What are the diagnostic steps for a patient presenting with congestive heart failure (CHF) exacerbation and preserved ejection fraction?

Diagnostic Workup for CHF Exacerbation with Preserved Ejection Fraction

Begin with a stepwise algorithmic approach: first confirm HFpEF diagnosis using echocardiography and natriuretic peptides, then systematically exclude noncardiac and cardiac mimics through targeted testing based on clinical red flags, and finally identify contributing comorbidities that require treatment. 1

Initial Diagnostic Confirmation

Core Testing to Establish HFpEF Diagnosis

• Obtain transthoracic echocardiography to confirm EF ≥50%, assess diastolic function (E/e' ratio), left ventricular wall thickness, left atrial size, estimated pulmonary artery systolic pressure, and valvular function 1, 2

• Measure natriuretic peptides (BNP or NT-proBNP) to support the diagnosis; elevated levels in the setting of dyspnea and preserved EF strengthen the likelihood of HFpEF 2, 3

• Perform 12-lead ECG to identify atrial fibrillation, left ventricular hypertrophy, conduction abnormalities, or evidence of prior myocardial infarction 4, 5

• Obtain chest radiography to assess for pulmonary congestion, pleural effusions, cardiomegaly, and exclude alternative pulmonary causes of dyspnea 4, 5

Calculate H2FPEF Score for Diagnostic Probability

• Apply the H2FPEF scoring system (0-9 points) using: obesity (BMI >30 = 2 points), atrial fibrillation (3 points), age >60 years (1 point), treatment with ≥2 antihypertensives (1 point), E/e' ratio >9 (1 point), and pulmonary artery systolic pressure >35 mmHg (1 point) 6

• Interpret scores: 0-1 points suggests low probability of HFpEF (consider noncardiac causes), 2-5 points indicates intermediate probability (may need invasive hemodynamic testing), 6-9 points indicates high probability of HFpEF 6

Systematic Exclusion of Mimics

Rule Out Noncardiac Mimics First

The 2023 ACC guidelines emphasize that not all congestion with preserved EF is HFpEF—you must actively exclude noncardiac causes before finalizing the diagnosis. 1

• Assess for kidney disease with serum creatinine, BUN, eGFR, and urinalysis to exclude volume overload from renal failure 1, 5

• Evaluate for liver disease with liver function tests (AST, ALT, albumin, bilirubin, INR) to exclude hepatic congestion or cirrhosis with ascites 1

• Examine for chronic venous insufficiency through physical examination of lower extremities for varicosities, skin changes, and venous stasis dermatitis 1

Screen for Cardiac Mimics Based on Clinical Red Flags

The key principle: clinical context and demographic factors guide which cardiac mimics warrant specific testing—not every patient needs exhaustive evaluation. 1

High-Suspicion Features Requiring Targeted Workup

• If carpal tunnel syndrome, lumbar spinal stenosis, or unexplained neuropathy are present: obtain monoclonal protein screen (serum/urine protein electrophoresis with immunofixation) and technetium pyrophosphate scan to exclude cardiac amyloidosis 1

• If marked LV wall thickness (septum or posterior wall ≥1.5 cm) with low BMI: strongly consider cardiac MRI to evaluate for infiltrative cardiomyopathy (amyloidosis, sarcoidosis) or hypertrophic cardiomyopathy 1

• If significant valvular abnormalities on echocardiography: quantify severity and determine if valve disease is the primary driver of symptoms rather than HFpEF 1

• If pericardial thickening or calcification on imaging: pursue cardiac MRI or CT to exclude constrictive pericarditis 1

• If right ventricular dysfunction or elevated pulmonary pressures disproportionate to left heart disease: consider right heart catheterization to evaluate for pulmonary hypertension or high-output heart failure 1

Additional Laboratory Testing

• Complete blood count to assess for anemia contributing to symptoms 5

• Comprehensive metabolic panel including electrolytes (sodium, potassium), glucose, and renal function 5

• Thyroid-stimulating hormone to exclude thyroid dysfunction as a contributor 5

• Lipid panel to assess cardiovascular risk 5

• Hemoglobin A1c if diabetes is suspected or not previously diagnosed 2

Identify and Characterize Contributing Comorbidities

Once HFpEF is confirmed and mimics excluded, systematically identify comorbidities that require treatment—this directly impacts mortality and quality of life. 1, 2

• Hypertension: document blood pressure control and current antihypertensive regimen; target BP <130/80 mmHg 2

• Obesity: calculate BMI and consider weight loss strategies if BMI ≥30 kg/m² 2

• Atrial fibrillation: assess rate control, rhythm status, and anticoagulation needs 2

• Coronary artery disease: evaluate for angina or prior MI; consider stress testing or coronary angiography if ischemia suspected 1, 2

• Chronic kidney disease: stage CKD based on eGFR and monitor for progression 2

• Obstructive sleep apnea: screen with clinical history (snoring, witnessed apneas, daytime somnolence) and consider polysomnography if positive 2

• Diabetes mellitus: assess glycemic control and optimize management 2

Advanced Testing for Equivocal Cases

• Exercise echocardiography can unmask diastolic dysfunction during stress if resting echocardiogram is borderline and clinical suspicion remains high 7

• Invasive hemodynamic testing (right and left heart catheterization with exercise) is the gold standard when diagnosis remains uncertain despite noninvasive testing, particularly if H2FPEF score is intermediate 1, 6

• Cardiac MRI provides superior tissue characterization for infiltrative diseases, hypertrophic cardiomyopathy, and pericardial disease when echocardiography is inconclusive 1

Critical Pitfalls to Avoid

• Do not assume all dyspnea with preserved EF is HFpEF—the differential diagnosis is broad and includes treatable specific entities like cardiac amyloidosis that require disease-directed therapy 1

• Pay attention to clinical context: a 68-year-old man with carpal tunnel syndrome and increased LV wall thickness likely has amyloidosis, not typical HFpEF, despite identical echocardiographic findings to a patient with hypertension and obesity 1

• Avoid exhaustive testing in every patient—use history, physical examination, and basic echocardiography to guide which patients need advanced workup for mimics 1

• Do not overlook noncardiac causes—kidney failure, liver disease, and venous insufficiency can all present with edema and dyspnea but require entirely different management 1