Chronic Dyspnea in a Patient With Stable CHD
A 72-year-old man has ongoing dyspnea on exertion since his non-ST-segment elevation myocardial infarction (NSTEMI) 1 year ago. At the time of his NSTEMI, he had an 80% left anterior descending artery lesion that was stented and minor disease elsewhere. He finds he gets short of breath when he walks on any incline but is fine on the flat. The dyspnea is not getting any worse over time, but he is worried that his shortness of breath means that he has something wrong and is too worried to exercise. He has no orthopnea, paroxysmal nocturnal dyspnea, ankle swelling, or angina. His risk factors for heart disease include that he is an ex-smoker for some years with a 20-year pack history of smoking, hypertension, and dyslipidemia. These have been well-managed since his NSTEMI. He is on dual antiplatelet treatment (aspirin 81 mg daily and clopidogrel 75 mg daily), atorvastatin 80 mg daily, ramipril 2.5 mg daily, and metoprolol CD 47.5 mg daily.
On examination, you notice that he looks frailer, and he admits to being more sedentary since his heart attack. His body mass index is 29 kg/m2, his blood pressure is 128/70 mmHg, and his heart rate is 65 bpm sinus rhythm. His chest is clear, he has no murmurs, and there is no clinical indication of failure. His hemoglobin is 147 g/dL, B-type natriuretic peptide and thyroid function tests are normal, and he has stage II chronic kidney disease. An exercise stress echocardiogram shows structurally normal heart and a left ventricular ejection fraction of 55% with mild diastolic dysfunction and normal pulmonary artery pressure. He has an appropriate chronotropic response to exercise. He felt short of breath in early stage 2 of the normal Bruce protocol, but there were no arrhythmia or electrocardiographic changes of ischemia. Lung function tests show mild chronic obstructive pulmonary disease (COPD) (FEV1 88% predicted). Diffusing capacity of the lungs for carbon monoxide is normal, and there is no response to salbutamol. A chest X-ray was normal.
What intervention is likely to be the most beneficial to the patient?