Pericardium

Looks like

A tough, two-layered sac wrapped around the heart, holding a thin film of fluid between its layers.

What it does

Lets the heart beat without friction, anchors it in place and limits sudden overstretching.

Keeping it well

Viral infection can inflame it: sharp chest pain that is worse lying flat and eased by sitting forward. Fluid building up fast in the sac squeezes the heart — breathlessness, faintness and low blood pressure after chest trauma or with known pericarditis are an emergency.

Related conditions

• 22q11.2 deletion syndrome (DiGeorge)
• Aortic stenosis
• Atrial flutter
• Cardiomyopathy (dilated, restrictive, arrhythmogenic)
• Chagas disease
• Congenital heart defects
• Coronary artery disease
• Diphtheria
• Down syndrome (trisomy 21)
• Eating disorders
• Extra heartbeats (ectopics and palpitations)
• Fainting (syncope)
• Friedreich's ataxia
• Heart failure
• Hypertrophic cardiomyopathy
• Hypothermia & frostbite
• Kawasaki disease
• Long QT syndrome
• Myocarditis
• Orthostatic hypotension & POTS
• Panic disorder
• Pericardial effusion & tamponade
• Pericarditis
• Shock (circulatory failure)
• Sudden cardiac arrest
• Sudden infant death syndrome
• Supraventricular tachycardia
• Takotsubo (stress) cardiomyopathy
• Tuberous sclerosis complex
• Wolff–Parkinson–White syndrome