What is the American Heart Association (AHA) step-wise approach for diagnosing and treating heart failure?

AHA Stepwise Approach for Heart Failure: Diagnostics and Treatment

The American Heart Association uses a four-stage progressive classification system (Stages A through D) that guides both diagnostic evaluation and treatment escalation, with each stage requiring specific interventions to prevent progression and reduce mortality. 1

Diagnostic Algorithm

Step 1: Clinical Assessment and Initial Testing

Obtain a focused history specifically documenting:

• Current and past alcohol use, illicit drugs, chemotherapy exposure, and alternative therapies that may be cardiotoxic 1, 2
• Symptoms of dyspnea, fatigue, exercise intolerance, and orthopnea 1
• Ability to perform routine and desired activities of daily living 1, 2

Physical examination must include:

• Volume status assessment: jugular venous distension, hepatojugular reflux, peripheral edema, pulmonary rales, and S3 gallop 2
• Orthostatic blood pressure changes 1, 2, 3
• Weight, height, and BMI calculation 1, 2, 3
• Displaced cardiac apex (highly specific for heart failure) 4

Mandatory initial laboratory tests:

• Complete blood count, urinalysis 1, 3
• Serum electrolytes including calcium and magnesium 1, 3
• Blood urea nitrogen, serum creatinine 1, 3
• Fasting blood glucose (or glycohemoglobin) 1
• Lipid profile 1, 3
• Liver function tests 1, 3
• Thyroid-stimulating hormone 1, 3

Step 2: Cardiac Imaging and Biomarkers

12-lead ECG is mandatory in all patients to assess for arrhythmias, conduction abnormalities, left ventricular hypertrophy, Q waves, or evidence of prior myocardial infarction. 1, 2, 3

Chest radiograph (PA and lateral) must be obtained to evaluate for cardiomegaly, pulmonary venous congestion, interstitial edema, pleural effusions, and Kerley B lines. 1, 2, 3

Two-dimensional echocardiography with Doppler is the definitive diagnostic test and must be performed to determine left ventricular ejection fraction (LVEF), assess left ventricular size, wall thickness, regional wall motion abnormalities, and valve function. 1, 2, 3 This establishes the ejection fraction-based classification:

• HFrEF: LVEF ≤40% 1, 5
• HFmrEF: LVEF 41-49% 1, 5
• HFpEF: LVEF ≥50% 1, 5

BNP or NT-proBNP measurement should be obtained when clinical diagnosis remains uncertain after initial evaluation, as normal levels make systolic heart failure unlikely. 1, 3, 4

Step 3: Coronary Artery Disease Evaluation

Coronary angiography is mandatory in patients with angina or significant ischemia unless the patient is not eligible for any form of revascularization. 1, 6, 3 This directly impacts mortality and morbidity outcomes. 6

Coronary angiography is reasonable (but not mandatory) for patients with chest pain of uncertain cardiac origin who have not had prior coronary evaluation and have no contraindications to revascularization. 1, 6

Alternative non-invasive strategies can serve as gatekeepers to angiography:

• Cardiac MRI with late gadolinium enhancement has 97% diagnostic accuracy for detecting ischemic myocardial damage 6
• Coronary CT angiography with calcium score of zero can exclude CAD and obviate need for angiography 6

Step 4: Specialized Testing (Selected Patients)

Consider screening for:

• Hemochromatosis, HIV, or sleep-disturbed breathing in selected patients 1, 2
• Rheumatologic diseases, amyloidosis, or pheochromocytoma when clinical suspicion exists 1, 2

Treatment Algorithm by Stage

Stage A: At Risk for Heart Failure

Definition: Patients with risk factors (hypertension, diabetes, obesity, metabolic syndrome, atherosclerotic disease, family history of cardiomyopathy) but no structural heart disease or symptoms. 1

Treatment priorities:

• Aggressive management of hypertension and hyperlipidemia 1
• Control of diabetes and obesity 1
• Smoking cessation and alcohol moderation 1

Stage B: Pre-Heart Failure (Structural Heart Disease, No Symptoms)

Definition: Patients with structural heart disease (LV remodeling, LVH, asymptomatic valvular disease, prior MI) but no current or prior symptoms. Includes NYHA Class I. 1

Mandatory pharmacotherapy to prevent symptomatic heart failure:

• ACE inhibitors (or ARBs if ACE-intolerant) in all patients with reduced ejection fraction 1, 3
• Beta-blockers in all patients with reduced ejection fraction 1, 3

Stage C: Symptomatic Heart Failure

Definition: Patients with structural heart disease who are currently symptomatic or have history of heart failure symptoms. Includes NYHA Classes I-IV. 1

Immediate management for fluid overload:

• Loop diuretics (furosemide) for symptomatic relief of congestion and edema 2, 3
• Monitor daily weights, strict intake/output, and clinical signs of decongestion 2
• Monitor renal function and electrolytes closely during diuresis, especially potassium and magnesium 2, 3

Guideline-directed medical therapy for HFrEF (must be initiated and titrated to target doses within 6-12 weeks):

1. Renin-angiotensin system inhibitors:

   • ACE inhibitors as first-line 1, 3, 7
   • ARBs if ACE-intolerant 1, 7
   • Angiotensin receptor/neprilysin inhibitors (ARNIs) for further mortality reduction 8, 7

2. Beta-blockers (carvedilol, metoprolol succinate, or bisoprolol) once patient is stabilized 1, 3, 7

   • Metoprolol succinate extended-release in doses of 100-400 mg once daily has been shown to reduce all-cause mortality by 34% in the MERIT-HF trial 9

3. Mineralocorticoid receptor antagonists (spironolactone or eplerenone) 8, 7

4. Sodium-glucose cotransporter-2 inhibitors (empagliflozin or dapagliflozin) to improve prognosis 10, 7

Secondary therapies for persistent symptoms:

• Digoxin for symptom control 1, 7
• Hydralazine and isosorbide dinitrate, particularly in Black patients 1, 7
• Ivabradine for heart rate control 7
• Vericiguat for worsening heart failure 7

For HFpEF specifically:

• Diuretics to relieve congestion 10
• SGLT2 inhibitors (empagliflozin or dapagliflozin) to improve prognosis 10
• Weight reduction for obesity and supervised exercise training 10

Stage D: Advanced/Refractory Heart Failure

Definition: Patients with refractory symptoms requiring specialized interventions despite maximal medical therapy. Includes NYHA Class IV. 1

Advanced interventions:

• Implantable cardioverter-defibrillators 1
• Cardiac resynchronization therapy (biventricular pacing) 1, 7
• Mechanical circulatory support 1
• Heart transplantation evaluation 1
• Palliative care 1

Critical Pitfalls to Avoid

Do not delay echocardiography as it is the definitive test to confirm heart failure and guide therapy. 2, 3

Do not assume the diagnosis without objective evidence. Always consider reversible causes such as peripartum cardiomyopathy, viral myocarditis, thyroid disease, alcohol-induced cardiomyopathy, or undiagnosed valvular disease. 2, 3

Do not perform coronary angiography in patients who are not candidates for any form of revascularization, as it provides no therapeutic benefit. 6

Monitor for adverse effects of guideline-directed medical therapy including hypotension, hyperkalemia, and worsening kidney function, which may require dosage adjustment. 7

Serial monitoring of renal function and electrolytes is essential, especially after medication dose changes. 3