A life-threatening presentation of coronary artery disease is acute coronary syndrome (ACS). The major adverse cardiac events (MACE) after acute coronary syndrome include life threatening arrhythmias, cardiac failure, cardiogenic shock, recurrent ischemia and sudden death. Patients with severe and moderate LV dysfunction are more likely to have triple vessel disease. Regional wall motion abnormality assessed by regional wall motion index using 2D-echocardiography correlates with infarct size which in turn predicts the occurrence of major adverse cardiac events (MACE) in patients with acute coronary syndrome. The cause for cardiogenic shock is left ventricular pump failure due to extensive damage to the myocardium and infarct related mechanical complications. In patients admitted with acute coronary syndrome, 5% develop ventricular tachycardia or ventricular fibrillation especially after 48 hours after hospital admission. Hyperglycemia causes stronger sympathetic activation in patients with severe illness and hence increased glucose levels. Insulin resistance not only causes hyperglycemia but can also lead to reduced energy production in the heart and lower tolerance to hypoperfusion and acts as an indicator of systemic and organ specific metabolic dysregulation and also stress hyperglycemia is implicated in the activation of pathological processes that causes cellular and tissue injury like increasing free radical formation and oxidative stress, inducing prothrombotic stress and worsening endothelial function. Hence higher levels of admission time blood glucose, hypoglycaemia during hospital stay, persistent hyperglycemia are considered as poor prognostic markers in patients with acute coronary syndrome.