Objective: To determine the frequency of hyponatremia and itsassociation of with associated factors and its impact on in-hospital outcome in patients with acute ST elevated myocardial infarction.

Study Design:AnalyticalStudy.

Study Setting: Study was conducted at Aga Khan University Hospital, Karachi (AKUH).

Subjects and Methods: This is an analytical study conducted at Aga Khan University Hospital, Karachi (AKUH) between the period of 2016 to 2017.Informed consent to enroll and use data of patients was obtained from all the 225 patients before commencing the study. All patients of age between 20 to 75 years of either gender diagnosed with ST elevation acute myocardial infarction in emergency or outpatient department were enrolled in the study.Hyponatremia was labelled as serum sodium level less than 135mEq/L (Normal is 135-145mEq/L).A detailed history was taken followed by complete examination at admission.In hospital outcomes were measured within 72 hours of admission. Report was collected and findings were noted in the Performa.Data was analyzed on SPSS Version 16.

Results:A total of 225 patients admitted in Department of Cardiology, Aga Khan University Hospital, Karachi were included in this study. Mean age in our study was 56.80±7.56 years.135 (60%) were male and 90 (40%) were female. Out of 225 patients, 43 (19.1%) had hyponatremia and 182 (80.9%) did not have hyponatremia. In-hospital mortality was 22 (100%) who had hyponatremia.

Conclusion:The results showed that hyponatremia has very strongly association with in-hospital mortality. Cardiovascular mortality among patients with acute STElevationmyocardial infarction. Plasma sodium levels may serve as a simple marker to identify patients at risk.

Key Words: Acute ST elevated myocardial infarction,Hyponatremia, in-hospital mortality, associated factors.