Acute Pericarditis: The Painful Inflammation Around Your Heart That Mimics a Heart Attack
Updated: 2 days ago
Medically reviewed by Dr. Baraa Alnahhal, MD · Last reviewed: September 2026
Acute pericarditis is painful inflammation of the pericardium — the fluid-filled, double-layered pouch surrounding your heart. The pain typically worsens when lying down and improves when sitting up or leaning forward, and it builds quickly, reaching full strength within one to two hours. It is usually not dangerous on its own and is almost always treatable, with most people recovering within one to three weeks. But it mimics a heart attack and can lead to cardiac tamponade — fluid crushing the heart, deadly within minutes — so chest pain should always be treated as a medical emergency. It accounts for about 5% of all ER chest pain visits.
Quick Answer
What it is: Acute pericarditis is painful inflammation of the pericardium, the fluid-filled pouch that surrounds the heart, holds it in place, and reduces friction with a thin fluid layer. The pain usually gets worse when lying down or breathing in.
The key symptom: Chest pain with fast onset (reaches full strength in 1–2 hours), which may feel sharp or dull, radiates to nearby areas, and gets better when sitting up or leaning forward. It closely mimics heart attack pain — so treat it as an emergency and seek care right away.
How it is diagnosed: Diagnosis requires two or more of five findings — chest pain, a pericardial friction rub heard with a stethoscope, electrical changes on an ECG, new or growing fluid around the heart, and pericardium inflammation seen on cardiac MRI or blood work.
How it is treated and what to expect: NSAIDs like ibuprofen and aspirin are the first-line treatment, often combined with colchicine; steroids and biologics follow if needed; pericardiocentesis drains fluid, and surgery removes the pouch in rare cases. Most people feel better within 1–3 weeks, though full recovery can take months, and 20%–50% may experience it more than once.
What Is Acute Pericarditis?
Acute pericarditis is painful inflammation of the pericardium, the fluid-filled pouch surrounding your heart. The pain usually gets worse when you are lying down or when you breathe in. Depending on the cause, it is almost always treatable, and most people with this condition recover with few or no complications.
While it is usually not dangerous on its own, acute pericarditis shares symptoms with a heart attack. That means you should not ignore symptoms and should get medical care right away if you have them.
What Is the Pericardium?
The pericardium is a double-layered pouch inside your chest. It holds your heart in place, and a thin layer of fluid between the heart and the inside layer reduces friction. It provides cushioning and support to protect the heart from outside movement.
Interestingly, you do not need a pericardium to survive. Many people are either born without one or have theirs removed with surgery and continue to live healthy lives.
How Does Acute Pericarditis Affect the Body?
Under normal circumstances, the pericardium has enough room inside it for the heart to expand and fill up with blood between heartbeats. Inflammation of the pericardium is usually not dangerous on its own, but it can lead to dangerous complications. These happen when fluid buildup inside the pericardium — a pericardial effusion — compresses the heart.
When fluid buildup happens slowly, the pericardium can sometimes stretch to allow the extra fluid while the heart still beats properly. But when it happens quickly, the fluid pushes on the heart, which cannot expand or fill with blood as it should. This reduces how much blood the heart can pump and causes cardiac tamponade, a life-threatening medical emergency. Tamponade can stop the heart, which is deadly within minutes.
Who Gets Acute Pericarditis?
Acute pericarditis can happen to people at any age, but it is more common in men and most likely in people between 20 and 50 years old. It is also very common overall, making up about 5% of all emergency room visits related to chest pain.
What Are the Symptoms of Acute Pericarditis?
Acute pericarditis can produce several symptoms, and some are more likely depending on the underlying cause. They include chest pain, fever, shortness of breath (dyspnea), a fast heartbeat (tachycardia) or palpitations (the unpleasant ability to feel your own heartbeat), muscle aches like those of a viral infection, hiccups or trouble swallowing (dysphagia), and a dry cough.
The chest pain: how it differs from a heart attack
The main symptom of acute pericarditis is chest pain. While it has many similarities to heart attack pain, there are important differences. The pain with acute pericarditis usually has these features:
Feature | What It Looks Like |
Fast onset | Reaches full strength very quickly — within one to two hours |
Variable quality | Can feel either sharp or dull, depending on the person |
Radiation | Spreads to nearby areas, similar to heart attack pain |
Position changes | Gets worse when lying down; gets better when sitting up or leaning forward |
What Causes Acute Pericarditis?
Acute pericarditis can happen for many reasons:
Cause Category | Specific Causes |
Infections | Bacterial infections (especially tuberculosis), viral infections such as HIV; fungal or parasitic infections are possible but rare |
Cancer | Pericardial cancer (rare), or tumors spreading from elsewhere and damaging the pericardium |
Immune or inflammatory disorders | Lupus, rheumatoid arthritis, Sjögren's syndrome |
Hormonal disorders | Hypothyroidism, ovarian hyperstimulation syndrome |
Trauma | Chest injuries — blunt impacts or penetrating wounds like knife or bullet injuries |
Heart or circulatory problems | Heart attacks, aortic dissection |
Medical causes | After heart surgery, radiation therapy for cancer, or as a medication side effect |
Other | Heart failure, chronic kidney disease or kidney failure, liver cirrhosis, or unknown reasons |
One common question: is it contagious? While acute pericarditis can happen because of contagious infections, you cannot catch it from or spread it to other people.
How Is Acute Pericarditis Diagnosed?
A doctor can diagnose acute pericarditis using a combination of medical history and symptoms, a physical exam, and diagnostic and laboratory tests. Diagnosis usually requires two or more of the following five signs:
Diagnostic Sign | How It Is Detected |
Chest pain | Reported by the patient |
Pericardial friction rub | The sound of the pericardium rubbing against the chest wall — never heard under normal circumstances — detected with a stethoscope |
Electrical activity changes | An ECG/EKG detects specific changes that can last for days or weeks |
New or growing pericardial effusion | A fluid buildup inside the pericardium that is new or increasing in size |
Inflammation of the pericardium | Visible on specialized cardiac MRI images and/or from blood work |
What tests will be done?
Lab tests look for blood changes and signs of certain infections. These usually include a complete blood count with differential, a troponin test, C-reactive protein, an erythrocyte sedimentation rate (sed rate), immune system tests for autoimmune diseases, a tuberculin test for tuberculosis, blood cultures for bacterial infections, and blood urea nitrogen and creatinine clearance tests.
Diagnostic tests help confirm pericarditis and offer clues about the cause. An ECG/EKG uses electrodes stuck to the chest to display the heart's electrical activity as a wave and detect abnormalities. A pericardial biopsy takes a tissue sample to help identify the underlying cause. Pericardiocentesis removes excess fluid when a pericardial effusion or cardiac tamponade is present, and analyzing the fluid can reveal the original cause.
Imaging may include chest X-rays, CT scans, MRI, and an echocardiogram. Some imaging forms can see acute pericarditis directly, while others detect the problems it causes.
How Is Acute Pericarditis Treated?
Treatment depends on what is causing the condition. When a specific underlying cause is found, treatment focuses on treating that cause. When no specific cause can be found, the focus is on treating the symptoms:
Treatment | How It Works |
NSAIDs (first-line) | Nonsteroidal anti-inflammatory drugs such as ibuprofen and aspirin are often the first treatment |
Colchicine | An anti-inflammatory often used in combination with NSAIDs |
Steroids | An option if NSAIDs and colchicine do not work, with a slightly higher risk of side effects |
Biologics | Potent medications for cases where other treatments fail — effective but with possible side effects |
Pericardiocentesis | Pericardial fluid extraction when an effusion is present, especially if the cause is infection or cancer |
Pericardiectomy | Rare surgery to remove part or all of the damaged pericardium — people can live without it without long-term harmful effects |
Your provider may also prescribe medications to protect the stomach lining from irritation caused by regular NSAID use. Possible complications of treatment depend strongly on the treatments received, especially medications — your healthcare provider is the best person to explain what to expect.
Your healthcare provider will likely also advise you to change your routine and rest while you recover.
How Do I Take Care of Myself?
Because acute pericarditis has symptoms similar to a heart attack, you should not try to self-diagnose or manage it without first seeing a healthcare provider. Since a heart attack is a life-threatening medical emergency, you should treat chest pain as if it is a heart attack. If it is not acute pericarditis, waiting too long for heart attack treatment can cause permanent heart damage.
How Soon Will I Feel Better?
The severity of your case, the underlying cause, and the treatments used all affect recovery time. In general, most people feel better within one to three weeks of treatment, but full recovery may take months.
What Happens After Treatment? Activity and Follow-Up
Untreated acute pericarditis can turn into other conditions, some of which are more serious or even dangerous — so it should not go untreated. With treatment, it should start to improve within weeks. However, most people need to avoid physical activity — including exercise and sports — until symptoms improve. It is common for symptoms to flare if you exercise too early. Your healthcare provider will explain what to expect and schedule follow-up appointments to monitor recovery.
Is Acute Pericarditis Curable?
Acute pericarditis is usually treatable and often curable, with most people recovering after treatment. However, between 20% and 50% of people will have the condition more than once, and certain anti-inflammatory treatment methods may reduce the risk of recurrence.
Depending on the cause, some people have an increased risk of constrictive pericarditis — a complication in which scarring makes the pericardium thicker and less flexible, restricting the heart's ability to pump:
Underlying Cause | Risk of Constrictive Pericarditis |
Tuberculosis or bacterial infections | About 20% to 30% of cases |
Cancer or immune disorder-related | 2% to 5% of cases |
Unknown or viral cause | Less than 1% of cases |
Can Acute Pericarditis Be Prevented?
Because acute pericarditis happens unpredictably, it is not a preventable condition. The only thing you can do is reduce your risk by avoiding the circumstances that can cause it:
Risk-Reduction Step | Why It Helps |
Get bacterial infections treated quickly | Untreated bacterial infections can damage the heart and nearby organs severely |
Avoid chest injuries | Wear your seatbelt, use proper safety equipment, and be cautious with tools or machinery that could injure the chest |
Follow your provider's guidance | Taking medications as prescribed and attending visits helps avoid recurrence or a chronic version of the condition |
When Should I Seek Care?
If you have a history of acute pericarditis, watch for any returning symptoms or symptoms that change or worsen during recovery, and call your provider or seek care outside business hours. The main symptoms to watch for are chest pain, fever, and trouble breathing (dyspnea).
Chest pain may be a sign of a heart attack — call 911 or your local emergency number immediately.
Conclusion
Acute pericarditis sits in an unusual place in medicine: it is usually not dangerous on its own, yet it wears the costume of the most feared emergency of all — a heart attack. The pericardium, a pouch most people have never heard of, becomes inflamed and painful, and its hallmark tells — pain that peaks within hours, eases when leaning forward, and radiates across the chest — are the clues that separate it from a coronary event, even though no one should make that call at home. The diagnostic bar is deliberately low: two of five findings, and treatment begins. First-line NSAIDs, colchicine, and rest do the work for most patients within a few weeks. The real dangers hide at both ends — cardiac tamponade arriving in minutes at one end, and constrictive scarring arriving months later at the other.
If you develop chest pain — especially pain that arrives fast, worsens when lying down, and improves when sitting up or leaning forward — do not try to diagnose yourself. Call 911 or your local emergency number and treat it as a heart attack until a provider proves otherwise. After diagnosis, ask your provider which of the five diagnostic signs confirmed your case, whether colchicine should be added to your NSAID treatment to lower recurrence risk, and how long you should avoid exercise.
Questions to Ask Your Provider
Which two (or more) of the five diagnostic signs confirmed my pericarditis?
What do you think caused my case — and can we find out?
Should I take colchicine along with NSAIDs to reduce recurrence?
Do I need imaging or fluid drainage (pericardiocentesis)?
How long should I avoid exercise and sports?
What symptoms during recovery mean I should seek care again?
Frequently Asked Questions
What is acute pericarditis?
Acute pericarditis is painful inflammation of the pericardium — the fluid-filled, double-layered pouch surrounding the heart. The pain usually gets worse when lying down or breathing in. Depending on the cause, it is almost always treatable, and most people recover with few or no complications.
What does acute pericarditis pain feel like?
The main symptom is chest pain that reaches full strength quickly — usually within one to two hours. It can feel sharp or dull, radiates to nearby areas, and typically gets worse when lying down and better when sitting up or leaning forward. It can closely mimic heart attack pain, which is why it must always be evaluated by a medical professional.
What causes acute pericarditis?
Possible causes include infections (especially tuberculosis and viral infections such as HIV), cancer that spreads to the pericardium, immune system or inflammatory disorders like lupus and rheumatoid arthritis, hormonal problems, chest trauma, heart attacks and aortic dissection, heart surgery, radiation therapy, certain medications, heart failure, kidney or liver disease, and unknown reasons. It is not contagious.
How is acute pericarditis diagnosed?
Diagnosis requires two or more of five findings: chest pain, a pericardial friction rub heard with a stethoscope, electrical activity changes on an ECG, a new or growing pericardial effusion, and inflammation of the pericardium seen on cardiac MRI or blood work. Lab tests, pericardial biopsy, pericardiocentesis, and imaging (X-ray, CT, MRI, echocardiogram) help confirm the diagnosis and the cause.
How is acute pericarditis treated?
When a specific cause is found, treatment targets that cause. Otherwise, treatment focuses on symptoms: NSAIDs (ibuprofen, aspirin) are first-line, often combined with colchicine; steroids are used if those fail; biologics are a potent later option; pericardiocentesis drains excess fluid; and pericardiectomy — surgery to remove part or all of the pericardium — is reserved for rare cases.
How long does acute pericarditis last?
Most people feel better within one to three weeks of treatment, though full recovery can take months. Symptoms commonly flare if exercise is resumed too early, so physical activity should be avoided until symptoms improve. Follow-up appointments monitor recovery for any signs of trouble.
Can acute pericarditis come back?
Yes. Between 20% and 50% of people will have the condition more than once, though certain anti-inflammatory treatment methods may reduce recurrence risk.
Is acute pericarditis dangerous?
The inflammation itself is usually not dangerous, but it shares symptoms with a heart attack and can lead to dangerous complications. Fluid buildup that compresses the heart causes cardiac tamponade — a life-threatening emergency that can stop the heart and is deadly within minutes. Long-term, some causes raise the risk of constrictive pericarditis: about 20%–30% of tuberculosis- or bacteria-related cases, 2%–5% of cancer- or immune-related cases, and less than 1% of viral or unknown-cause cases.
References
Ismail TF. — Acute pericarditis: Update on diagnosis and management. Clin Med (Lond) (2020)
Braunwald E. — Chapter 265: Pericardial Disease. In: Harrison's Principles of Internal Medicine, 20e. McGraw Hill; 2018.
Imazio M. — Chapter 28: Pericardial Diseases. In: CURRENT Diagnosis & Treatment: Cardiology, 5e. McGraw Hill; 2017.
Medical Disclaimer: This article is for general informational purposes only and is not a substitute for professional medical advice, diagnosis, or treatment. Acute pericarditis shares symptoms with a heart attack — a life-threatening medical emergency. If you experience chest pain, do not attempt to self-diagnose; call 911 or your local emergency number immediately and treat chest pain as a heart attack until a licensed healthcare provider evaluates you. Untreated chest pain that turns out to be a heart attack can cause permanent heart damage, and untreated pericarditis can lead to cardiac tamponade, which can be deadly within minutes. Only a licensed healthcare provider can diagnose acute pericarditis, determine its cause, and prescribe appropriate treatment. Never delay seeking emergency care because of something you have read here.
Comments