Left ventricle

The left ventricle is one of four heart chambers. It receives oxygenated blood from the left atrium and pumps it into the systemic circulation via the aorta.

Gross anatomy

The left ventricle is conical in shape with an anteroinferiorly projecting apex and is longer with thicker walls than the right ventricle. It is separated from the right ventricle by the interventricular septum, which is concave in shape (i.e. bulges into the right ventricle). Internally, there are smooth inflow and outflow tracts and the remainder of the left ventricle (mainly apical) is lined by fine trabeculae carneae. The ventricular wall is thickest at the base and thins to only 1-2 mm at the apex.

Blood flows in via the atrioventricular orifice lined by the mitral valve and flows out passing through the aortic valve into the aorta. 

The ventricular myocardium underlies the papillary muscles forming components of the mitral subvalvular apparatus;

• the anterolateral and posteromedial papillary muscles project into the left ventricular cavity, anchored to the underlying myocardium via tracebluae carnae. The respective origins/anatomic locations are commonly as follows:

  • arising between the anterolateral/inferolateral walls

  • at the interface of the inferor wall and the inferoseptum

Each muscle is composed of roughly six discrete subunits, each of which elaborates numerous linear projections of connective tissue, known as the primary chordae tendinae;

• two sequential bifurcations follow, forming secondary and tertiary chordae, both of which respectively insert at the tips of the anterior and posterior leaflets of the mitral valve which are anchored by a the valvular annulus

Relations

• anterior: interventricular septum, right ventricle

• posterior: descending aorta, left vagus nerve, sympathetic chain

• superior: left atrium

• inferior: diaphragmatic pericardium, diaphragm

• right: right side of pleura

• left: left lung and pleura, left phrenic nerve and pericardioacophrenic vessels 

Arterial supply

• left anterior descending artery

  • supplies the anteroseptum, anterior and commonly anterolateral walls

    • supplies the former via septal perforators and the latter commonly by diagonal branches

    • supplies the bundle branches and the anterolateral papillary muscle, the latter via the first diagonal branch

  • apical segments with a variable wraparound variant to the apical inferior wall

• left circumflex artery

  • supplies the lateral wall, variable contribution to the inferior wall and anterolateral papillary muscle via its first obtuse marginal branch

    • may less commonly supply the posteromedial papillary muscle via an obtuse marginal branch (typically the third) ⁹

  • variable shared perfusion territory with a ramus intermedius or prominent diagonal branch from the left anterior descending coronary artery

• right coronary artery

  • may supply segments of the inferior and basal inferolateral wall

  • contribution to apical segments via the posterior descending artery, also supplies the posteromedial papillary muscle

Venous drainage

• great cardiac vein, middle cardiac vein, and posterior vein of the left ventricle: drain into the coronary sinus

• tiny myocardial thebesian veins drain directly into the left ventricle

Innervation

See innervation of the heart.

Variant anatomy

• double-inlet ventricle: inflow from both the right and left atria

• parachute valve: mitral valve chordae tendineae inserting into a single papillary muscle

Development

See development of the heart.

Radiographic features

On contrast-enhanced chest CT and cardiac MRI, the left ventricle when measured on axial slices can be considered enlarged when the transverse diameter is ≥58 mm (male) and ≥53 mm (female) ⁸.

Related pathology

• left ventricular hypertrophy (LVH)

• left ventricular enlargement

• non-compaction of the left ventricle

• hypoplastic left heart syndrome

• left ventricular aneurysm

• left ventricular pseudoaneurysm

• left ventricular assist device

• cardiac neoplasms