Three-dimensional speckle tracking echocardiography to evaluate left ventricular function in patients with acute ST-segment elevation myocardial infarction after percutaneous coronary intervention following Tongxinluo treatment

Objective: Bying comparing the correlation between three-dimensional speckle tracking echocardiography (3D-STE) and troponin I (cTn I), three-dimensional left ventricular ejection fraction (3D-LVEF), to explore the 3D-STE to evaluate the left ventricle of patients with acute ST-segment elevation myocardial infarction (AMI) after percutaneous coronary intervention (PCI) following routine treatment with Tongxinluo drugs. Methods: Altogether, 61 patients with AMI and 30 healthy adults were selected, and the patients were divided into the routine group and the Tongxinluo group. The serum creatine kinase isoenzyme (CK-MB) and troponin I (cTn No significant difference was observed between the two groups at 72 h after PCI ( p > 0.05). At 12 months after PCI, the LVEF, GLS, GCS, LVtw, Tor, and MCI of the Tongxinluo group were higher than those of the routine group. The PSD was significantly lower in the Tongxinluo group ( p < 0.05). MCI and 3D-LVEF, cTn I have the strongest correlation and the highest consistency, which can best reflect the changes in the left ventricular function in patients with AMI after PCI. Conclusion: 3D-STE can be used to evaluate the protective effect of Tongxinluo on the left ventricular function in patients with AMI after PCI.

No significant difference was observed between the two groups at 72 h after PCI (p > 0.05). At 12 months after PCI, the LVEF, GLS, GCS, LVtw, Tor, and MCI of the Tongxinluo group were higher than those of the routine group. The PSD was significantly lower in the Tongxinluo group (p < 0.05). MCI and 3D-LVEF, cTn I have the strongest correlation and the highest consistency, which can best reflect the changes in the left ventricular function in patients with AMI after PCI.
Conclusion: 3D-STE can be used to evaluate the protective effect of Tongxinluo on the left ventricular function in patients with AMI after PCI.

K E Y W O R D S
acute ST-segment elevation myocardial infarction, myocardial comprehensive index, threedimensional speckle echocardiography, Tongxinluo

| INTRODUCTION
Acute myocardial infarction (MI) is a common cardiovascular disease with a rapid onset and high fatality rate, and the age of onset has gradually become younger in the recent years. 1,2 Acute ST-segment elevation MI (AMI) should be used when there is evidence of myocardial injury with necrosis in a clinical setting consistent with myocardial ischaemia. 3 PCI and adjuvant drugs after PCI are the first choice in clinical treatment, and the treatment effect is better. 4 Tongxinluo is one of the commonly used drugs after PCI in patients with AMI in traditional Chinese medicine. It protects myocardial cells and helps regenerate blood vessels, thereby promoting the recovery of cardiac function in patients. 5,6 However, the current research on the longterm use of Tongxinluo drugs to promote the recovery of AMI after PCI remains insufficient. Traditional two-dimensional echocardiography can promptly obtain relevant parameters reflecting the patient's cardiac function; however, its sensitivity is inadequate, and it is difficult to identify the subtle changes in cardiac structure and function after PCI. 7 Three-dimensional speckle tracking echocardiography (3D-STE) can effectively avoid the interference of the measurement plane motion. It is a sensitive and repeatable and noninvasive detection method that can identify the changes in the patient's left heart function early. 8,9 Therefore, this study used 3D-STE to evaluate the changes in left ventricular function in patients with AMI who received Tongxinluo after PCI, and judged its clinical application value.

| Participants
This study is a prospective, non-randomized and single-blind study. 97 patients with AMI admitted from October 2019 to October 2020 were selected, and 61 patients finally met the inclusion criteria. All patients underwent emergency PCI. According to the wishes of the patients and their families, patients were treated with different drugs before and after PCI, and were divided into routine group (n = 30, 13 cases of anterior MI and 17 cases of inferior MI) and Tongxinluo group (n = 31, 12 cases of anterior MI and 19 cases of inferior MI) based on the types of drugs. Additionally, 30 healthy people were selected as the control group. The routine group was given conventional treatment drugs (aspirin enteric-coated tablets + ticagrelor tablets + statin lipidlowering drugs +β-blocker) after emergency PCI. The Tongxinluo group was prescribed with eight capsules of Tongxinluo taken orally before emergency PCI, and prescribed with Tongxinluo in addition to the conventional treatment drugs after PCI (4 capsules/time, 3 times/day, continuous use for 12 months). Meanwhile, the routine group and Tongxinluo groups decided whether to choose angiotensin-converting enzyme inhibitors, angiotensin receptor blockers, diuretics, and hypoglycemic drugs according to the needs of their conditions ( Figure 1).
The inclusion criteria were as follows: (1) chest pain from acute infarction onset within 24 h, (2) meeting the diagnostic criteria for acute MI established by the European Society of Cardiology (ESC) in 2017, 3 (3) all AMI patients after PCI. (4) myocardial reinfarction did not occur within 1 year after PCI, and (5) willingness to participate in this study.
The exclusion criteria were as follows 3 : (1) non-ST-segment elevation MI, (2) with severe heart failure, uncontrollable arrhythmia, F I G U R E 1 Experimental data comparison process severe liver and kidney diseases, severe infection, severe coagulation abnormality, malignant tumors, or suffering from neuropsychiatric illnesses, (3) Recurrent myocardial infarction within 1 year after PCI, and (4) the images obtained by the ultrasound are of poor quality and the complete study data of the patients cannot be obtained.
The institutional ethics committee approved the study protocol, and all patients and their families provided informed consent.

| Statistical analysis
Statistical analysis was performed using the SPSS 22.0 software.
Non-normally distributed data were analyzed by χ 2 test, and normally distributed data were analyzed using x±s, respectively. Data comparison between two groups was conducted by LSD-t test, and data comparison between multiple groups was conducted by one-way analysis of variance (ANOVA). The Pearson correlation coefficient was used to evaluate the relationship. The repeatability test was evaluated using intra-group correlation coefficient (ICC), ICC >0.75 indicates high reproducibility. Statistical significance was defined as P < 0.05.

| Baseline characteristics of the study population
The baseline characteristics of the study population are summarized in Table 1. Altogether, 61 patients and 30 healthy people were included in this study. No significant differences in sex, age, body mass index, heart rate, systolic blood pressure, diastolic blood pressure, and adjuvant medication among all groups (P > 0.05)( Table 1).

| Serum myocardial enzyme
No significant differences in serum myocardial enzyme levels between routine group and Tongxinluo group (p > 0.05). (Table 2).

| Conventional two-dimensional ultrasound parameters
Compared with the control group, the LVFS, LVEF (Simpson) at 72 h after PCI in patients with AMI in were significantly lower (p < 0.05).
Meanwhile, the LVFS and LVEF (Simpson) at 12 m after PCI are lower in patients with AMI than those in the control group, and LVEDD was significantly higher in the patients than that in the control group (p < 0.05). No significant difference in parameters between Tongxinluo group and routine group at the same time (Table 3).

| 3D-STE strain parameters and 3D-LVEF
Compared with the control group, the 3D-LVEF, GLS, GCS, LVtw, Tor, and MCI of patients with AMI after PCI significantly decreased, and the PSD significantly increased (p < 0.05).

| Correlation analysis between 3D-LVEF, cTn I and three-dimensional strain parameters
At 72 h after PCI, GCS, GLS, LVtw, Tor, and MCI were negatively correlated with cTn I. The absolute value of its correlation was:
At 12 m after PCI, GCS, GLS, LVtw, Tor, and MCI were positively correlated with 3D-LVEF. The absolute value of its correlation was:

| DISCUSSION
Acute MI is one of the leading causes of mortality in developed countries and can be seriously life-threatening. 10 22 Moreover, the correlation analysis results indicate that the correlation between GLS and LVEF is higher than that of GCS. This may be due to the reason that when the coronary artery is blocked, the inner myocardium of the coronary blood supply area is the first to be affected, including the longitudinally arranged deep spiral muscles. The most evident involvement is that GLS is reduced, which causes a decrease in myocardial contractility. Meanwhile, GLS can also reflect the relationship between heart strain and time, so the use of GLS has a high diagnostic value in assessing left ventricular function. 20,23 Studies have revealed that the left ventricle function may be related to the myocardial rotation ability. 7 PSD can reflect the synchrony of the movement of the subject's heart in various stages and may be related to the GLS of each layer of the heart. 28 The results of the PSD parameters in this study showed that the PSD measured after PCI in AMI patients was significantly higher than that of the control group, and the PSD value decreased with the prolongation of drug use, and the Tongxinluo group decreased more significantly (p < 0.05). This means that in patients with AMI after PCI, the movement synchronization between the segments of the left ventricular wall is reduced, and the degree of dispersion is increased. This may be because AMI is often accompanied by localized myocardial injury and causes local myocardium. The torsion and strain capacity changes, which may cause unsynchronized and uncoordinated movement of the ventricular wall. This movement can be assessed on the basis of the PSD values. However, after long-term drug adjuvant treatment, the synchronized movement of the left ventricle gradually recovered, especially in patients who took Tongxinluo.

| LIMITATIONS
Firstly, the sample size of the study was small. Secondly, we did not directly compare and analyze cardiac magnetic resonance. Lastly, human subjective factors may have an impact on the image collection and data measurement. These factors may cause certain errors in the results of this study.
We will expand the sample size in a follow-up research and combine it with CMR to conduct further in-depth research on the results of this research.

| CONCLUSIONS
The addition of Tongxinluo drugs on the basis of conventional drug treatment can improve the long-term (≥12 months) prognosis of patients with STEMI after PCI. In the 3D-STE, higher left ventricular function changes after PCI were noted in patients with AMI who received Tongxinluo, indicating its clinical application value.