Laboratory Tests for HFpEF Patient with Atrial Fibrillation
For this patient with established HFpEF and atrial fibrillation who had imaging two months ago, the following laboratory panel should have been ordered today: complete blood count, serum electrolytes (including calcium and magnesium), blood urea nitrogen, serum creatinine, fasting blood glucose or glycohemoglobin, lipid profile, liver function tests, thyroid-stimulating hormone, and urinalysis. 1, 2
Core Laboratory Panel
The ACC/AHA guidelines mandate a comprehensive initial laboratory evaluation for all heart failure patients, regardless of ejection fraction status 1, 2. This panel addresses multiple potential contributors to both HFpEF and atrial fibrillation while guiding therapeutic decisions:
Essential Tests
Complete blood count (CBC): Identifies anemia, which worsens heart failure symptoms and affects prognosis in HFpEF patients 2
Serum electrolytes (sodium, potassium, calcium, magnesium): Critical for monitoring diuretic therapy effects and identifying disturbances that affect cardiac function and arrhythmia risk 1, 2
Renal function tests (BUN and creatinine): Essential for medication dosing (particularly ACE inhibitors, ARBs, and diuretics) and provide prognostic information 1, 2
Fasting blood glucose or glycohemoglobin: Necessary to manage diabetes, a major comorbidity in HFpEF that requires aggressive control 1, 2
Lipid profile: Assesses cardiovascular risk and guides statin therapy 1, 2
Liver function tests: Important for detecting hepatic congestion from right heart failure and for medication safety monitoring 1, 2
Thyroid-stimulating hormone (TSH): Necessary to diagnose thyroid dysfunction, which can cause or exacerbate both heart failure and atrial fibrillation 1, 2
Urinalysis: Screens for proteinuria and other renal abnormalities 1, 2
Additional Testing Considerations
Natriuretic Peptide Testing
- BNP or NT-proBNP measurement: Useful to support clinical decision-making regarding diagnosis when uncertainty exists, establish prognosis, and assess disease severity 1, 2
- In HFpEF specifically, BNP levels combined with echocardiographic filling patterns improve diagnostic accuracy 1
- A normal BNP level with completely normal diastolic parameters makes HF much less likely 1
Serial Monitoring Requirements
- Repeat electrolytes and renal function: Should be monitored when adjusting diuretic doses or other medications affecting these parameters 2
- This is particularly important in patients with atrial fibrillation on rate-control medications or anticoagulation 3, 4
Critical Pitfalls to Avoid
Do Not Skip TSH Testing
Thyroid dysfunction is a reversible cause of both heart failure and atrial fibrillation that is easily missed 2, 5. This is especially important in elderly patients with HFpEF and AF, where thyroid disease prevalence is higher 6
Include Calcium and Magnesium
These electrolytes should not be omitted from standard panels despite common practice 2, 5. They are specifically mentioned in ACC/AHA guidelines and are particularly relevant in atrial fibrillation management 1
Consider Comorbidity Burden
Patients with both AF and HFpEF frequently have multiple comorbidities including diabetes, obesity, and renal dysfunction 4, 6. The laboratory evaluation helps identify and manage these conditions, which directly impact outcomes 4
Clinical Context
Since this patient had echocardiography and chest X-ray two months ago, the focus today is on laboratory assessment to:
- Monitor disease progression and treatment effects 2
- Assess for reversible causes or exacerbating factors 1, 2
- Guide medication adjustments for both HFpEF and atrial fibrillation management 3, 4
- Evaluate comorbidities that affect prognosis in this high-risk population 4, 6
The combination of HFpEF and atrial fibrillation carries particularly high cardiovascular morbidity and mortality 3, 4, making comprehensive laboratory assessment essential for optimal management.