Abstract
Aim. This study was carried out to compare the effect of trinitroglycerin (TNG) spray and sublingual pearl on chest pain severity and some physiological indices of people with chest pain visited by emergency medical services.
Background. Glyceryl trinitrate is used as an anti-anginal vasodilating agent with various forms including spray and pearl with probable different therapeutic effects.
Method. In this quasi-experimental study, 80 patients with chest pain were recruited through convenience sampling and then allocated to pearl and spray groups by minimization method. After arriving at the patient's bedside, vital signs and chest pain severity were measured and recorded, then the drug was administered every 5 minutes for 3 times; thereafter, the measurements were repeated. The data analyzed in SPSS software 1) using descriptive and inferential statistics.
Findings. The results showed that after intervention, the mean score of pain in pearl and spray groups were 6.05±0.98 and 5.60±1.25, respectively. There was no statistically significant difference between groups in terms of pain score. Whereas after intervention, the mean systolic and diastolic pressure in pearl group was significantly lower than the spray group, the heart rate in both groups were increased.  
Conclusion. Nitroglycerin in the pearl form has the same effect as spray form in relieving chest pain. According to the circumstances and drug accessibility, emergency staff might use every two forms of Nitroglycerin.

Abstract
Aim. This review study aims to investigate the impact of reducing Door-to-ECG (DTE) time on on morbidity and mortality of patients with chest pain referred to emergency department.
Background. Chest pain is the second most common reason for referral to an emergency unit. According to American Heart Association, all patients with chest pain presenting to the emergency ward should be approached with an ECG within 10 minutes of entrance to the emergency department. This is considered as the first line of diagnostic tests for myocardial infarction.
Method. In this narrative review study, several databases and search engines including SID, Pub Med, Google Scholar, Web of Science and Scopus were used to find the articles published between 2000 and 2018. The keywords used to search articles were “Door to ECG”, “chest pain”, “emergency unit” and “triage”. The articles selected for review were interventional or descriptive in terms of design, in Persian or English, with available full text. The criterion for selecting articles was the similarity of the their subject with the search keywords including Door to ECG (DTE) time and triage and their value in the early diagnosis and treatment of coronary disorders.
Findings. A total of 20 articles were found. After removing the articles that didn’t meet the inclusion criteria, 11 articles related to the subject of the study remained in review. The significant outcomes of timely triage, appropriate time to perform ECG, barriers to access and suggestions for faster treatment by the system especially the role of nurses, were investigated.
Conclusion. The reduction of triage time and Door to ECG (DTE) time as well as the role of the nurse in those cases are associated with a reduction in the morbidity and mortality of cardiac patients.

Abstract
Aim. The present study aims to determine the performance of “Tehran 115 medical emergency” dispatchers in providing services to patients with chest pain.
Background. Chest pain is one of the most common problems for which individuals call medical emergency services. The pace, accuracy, and integration of services by medical emergency dispatchers are highly important to decrease mortality and disability rates.
Method. A cross-sectional descriptive study was carried out on 397 voice records of 80 dispatchers in “Tehran 115 medical emergency services” about chest pain in January 2019. Data gathering was done using the Dispatcher Performance Assessment Checklist. All the obtained scores by the checklist were analyzed in SPSS (V.22).
Findings. All voice records demonstrated an acceptable performance of the dispatchers. The mean score of performance in consultation section was 18±2.66 ranged from 9 to 20. The mean score of performance in key questions section was 35.95±2.16 with a score range from 28 to 38. The total mean score of performance was 53.95±3.57 with a score range from 43 to 58. In addition, employment status (P=0.039) and work experience (P=0.020) were significantly related to dispatchers’ performance in terms of assessing chest pain.
Conclusion. Assessment according to the checklist items and provision of proper consultation services to the patients and patient companions by the 115 dispatchers resulted in a better and timely diagnosis, faster dispatch of ambulance, less damages sustained by heart patients, and prevention of death. The findings emphasized on the necessity of adhering to the questions algorithm and uniform work procedure by dispatchers nationwide. This should be an integral part of telephone triage. Observation of national standard prevents probable damages to patients due to wrong or personalized decision making.

Abstract
Aim. This study aimed at examining the convergence of calculated HEART pathway by physician and nurse along its utility to predict the 3-month occurrence of major adverse cardiac even (MACE) in patients with chest pain admitted to emergency department (ED).
Background. The HEART pathway is a tool to predict MACE in patients with chest pain admitted to ED, to help risk stratification for early discharge and reduce unnecessary cardiac tests.
Method. In the present study, a diagnostic tool was evaluated. Ninety-seven ED patients with acute chest pain, hospitalized in Rajaie Cardiovascular Medical and Research Center, were recruited prospectively. Risk stratification was performed by an ED nurse, a cardiology resident, and a cardiology attending physician. The correlation and the 3-month MACE outcomes were analyzed. 
Findings. Pairwise agreements were excellent between the raters. The Intraclass Correlation Coefficient (ICC) among raters were 0.84 (95% CI: 0.73–0.97) and thus, overall agreement was excellent. The HEART pathway score showed a high predictive power (AUC: 0.85 for 3-month MACE). For a cut-off score of 4, sensitivity, specificity, and negative predictive values were 87.5, 58.9, and 95.8 percent, respectively.
Conclusion. The HEART pathway score predicted effectively 3-month MACE in patients with acute non-traumatic chest pain. The high agreement among the three different raters suggests that nurses might use efficiently the score.