Diagnosing heart failure with preserved ejection fraction (HFpEF) requires a combination of tests because the heart’s pumping strength looks normal on standard imaging. Unlike other forms of heart failure where the heart clearly pumps too weakly, HFpEF involves a heart that pumps fine but stiffens and struggles to fill properly. That filling problem drives up pressure inside the heart, causing fluid buildup and shortness of breath. Confirming the diagnosis typically involves blood tests, echocardiography, and sometimes invasive pressure measurements.
What Defines HFpEF
HFpEF is defined by a left ventricular ejection fraction of 50% or higher, combined with evidence that filling pressures inside the heart are abnormally elevated. Ejection fraction measures the percentage of blood the heart pumps out with each beat. In HFpEF, that number looks reassuringly normal, which is exactly what makes the condition tricky to catch. The 2022 guidelines from the American College of Cardiology, American Heart Association, and Heart Failure Society of America distinguish it from heart failure with reduced ejection fraction (40% or below) and heart failure with mildly reduced ejection fraction (41% to 49%).
A normal ejection fraction alone does not rule out heart failure. The key question is whether pressure builds up abnormally when the heart tries to fill between beats. Proving that elevated pressure exists is the central challenge of HFpEF diagnosis.
Symptoms and Physical Exam
Most people with HFpEF first notice shortness of breath during activity, fatigue that seems out of proportion, or swelling in the legs and ankles. These symptoms overlap with many other conditions, from lung disease to deconditioning, which is one reason HFpEF often goes undiagnosed for months or years.
A physical exam can reveal signs of fluid overload: elevated jugular venous pressure in the neck, a third heart sound, lung crackles, abdominal tenderness from liver congestion, and leg swelling. However, these exam findings have limited sensitivity. Lung crackles are frequently absent even when pressures inside the heart are elevated, because the lungs adapt over time by increasing lymphatic drainage. There is also significant variability between clinicians in detecting subtle signs like jugular venous pressure elevation. Overall, even a careful clinical assessment by an experienced cardiologist has an accuracy of only about 72% for identifying elevated filling pressures. That is why the diagnosis leans heavily on objective testing.
Blood Tests: Natriuretic Peptides
A blood test measuring natriuretic peptides, most commonly NT-proBNP, is one of the first steps. These proteins are released by the heart when its walls are stretched by excess pressure or volume. Elevated levels support a heart failure diagnosis, while very low levels help rule it out.
The standard rule-out threshold for NT-proBNP is 125 ng/L, but recent research shows this cutoff performs poorly in certain groups, particularly people with a BMI of 35 or higher. Fat tissue reduces natriuretic peptide levels, meaning heavier patients can have misleadingly low readings. A lower rule-out cutoff of 50 ng/L substantially improves the test’s ability to catch true cases in this group. For ruling the diagnosis in, thresholds adjusted by BMI rather than age appear to perform better.
In patients who already have atrial fibrillation, natriuretic peptide testing adds less diagnostic value. Atrial fibrillation itself stretches the heart’s upper chambers and raises natriuretic peptide levels, muddying the picture. At the same time, chronic shortness of breath in someone with atrial fibrillation already carries a high probability of HFpEF, so the blood test is less decisive in that scenario.
Echocardiography: The Core Imaging Test
An echocardiogram, or cardiac ultrasound, is the primary imaging tool. It measures ejection fraction and, critically, assesses how well the heart relaxes and fills. Several specific measurements help identify diastolic dysfunction, the hallmark of HFpEF.
The septal e’ velocity measures how quickly the heart muscle relaxes in early filling. A value below 6 cm/s indicates impaired relaxation regardless of age. The E/e’ ratio compares the speed of blood flowing into the heart with the speed of the heart wall’s relaxation. An average E/e’ ratio above 14 has high specificity for elevated filling pressures. The left atrial volume index (LAVI) measures the size of the left atrium relative to body size. A LAVI above 34 mL/m² suggests the atrium has stretched over time from chronically elevated pressures. Each of these measurements provides a piece of the puzzle, and clinicians typically look at them in combination.
When Resting Tests Are Inconclusive
Many people with HFpEF have normal or borderline filling pressures when they are sitting or lying still. Their symptoms appear only during exertion, when the stiff heart cannot keep up with the body’s increased demand for blood flow. This means a resting echocardiogram can come back looking unremarkable even though the patient is genuinely struggling.
Exercise stress echocardiography helps in these cases. The patient exercises on a stationary bike or treadmill while echocardiographic measurements are taken. In HFpEF, intracardiac pressures rise dramatically during exercise compared to healthy hearts. Clinicians look for changes in the E/e’ ratio during exertion and may also count B-lines on lung ultrasound, which indicate fluid seeping into the lungs. An increased number of B-lines during exercise correlates with higher pressures and reduced exercise capacity.
Invasive Hemodynamic Testing
Right heart catheterization remains the gold standard for diagnosing HFpEF. A thin catheter is threaded through a vein into the right side of the heart and into the pulmonary artery, where it directly measures pressures. A resting pulmonary capillary wedge pressure (PCWP) above 15 mmHg, or a peak exercise PCWP above 25 mmHg, is considered diagnostic.
This test is not performed on every patient. It is typically reserved for cases where noninvasive tests produce ambiguous results or where the clinical picture does not add up. For many people, a combination of symptoms, elevated natriuretic peptides, and clear echocardiographic abnormalities is sufficient to make the diagnosis without catheterization.
Clinical Scoring Systems
Two scoring systems help clinicians estimate the likelihood of HFpEF when the diagnosis is uncertain. The H2FPEF score assigns points based on six variables: a history of atrial fibrillation (3 points), BMI above 30 (2 points), treatment with two or more blood pressure medications (1 point), estimated pulmonary artery systolic pressure above 35 mmHg on echo (1 point), age over 60 (1 point), and an E/e’ ratio above 9 (1 point). Scores range from 0 to 9, with higher scores indicating greater probability of HFpEF.
The HFA-PEFF algorithm, developed by the European Society of Cardiology’s Heart Failure Association, takes a stepwise approach. It assigns major criteria (2 points each) and minor criteria (1 point each) across functional, morphological, and biomarker domains. A total score of 5 or more points means HFpEF is definite. A score of 1 or below makes it unlikely. Scores between 2 and 4 fall into a gray zone where exercise stress testing or invasive hemodynamic assessment is recommended to resolve the uncertainty. A final step investigates the underlying cause.
Ruling Out Conditions That Mimic HFpEF
Several conditions produce a clinical picture nearly identical to HFpEF but require very different treatment. Cardiac amyloidosis, where abnormal proteins deposit in the heart muscle and cause it to stiffen, is one of the most important mimics. Hypertrophic cardiomyopathy, constrictive pericarditis, and valvular heart disease can also look similar on initial testing.
When a specific cause is suspected, additional imaging helps sort it out. Cardiac MRI provides detailed information about tissue composition, revealing patterns of scarring or protein infiltration that echocardiography cannot detect. For suspected amyloidosis, a bone scintigraphy scan (pyrophosphate scan) can identify one of the two major types without requiring a tissue biopsy. Identifying these conditions matters because some have targeted therapies that can slow or stop disease progression, making accurate diagnosis more than an academic exercise.