A 38 year old male presents to OPD with history of progressive sholess of breath since 2 weeks.He gives past history of type II diabetes mellitus. An echocardiogram was done which revealed , an EF of 25% with anterior, septal, and lateral wall motion defects.He is admitted to the ward and stabilized on furosemide, spironolactone, bisoprolol, and ramipril. What would be the next investigation in course of management ?