A pericardial fat pad is almost always harmless. It is a normal collection of fatty tissue found around the heart, present in a large proportion of the general population, and typically measures less than 5 mm. Most people discover they have one after a chest X-ray or CT scan done for an unrelated reason, and in the vast majority of cases, no treatment is needed.
That said, the size and location of fat around the heart do matter in certain contexts. Understanding the difference between a routine fat pad and something worth monitoring can help you make sense of what showed up on your imaging report.
What a Pericardial Fat Pad Actually Is
The pericardium is the double-layered sac that surrounds your heart. A pericardial fat pad sits on the outer surface of this sac, most often at the cardiophrenic angle, which is the spot where the heart meets the diaphragm on a chest image. It is composed of ordinary adipose (fatty) tissue and is supplied by non-coronary blood vessels, meaning it doesn’t share a blood supply with your heart muscle.
This is an important distinction, because there is a separate fat deposit called epicardial fat that sits directly on the heart muscle, beneath the pericardium. Epicardial fat shares the same tiny blood vessels as the heart and is metabolically active, releasing inflammatory signaling molecules that can directly affect the heart and coronary arteries. Pericardial fat, by contrast, does not have this direct paracrine connection. The two are sometimes lumped together in imaging reports, but they are anatomically, biochemically, and clinically different.
When a Fat Pad Is Just a Fat Pad
In routine clinical practice, a small pericardial fat pad is considered an incidental finding with little significance. It requires no immediate intervention. If your doctor is satisfied that the imaging appearance is consistent with fat and nothing else, the standard approach is outpatient monitoring, meaning you simply keep an eye on it at future checkups rather than pursuing any urgent workup.
Most people with a pericardial fat pad have no symptoms at all. They feel nothing, and the fat pad causes no mechanical problems for the heart. It does not compress the heart, obstruct blood flow, or interfere with the heart’s electrical system.
What Doctors Rule Out First
The reason your radiologist may have mentioned the fat pad at all is that several other things can look similar on imaging. A mass at the cardiophrenic angle could be a fat pad (the most common cause), but it could also be a pericardial cyst, a diaphragmatic hernia known as a Morgagni hernia, enlarged lymph nodes from lymphoma or metastatic cancer, a benign lipoma, or even an aneurysm.
CT imaging is especially helpful here. Fat has a characteristic low density on CT that distinguishes it from fluid-filled cysts or solid lymph nodes. When the mass contains only fat, CT can confirm it is benign, though it sometimes cannot distinguish between a prominent fat pad and a lipoma (a benign fatty tumor). Either way, both are noncancerous. If the appearance is clearly fatty and there are no other concerning features, the workup typically ends there.
A Morgagni hernia, where abdominal fat or organs push through a small opening in the diaphragm, can look identical to a fat pad on imaging when it contains only omental fat. This is worth identifying because symptomatic Morgagni hernias carry a 10 to 15 percent risk of strangulation of the herniated contents and may need surgical repair.
Excess Pericardial Fat and Heart Risk
While a small fat pad is benign, larger volumes of pericardial fat have been linked to cardiovascular problems. Research measuring pericardial fat volume on CT scans found a strong correlation between greater pericardial fat volume and more severe coronary artery narrowing (a correlation coefficient of 0.75, which is considered strong). Pericardial fat volume also correlated with coronary artery calcification, a marker of plaque buildup, and increased with age.
When doctors identify a large amount of circumferential pericardial or paracardial fat (fat surrounding the heart on multiple sides rather than sitting in one small pad), they consider additional causes such as obesity, steroid use, or other metabolic conditions that can drive excessive fat deposition.
It’s worth noting that much of the cardiovascular risk research on “heart fat” focuses specifically on epicardial fat, the layer beneath the pericardium. Epicardial fat is a proven predictor of metabolic syndrome, insulin resistance, visceral obesity, and early atherosclerosis. It acts as an endocrine organ, releasing inflammatory molecules that can promote coronary artery disease, cardiac fibrosis, and atrial arrhythmias. Pericardial fat has not been shown to have these same direct paracrine effects on the heart, because it is separated from the heart muscle by the pericardial sac. So if your report specifically says “pericardial fat pad” rather than “epicardial fat,” the risk profile is lower.
Can a Pericardial Fat Pad Cause Chest Pain?
A stable pericardial fat pad does not cause pain. However, there is a rare condition called epipericardial fat necrosis, where a portion of the fat tissue loses its blood supply and dies. This triggers sudden, sharp chest pain that worsens with breathing or changes in position. The pain is usually on the left side and can radiate to the arm or upper body, closely mimicking a heart attack or pulmonary embolism.
Epipericardial fat necrosis is often missed initially because it is relatively unknown even among radiologists. Standard cardiac tests like ECGs and troponin levels come back normal, which can be reassuring but also confusing. CT imaging reveals the telltale appearance of inflamed, necrotic fat next to the pericardium. The good news is that it is self-limiting, meaning it resolves on its own, typically with anti-inflammatory pain management. The pain can be intense and may last weeks, with intermittent episodes persisting for up to a year in some cases, but no surgery or invasive treatment is needed.
What to Do If Your Imaging Shows One
If a pericardial fat pad appeared on your chest X-ray or CT, the most likely next step is nothing. A small, clearly fatty collection at the cardiophrenic angle in an otherwise healthy person is a normal variant. Your doctor may recommend a follow-up scan at some interval to confirm it hasn’t changed, particularly if the initial imaging was ambiguous.
If you carry excess weight, the more relevant concern is likely the epicardial fat that research has linked to coronary disease and metabolic syndrome. Reducing overall body fat through sustained weight loss has been shown to decrease epicardial fat thickness, and this is one of the reasons doctors emphasize weight management for cardiovascular health. You cannot selectively target heart fat, but whole-body fat reduction brings it down along with everything else.