Pericarditis ECG

Pericarditis ECG: The Classic Signs of an Inflamed Heart Lining

If your ECG shows unusual ST elevations but no heart attack, your doctor might mention pericarditis — inflammation of the pericardium, the thin sac surrounding the heart.

Pericarditis can mimic a heart attack in pain, pattern, and panic. But on an ECG, it has a distinct fingerprint that sets it apart — if you know what to look for.

Let’s decode what pericarditis on ECG really looks like, why it happens, and why recognizing it early is critical.

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What Is Pericarditis?

Pericarditis is inflammation of the pericardium, the double-layered membrane that wraps around your heart like protective cling film.

When this lining becomes irritated or infected, it causes:

• Sharp, stabbing chest pain (often worse when lying flat or breathing deeply)

• Pain relief when sitting up or leaning forward

• Sometimes low-grade fever or general malaise

The inflammation also disrupts the heart’s electrical environment — which shows up clearly on an electrocardiogram (ECG).

How Pericarditis Affects the ECG

The electrical changes in pericarditis reflect inflammation affecting the heart’s surface layers. These cause characteristic shifts in the ECG’s baseline and waveforms.

Classic acute pericarditis evolves in four stages:

Stage 1: Diffuse ST-Segment Elevation and PR-Segment Depression

This is the signature pattern of pericarditis.

• Widespread (diffuse) ST elevation — appears in almost all leads, unlike a heart attack which affects specific regions.

• The ST elevation is concave upward (“smiling” shape).

• PR-segment depression — especially in limb leads; caused by atrial inflammation.

• No reciprocal ST depression (except possibly in aVR and V1).

This stage lasts a few hours to several days and is usually when chest pain is most severe.

Stage 2: ST and PR Normalization

The ST segments return to baseline, and the PR depression resolves.
T waves may flatten temporarily.

This marks the resolution of the acute inflammation phase.

Stage 3: T-Wave Inversion

As healing continues, the T waves become inverted — usually without any ST elevation.
This stage can last for days or weeks.

Stage 4: Return to Normal ECG

All changes gradually normalize, and the ECG returns to baseline — unless chronic or recurrent pericarditis develops.

Key ECG Features That Distinguish Pericarditis

It’s easy to confuse pericarditis with myocardial infarction (heart attack), but the ECG holds the clues.

In pericarditis:

• ST elevation is diffuse, not localized to one coronary artery region.

• The ST segments are concave (upward curving), not convex.

• PR depression is often present — a telltale sign.

• No pathological Q waves or reciprocal changes (which appear in heart attacks).

• T-wave inversion occurs only after ST segments normalize, not simultaneously.

In short:

Pericarditis = widespread, “smiley” ST elevation + PR depression + no Q waves.

Common Causes of Pericarditis

Pericarditis can be triggered by various conditions:

• Viral infections (most common)

• Post-heart attack inflammation (Dressler’s syndrome)

• Autoimmune diseases like lupus or rheumatoid arthritis

• Kidney failure (uremic pericarditis)

• Post-surgery or chest trauma

• Certain medications

• Cancer spreading to the pericardium

Sometimes, the cause remains unknown — called idiopathic pericarditis — but most of these cases are viral in origin.

Symptoms That Accompany ECG Findings

Besides chest pain that shifts with position or breathing, patients may experience:

• Fever and fatigue

• Shortness of breath when lying flat

• A pericardial friction rub (a scratchy sound heard with a stethoscope)

• Mild swelling of legs or abdomen in severe cases

The ECG helps confirm the diagnosis alongside symptoms, blood tests (showing inflammation), and echocardiography (showing fluid around the heart).

Why Early ECG Recognition Matters

Catching pericarditis early prevents complications like:

• Pericardial effusion: Fluid accumulation around the heart.

• Cardiac tamponade: Dangerous compression of the heart by excess fluid.

• Constrictive pericarditis: Long-term scarring that restricts heart motion.

Prompt recognition and treatment with anti-inflammatory medications can stop these from developing.

Treatment Overview

Treatment depends on the underlying cause but often includes:

• Anti-inflammatory drugs (NSAIDs like ibuprofen or aspirin)

• Colchicine, to reduce recurrence

• Steroids, if symptoms persist or are autoimmune-related

• Antibiotics, if bacterial infection is the cause

• Pericardiocentesis, if fluid around the heart becomes excessive

Rest and hydration are also essential while inflammation subsides.

The Bottom Line

Pericarditis on ECG has one of the most recognizable patterns in cardiology — widespread concave ST elevation with PR depression. It looks dramatic, but unlike a heart attack, it’s not caused by blocked arteries — it’s the surface of your heart crying out from irritation.

The good news: with timely treatment, most people recover fully, and the ECG normalizes over days to weeks.

So if you ever hear “ST elevation” but your troponin levels are normal and the pain eases when you sit up — you’re likely looking at pericarditis, not a heart attack.