVEDV, LVESV, E/Em were increased gradually, and LVEF, GLS, GCS, GRS were decreased gradually in dead patients. In septic shock patients, compared with survival group, GCS was significantly different on day 1 [(-15.98±1.41)% vs. (-17.66±1.22)%, P < 0.05], HR, LVEDV, LVESV, GLS were significantly different on the 3rd day [HR (bpm): 104.60±10.94 vs. 88.71±5.06, LVEDV (mL): 109.69±10.00 vs. 103.99±5.74, LVESV (mL): 47.78±7.21 vs. 42.29±5.13, GLS: (-14.44±0.92)% vs. (-16.36±1.00)%, all P < 0.05], LVEF, GRS were significantly different on the 7th day [LVEF: 0.47±0.07 vs. 0.58±0.04, GRS: (28.27±3.23)% vs. (31.48±3.12)%, both P < 0.05], and E/Em was significantly different on the 14th day (12.81±1.56 vs. 10.61±1.27) in dead group (P < 0.05).

Our study demonstrates myocardial dysfunction at the early phase in septic shock patients, and 2D-STI GCS can be more sensitive than the conventional echocardiography to determine prognosis. 2D-STI GCS, GLS, GRS were not volume-load dependent parameter. Low levels of GLS, GCS might suggest a poor prognosis.