A Berlin Heart is a mechanical pump that sits outside the body and helps a child’s failing heart move blood. Formally called the EXCOR Pediatric Ventricular Assist Device, it is the only FDA-approved heart pump specifically designed for children, including newborns and infants too small for adult devices. Its primary purpose is to keep a child alive while waiting for a heart transplant, a role doctors call “bridge to transplant.” In a major clinical trial, 90% of children on the Berlin Heart survived to transplant or recovered enough heart function to have the device removed.
How the Device Works
The Berlin Heart is a pneumatic device, meaning it uses pulses of air to pump blood. One or two clear plastic blood pumps sit outside the child’s body, connected to the heart through tubes (called cannulas) that are surgically sewn onto the heart and major blood vessels. A flexible membrane inside each pump divides it into two chambers: one for air and one for blood. A bedside machine called the Ikus pushes air into the air chamber, which flexes the membrane and pushes blood out. When the air pressure reverses, the membrane pulls back, drawing fresh blood in. Valves inside the pump ensure blood moves in only one direction, mimicking the natural rhythm of a heartbeat.
The Ikus driving unit contains three independent pneumatic systems. One powers each pump, and the third serves as an emergency backup. Medical teams can fine-tune the air pressure to match what each child needs, adjusting the pump rate and force to deliver the right amount of blood flow.
Because the pumps are transparent, nurses and families can actually see the blood flowing through the device. This visibility also lets clinicians watch for blood clots forming inside the pump, one of the ongoing monitoring tasks during support.
Who Needs a Berlin Heart
The Berlin Heart is approved for pediatric patients with severe heart failure who are candidates for a heart transplant and need mechanical support while they wait. This includes children with severe left ventricular dysfunction (where the main pumping chamber can’t do its job) or biventricular dysfunction (where both sides of the heart are failing). The device can support just the left side, just the right side, or both ventricles at once, depending on the child’s condition.
Common reasons a child might need this level of support include dilated cardiomyopathy, myocarditis (inflammation of the heart muscle), and congenital heart defects that have led to heart failure. In some cases, children’s hearts recover enough function while on the device that they can be weaned off without needing a transplant at all.
Pump Sizes for Different Ages
One of the Berlin Heart’s defining features is its range of sizes. The pumps come in 10 ml, 15 ml, 25 ml, 30 ml, 50 ml, and 60 ml volumes. This range allows the device to support patients from newborns weighing just a few kilograms up through teenagers. No other approved heart pump covers this spectrum, which is why the Berlin Heart has become the standard mechanical support option for the smallest and youngest heart failure patients.
Risks and Complications
The Berlin Heart can be lifesaving, but it carries serious risks. The most significant is neurological injury. In the pivotal clinical trial of 204 children, 29% experienced at least one neurological event, and 21% of the entire group had a stroke. Many of these events happened early, with 30 of 73 neurological events occurring within the first 14 days of support. Most strokes were caused by blood clots traveling to the brain, which is why children on the device require careful blood-thinning therapy throughout their time on support.
Neurological injury was the leading cause of death after device implantation. Children who experienced a neurological event had a 42% mortality rate, compared to 18% for those who did not. Researchers found no reliable way to predict beforehand which children would develop these complications.
Infection at the sites where the tubes exit the body is another ongoing concern. Because the cannulas pass through the skin, bacteria can enter. The risk increases with physical movement, particularly in small children where the cannulas are large relative to body size.
Daily Life on the Device
Children on the Berlin Heart remain in the hospital for the duration of support, tethered to the Ikus driving unit. Despite this, rehabilitation is a major part of their care. After the initial surgical recovery, physical therapy teams work to get children sitting, standing, and walking. Some centers even perform exercise testing on a stationary bike to track fitness.
Movement requires careful management. Hospitals use harnesses, abdominal binders, and reinforced dressings to keep the cannulas immobilized during activity, since any shifting at the exit sites raises the risk of infection or disruption. For older children, the goal is independent walking and as much normal activity as the hospital setting allows. For younger children who cannot understand the restrictions, keeping them safe around the device requires constant supervision.
How It Compares to Other Heart Pumps
The Berlin Heart is a pulsatile device, meaning it pumps in beats like a natural heart. Newer continuous-flow pumps, which spin blood in a steady stream using a small internal rotor, have become common in adults and older children. These devices are fully implanted inside the body, with only a thin power cable exiting through the skin, which can allow patients to go home while waiting for transplant.
Early comparisons between the Berlin Heart and continuous-flow devices in children showed similar survival rates and stroke risk. The Berlin Heart group did require longer time on mechanical ventilation after surgery (31.3% vs. 0%). The potential advantage of continuous-flow devices is durability and the possibility of hospital discharge, improving quality of life during what can be a months-long wait. For the smallest patients, though, continuous-flow devices are simply too large to implant, making the Berlin Heart the only option.
FDA Approval and Availability
The Berlin Heart EXCOR Pediatric initially entered the U.S. market under a Humanitarian Device Exemption, a pathway for devices that treat conditions affecting fewer than 8,000 patients per year. It received full premarket approval (PMA) from the FDA on June 6, 2017, for use as a bridge to heart transplant in children. The device has undergone more than 55 regulatory supplements since then, reflecting ongoing updates to its design, labeling, and clinical protocols. It is manufactured by Berlin Heart, with U.S. operations based in The Woodlands, Texas, and is available at specialized pediatric heart failure centers across the country.