Tehran University Medical Journal

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Background: For the purpose of ascertaining myocardial infarction (MI) and ischemia, the sensitivity of the initial 12-lead ECG is inadequate. It is risky to diagnose posterior MI using only precordial reciprocal changes, since the other leads may be more optimally positioned for the identification of electrocardiographic changes. In this study, we evaluated the relationship between electrocardiography changes and wall motion abnormalities in patients with posterior MI for earlier and better diagnosis of posterior MI.
Methods: In this prospective cross-sectional study, we enrolled patients with posterior MI who had come to the Emergency Department of Shariati Hospital with their first episode of chest pain. A 12-lead surface electrocardiogram using posterior leads (V7-V9) was performed for all participants. Patients with ST elevation >0.05 mV or pathologic Q wave in the posterior leads, as well as those with specific changes indicating posterior MI in V1-V2, were evaluated by echocardiography in terms of wall motion abnormalities. All data were analyzed using SPSS and p<0.05 were considered statistically significant.
Results: Of a total 79 patients enrolled, 48 (60.8%) were men, and the mean age was 57.35±8.22 years. Smoking (54.4%) and diabetes (48%) were the most prevalent risk factors. In the echocardiographic evaluation, all patients had wall motion abnormalities in the left ventricle and 19 patients (24.1%) had wall motion abnormalities in the right ventricle. The most frequent segment with motion abnormality among the all patients was the mid-posterior. The posterior leads showed better positive predictive value than the anterior leads for posterior wall motion abnormality.
Conclusion: Electrocardiography of the posterior leads in patients with acute chest pain can help in earlier diagnosis and in time treatment of posterior MI.

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Background: In patients with ST-segment elevation myocardial infarction (STEMI), Primary percutaneous coronary intervention (PCI) is the preferred reperfusion therapy. Timely primary PCI is essential in improving the clinical outcomes of these patients. The aim of this study was to evaluate the factors affecting balloon delay in STEMI treated patients by primary PCI and its relationship with major adverse cardiac events (MACE).
Methods: This prospective observational study was conducted on 143 cases of STEMI patients, who had the inclusion criteria and were treated by primary PCI, after obtaining written consent in Imam Khomeini hospital in Ahvaz, between May 2019 to May 2020. All-time components from symptom onset to PCI treatment include symptom-to-balloon time or ischemic time, symptom-to-door time and door-to-balloon time calculated. The incidence of major adverse cardiovascular events (MACE) including decompensated heart failure (DHF), acute coronary syndrome (ACS), sudden cardiac death (SCD) and cerebrovascular accident (CVA) was evaluated during 12 months follow up after primary PCI. left ventricular ejection fraction (LVEF) changes were evaluated 3 months after primary PCI.

Results: The median symptom-to-door time was 200.5 minutes (IQR: 90-438.75 min), the median ischemic time was 406 minutes (IQR: 231-671 min), and most patients had an ischemic time ≥120 minutes (92.4%) and door-to-device time ≥90 minutes (64.3%). The most common delay for treatment was in the symptom-to-door time (76.9%) and then the decision for primary PCI to transfer to the cat lab (17.5%). Overall, 59 (41.3%) of the patients experienced MACE during 1-year of follow-up, including ACS (13.3%), DHF (22.4%), cardiac death (9.8%) and CVA (2.1%). The patients age (OR: 0.96, P=0.020), LVEF changes (OR: 1.123, P=0.005) and STEMI type (OR: 0.705; P=0.039) predicted in-hospital MACE, while the symptom-to-balloon time (P=0.607) and door-to-balloon time (P=0.347) were not associated with MACE. Conclusion: None of the time intervals were associated with the occurrence of MACE in one-year follow-up, and most STEMI patients were admitted to the hospital with a long delay. Therefore, efforts to shorten the time of hospitalization admission can help improve the MACE in STEMI patients under primary PCI in our medical centers.