Interatrial septum & fossa ovalis

Looks like

The thin wall between the two upper chambers of the heart, with a shallow dip (the fossa ovalis) where a flap-valve let blood cross before birth.

What it does

Keeps the returning blue blood of the right atrium apart from the red blood of the left.

Keeping it well

In about one adult in four the flap never seals (patent foramen ovale), usually harmlessly; a larger hole (atrial septal defect) overloads the right heart and is closed by a device or surgery.

Related conditions

• 22q11.2 deletion syndrome (DiGeorge)
• Aortic stenosis
• Atrial flutter
• Botulism
• 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)
• Fibromyalgia
• Frailty & falls in older age
• Friedreich's ataxia
• Heart failure
• Heat exhaustion & heatstroke
• Hypertrophic cardiomyopathy
• Hypothermia & frostbite
• Kawasaki disease
• Long QT syndrome
• Malnutrition & refeeding syndrome
• Muscular dystrophy
• Myocarditis
• Orthostatic hypotension & POTS
• Panic disorder
• Pericardial effusion & tamponade
• Pericarditis
• Polymyalgia rheumatica
• Rhabdomyolysis
• Sarcoma
• Sarcopenia
• Shock (circulatory failure)
• Sudden cardiac arrest
• Sudden infant death syndrome
• Supraventricular tachycardia
• Takotsubo (stress) cardiomyopathy
• Tetanus
• Tuberous sclerosis complex
• Wolff–Parkinson–White syndrome