Morphine Post-Conditioning Effect on QT Dispersion in Patients Undergoing Primary Percutaneous Coronary Intervention on Anterior Descending Cardiac Artery: A Cohort Study

INTRODUCTION: QT dispersion is the difference between the maximum and minimum QTc interval in a 12-lead electrocardiogram (ECG). Some researchers have demonstrated the effects of an increase of QT-d in STEMI and its reduction with successful therapy. The aim of this study was to investigate the morphine post-conditioning effect on the QT dispersion in patients undergoing primary percutaneous coronary intervention (PCI) on anterior descending cardiac artery. METHODS: This cohort study was conducted on STEMI patients admitted to the Hospital of Imam Reza (AS), Mashhad, Iran, from March 2015 to February 2016 who were undergoing primary angioplasty on the anterior descending cardiac artery. The patients were divided into two groups based on the intake or non-intake of morphine (5 mg morphine for the period of 30 minutes prior to PCI). Parameters, including age, gender, history of diabetes, and blood pressure as well as admission and 24 hours after PCI ejection fraction (EF) and QT-d, were recorded in all patients and compared between the two intervention and control groups. Independent and paired t-tests and chi-square test were used to compare the qualitative and quantitative data between the two groups using SPSS version 19 software. RESULTS: The present research was performed on 77 patients (61 males) with mean age of 58.71±11.84 years in the two groups of morphine consumption before PCI (n=46) and control (n=31). No statistical difference was found among the groups in age, gender, diabetes, hypertension, and onset of symptoms until primary PCI. Admission electrocardiogram QT-d value in the positive exposure group showed no significant difference with the control group, but QT-d value at 24 hours after PCI was lower in the positive exposure group than in the control group (morphine versus control: 40.32±6.98 versus 59.64±8.89; p=0.000). QT-d value 24 hours after PCI compared with the admission QT-d value was significantly reduced in both groups. The mean decrease of admission QT-d relative to QT-d 24 hours after PCI was higher in the positive exposure group than in the control group, and this difference was also statistically significant (morphine versus control: 48.65±9.95 versus 25.74±6.66; p=0.000). CONCLUSION: The findings of the current survey demonstrated that morphine consumption before PCI can further reduce QT-d value in an electrocardiogram for PCI as compared to patients who did not take morphine before PCI.