Cardiac Tamponade

How tamponade affects the heart

The heart sits inside the pericardium, a two-layered sac with a small amount of lubricating fluid (about 15 to 50 ml). When extra fluid accumulates, called a pericardial effusion, pressure inside the sac rises. Once that pressure exceeds the pressure in the heart's chambers, the right side of the heart collapses during filling, less blood enters the heart, less is pumped out, and blood pressure falls.

How much fluid causes tamponade depends on speed:

• Acute: as little as 100 to 200 ml of blood can cause tamponade within minutes because the pericardium cannot stretch quickly.
• Subacute or chronic: the pericardium gradually stretches, so 1 to 2 liters may build up over weeks before tamponade develops.

Causes

Rapid (acute) tamponade

• penetrating chest trauma, such as stab or gunshot wounds
• blunt chest trauma
• aortic dissection bleeding into the pericardium
• rupture of the heart wall after a heart attack
• complications of cardiac catheterization, pacemaker placement, ablation or heart surgery

Slower (subacute) tamponade

• cancer, especially lung cancer, breast cancer and lymphoma, spreading to the pericardium
• pericarditis from viral infection, tuberculosis or bacterial infection
• kidney failure (uremic pericarditis)
• autoimmune diseases such as lupus and rheumatoid arthritis
• radiation therapy to the chest
• severe hypothyroidism
• blood thinners and bleeding disorders
• after heart surgery (post-pericardiotomy syndrome)

Symptoms

• shortness of breath, worse lying flat, and fast breathing
• chest pain or pressure, sometimes spreading to the neck, shoulders or back
• a fast heartbeat (tachycardia)
• lightheadedness, fainting, or feeling faint on standing
• anxiety, restlessness, confusion
• cold, pale or bluish skin, sweating
• reduced urine output
• with slower causes: fatigue, cough, swelling of the legs and belly, hiccups or hoarseness from pressure on nearby nerves

Signs doctors look for

• Beck's triad: low blood pressure, distended neck veins and muffled (quiet) heart sounds. The full triad is present in only a minority of cases.
• Pulsus paradoxus: blood pressure drops by more than 10 mmHg when breathing in.
• Fast heart rate, fast breathing.
• Electrical alternans: beat-to-beat variation in the height of ECG complexes as the heart swings within the fluid.

Diagnosis

• Echocardiogram (heart ultrasound): the key test. It shows the fluid and whether the heart chambers are collapsing during filling. A bedside ultrasound (FAST scan) is used in trauma.
• ECG: a fast heart rate, low voltage, and sometimes electrical alternans.
• Chest X-ray: an enlarged, "water bottle" heart shadow when the effusion is large and slow.
• CT or MRI: to look at the pericardium and causes when the patient is stable.
• Fluid analysis after drainage: cell count, culture, cancer cells and other tests to find the cause.

Treatment

Cardiac tamponade is a medical emergency.

• Pericardiocentesis: a needle is inserted under the breastbone, guided by ultrasound, into the pericardial sac, and fluid is drained. Removing even a small amount can dramatically improve blood pressure. A thin drain is often left in place for a few days.
• Surgical drainage: needed for trauma, aortic dissection, heart rupture, clotted blood, or fluid that cannot be reached with a needle. In trauma, an emergency thoracotomy may be required.
• Pericardial window: surgery to create an opening so fluid drains into the chest or abdomen, used for recurrent effusions such as those from cancer.
• Supportive care: IV fluids to maintain filling and oxygen while preparing for drainage. Medicines that lower preload, like diuretics, and mechanical ventilation can worsen tamponade and are avoided where possible.
• Treat the cause: anti-inflammatory medicines and colchicine for pericarditis, antibiotics or tuberculosis treatment, dialysis for uremia, cancer therapy, and stopping blood thinners.

Outlook

With prompt drainage, survival from tamponade itself is high. Long-term outlook depends on the cause: excellent after viral pericarditis or a procedural complication, poorer when caused by advanced cancer or aortic dissection. Recurrence is common with cancer-related effusions.

Frequently asked questions

What are the symptoms of cardiac tamponade?

Symptoms include shortness of breath, chest pain or pressure, a fast heartbeat, lightheadedness or fainting, anxiety and confusion, and cold, clammy skin. In slow-onset cases, fatigue, cough and leg swelling may come first.

What is Beck's triad?

Beck's triad is three classic signs of cardiac tamponade: low blood pressure, swollen neck veins and muffled heart sounds. Not every patient shows all three, so doctors rely on ultrasound to confirm the diagnosis.

What causes cardiac tamponade?

Fast tamponade is usually caused by chest trauma, aortic dissection, heart rupture or complications of heart procedures. Slow tamponade is often caused by cancer, pericarditis, kidney failure, tuberculosis, autoimmune disease or radiation.

How is cardiac tamponade treated?

It is treated by urgently draining the fluid, usually with a needle guided by ultrasound (pericardiocentesis), or by surgery for trauma, bleeding or recurrent cases. The underlying cause is then treated to prevent the fluid from returning.

Can you survive cardiac tamponade?

Yes, if it is recognized and drained quickly. Untreated tamponade is fatal. After drainage, the outlook depends mainly on what caused the fluid to accumulate.