Right ventricle

Ventriculus dexter

Also known as: RV

The right ventricle is a crescent-shaped chamber that forms most of the anterior (sternocostal) surface of the heart. It receives blood through the tricuspid valve and pumps it at low pressure through the pulmonary valve into the pulmonary trunk.

Overview

Pressure≈15–30 / 2–8 mmHg

Free-wall thickness≈3–5 mm

Inflow and outflow. The inflow part of the right ventricle is rough with trabeculae carneae (muscular ridges and bridges) and contains the papillary muscles. The outflow part, the conus arteriosus or infundibulum, is smooth-walled and funnel-shaped and leads up to the pulmonary valve. A thick muscular ridge, the supraventricular crest, separates the two.

Papillary muscles. There are three: the anterior (the largest), the posterior (inferior) and the small, variable septal muscle. Their chordae attach to the three tricuspid cusps. The septomarginal trabecula (moderator band) crosses the chamber from the septum to the base of the anterior papillary muscle. It carries the right bundle branch, so the anterior papillary muscle is activated early.

Shape and function. Because the interventricular septum bulges into it, the right ventricle is crescent-shaped in cross-section and wraps around the left ventricle. Its free wall is only 3–5 mm thick. This is enough, because it pumps into the low-resistance pulmonary circulation at about 25/5 mmHg. It works like a bellows, with the free wall moving toward the septum. It tolerates rises in afterload poorly, for example in pulmonary embolism or pulmonary hypertension.

Location

Front and right of the heart. It forms most of the sternocostal surface and the inferior border of the cardiac silhouette.

Parts & subdivisions

Trabeculae carneae

Coarse, irregular muscular ridges in the inflow part.

Papillary muscles

Anterior, posterior and septal. They anchor the tricuspid chordae.

Moderator band

Septomarginal trabecula carrying the right bundle branch.

Supraventricular crest

Muscular ridge separating inflow from outflow.

Conus arteriosus (infundibulum)

Smooth outflow tract leading to the pulmonary valve.

Tricuspid orifice

Inlet from the right atrium.

Pulmonary orifice

Outlet to the pulmonary trunk.

Function

Pumps all of the systemic venous return through the lungs for gas exchange.

Ejects the same stroke volume as the left ventricle, but at about one-fifth of the pressure.

Physiology

Right ventricular pressure is about 15–30 mmHg in systole and 2–8 mmHg at end-diastole. Its end-diastolic volume is similar to, or slightly larger than, that of the left ventricle. Inspiration increases venous return, so right ventricular output rises and pulmonary valve closure is delayed. This produces physiological splitting of the second heart sound (S2).

Clinical significance

Right ventricular infarction

Right ventricular infarction complicates a proximal RCA occlusion causing an inferior MI. Patients are hypotensive with a raised JVP but clear lungs. The right-sided chest lead V4R shows ST elevation. Because the failing right ventricle depends on preload, give fluids and avoid nitrates.

Cor pulmonale

Cor pulmonale is right ventricular hypertrophy and failure caused by lung disease or pulmonary hypertension. The ECG shows right axis deviation and a dominant R wave in V1.

Arrhythmogenic right ventricular cardiomyopathy

In arrhythmogenic right ventricular cardiomyopathy, mutations in desmosomal genes cause right ventricular muscle to be replaced by fibrous tissue and fat. It causes ventricular arrhythmias and sudden death in young people. The ECG may show epsilon waves.