What are the American Heart Association guideline‑recommended treatments for chronic heart failure with reduced ejection fraction (≤40%) across NYHA classes?

Heart Failure with Reduced Ejection Fraction (≤40%): AHA Guideline-Directed Medical Therapy

All patients with HFrEF (LVEF ≤40%) should receive simultaneous quadruple therapy consisting of ARNI/ACEi/ARB, beta-blocker, mineralocorticoid receptor antagonist, and SGLT2 inhibitor, regardless of NYHA class, to reduce mortality and hospitalization. 1

Foundational Four-Pillar Pharmacotherapy

Pillar 1: Renin-Angiotensin System Inhibition

First-Line ARNI Therapy:

• ARNI (sacubitril/valsartan) is the preferred first-line agent for NYHA class II-III patients to reduce morbidity and mortality. 1
• Start ARNI at low dose and uptitrate every 2-4 weeks to target dosing. 2

ACE Inhibitor Alternative:

• When ARNI is not feasible, use ACE inhibitor (enalapril 10-20 mg twice daily, lisinopril 20-40 mg daily, or ramipril 10 mg daily as target doses). 1, 3
• Initiate at low dose and uptitrate every 1-2 weeks while monitoring blood pressure, creatinine, and potassium after each increase, then at 3 months and every 6 months. 3
• Withhold or reduce loop diuretics for 24 hours before starting ACE inhibitor to prevent first-dose hypotension. 2, 3

ARB for ACE Inhibitor Intolerance:

• Switch to ARB (valsartan or candesartan) if ACE inhibitor causes intolerable cough or angioedema. 1, 3

Pillar 2: Beta-Blocker Therapy

• Use one of three evidence-based beta-blockers: bisoprolol, carvedilol, or sustained-release metoprolol succinate. 1
• Initiate only after the patient is euvolemic and stable on ACE inhibitor/ARNI therapy. 2, 3
• Start at very low doses (bisoprolol 1.25 mg daily, carvedilol 3.125 mg twice daily, metoprolol succinate 12.5-25 mg daily) and uptitrate every 1-2 weeks using a "start-low, go-slow" approach. 3, 4
• Target doses: bisoprolol 10 mg daily, carvedilol 50 mg daily, metoprolol succinate 200 mg daily. 3
• If worsening symptoms occur during titration, first increase diuretics or ACE inhibitor before reducing beta-blocker dose. 4

Pillar 3: Mineralocorticoid Receptor Antagonist (MRA)

• Add spironolactone or eplerenone for NYHA class II-IV patients if eGFR >30 mL/min/1.73 m² and serum potassium <5.0 mEq/L. 1
• Start spironolactone 25 mg daily after optimizing ARNI/ACEi and beta-blocker. 2, 3
• Greatest mortality benefit occurs in NYHA class III-IV patients. 3
• Check potassium and creatinine 4-6 days after initiation; reduce dose by 50% or discontinue if potassium ≥5.5 mmol/L. 3, 4
• Avoid concurrent potassium supplements or potassium-sparing diuretics. 2, 3

Pillar 4: SGLT2 Inhibitor

• SGLT2 inhibitors reduce cardiovascular death and heart failure hospitalization regardless of diabetes status and should be initiated early. 1
• Benefits are consistent across NYHA class II and III/IV, with greater symptom improvement in more advanced classes. 5

Diuretic Management for Congestion

• Loop diuretics (furosemide 20-40 mg daily initially) are required for pulmonary congestion or peripheral edema and must be combined with ACE inhibitor/ARNI. 2, 3
• Titrate to the lowest dose that achieves euvolemia. 3
• If inadequate response, increase loop diuretic dose, split dosing twice daily, or add thiazide-type diuretic. 3
• Avoid thiazides when eGFR <30 mL/min unless used synergistically with loop diuretic. 2, 3
• For severe refractory fluid retention, add metolazone with close electrolyte and renal monitoring. 3

Device Therapy by NYHA Class

Cardiac Resynchronization Therapy (CRT)

NYHA Class III-IV:

• CRT-P/CRT-D is Class I recommendation for patients in sinus rhythm with QRS ≥120 ms, LBBB morphology, and LVEF ≤35% who are expected to survive >1 year with good functional status. 6
• For non-LBBB morphology, CRT should be considered if QRS ≥150 ms (Class IIa). 6

NYHA Class II:

• CRT (preferably CRT-D) is Class I recommendation for patients in sinus rhythm with QRS ≥130 ms, LBBB morphology, and LVEF ≤30%. 6
• For non-LBBB morphology, CRT should be considered if QRS ≥150 ms and LVEF ≤30% (Class IIa). 6

Implantable Cardioverter-Defibrillator (ICD)

• ICD is recommended for primary prevention in patients with LVEF ≤35% despite ≥3 months of optimal medical therapy, NYHA class II-III, and expected survival >1 year. 7, 2
• Do not implant ICD within 40 days of myocardial infarction as it does not improve prognosis during this period. 7, 2
• ICD combined with CRT can be considered for NYHA class III-IV with LVEF ≤35% and QRS ≥120 ms. 7

Monitoring Protocols

ACE Inhibitor/ARNI Monitoring:

• Check blood pressure, creatinine, and potassium 1-2 weeks after each dose increase, at 3 months, then every 6 months. 2, 3
• Discontinue if substantial decline in renal function occurs. 2, 3

Beta-Blocker Monitoring:

• Monitor for worsening heart failure symptoms, fluid retention, hypotension, and symptomatic bradycardia during titration. 3, 4
• Adjust diuretic or ACE inhibitor doses before reducing beta-blocker if adverse effects arise. 3

MRA Monitoring:

• Repeat potassium and renal function 4-6 days after initiation and after any dose change. 3, 4

Critical Medications to Avoid

• NSAIDs worsen renal function, promote fluid retention, and blunt ACE inhibitor effects. 2, 3
• Avoid diltiazem and verapamil as they worsen heart failure and increase hospitalization risk. 2
• Do not combine ACE inhibitor with ARB and MRA due to increased risk of renal dysfunction and life-threatening hyperkalemia. 2

Forced-Titration Strategy

• Landmark trials demonstrated mortality benefits only when drugs were uptitrated to target doses using forced-titration protocols; sub-target dosing has not shown mortality advantage. 3
• Continue uptitration until target dose is reached or intolerable adverse events occur; asymptomatic laboratory changes should not halt progression. 3
• If medication must be temporarily discontinued, reinstate and titrate back to target dose as soon as clinically feasible. 3

Adjunctive Therapies

Digoxin:

• Indicated for atrial fibrillation with symptomatic HF to control ventricular rate (0.125-0.25 mg daily). 3, 4
• May improve clinical status in sinus rhythm patients with persistent symptoms despite optimal therapy. 3

Hydralazine-Isosorbide Dinitrate:

• Recommended for African-American patients with NYHA class III-IV symptoms despite optimal therapy. 3
• Alternative when both ACE inhibitors and ARBs are contraindicated. 3

Duration of Therapy

Guideline-directed medical therapy must be continued indefinitely, even if LVEF improves or symptoms resolve, as discontinuation frequently causes relapse of left-ventricular dysfunction and heart failure symptoms. 3