<prompt>  A 70-year old male patient presented to the emergency department with pain in epigastrium and difficulty in breathing for 6 hours. On examination, his heart rate was 56 beats per minute and the blood pressure was 10660 mm Hg. Chest examination was normal. The patient has been taking omeprazole for gastroesophageal reflux disease for last 6 months. What should be the intial investigation -An ECGAn upper GI endoscopyUrgent ultrasound of the abdomenAn x-ray chest 