Riaz-ud Din, Abdul Rehman Abid, Shahid Hameed, Muhammad Azhar.
QT interval prolongation in patients of acute ST elevation myocardial infarction.
J Cardiovascular Dis Jan ;8(3):80-4.

Objective: To determine the frequency of QT interval prolongation in patients of acute ST elevation myocardial infarction (MI). Patients and methods: This Cross sectional survey was conducted at the Department of Cardiology, Punjab Institute of Cardiology Lahore, from May to November 2009. A total of 660 cases were recruited for this study. The QT interval was measured manually from Leads II and V5, three QT intervals were measured from each lead and averaged. Where the U wave was prominent in these leads the dip or notch between T and U was taken as the end of T wave. Upper limit of QT was taken (0.44sec) in male and (0.46sec) in females. Frequency of QT prolongation was observed in patients during the early 24 hours in hospital stay. Results: The mean age of the patients was 54.9±11.9 years, mean age of the male patients was 55.3±12 years and female patients was 54.5±12.1 years. There were 524(79.4%) male patients and 136 (20.6%) female patients. There were 222(33.6%) patients with diabetes mellitus, 424(64.2%) patients had hypertension, 344(52.1%) patients were smokers, 60(9.1%) patients had hyperlipidemia and 86(13%) patients had family history of IHD. Overall 358(54.2%) patients were thrombolysed and 302(45.8%) patients were not thrombolysed. Distribution of electrolytes revealed that 152(23%) patients had below normal potassium, 36(5.5%) patients had below normal calcium and 362(54.8%) patients had below normal magnesium level.QT prolongation was observed in 450(68.2%) patients while 210(31.8%) patients had normal QT interval. In patients who were having prolonged QT 60(11.4%) were male and 36(26.4%) were female. Conclusion: QTc prolongation occurred in a significant number of patients with ST elevation MI in first 24 hours. Key words: Acute myocardial infarction; ST elevation myocardial infarction; QT interval prolongation; Coronary artery disease.

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