MRCP2-0079

MRCP2-0079

A 70-year-old woman presents to the cardiology clinic for evaluation of severe heart failure. She has a history of multiple myocardial infarctions and can only walk short distances on level ground. She experiences shortness of breath at night once or twice a week and is unable to climb stairs. Her current medications include ramipril 10 mg, furosemide 80 mg, bisoprolol 10 mg, and spironolactone 25 mg. On examination, she has bilateral chest crackles and mild ankle swelling. Her blood pressure is 100/60 mmHg, and her pulse is regular at 64 beats per minute. Laboratory results show a hemoglobin level of 117 g/L, a white cell count of 7.9 ×109/L, a platelet count of 200 ×109/L, a sodium level of 137 mmol/L, a potassium level of 5.1 mmol/L, and a creatinine level of 132 µmol/L. An ECG reveals left bundle branch block, sinus rhythm with first-degree block QRS widening (155 msec), and angiography shows 60% stenosis of circumflex. What is the best intervention to improve heart failure symptoms?