Most heart conditions will not be seen on a chest X-ray. The heart is seen on every chest X-ray but there is usually not enough detail seen to provide a specific diagnosis. We can sometimes see clues to a heart condition being present. Heart conditions are best diagnosed with dedicated tests like electrocardiograms, echocardiograms, and MRI.
What do chest X-rays tell us about the heart?
Chest X-rays can show us the shape of the heart, how big it is and it’s position in the chest. We can’t see the heart chambers, the valves separating chambers or the arteries feeding it. We can not determine if the heart rhythm is normal or abnormal. We can not usually see fluid around the heart directly.
We can sometimes see fluid in the lungs when there is heart failure. We may see fluid in the pleural space or the space around the lungs. We can see that the blood vessels in the lung will be enlarged in the upper lungs. We will also sometimes see a big heart. An ultrasound of the heart or echocardiogram can provide a detailed look at the heart and provide a cause in some cases.
Fluid around the heart
A pericardial effusion is fluid around the heart. We can not see the fluid directly around the heart. This is because the fluid and heart have the same density. Fluid and heart tissues both look white and blend together. The heart may look bigger then usual because of fluid. But we can not be sure it’s fluid because sometimes the heart itself gets bigger. A CT or echocardiogram can diagnose fluid around the heart.
An enlarged heart or cardiomegaly has many causes. Usually radiologists just eye ball the size based on their experience. An enlarged heart has numerous causes. These can include: heart failure, high blood pressure, lung disease, diseases of the heart valves, conditions of the heart you are born with in addition to others. We can not usually tell the cause of the enlarged heart from a chest X-ray alone.
Enlargement of heart chambers
We can also sometimes see specific chambers of the heart enlarged on a chest X-ray. The heart consists of the right and left atrium and ventricles. Enlargement of the heart chambers can be seen because of multiple conditions like valve disease, heart rhythm disturbances and conditions of heart structure you are born with. This can be difficult to diagnose on chest X-ray but can sometimes be seen because of an abnormal heart outline.
Most heart conditions can not be diagnosed with a chest X-ray. But given how common chest X-rays are, we can sometimes see clues to a heart conditions. Often this will need further testing. This is often done with echocardiograms or ultrasounds of the heart. Heart specialists or cardiologists may also offer additional testing for suspected heart conditions.