Can WeChat group-based intervention reduce reperfusion time in patients with ST-segment myocardial infarction? A controlled before and after study

Abstract

Background

Pre-hospital identification of acute ST-elevation myocardial infarction and activation of the catheterization laboratory can reduce first medical contact to wire-crossing times. We conducted a study on providing 24-hour tele-electrocardiography services via the WeChat group application, aiming to reduce the time taken for diagnosis and treatment of ST-elevation myocardial infarction.

Methods

A controlled before and after study was conducted on 140 ST-elevation myocardial infarction patients who were initially seen in non-percutaneous coronary intervention-capable hospital and transferred for primary percutaneous coronary intervention at our percutaneous coronary intervention centre from 1 February to 31 October 2018. The WeChat group had 70 patients with pre-hospital electrocardiography transmission via WeChat and the control group had 70 patients who did not transfer pre-hospital electrocardiography. The reperfusion time of the two groups was compared to evaluate the effect of the WeChat group intervention.

Results

In the WeChat group versus the control group, the median symptom onset to first medical contact time was similar (129 vs 150 min, p > 0.05), but the median first medical contact to wire, door to wire and first medical contact to catheterization laboratory activity were significantly shorter (132 vs 171 minutes, p < 0.001; 60 vs 95 minutes, p < 0.001; 29 vs 74 minutes, p < 0.001, respectively).

Conclusions

Pre-hospital electrocardiography transfer via a WeChat group resulted in earlier reperfusion of ST-elevation myocardial infarction patients who were transferred from the non-percutaneous coronary intervention centre.

Keywords

Telemedicine WeChat application ST-segment myocardial infarction mobile health

Introduction

Myocardial infarction is one of the leading causes of morbidity and mortality worldwide and it imposes a huge economic burden on society and patients.¹ It has been reported that ST-segment elevation myocardial infarction (STEMI) accounts for 25–40% of myocardial infarction.² For patients with clinically suspected STEMI, it is necessary to open the occluded blood vessels in the shortest time possible and perform reperfusion therapy. Delayed diagnosis and treatment have a major impact on morbidity and mortality in STEMI patients. With a 30-minute delay in reperfusion therapy, patient mortality increased by 8%.³ Therefore, the European Society of Cardiology recommends a target time of <90 min from first medical contact (FMC) to primary percutaneous coronary intervention (pPCI).⁴ In patients with STEMI who do not receive reperfusion therapy, the in-hospital mortality rate is 4–12% and the annual mortality rate is approximately 10%.⁵

Due to the prevalence of risk factors and an aging population, China will have at least 75 million new cases of acute myocardial infarction (AMI) in the next 15 years, which will place a serious disease burden on existing health services.⁶ According to data from the National Health and Family Planning Commission, although the total number of PCI in China has increased significantly in recent years, ranking second only to the United States, the proportion of AMI patients receiving pPCI has remained approximately 30%.⁷ From the overall population of 500,000 newly occurring AMIs every year in China, only 5% of patients receive pPCI,⁸ whereas the proportion in Germany was 97% for the same period.⁸ The level of AMI treatment in China is still far behind that of developed countries and no significant progress has been made in the past decade.⁹

Patients and system delay are two main reasons for the low pPCI rate in the early stages.¹⁰ According to the results of the registration studies on acute coronary syndrome in China, the average time for AMI patients to visit the hospital is 5–8 h,¹¹ whereas the best window for reperfusion treatment is within 2 h of symptom onset.¹² Therefore, many patients miss the optimal treatment timing and fail to receive pPCI treatment. System delays can occur in the pre-hospital emergency system, the non-PCI centre, the PCI centre and in referral between non-PCI and PCI centres.¹³ STEMI patients should ideally go directly to a PCI centre by ambulance after symptom onset. However, most of PCI centres in China are located in the middle of towns. Patients with AMI in the suburbs and countryside often first report to the nearest hospital manned by primary care physicians, who may be unskilled in electrocardiography (ECG) and AMI management.⁷ Moreover, most of these hospitals are not qualified to perform pPCI.⁷ Therefore, primary care physicians refer patients to the urban PCI centre, which can lead to a long delay.

Dracup et al. (2009), Mooney et al. (2014) and Darsin et al. (2016) have conducted studies to evaluate whether education programmes are effective at reducing patient-related prehospital delay.^14–16 It was supposed that through education, patients can identify symptoms early and seek medical help as soon as possible. However, for system delays, especially for patients who first go to non-PCI hospitals for medical treatment, the best way to reduce the delay is to set up a regional collaborative rescue network and open the green channel in hospitals.¹⁷ Through the network, the ECG of the patient can be sent to an experienced cardiologist in the PCI centre to obtain a diagnosis as soon as possible. If STEMI is diagnosed, patients can be transferred to a PCI hospital for reperfusion treatment immediately. The in-hospital green channel for STEMI patients promoted by Professor Dayi Hu in the 1990s has significantly reduced the in-hospital delay in China.⁷ For patients arriving in the non-PCI centre, the biggest challenge is to finish the first ECG and receive ECG diagnoses within 10 min then activate the catheterization laboratory in the PCI centre as soon as possible.¹⁸ To solve this problem, China has made many explorations in recent years. As the first standardized pilot chest pain centre in China that was accredited by the America-based Society of Cardiovascular Patient Care, Guangzhou General Hospital proposed the concept of integrated regional medical resources then created the first regional collaborative rescue network based on the Bianque First Aid and Quality Control System. Regional information sharing and pre-hospital diagnosis were achieved through remote transmission of real-time ECGs by the system.⁷ When an acute chest pain patient arrived at a non-PCI hospital, the primary physician completed the first ECG within 10 min. Then, the first ECG was transmitted to the PCI centre through the Bianque First Aid and Quality Control System immediately and cardiologists at the PCI hospital read and reported the ECG within 10 min. For a well-diagnosed STEMI, if the ECG can be sent to the nearest pPCI hospital and the pPCI completed within 120 min, patients can bypass the emergency department (ED) and Coronary Care Unit (CCU) and be sent directly to the catheterization laboratory. If the transhipment and pPCI cannot be completed within 120 min, thrombolysis is initiated in the ambulance and the patient is then sent directly to the pPCI hospital for subsequent coronary angiography after thrombolysis. The regional collaborative network significantly shortens the rescue timeline of STEMI patients in non-PCI-capable hospitals. However, these remote transmission systems are expensive and not every region has the ability to purchase them, especially in undeveloped areas. Moreover, it requires training and maintenance, limiting its applicability. Therefore, it is necessary to study an economical, practical tool for the remote transmission of pre-hospital ECG.

WeChat was first released globally by the Chinese company Tencent in January 2011.¹⁹ At present, there are more than 1 billion monthly active WeChat users worldwide and it has become one of the most widely used social communication applications (apps) in China.²⁰ It has been widely used in chronic disease management because it delivers image, video and voice messages.^21–23 WeChat is a secure and private app. WeChat app users have their own unique username and password. They need to enter a password each time when they log in. The ‘WeChat Privacy Protection Guidelines’, which were announced by the Tencent Legal Department (Privacy and Data Protection Center) on 22 August 2017, claimed they had taken user data protection seriously in product development and daily operation.²⁴ Meanwhile, the WeChat app was certified by TRUSTe, a leading global Data Privacy Management company that provides privacy assessments, certifications, monitoring tools and compliance controls.²⁵

The aim of this study was to test whether the WeChat group-based regional collaborative rescue system is effective in reducing reperfusion time in STEMI patients who transferred from a non-PCI hospital. This paper begins with an introduction to the study methods. Research setting and samples, details of the intervention, procedure and measures and data analysis methods are presented in this section. The results of this study are displayed following the Methods section. This is followed by a critical discussion about the study results. Finally, a conclusion of the proposed study is displayed.

Methods

Setting and samples

The study was a controlled before and after study. The setting was a 1400-bed university hospital with a PCI centre that offers 24-hour PCI reperfusion therapy, 7 days a week and seven primary hospitals without PCI capacity. There are four PCI centres in our city, located in the west (two), north (one) and south (one). Our PCI centrr is in the north of the city and the healthcare network covers an area of 700 km². The hospital provides healthcare services for a population of 1.8 million people. Approximately 350–400 patients with STEMI are referred to our PCI centre each year. The seven collaborating primary hospitals without PCI capability were 5–47 km away from our PCI centre. The non-PCI centres are connected by highways. Normally, patients can be transferred from non-PCI hospitals to our PCI centre within 30–40 min. Site maps of seven non-PCI centres are shown in Figure 1. The research programme leader was the chief head nurse in charge of the CCU and two cardiovascular departments in this PCI centre. She is a cardiovascular nursing specialist and has more than 15 years of management experience.

The sample consisted of all patients with suspected STEMI who transferred from seven non-PCI hospitals and subsequently underwent pPCI at our PCI centre during two time periods. The control was carried out between 1 February 2018 and 31 June 2018 and the intervention was carried out between 1 July 2018 and 31 October 2018 in the next set of patients. To reduce the seasonality and historical effects affecting patient acuity, illness types and staffing patterns, we choose two time periods. Patients were eligible for the study if they had a diagnosis of STEMI, were referred from the seven non-PCI centres, underwent pPCI in our hospital and agreed to participate in this study. The exclusion criteria were the patient having a psychiatric illness or inability to communicate. This study was approved by the research ethics committees of the hospital. Informed consent was acquired if patients agreed to participate in this study.

Intervention

The seven non-PCI hospitals were equipped with normal 12-channel ECG machines. After being assigned as the cooperation hospitals of our PCI centre, 158 doctors, nurses, technicians and administrators in the seven primary hospitals and in our PCI centre accepted the phase 1 training course. The content of the training course is shown in Table 1.

Table 1.

Content of the training course in the two groups.

Content	Phase 1Control group	Phase 2Intervention group	Date
Diagnosis and antidiastole of acute chest pain	√	√	January 2018
Operation of ECG machine and record ECG	√	√	January 2018
Characteristics of ECG in AMI	√	√	January 2018
Time is heart muscle, time is life	√	√	January 2018
Green channel flow chart for patients with STEMI	√	√	January 2018
Introduction of WeChat group and flow chart of STEMI patients transferred from non-PCI centres	×	√	June 2018
Introduction of PCI centre layout and bypass ED and CCU map	×	√	June 2018
Data safety and confidentiality issues	×	√	June 2018

AMI: acute myocardial infarction; CCU: Coronary Care Unit; ECG: electrocardiography; ED: emergency department; PCI: percutaneous coronary intervention; STEMI: ST-segment elevation myocardial infarction.

Control group

The control group was treated according to the traditional emergency green channel in our hospital. Each patient presented with acute chest pain and went to one of the seven non-PCI hospitals for treatment. The primary physician in these non-PCI hospitals completed the first ECG and made a preliminary judgment. If STEMI was suspected, the patient was immediately transferred by ambulance to the ED of our PCI centre. The physician in the ED of our hospital repeated the ECG and made a preliminary diagnosis. At the same time, the physician in the ED called the cardiologist on duty in the CCU of our hospital for consultation. The cardiologist in the CCU went to the ED, assessed the disease history and read the ECG. If STEMI was diagnosed, the cardiologist invited the patient to sign the consent form and the patient was required to take 300 mg of aspirin and 300 mg of clopidogrel. Nurses performed preoperative preparation. Meanwhile, the cardiologist called the nurses to activate the catheterization laboratory and used a smartphone to inform the interventional doctors to prepare for the procedure. After that, the patient was sent to the catheterization laboratory to receive the PCI. Details of the process are shown in Figure 2.

Figure 1.

Site maps of seven non-PCI centres.

WeChat intervention group

Before intervention, we downloaded and installed the WeChat app through a smartphone. After that, a WeChat group called the ‘Platform for Chest Pain Rescue’ was established. The WeChat group has a leader who is responsible for maintaining orders. She is one of our research members and her core responsibility is to control the access to the WeChat group. A total of 158 physicians, nurses and other related healthcare providers of ED, cardiology department, pre-hospital first aid department, catheterization laboratory and others were added to this group. There were no small groups within the WeChat group. A 1-day training programme was conducted in our PCI centre before the WeChat intervention. All group members are expected to attend the training course. Providers who participated in this training (phase 2) are the same as those who attended the phase 1 training course. The content of the training course is shown in Table 1.

The FMC physician completed the first ECG and conducted a primary analysis of the ECG when the patient presented with chest pain and sought medical treatment in one of the non-PCI hospitals. If ST-T waves changed, ECG images were immediately uploaded to the WeChat group, using a smartphone. The cardiologist on duty in our PCI centre read the ECG and the report was sent back to the WeChat group within 10 min. If clearly diagnosed as STEMI, the patient was given 300 mg of aspirin and 300 mg of clopidogrel according to the recommendations of the American Heart Association.²⁶ The non-PCI hospital immediately used an ambulance to transfer the patient to our PCI centre. Informed consent and preoperative preparation were conducted in the ambulance by a primary physician and nurse. At the same time, the cardiologist on duty in our PCI hospital activated the catheterization laboratory and informed the interventional doctor to be in place via the WeChat group and telephone. On arriving at our PCI hospital, the patient bypassed the ED and CCU and arrived at the catheterization laboratory directly for interventional treatment.

When the primary physician of the non-PCI hospitals uploaded the first ECG to the WeChat group, the cardiologist on duty in the CCU of our hospital could not always make a definite diagnosis. In this case, the cardiologist immediately consulted the senior cardiologist with more experience in our hospital through the WeChat group using the app’s @ function. If STEMI was diagnosed, the patient bypassed the ED and CCU for direct intervention in the catheterization laboratory. If STEMI was ruled out, the patient remained in the Emergency Intensive Care Unit (EICU) or CCU for dynamic observation. No patient identifiers were shared on the WeChat platform. Identifying information and medical information of patients was transmitted separately. The WeChat group manager deleted all the information transmitted through the WeChat using the remote data wiping function of the WeChat app within 2 h of revascularization. The primary physician obtained informed consent before sharing the ECG images of the patient and the hospital also had established policies and regulations regarding patient privacy and data protection. Details of the process are shown in Figure 3.

Figure 2.

Traditional green channel for ST-segment elevation myocardial infarction (STEMI) patients (control group).

Figure 3.

Flow chart of the WeChat group (intervention group).

In addition, real-time feedback of the key timeline of the patients from FMC to wire-crossing was provided by the WeChat group owner. Some motivational words were used if the reperfusion time met the requirement of the guidelines. Details are shown in the screenshot of the WeChat in Figure 4.

Figure 4.

Screenshot of the WeChat group.

Procedure and measures

Data were collected from the seven non-PCI hospitals and our PCI centre with consecutive sampling between 1 February 2018 and 31 October 2018. Sociodemographic characteristic data were collected from the electronic medical records of the health information system. Characteristics of symptom presentation were collected from the first progress note and confirmed through face-to-face interviews with the research nurse. Critical time points, which included symptom onset, FMC, first ECG, ECG diagnosis, time of arriving at and being discharged from the non-PCI hospital, time of arrival at the PCI hospital, catheterization laboratory activation and wire-crossing, were recorded by the healthcare providers involved with the events in a specially designed form (Time management form for patients with chest pain). All time-point definitions followed the guidelines.⁴ All the data on sociodemographic characteristics and characteristics of symptom presentation were checked against the information from the cloud platform of China Chest Pain Center. All of the data were stored in a folder on a private computer. A password was used to code data in the folder and another password was needed when using a private computer. To prevent data loss, we created a backup copy of the data. This copy was stored on a USB flash drive, which has a password that is only known by the core members of the research programme. Only the core members of the research programme had the access to the data and the password for inputting data. The principal investigator of this study was responsible for the data. The satisfaction survey on WeChat usage was conducted within 1 week of study completion.

Data analysis

SPSS version 17.0 was used to analyse data. The basic characteristics of the sample were described by frequency and mean ± standard deviation (SD). Baseline characteristics of the two groups were compared using x² tests for categorical data and independent t tests for continuous variables. The median was calculated because the time of treatment had some extreme values. Wilcoxon signed-rank sum test was used for non-parametrical variables. A p value < 0.05 was considered significantly different.

Results

Baseline characteristics

A total of 140 patients were evaluated. On average, patients who enrolled in the study were 62±12.4 years old. In total, 114 (81.4%) of the participants were male. The majority were married (75.7%) and 120 (85.7%) had healthcare insurance; 105 (75%) patients presented with continuous chest pain symptoms and 114 (81.4%) had Level 1 Killip classification for heart function. The media time of symptom onset to FMC was 138.5 min in the whole study population. There was no significant difference in the control and intervention group for baseline characteristics. Table 2 showed the baseline characteristics of the two groups.

Table 2.

Baseline of the two groups.

Variable	Total	Phase 1Control group(n = 70)	Phase 2Intervention group (n = 70)	p value
Age (M±SD)	62.2 ± 12.4	63.7 ± 12.8	60.6 ± 11.8	0.667
Gender				0.523
Male	114 (81.4)	56 (80)	58 (82.9)
Female	26 (18.6)	14 (20)	12 (17.1)
Education				0.421
No formal education	18 (12.9)	8 (11.3)	10 (14.9)
Primary school	58 (41.4)	25 (34.8)	33 (46.3)
Secondary school	46 (32.8)	29 (41.6)	17 (23.9)
Tertiary or above	18 (12.9)	8 (12.3)	10 (14.9)
Marital status				0.623
Married	106 (75.7)	55 (70.8)	51 (73.1)
Single/widowed/divorced	34 (24.3)	15 (29.2)	19 (26.9)
Health insurance				0.442
Yes	120 (85.7)	57 (85.7)	60 (85.7)
No	20 (14.3)	13 (14.3)	10 (14.3)
Nature of symptoms				0.753
Continuous chest pain	105 (75)	51 (72.9)	54 (77.1)
Intermittent chest pain	29 (20.7)	15 (21.4)	14 (20)
Abdominal pain	2 (1.4)	2 (2.9)	0 (0)
Shock	4 (2.9)	2 (2.9)	2 (2.9)
Killip classification				0.465
Level I	114 (81.4)	58 (82.9)	56 (80)
Level II	11 (7.9)	6 (8.6)	5 (7.1)
Level III	6 (4.3)	1 (1.4)	5 (7.1)
Level IV	9 (6.4)	5 (7.1)	4 (5.7)
S to FMC (Median)	138.5	129.5	150.0	0.534

FMC: first medical contact. Data in parentheses signifies percentage.

Clinical outcomes

Median door-in to door-out time in the intervention group was 4 min shorter than the control group (40 min), but the difference was not statistically significant (p = 0.675). No patients bypassed the ED and CCU in the control group, whereas ED bypass occurred in 63 patients (90%) in the intervention group. The door to wire time was 95.5 min in the control group compared with 60 min in the intervention group (p < 0.001). The FMC to wire time in the intervention group was 171 min and in the control group it was 132 min (p < 0.001). The FMC to catheterization laboratory initiation time was 74 min in the control group compared with 29 min in the intervention group (p < 0.001). The symptom onset to wire-crossing time was compared between two groups and there was no significant difference (p = 0.254). There was no significant difference in the two groups in proportion of left heart failure, duration of admission and cost during hospitalization. The details are shown in Table 3.

Table 3.

Comparison of the outcomes of WeChat group and control group.

Variable	Phase 1Control group(n = 70)	Phase 2Intervention group (n = 70)	p value
Door in-door out (median)	40	36	0.675
Duration of ECG diagnosis (mean ± SD)	4.21 ± 2.8	4.43 ± 9.0	0.851
Bypass ED and CCU			<0.001
Yes n (% )	0 (0)	63 (90)
No n (% )	70 (100)	7 (10)
Door to wire (median)	95.5	60.0	<0.001
FMC to wire (median)	171.0	132.0	<0.001
FMC to catheterization laboratory activity (Median)	74	29	0.028
S to wire (Median)	329	344.6	0.254
Left heart failure			0.241
Yes n (% )	19 (27.1)	11 (15.7)
No n (% )	42 (60)	59 (84.3)
Duration of admission days (mean ± SD)	9.53 ± 4.9	10.29 ± 4.1	0.325
Spending (mean ± SD)	57,681 ± 569.5	49,467.2 ± 192.6	0.255

CCU: critical care unit; ECG: electrocardiography; ED: emergency department; FMC: first medical contact. Data in parentheses signifies percentage.

User feedback on the WeChat group intervention

Direct feedback is gathered by encouraging WeChat group members to directly state what they think about the WeChat intervention by means of questionnaires. WeChat group members were invited to finish the online survey within 1 week (from 1–7 November 2018). In total, 126 (82.3%) group members completed the online survey. All respondents owned a smartphone and use the WeChat group application; 74 (58.7%) group members were male, with an average age of 36 ± 6.9 years, ranging from 19 to 57. Overall, 120 (95.2%) group members reported the WeChat platform was easy to use, simple and convenient for the remote transfer of ECG and 124 (98.3%) members were satisfied with the service provide by the WeChat group. Data show that 82 (65.1%) were doctors, 34 (27%) were nurses, five (3.9%) were administrators, one (0.8%) was a technician and four (3.2%) were other. Four (3.2%) doctors, one (0.8%) nurse and one (0.8%) administrator thought the app was not easy to use. Three (2.4%) doctors and one (0.8%) nurse thought the app was not convenient; 11 (8.7%) doctors, 3 (2.4%) nurses and one (0.8%) administrator preferred not to use the app. For the overall satisfaction, two (1.6%) doctors were not satisfied with the app.

The following is feedback from different occupations.

‘In the process of transferring patients, especially on the highway, there is sometimes a poor mobile phone signal, so I am worried that I cannot receive information in time’ (three doctors and two nurses from the seven non-PCI centres).

‘I recommend that a typical case discussion should be held weekly in the WeChat group. Cases with delay should be analysed to find out the reasons, so as to make improvements in the future’ (seven doctors in the non-PCI centre and one doctor in our PCI centre).

‘I hope that group members do not send information irrelevant to the treatment of patients with chest pain in the group, such as canvassing for group or individual activities, which may interfere with the timely transfer and report of the ECG’ (two doctors in our PCI centre).

‘Round-the-clock messaging occasionally interferes with my personal life, especially at night’ (five nurses).

Discussion

The WeChat group-based pre-hospital ECG transfer project was an attempt to reduce reperfusion time in STEMI patients who were transferred from a non-PCI hospital to our PCI centre. The system should provide a better link between healthcare providers in the primary hospitals that do not have PCI capabilities, the pPCI hospitals and pre-hospital emergency systems so patients with STEMI can be treated in time. Many systems can be used for the real-time transfer of ECG images, whereas these tele-ECG systems in the market were expensive and need high requirements of wireless networks which was not available in some developing and undeveloped areas. Therefore, we planned to use the free-of-charge smartphone-based app, WeChat, for transmitting the ECG images to our PCI centre and communicating with primary hospital physicians. The WeChat group application is already used by most populations in China for social communication; therefore, special training was not required to train people in using it. The app allowed unlimited images to be shared without any charge. Communication through this app was smooth and clear and images were of good quality.

The WeChat group-based tele-ECG intervention was carried out successfully in seven non-PCI hospitals that have regional cooperation with our PCI centre. Many previous studies have already reported that for patients identified with STEMI before hospital arrival, bypassing the ED with direct transport to the catheterization laboratory may shorten reperfusion times. Bypassing the ED is associated with a 20-minute time saving from FMC to wire-crossing.²⁷ The result of our research is consistent with previous studies. However, bypassing the ED can be allowed only if the pre-hospital ECG was obtained and diagnosed before patients went to the PCI hospital. Our current research confirmed the WeChat application can help with regional information sharing and pre-hospital diagnosis through remote transmission of real-time ECGs, so that STEMI patients can now bypass the ED and CCU and be sent directly to the catheterization laboratory.

When STEMI diagnosis was made in the pre-hospital setting, immediate activation of the catheterization laboratory not only reduced treatment delays but may have also reduced patient mortality. Our study indicated that FMC to catheterization laboratory activity time was significantly reduced by using the WeChat group app. Through the WeChat group, primary physicians can upload the patient's history of chest pain, ECG, biochemical test results and other information in the form of photos, so the cardiologist on duty in our PCI hospital can immediately provide a consultation, determine whether the patient needs PCI, then activate the catheterization laboratory. All relevant personnel, including interventional doctors and nurses, wait for the arrival of the patient in advance according to the dynamic changes of WeChat platform information so the time for activating the catheterization laboratory can be reduced.

Our study demonstrated a median 40-minute faster FMC to wire time and 30-minute faster door to wire time in the WeChat group. The median 40-minute reduction in FMC to wire time demonstrated in this study provided further reduction in the total reperfusion time, which might contribute to a substantial improvement in the achievement of reperfusion quality benchmark and might be associated with the reduction in mortality.

Although the use of the WeChat group had positive results in shortening the time of FMC-wire, door-wire and FMC-catheterization laboratory activity and increase the proportion of bypassing ED rate, the time between symptom onset to wire-crossing showed no significant difference between the WeChat group and control group. The main reason for this is the relatively long time from symptom onset to FMC, that is, the pre-hospital delay. Therefore, a mass education campaign and better access to ambulances are needed in the future.

Moreover, for patients presenting in a non-PCI centre, door-in to door-out time, defined as the duration between arrival of the patient at the hospital to discharge of the patient in an ambulance to the PCI centre, is a new clinical performance measure, and ≤30 min is recommended to expedite reperfusion care.⁴ The WeChat group intervention did not reduce the door-in to door-out time in our study. Patients had a median 40-min retention in the non-PCI hospital in both groups. Training programmes are needed to enhance the awareness of primary physicians in the non-PCI hospital to transfer patients with suspected STEMI as soon as possible.

Additionally, the results of our study showed there were no significant differences between the WeChat group and the control group in the incidence of left heart failure, length of hospital stay and cost of hospitalization. However, the cost per patient in the WeChat intervention group was reduced by about 3000 yuan. This part of the cost reduction is mainly related to patients bypassing the ED. The reduction of hospitalization costs benefits patients, but in China, hospitalization costs are positively correlated with the income of medical staff. When patients bypass the ED, the income of ED will also decrease, which will reduce the income of ED staff. The hospital should provide economical and policy support for the effective management of STEMI patients.²⁸

According to the guidelines for reporting of health interventions using mobile phones,²⁹ user satisfaction with the WeChat intervention was evaluated in our study in the intervention group. The majority of users were satisfied with the WeChat group app and thought the app was simple and convenient, whereas some group members thought round-the-clock transmission of information sometimes interfered with their normal life. So, in the future, measures should be taken to reduce unnecessary interference to group members’ lives, such as turning down the phone’s volume or changing the ringtone to vibrate.

The present study has some limitations. First, no participant in our study accepted thrombolysis before or during transfer. To shorten the time to treatment, thrombolysis should be administered in the pre-hospital setting if possible.⁴ Based on the results of our survey, the biggest challenge for pre-hospital thrombolytic administration was that primary physicians were worried about the risks of thrombolysis and did not have the knowledge, skills and medicine for fibrinolysis. Second, our study relied on retrospective patients’ self-reporting the symptom onset and presentation, which might introduce recall bias. To minimize such bias, we initiated the interviews as soon as the patients were stabilized. Third, the design was a single-centre, controlled, before and after study, which is a weaker design. Fourth, to better protect data safety, a dedicated ECG recorder should be used in the future to share encrypted ECG data.

Conclusion

In conclusion, pre-hospital identification of STEMI and activation of the catheterization laboratory can reduce the time taken for diagnosis and treatment of STEMI. However, remote transmission systems in the market are expensive. Therefore, our study evaluated an economical, practical, mobile application for remote transmission of pre-hospital ECG. The results of this study demonstrated that the use of a WeChat group was associated with more rapid door-to-wire, FMC-to-wire and FMC to catheterization laboratory activity times and increased the proportion of bypassing the ED and CCU in STEMI patients presenting to non-PCI capability hospitals. Primary physicians in the non-PCI capability hospitals and staffs in our PCI centre were satisfied with using this app, although there were some suggestions for improvement. Pre-hospital ECG transfer via a WeChat group is an innovative approach to accelerate the diagnosis and treatment of STEMI patients. Moreover, the app is free to use, so it will facilitate the treatment of STEMI patients in remote and underdeveloped areas.

Footnotes

Acknowledgements

The authors want to thank Shizheng-Du in the FuDan University, Irene Su in the Baker College School of Nursing and xianliang Liu in PolyU who helped us modify the grammar and spelling mistakes in our original paper.

Declaration of conflicting interests

The author(s) declared no potential conflicts of interest with respect to the research, authorship, and/or publication of this article.

Funding

The author(s) received no financial support for the research, authorship, and/or publication of this article.

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