Dressler Syndrome (Post-MI Pericarditis)

Overview

Dressler syndrome is a condition in which the sac surrounding the heart (the pericardium) becomes inflamed following a heart attack, heart surgery, or cardiac trauma. The form that develops after a heart attack is also known as post-MI pericarditis. It typically appears weeks to months after the triggering event rather than immediately.

The underlying mechanism of Dressler syndrome is an immune system response. When heart muscle is damaged, the body may mount an immune reaction against the injured tissue. In some people, this response goes on to cause inflammation of the pericardium and sometimes the lining of the lungs as well. It is considered a form of autoimmune reaction.

Dressler syndrome was once quite common but has become much rarer in recent decades, largely because advances in heart attack treatment have made it possible to open blocked arteries quickly and limit the extent of heart muscle damage. Less damaged tissue means a weaker immune trigger. It does still occur, however, and recognising it is important because its symptoms can sometimes be confused with a new heart attack or other serious conditions.

Dressler syndrome is a serious condition, but the great majority of cases respond well to treatment and resolve completely.

Symptoms

Dressler syndrome symptoms typically begin several weeks after a heart attack or heart surgery, though in some cases they can appear up to a few months later.

The main possible symptoms of Dressler syndrome include the following:

• Chest pain. The most prominent symptom. It is typically sharp and stabbing in character and tends to worsen when breathing deeply, coughing, or swallowing. Leaning forward often eases it, while lying flat tends to make it worse. This pattern is one of the important features that can help distinguish Dressler syndrome chest pain from the pain of a heart attack.
• Fever. A moderate fever is commonly seen. High fever is less frequent but can occur in some cases.
• General malaise and fatigue. Feeling unwell, tiredness, and low energy are among the frequently accompanying symptoms.
• Shortness of breath. Fluid accumulation around the heart or in the lining of the lungs can make breathing harder. Breathlessness that is particularly noticeable when lying flat warrants attention.
• Joint pain and swelling. Some people develop pain and swelling in the joints, reflecting the systemic inflammatory component of Dressler syndrome.

When these symptoms arise during what is already a challenging recovery period after a heart attack, they can be worrying for both the patient and their loved ones. The chest pain of Dressler syndrome is generally distinguishable from heart attack pain by its sharp character and its tendency to change with breathing and body position.

When to See a Doctor

New chest pain or fever developing after a heart attack or heart surgery should always be evaluated. Dressler syndrome does not resolve on its own and can give rise to complications.

Schedule a medical evaluation if:

• New chest pain develops weeks after a heart attack or heart surgery
• Unexplained fever and general malaise have developed
• Breathlessness has returned or worsened
• You have noticed pain and swelling in your joints

Call emergency services immediately if:

• Chest pain is very severe and is not easing with rest (a new heart attack needs to be ruled out)
• Sudden severe breathlessness develops
• Blood pressure drops suddenly and general condition deteriorates rapidly (this may indicate cardiac tamponade)
• You faint or feel you are about to faint

Causes

The fundamental cause of Dressler syndrome is an exaggerated immune response to heart muscle damage. When cardiac tissue is injured, certain proteins and cell fragments enter the bloodstream. The immune system may identify these as foreign and mount a response against them. This response can go on to affect the pericardium and sometimes the lining of the lungs.

Situations that can trigger Dressler syndrome include the following:

• Heart attack (myocardial infarction). The classic trigger. Larger heart attacks affecting a wider area of tissue tend to produce a stronger immune trigger and may carry a higher risk of Dressler syndrome.
• Heart surgery. Open heart procedures such as bypass surgery or valve repair and replacement directly affect the pericardium and can trigger this condition. This form is sometimes called post-operative pericarditis or post-pericardiotomy syndrome.
• Cardiac trauma. Blunt injury to the chest, such as in a road traffic accident, can damage cardiac tissue and trigger a similar immune response.
• Cardiac procedures. Some interventional cardiac procedures such as catheter ablation or pacemaker implantation can occasionally contribute to the development of Dressler syndrome.

Risk Factors

The established risk factors for Dressler syndrome include the following:

• Large area heart attack. Greater heart muscle damage may produce a stronger immune response and increase the likelihood of Dressler syndrome developing.
• Delayed or inadequately treated heart attack. Late opening of the blocked artery leads to more extensive heart muscle damage, which can amplify the immune trigger. The current practice of opening arteries as quickly as possible is thought to be a significant reason for the decline in Dressler syndrome frequency.
• Open heart surgery. Direct surgical intervention affecting the heart carries a risk of pericardial inflammation.
• Previous Dressler syndrome. People who have had Dressler syndrome once may be at higher risk of experiencing it again.

Diagnosis

Dressler syndrome is diagnosed through careful assessment of symptoms combined with a range of tests. The most important step is ruling out a new heart attack or other serious condition as the cause of the symptoms.

Methods used to diagnose Dressler syndrome include the following:

• Blood tests. Inflammatory markers including CRP (C-reactive protein) and ESR (erythrocyte sedimentation rate) are typically significantly elevated. A raised white blood cell count may also be seen. Troponin may be mildly elevated; careful interpretation is needed to distinguish this from a new heart attack.
• ECG. Widespread ST changes characteristic of pericarditis may be present. These changes typically have a different appearance from the localised ST changes seen in heart attack and can be distinguished by an experienced clinician.
• Echocardiogram. Can show fluid accumulation between the pericardium and the heart. Assesses the heart's pumping function and is valuable for ruling out serious complications such as cardiac tamponade.
• Chest X-ray. May show fluid around the lungs or an enlarged cardiac silhouette. Characteristic findings on chest X-ray can support the diagnosis.
• Cardiac MRI. Can provide very detailed images of pericardial inflammation and fluid accumulation. Particularly useful in cases where the diagnosis needs further clarification.

Treatment

The goals of treatment for Dressler syndrome are to suppress inflammation, relieve pain, and prevent complications. The great majority of cases can be managed successfully with medication.

• Aspirin. Often the first choice, with both anti-inflammatory and analgesic effects. In patients who are already taking aspirin after a heart attack, the dose can be increased to address the pericarditis. A course of higher-dose aspirin over several weeks is typically recommended, followed by gradual dose reduction.
• NSAIDs (ibuprofen, naproxen). Effective for reducing inflammation and pain. However, some caution may be needed in post-heart attack patients because of concerns that these drugs could affect heart muscle healing; your doctor will make an individual assessment of whether they are appropriate for you.
• Colchicine. Has been shown to be effective at suppressing inflammation in pericarditis. When used alongside aspirin or NSAIDs, it can both speed up symptom resolution and reduce the risk of recurrence. It is generally used for a period of several months.
• Corticosteroids. Used in severe cases that do not respond to aspirin, NSAIDs, and colchicine. Because corticosteroids are known to potentially interfere with post-heart attack healing, the aim is to use the lowest effective dose for the shortest possible time.
• Rest. Restricting physical activity while symptoms are active helps reduce pain and supports recovery. A gradual return to activity is planned once pain has resolved and inflammatory markers have returned to normal.
• Drainage of pericardial fluid (pericardiocentesis). If a significant amount of fluid has accumulated around the heart and cardiac tamponade has developed, draining the fluid through a needle or catheter may be necessary. This procedure can be life-saving in an emergency situation.

Complications

Dressler syndrome usually follows a favourable course, but serious complications can occasionally develop.

• Cardiac tamponade. If too much fluid accumulates in the pericardial sac, it can compress the heart and prevent it from pumping effectively. A sudden drop in blood pressure, breathlessness, and altered consciousness are among the signs of this complication. It requires urgent intervention.
• Chronic and constrictive pericarditis. In rare cases, inflammation persists and the pericardium becomes thickened and scarred, restricting the heart's ability to fill and contract. This condition, called constrictive pericarditis, may require surgery in severe cases.
• Recurrence. Dressler syndrome can recur in some people. Colchicine treatment can meaningfully reduce the risk of recurrence.

Living with Dressler Syndrome

Receiving a diagnosis of Dressler syndrome during what is already a challenging recovery after a heart attack can feel like an additional burden. However, the condition is one that can almost always be brought under control with medication and resolved completely.

Take Your Medications as Prescribed

Taking aspirin, colchicine, or other prescribed medications for the full recommended duration helps speed up recovery and reduces the risk of recurrence. Stopping treatment early when symptoms ease can allow the inflammation to return.

Physical Activity

While pain and inflammation are present, it is advisable to avoid strenuous physical activity. Once symptoms have resolved and your doctor has given the go-ahead, a gradual return to activity can be planned. The cardiac rehabilitation programme that follows a heart attack can help guide this process.

Monitor Your Symptoms

During treatment, keep track of whether fever, chest pain, and breathlessness are improving or worsening. If symptoms deteriorate or new ones develop, contact your doctor.

Preparing for Your Appointment

Coming prepared to your appointment when Dressler syndrome is suspected or has been diagnosed can help make the assessment and treatment process more straightforward.

What you can do:

• Note when the chest pain began, how it feels, and whether it changes with breathing
• Mention how many days or weeks have passed since your heart attack or surgery
• Record your temperature if you have measured it
• List all current medications
• Mention if you have previously had Dressler syndrome or pericarditis
• Write your questions down in advance

Questions you may wish to ask your doctor:

• Is this chest pain from Dressler syndrome or could it be a new heart attack?
• Which medications do I need and for how long?
• Is there fluid around my heart?
• When can I return to exercise?
• Is there a risk of recurrence and how can I reduce it?
• Which symptoms should prompt me to go to the emergency department?

Questions your doctor may ask:

• When did the chest pain start and how does it feel?
• Does the pain worsen when you breathe deeply or lie flat?
• Does leaning forward ease the pain?
• Do you have a fever?
• Are you experiencing breathlessness?
• How long has it been since your heart attack or surgery?
• What medications are you currently taking?