To explore the emergency PCI symptom-onset-to-balloon time (SOTBT) influence on the local cardial function in patients with acute ST-segment elevation myocardial infarction (STEMI) by two-dimensional speckle tracking imaging (2D-STI) technology.

Sixty cases were first diagnosed with ST-elevation myocardial infarction (STEMI) and undergone emergency PCI surgery in Huangshi central hospital from June 2014 to June 2016. According to SOTBT, patients were divided into two groups: SOTBT≤6h myocardial infarction group, 6 h<SOTBT<126 h myocardial infarction group. Thirty cases of healthy subjects were as normal control group. Twenty-four hours and one month after surgery, echocardiographic examinations were performed. To measure myocardial longitudinal strain (LS), circumferential strain (CS) and radial strain (RS). One-way ANOVA and LSD test were used to analyze the clinical and angiographic characteristics, two-dimensional strain parameters among two myocardial infarction groups and the healthy controls group. Line correlation analysis was applied to dispose the relativity between the two-dimensional strain parameters and SOTBT.

After 24 hours, Longitudinal and circumferential and radial strain of the 6 h<SOTBT<126 h MI group were lower than normal control group, the difference was statistically significant (t=4.53, 3.76, 2.59, P<0.05). But only longitudinal and circumferential strain of the SOTBT≤6 h MI group were lower than the healthy group, the difference was statistically significant (t=3.13, 2.17, P<0.01). The area under the ROC curve of LS to predict survival myocardium is biggest (AUC=0.728, P<0.01). And when the cut off valve was -17.92%, the sensitivity was 62.9%, the specificity was 64.0%.

2D-STI can evaluate local myocardial strain of patients with STEMI, and identify the symptoms-onset-to-balloon time influence on the prognosis of patients with STEMI. The longitudinal strain is the most sensitive strain parameter.