BACKGROUND Cardiovascular disease is a significant health problem in India with an estimate 3.7 million deaths each year. Mechanisms of myocardial ischemia include inflammation, endothelial dysfunction, platelet aggregation and coagulation. Acute coronary syndrome occurs due to rupture of atherosclerotic plaque. Platelets play a role in both development and rupture of the atherosclerotic plaque. Lymphocytes play a role in chronic inflammation of atherosclerosis. Lower lymphocyte count has increased mortality after acute myocardial infarction. METHODS The study was conducted in Department of General Medicine, Karnataka Institute of Medical Sciences, Hubli from February 2019 to December 2020. It is a prospective observational study. Patients aged ≥ 18 years with ST-elevated myocardial infarction (STEMI) were included in the study. Total 156 cases were selected based on inclusion and exclusion criteria. Cardiovascular events during the in-hospital period were noted. The study population was divided into tertiles based on the platelet-lymphocyte ratio (PLR) values. The low PLR group (n = 104) was defined as having values in the lower 2 tertiles (PLR ≤ 148.4) and the high PLR group (n = 52) was defined as having values in the highest tertile (PLR > 148.4). A ‘P’ value < 0.05 was considered statistically significant. RESULTS Out of 156 patients, 103 (66 %) were males and 53 (34 %) cases were female. Mean age group was 59 ± 10 years. Percentage of patients who underwent thrombolysis was higher in high PLR group (65.38 % vs. 48.07 %, P = 0.041). Death rate was higher in high PLR group (28.84 % vs. 8.65 %, P = 0.001). PLR > 148.4 was found to be an independent predictor of in-hospital cardiovascular mortality in multivariate analyses (hazard ratio: 13.222 (2.113-21.749) P = 0.006 with 95 % confidence interval). Receiver operating curve (ROC) analyses, a PLR value of 148.4 for in-hospital mortality rate had sensitivity of 62.5 % and a specificity of 72 % (area under the curve = 0.627, 95% confidence interval 0.485 – 0.769). CONCLUSIONS In our study, higher PLR had significant association with in-hospital mortality in patients with STEMI. KEYWORDS ST Elevation Myocardial Infarction (STEMI), Platelet/Lymphocyte Ratio (PLR), Ischemic Heart Disease (IHD)

BACKGROUND Cardiovascular diseases are one of the leading causes of morbidity and mortality worldwide. High Ca levels and low Mg levels are associated with increased cardiovascular risk in the general population.1 The balance between Ca and Mg seems to play an important role in homeostasis since Mg is considered as physiologic antagonist of Ca.2 Hence Ca/Mg ratio was considered to study its association with acute coronary syndrome (ACS). METHODS This is a case control study conducted in Karnataka Institute of Medical Sciences, Hubli over a period of 2 years, February 2019 to December 2020. 200 cases and 150 controls were included in the study. The biochemical measurements including complete blood count (CBC), cardiac biomarkers, liver function tests, renal function tests (RFT), serum electrolytes and lipid profile were measured using standard laboratory methods. Student ‘t’ test was used to compare the data. Optimum cut-offs for diagnosis of acute myocardial infarction was calculated using receiver operating characteristics (ROC) analysis. The association among markers was established by calculating Pearson’s correlation. RESULTS Serum Ca/Mg ratio was significantly higher (p value < 0.001) in ACS when compared to control groups. It was also found that Ca/Mg ratio was significantly lower (p value < 0.001) in non-ST elevation myocardial infarction (NSTEMI) when compared to STEMI group. Serum Mg was significantly lower (p value < 0.001) in ACS group when compared to control group. Significant correlation (p value < 0.05) was found between serum Ca/Mg ratio and cardiac markers (CKMB, Troponin-I). ROC analysis of Ca/Mg (4.19) ratios showed optimum cut-offs in diagnosis of AMI. CONCLUSIONS Serum Ca/Mg could be useful adjuvant marker in diagnosis of AMI. The ratio is higher in ST-segment elevation myocardial infarction when compared to non-STsegment myocardial infarction, which could be due to greater decrease in Mg levels when compared Ca in ACS. KEYWORDS ST Elevation Myocardial Infarction (STEMI), Non ST Elevation Myocardial Infarction (NSTEMI), Calcium (Ca), Magnesium (Mg), Acute Coronary Syndrome (ACS), Creatine Kinase-MB (CK-MB).