What is the step‑by‑step approach to diagnosing heart failure?

How to Diagnose Heart Failure

The diagnosis of heart failure requires three mandatory components: typical symptoms (dyspnea, fatigue, edema), objective evidence of cardiac dysfunction on echocardiography, and an abnormal ECG or chest X-ray—a completely normal ECG makes heart failure highly unlikely (negative predictive value >90%). 1, 2

Step 1: Clinical Assessment

Evaluate specific symptoms and physical findings:

• Key symptoms to elicit: exertional dyspnea, orthopnea, paroxysmal nocturnal dyspnea, exercise-limiting fatigue, bilateral peripheral edema 1
• Critical physical signs: elevated jugular venous pressure, third heart sound (S3), hepatojugular reflux, lateral displacement of apical impulse 1, 3
• Volume status assessment: orthostatic blood pressure changes, weight, height, body mass index 3
• Detailed exposure history: alcohol use, illicit drugs, chemotherapy agents (anthracyclines, trastuzumab, cyclophosphamide), cardiotoxic medications 3

Important caveat: Symptoms alone are insufficient for diagnosis and correlate poorly with severity of cardiac dysfunction. 3, 1 A normal physical examination does not exclude heart failure. 2

Step 2: Obtain 12-Lead ECG (Mandatory First Test)

Perform a 12-lead ECG in all patients with suspected heart failure. 3, 1

• If the ECG is completely normal, seriously reconsider the diagnosis—the negative predictive value exceeds 90% for excluding left ventricular systolic dysfunction 3, 1, 2
• An abnormal ECG supports further workup but does not confirm the diagnosis 3

Step 3: Chest Radiography (PA and Lateral)

Obtain chest X-ray to identify cardiomegaly and pulmonary congestion. 3, 1

• Chest X-ray has predictive value only when combined with typical symptoms and an abnormal ECG 3, 2
• Do not rely on chest radiography alone for diagnosis 1

Step 4: Initial Laboratory Panel (Mandatory)

Order the following baseline tests in all patients: 3, 1

• Complete blood count 3
• Serum electrolytes (including calcium and magnesium) 3
• Blood urea nitrogen and serum creatinine 3
• Fasting blood glucose and glycohemoglobin 3
• Lipid profile 3
• Liver function tests 3
• Thyroid-stimulating hormone 3
• Urinalysis 3
• Fasting transferrin saturation (to screen for hemochromatosis) 3

Step 5: Natriuretic Peptide Testing (When Diagnosis Uncertain)

Measure BNP or NT-proBNP when clinical diagnosis remains uncertain after initial assessment. 1, 2

• High negative predictive value: Normal levels (BNP <35 pg/mL or NT-proBNP <125 pg/mL) make heart failure unlikely in untreated patients 2, 4
• Elevated levels indicate need for confirmatory echocardiography 1
• Pitfall to avoid: BNP may be falsely normal in obesity or heart failure with preserved ejection fraction 2

Step 6: Echocardiography with Doppler (Definitive Test)

Perform comprehensive 2D echocardiography with Doppler—this is the gold standard and mandatory for confirming heart failure. 3, 1, 2

The echocardiogram must answer three fundamental questions: 3, 2

1. Is left ventricular ejection fraction (LVEF) preserved or reduced?

   • Reduced EF: LVEF <45-50% 1
   • Preserved EF: LVEF ≥45-50% 1

2. Is left ventricular structure normal or abnormal?

   • Measure ventricular dimensions/volumes, wall thickness, chamber geometry, regional wall motion 3

3. Are there other structural abnormalities?

   • Evaluate all valves for anatomic and flow abnormalities 3
   • Assess right ventricular size and systolic performance 3
   • Measure atrial dimensions/volumes 3
   • Quantify mitral and tricuspid regurgitation severity 3

Additional hemodynamic assessment: 3

• Mitral valve inflow pattern, pulmonary venous inflow pattern, mitral annular velocity (for LV filling characteristics and left atrial pressure) 3
• Tricuspid regurgitant gradient and inferior vena cava dimension (for right-sided pressures) 3

Do not delay echocardiography—it should be performed early to guide management. 1

Step 7: Classify Heart Failure Type

Based on echocardiographic findings: 1

• Heart failure with reduced ejection fraction (HFrEF): LVEF <45-50% 1
• Heart failure with preserved ejection fraction (HFpEF): LVEF ≥45-50% with evidence of diastolic dysfunction 1

Step 8: Identify Underlying Etiology

Coronary artery disease is the most common cause (approximately two-thirds of cases with reduced EF). 3, 5

Perform coronary evaluation when indicated: 3

• Coronary arteriography is mandatory for patients with angina or significant ischemia (unless not eligible for revascularization) 3
• Coronary arteriography is reasonable for patients with chest pain of uncertain origin or known/suspected coronary disease without angina 3
• Noninvasive stress imaging (stress echocardiography or nuclear cardiology) is reasonable for detecting ischemia and viability in patients with known coronary disease 3

Screen for other etiologies based on clinical context: 3

• Valvular heart disease (assess on echocardiography) 3
• Hypertension 3
• Familial cardiomyopathy (obtain detailed family history; consider ECG and echocardiogram in first-degree relatives) 3
• Thyroid disease (TSH already obtained) 3
• HIV infection (screen in high-risk patients) 3
• Hemochromatosis (transferrin saturation already obtained; confirm with cardiac MRI if elevated) 3
• Sleep-disordered breathing 3
• Rheumatologic diseases, amyloidosis, pheochromocytoma (when clinically suspected) 3

Additional Testing in Selected Cases

Cardiac magnetic resonance imaging (CMR): 2, 4

• Use for tissue characterization, detecting infiltrative disease, or when echocardiography is technically limited 2, 4

Exercise testing: 3, 1

• Limited diagnostic value for confirming heart failure, but a normal maximal exercise test excludes the diagnosis 3, 2
• Useful for determining if heart failure causes exercise limitation when contribution is uncertain 3, 1
• Maximal exercise testing with respiratory gas exchange identifies high-risk patients for transplant evaluation 3

Pulmonary function testing: 3, 1

• Not useful for diagnosing heart failure but helpful to exclude respiratory causes of dyspnea 3, 1

Critical Pitfalls to Avoid

• Never accept heart failure as the final diagnosis—always identify the underlying etiology (ischemic, valvular, hypertensive, etc.) 3, 2
• Do not rely solely on symptoms—objective evidence of cardiac dysfunction is mandatory 1, 2
• Do not skip echocardiography—clinical assessment alone is insufficient 1, 2
• Do not ignore a completely normal ECG—this finding has excellent negative predictive value and should prompt reconsideration of the diagnosis 3, 1, 2
• Do not depend exclusively on chest radiography—its predictive value is limited without typical symptoms and abnormal ECG 3, 1, 2