The right ventricle (RV) is the most anterior of the four heart chambers. It receives deoxygenated blood from the right atrium (RA) and pumps it into the pulmonary circulation. During diastole, blood enters the right ventricle through the atrioventricular orifice through an open tricuspid valve (TV). During systole, blood is ejected through the open pulmonary valve (PV) into the pulmonary trunk.
The right ventricle projects to the left of the right atrium and when viewed in the cardiac short axis plane, is semilunar in shape wrapping around the anterolateral aspect of the left ventricle (LV). It has thinner walls than the left ventricle due to lower right sided pressures compared to the left ventricle. It forms almost all of the anterior and inferior borders of the heart. It is separated from the left ventricle by the interventricular (IV) septum, which is concave in shape (i.e. bulges into the right ventricle). It has three walls named anterior, inferior, and septal.
The interior ventricular surface has irregular muscular ridges known as trabeculae carneae. A prominent trabecula, the supraventricular crest, separates the trabeculated inferior ventricle from the smooth wall of the right ventricular outflow tract. It acts to redirect blood approximately 140° from the inflow tract to the outflow tract.
The inflow part of the ventricle receives blood from the right atrium via the tricuspid valve. The fibrous ring surrounding the valve forms part of the fibrous skeleton of the heart. Superiorly the chamber tapers as the funnel-shaped outflow tract, known as the conus arteriosus (or infundibulum), which lack trabeculae and continues beyond the pulmonary valve as the pulmonary trunk.
- anterior (largest), with chordae tendineae which attach to the anterior and posterior cusps of the tricuspid valve
- posterior (smallest), with chordae tendineae which attach to the posterior and septal cusps of the tricuspid valve
- septal, with chordae tendineae which attach to the anterior and septal cusps of the tricuspid valve
Arising from the apical aspect of the IV septum, the septomarginal trabecula (or moderator band) extends to the anterior papillary muscle and contains the right branch of the atrioventricular (AV) bundle.
Contraction of the right ventricle occurs in sequence, initiated by the inlet and apical regions followed by outflow/infundibular contraction. In contrast to the left ventricle, longitudinal shortening is the primary contractile determinant of right ventricular stroke volume; this facet of right ventricular function is appreciated clinically by the excursion of the tricuspid annulus, drawn toward the apex with each systole. An inward "bellows-like" motion of the right ventricular free wall and traction from left ventricular contraction also contribute to overall systolic function .
The right ventricle ejects into a low-impedance, highly distensible vascular bed, achieving an equal cardiac output to the left ventricle, albeit with one-sixth the stroke work required. These characteristics of the pulmonary arterial circulation, representing the right ventricular afterload, explain in part the unique features of right ventricular ejection in health; the lower pressures result in minimal isovolumic contraction, and the capacious upstream vasculature allows flow to continue during the pressure decline in late systole. This "hangout" phenomenon may account for more than half of right ventricular output .
- predominantly from the right coronary artery and its branches
- conus artery supplies the infundibulum
- acute marginal arteries supply the anterior free wall
- posterior descending artery via septal branches supply the posterior 1/3 IV septum
- the other 2/3 of the IV septum is supplied by septal branches of the left anterior descending artery
- middle cardiac vein and small cardiac vein drain into the coronary sinus
- anterior cardiac veins drain the anterior surface directly into the right atrium
- tiny myocardial thebesian veins drain directly into the right ventricle
On contrast-enhanced chest CT and cardiac MRI, the right ventricle when measured on axial slices can be considered enlarged when the transverse diameter is ≥60 mm (male) and ≥57 mm (female) .
On transthoracic echocardiography the right ventricle can be considered enlarged when :
- the basal diameter exceeds 42 mm
- the mid-cavity diameter exceeds 35 mm
- the longitudinal diameter exceeds 86 mm
- the proximal outflow tract diameter exceeds 35 mm
- the distal outflow tract diameter exceeds 27 mm