Heart Failure: Given the patient's history of hypertension and symptoms of shortness of breath and fatigue, heart failure is a highly plausible diagnosis. Hypertension is a significant risk factor for the development of heart failure, and the symptoms presented are classic for this condition.

Chronic Obstructive Pulmonary Disease (COPD): Although not directly linked to hypertension, COPD is a common cause of shortness of breath in older adults, especially if the patient has a history of smoking.
Anemia: Fatigue is a prominent symptom of anemia, and shortness of breath can occur if the anemia is severe enough to reduce oxygen delivery to tissues.
Diabetes with Cardiac Involvement: Diabetes can lead to heart failure and also cause fatigue due to high blood sugar levels and potential renal involvement.

Pulmonary Embolism: Although less likely, pulmonary embolism is a life-threatening condition that can present with sudden onset of shortness of breath and fatigue. It's crucial to consider this diagnosis to avoid missing a potentially fatal condition.
Cardiac Ischemia/Myocardial Infarction: The patient's symptoms could also be indicative of cardiac ischemia or myocardial infarction, especially if there's a history of coronary artery disease or risk factors such as hypertension.
Pneumonia: An infection like pneumonia could cause these symptoms, especially in an older adult, and requires prompt treatment to prevent serious complications.

Amyloidosis: A rare condition that can affect the heart, leading to heart failure, and cause fatigue due to its systemic effects.
Sarcoidosis: Although rare, sarcoidosis can affect the lungs and heart, leading to symptoms of shortness of breath and fatigue.
Hemochromatosis: A genetic disorder leading to iron overload, which can cause heart failure and fatigue among other symptoms, but is less common and would require specific diagnostic testing to identify.