Diagnosing heart failure with preserved ejection fraction (HFpEF) is notoriously difficult because the heart’s pumping strength looks normal on standard tests. The hallmark criterion is an ejection fraction of 50% or higher in a patient who has clear signs of heart failure, such as shortness of breath, fluid retention, or exercise intolerance. But reaching that diagnosis requires piecing together symptoms, blood tests, imaging, and sometimes invasive pressure measurements, because no single test can confirm it on its own.
Why HFpEF Is Hard to Pin Down
In most forms of heart failure, the heart muscle is too weak to pump effectively, and that weakness shows up immediately on an echocardiogram. In HFpEF, the heart pumps with normal force but is too stiff to fill properly between beats. This stiffness causes blood to back up into the lungs and body, producing the same symptoms as other heart failure types: breathlessness, swollen ankles, fatigue, and difficulty exercising. The challenge is that these symptoms overlap with dozens of other conditions, from lung disease to deconditioning to obesity.
Making matters worse, many patients with HFpEF look completely normal at rest. Their pressures and heart function only become abnormal during physical exertion, which means a standard resting exam can miss the diagnosis entirely. This is sometimes called “masked HFpEF.”
Step 1: Clinical Suspicion and Risk Factors
The diagnostic process starts with recognizing which patients are likely candidates. Hypertension is the single most common associated condition, present in roughly 75% of HFpEF patients. Other factors that raise suspicion include obesity, type 2 diabetes, chronic kidney disease (found in 20 to 30% of HFpEF patients), atrial fibrillation, sleep apnea, and age over 60. Depression, anemia, chronic lung disease, and high cholesterol are also frequently seen alongside HFpEF and are independent risk factors for developing heart failure.
If you have several of these conditions and you’re experiencing unexplained breathlessness or fluid retention, your doctor’s index of suspicion for HFpEF should be high.
Step 2: Blood Tests for Natriuretic Peptides
The first objective test is usually a blood draw measuring NT-proBNP, a protein released when the heart is under stress. European guidelines use a threshold of 125 ng/L to trigger further workup in outpatient settings, while UK (NICE) guidelines use 400 ng/L. Below these levels, heart failure is considered unlikely.
These thresholds are better at ruling heart failure out than ruling it in. At the 125 ng/L cutoff, 95% of people who test below that level truly do not have significant heart dysfunction. But only about 52% of people who test above it actually have it. At the higher 400 ng/L cutoff, the positive predictive value rises modestly to 57%. This means an elevated NT-proBNP alone isn’t enough for a diagnosis. It’s a screening gate that determines whether you need an echocardiogram.
For acute settings, age-adjusted cutoffs apply: 450 pg/mL for people under 50, 900 pg/mL for those 50 to 75, and 1,800 pg/mL for those over 75. Atrial fibrillation also raises NT-proBNP levels independently, which can complicate interpretation.
Step 3: Echocardiography
A comprehensive echocardiogram is the cornerstone of HFpEF diagnosis. The first thing it confirms is that the ejection fraction is 50% or higher, which separates HFpEF from heart failure with reduced pumping strength. But the exam goes much further, looking for signs that the heart is stiff and filling pressures are elevated.
The key measurements include:
- E/e’ ratio: This compares how fast blood flows into the heart with how fast the heart muscle relaxes. An average E/e’ above 14 suggests elevated filling pressures.
- Left atrial volume index: A left atrium larger than 34 mL/m² indicates chronic pressure overload, since the left atrium stretches over time when the ventricle is stiff.
- Tricuspid regurgitation velocity: A value above 2.8 m/s suggests elevated pressures in the lung circulation.
- e’ velocity: The speed at which the heart muscle relaxes early in filling. Values below 7 cm/s on the septal side or below 10 cm/s on the lateral side indicate impaired relaxation.
Diastolic dysfunction is typically diagnosed when at least three of these four criteria are abnormal. The echocardiogram also assesses heart wall thickness, overall heart mass, and how well the muscle contracts along its length (global longitudinal strain), all of which can be altered in HFpEF even when the ejection fraction looks normal.
Using Clinical Scoring Systems
Because no single test is definitive, two validated scoring systems help doctors weigh all the evidence together.
The H2FPEF Score
This six-variable tool was developed specifically to diagnose HFpEF in patients with unexplained breathlessness. Each letter in the name corresponds to a risk factor or finding, and each is assigned points:
- H (Heavy): BMI above 30 scores 2 points
- H (Hypertension): Use of two or more blood pressure medications scores 1 point
- F (atrial Fibrillation): Any history of atrial fibrillation, whether persistent or intermittent, scores 3 points
- P (Pulmonary hypertension): Pulmonary artery systolic pressure above 35 mmHg scores 1 point
- E (Elderly): Age over 60 scores 1 point
- F (Filling pressure): E/e’ ratio above 9 scores 1 point
Higher totals indicate greater likelihood of HFpEF. Notice that atrial fibrillation carries the most weight at 3 points, reflecting its strong association with the condition.
The HFA-PEFF Algorithm
The European Society of Cardiology’s Heart Failure Association developed a four-step process. The second step combines echocardiographic measurements and natriuretic peptide levels into a point-based score, with major criteria earning 2 points and minor criteria earning 1 point. A total of 5 or more points makes HFpEF definite. A score of 1 or below makes it unlikely. Scores in between (2 to 4) fall into a gray zone that requires further testing.
Step 4: Exercise Testing for Borderline Cases
Many patients fall into that gray zone because their heart looks normal at rest. For these people, exercise stress testing can unmask the problem. This can be done with a stress echocardiogram, where ultrasound images are taken while you exercise on a bike or treadmill, looking for filling pressures that rise abnormally with exertion.
The most definitive version is invasive hemodynamic exercise testing, where a catheter is placed into the heart to directly measure pressures. At rest, a pulmonary capillary wedge pressure of 15 mmHg or higher confirms overt HFpEF. If resting pressures are normal (below 15 mmHg) but rise to 25 mmHg or higher during exercise, the diagnosis is masked HFpEF. This test is considered the gold standard, but it’s invasive and not available everywhere, so it’s typically reserved for cases where noninvasive testing hasn’t provided a clear answer.
Ruling Out Conditions That Mimic HFpEF
Several serious conditions look almost identical to HFpEF on initial evaluation and require different treatment. These include cardiac amyloidosis (where abnormal proteins stiffen the heart), hypertrophic cardiomyopathy, severe valve disease, pericardial effusion (fluid around the heart), and precapillary pulmonary hypertension (high lung pressures from a lung problem rather than a heart problem). End-stage kidney failure can also mimic the syndrome.
Research on HFpEF trial populations has found that when these mimics are carefully excluded, the number of patients with “pure” guideline-defined HFpEF drops dramatically, with one analysis finding fewer than 10% of initially suspected cases remained after thorough evaluation. This underscores why the diagnostic workup needs to go beyond confirming HFpEF and also actively look for alternative explanations.
Cardiac MRI for Deeper Tissue Analysis
When echocardiography leaves questions unanswered, cardiac MRI provides a more detailed look at heart structure and tissue composition. It’s particularly useful for detecting myocardial fibrosis, the scarring and stiffening of heart muscle that drives much of HFpEF’s pathology.
Two MRI techniques are especially relevant. Late gadolinium enhancement detects focal areas of scarring, such as those caused by a previous heart attack or an infiltrative disease like amyloidosis. T1 mapping goes further by detecting diffuse fibrosis spread throughout the heart muscle, which is the more typical pattern in HFpEF. By measuring how the tissue responds to a contrast agent, T1 mapping can quantify the extracellular volume fraction, essentially telling doctors how much of the heart wall is fibrous tissue versus healthy muscle. These findings help confirm HFpEF, gauge its severity, and identify specific underlying causes that might otherwise go undetected.