The volume of the heart's left atrium (left atrial volume) is an important biomarker for cardiovascular physiology and clinical

cardiology Cardiology () is a branch of medicine that deals with disorders of the heart and the cardiovascular system. The field includes medical diagnosis and treatment of congenital heart defects, coronary artery disease, heart failure, valvular heart d ...

. It is usually calculated as left atrial volume index in terms of body surface area.

Measurement

The left atrial volume is commonly measured by

echocardiography An echocardiography, echocardiogram, cardiac echo or simply an echo, is an ultrasound of the heart. It is a type of medical imaging of the heart, using standard ultrasound or Doppler ultrasound. Echocardiography has become routinely used in t ...

magnetic resonance tomography Magnetic resonance imaging (MRI) is a medical imaging technique used in radiology to form pictures of the anatomy and the physiological processes of the body. MRI scanners use strong magnetic fields, magnetic field gradients, and radio waves ...

. It is calculated from biplane recordings with the equation: :

_=\frac\frac

where ''A''4''c'' and ''A''2''c'' denote LA areas in 4- and 2-chamber views respectively, and ''L'' corresponds to the shortest long-axis length measured in either views. Usually, the volume of the left atrium is divided by the body surface area in order to provide an

extensive property Physical properties of materials and systems can often be categorized as being either intensive or extensive, according to how the property changes when the size (or extent) of the system changes. According to IUPAC, an intensive quantity is one ...

, which is independent from body size. The resulting index is referred to as left atrial volume index (LAVI): :

LAVI=\frac

Physiology

LAVI between 21 and 52 mL/m² is regarded as normal.

Pathophysiologiy and clinical implications

Enlargement of the left atrium is a form of

cardiomegaly Cardiomegaly (sometimes megacardia or megalocardia) is a medical condition in which the heart is enlarged. As such, it is more commonly referred to simply as "having an enlarged heart". It is usually the result of underlying conditions that make t ...

. Moderately increased LAVI (63 to 73 mL/m²) is associated with slightly elevated

mortality Mortality is the state of being mortal, or susceptible to death; the opposite of immortality. Mortality may also refer to: * Fish mortality, a parameter used in fisheries population dynamics to account for the loss of fish in a fish stock throug ...

hazard and severely increased LAVI (>73 mL/m²) with significantly higher hazard ratio of mortality. LAVI predicts survival after acute myocardial infarction, postoperative atrial fibrillation in subjects undergoing heart surgery, atrial fibrillation and stroke as well as hospital admission in ambulatory patients.

References

{{Cardiovascular physiology Cardiovascular physiology