A 70 year old male patient presented to the emergency depament with pain in epigastrium and difficulty in breathing for 6 hours. On examination his hea rate was 56 per minute and the blood pressure was 106/60 mm Hg. Chest examination was normal. The patient has been taking omeprazole for gastroesophageal reflux disease for last 6 months. What should be the initial investigation:

The patient appears to be an old patient with bradycardia and hypotension. The age is a risk factor for coronary aery disease. Chest pain can be misleading. The breathlessness and bradycardia and hypotension point towards cardiac infarction. Hence the initial evaluation at presentation should be ECG. Second-degree hea block (intermittent AV block) may occur as a transient abnormality in inferior wall MI Although many patients have a normal pulse rate and blood pressure within the first hour of STEMI, about one-fouh of patients with anterior infarction have manifestations of sympathetic nervous system hyperactivity (tachycardia and/ or hypeension), and up to one-half with inferior infarction show evidence of parasympathetic hyperactivity (bradycardia and/or hypotension).