A 52-year-old man with a history of hypertension and diabetes presents to the emergency department with acute onset severe chest pain radiating to the back, lasting 2 hours. His BP is 180/110 mmHg. ECG shows no ST elevation. Troponin I is normal. A stat CT angiography of the chest is ordered and shows no pulmonary embolism. However, the radiologist notes a small area of hypoattenuation in the left ventricular wall on the cardiac phase. You suspect acute myocardial injury from demand ischemia secondary to hypertensive emergency. The myocardium at this stage is still potentially salvageable. What is the most appropriate immediate next step in management?