The right ventricle, your heart’s lower right chamber, is the part that pumps blood to the lungs. Every beat, it pushes oxygen-poor blood through the pulmonary valve and into the pulmonary arteries, which carry that blood into lung tissue where it picks up fresh oxygen and releases carbon dioxide.
How the Right Ventricle Works
Your heart has four chambers: two upper ones (atria) that receive blood, and two lower ones (ventricles) that pump it out. The right ventricle handles the lung-bound route, known as pulmonary circulation. Blood that has already delivered its oxygen to your body returns to the heart through large veins, enters the right atrium, then drops down into the right ventricle. From there, it gets pumped out to the lungs.
Unlike the left ventricle, which squeezes blood out to the entire body, the right ventricle only needs to push blood a short distance into the lungs. This is a low-pressure system. Normal pressure in the pulmonary arteries averages around 21 mmHg on the systolic (pumping) side, compared to roughly 120 mmHg in the body’s main artery. Because of this lighter workload, the right ventricle’s muscular wall is noticeably thinner than the left ventricle’s. The wall thickness directly reflects how hard each chamber has to work.
The right ventricle also contracts differently. Rather than squeezing inward from all sides the way the left ventricle does, it shortens lengthwise in a wave-like motion. Contraction starts near the inflow area, moves through the mid-wall, and finishes at the outflow tract, all within about 25 to 50 milliseconds. This peristaltic pattern is efficient for moving blood into the compliant, flexible pulmonary vessels.
The Path From Heart to Lungs
When the right ventricle contracts, blood passes through the pulmonary valve, a one-way gate with crescent-shaped flaps that sits between the ventricle and the main pulmonary artery (also called the pulmonary trunk). The valve opens during each heartbeat to let blood through, then snaps shut between beats so blood doesn’t flow backward into the ventricle. This closing is what allows the right ventricle to refill properly before the next contraction.
Once past the valve, blood enters the pulmonary trunk, which quickly splits into a left and right pulmonary artery, one heading to each lung. Inside the lungs, these arteries branch into increasingly smaller vessels until they reach tiny capillaries wrapped around air sacs. That’s where gas exchange happens: carbon dioxide moves out of the blood and into the air you exhale, while oxygen moves in. The now oxygen-rich blood travels back to the heart through the pulmonary veins, entering the left atrium, and from there it’s pumped out to the rest of your body by the left ventricle.
Right Ventricle Performance
A healthy right ventricle ejects about 52% of its blood volume with each beat, a measurement called ejection fraction. Anything above 40% is generally considered normal. This means the chamber doesn’t empty completely with each contraction, which is by design. Some blood always remains to help maintain smooth, continuous flow.
The electrical signal that triggers right ventricle contraction travels through a dedicated wiring pathway called the right bundle branch. This thin strand of fast-conducting fibers runs down the wall separating the two ventricles, then fans out across the right ventricle’s inner surface. It ensures the muscle fibers contract in a coordinated sequence rather than firing randomly.
What Happens When This System Struggles
The right ventricle is built for a low-pressure job, which makes it vulnerable when that pressure rises. In pulmonary hypertension, the arteries in the lungs narrow or stiffen, forcing the right ventricle to push harder than usual. A pulmonary artery systolic pressure above 30 mmHg on an ultrasound of the heart is considered outside the normal range for most people.
Over time, that extra effort causes the right ventricle’s walls to thicken and the chamber itself to stretch, trying to compensate for the increased resistance. These changes create progressively more strain. If the condition goes unchecked, the right ventricle can weaken to the point of failure, meaning it can no longer pump enough blood to the lungs. This is called right heart failure, and it leads to symptoms like swelling in the legs and abdomen, fatigue, and shortness of breath, because blood backs up in the veins instead of moving forward through the lungs.
Conditions that can raise pulmonary pressure include chronic lung diseases, blood clots in the lungs, sleep apnea, and certain heart valve problems. The right ventricle can tolerate modest increases in pressure for years, but sustained high pressure eventually outpaces its ability to adapt.