✅ Answer: C - HFrEF is defined by LVEF ≤ 40%. This patient's LVEF of 32% falls squarely in this category. HFpEF requires LVEF ≥ 50%, and HFmrEF spans 41-49%. (Goldman-Cecil Medicine, p. 479)

✅ Answer: B - Guidelines specify four foundational therapies for HFrEF: an angiotensin receptor-neprilysin inhibitor (ARNI), a β-blocker, a mineralocorticoid receptor antagonist (MRA), and an SGLT2 inhibitor. Diuretics are also required for congestion control but are not among the four mortality-reducing pillars. (Goldman-Cecil Medicine, p. 480; Braunwald's Heart Disease)

✅ Answer: C - NYHA Class III is defined by marked limitation of physical activity - the patient is comfortable at rest but symptoms arise with less-than-ordinary exertion. Class II = symptoms only with ordinary exertion; Class IV = symptoms at rest. (Braunwald's Heart Disease; Goldman-Cecil Medicine)

✅ Answer: C - The key principle of diuretic therapy in CHF is to prescribe the minimum dose needed to maintain an edema-free "dry weight," with temporary dose increases for fluid retention. Stopping the diuretic would worsen congestion. NSAIDs should be avoided as they worsen renal function in this setting. (Goldman-Cecil Medicine, p. 480)

✅ Answer: B - In patients with systolic heart failure, beta-blockers and digoxin are the preferred rate-control agents. Non-dihydropyridine calcium channel blockers (verapamil, diltiazem) are contraindicated in systolic HF as they further depress myocardial function. For rhythm control, only amiodarone and dofetilide are safe in HF (flecainide is pro-arrhythmic in structural heart disease). (Braunwald's Heart Disease, p. 533)

✅ Answer: C - Obesity reduces circulating BNP levels, which can lead to a falsely low result even when heart failure is present. In contrast, advancing age and renal dysfunction are associated with higher BNP levels. BNP is sensitive (95-99%) but less specific (50-60%) for heart failure diagnosis. (Goldman-Cecil Medicine, p. 472)

✅ Answer: D - An echocardiogram should be obtained during the initial evaluation of all heart failure patients. It assesses systolic and diastolic function, wall thickness, chamber size, regional wall motion abnormalities, and valvular dysfunction. Repeated echocardiograms are indicated for significant clinical changes, but routine repeat measurements without clinical change are not recommended. (Goldman-Cecil Medicine, p. 472)

✅ Answer: C - A history of angioedema with an ACE inhibitor is an absolute contraindication to their use. Known bilateral renal artery stenosis is another absolute contraindication. Potassium >5.0 mmol/L, creatinine ≥2.5 mg/dL, and systolic BP <90 mmHg are cautions requiring specialist advice, but are not absolute contraindications at the thresholds listed in options A, B, and D. (Goldman-Cecil Medicine, p. 480)

✅ Answer: B - Spironolactone can cause painful gynecomastia in men due to its antiandrogenic effects. Eplerenone, also a mineralocorticoid receptor antagonist (MRA), has less action on the androgen receptor and is the appropriate substitute in this situation. The clinical benefit of MRA therapy (reduced mortality and morbidity) means it should be continued in a suitable form rather than stopped. (Goldman-Cecil Medicine, p. 480)

✅ Answer: B - The only contraindications to SGLT2 inhibitors in HFrEF are type 1 diabetes, history of diabetic ketoacidosis, and severe renal dysfunction defined as eGFR <20 mL/min/1.73 m². This patient's eGFR of 18 falls below that threshold, making it a contraindication. Importantly, SGLT2 inhibitors benefit HFrEF patients regardless of diabetes status. (Goldman-Cecil Medicine, p. 480)