Artificial hearts represent a significant advancement in medical technology, designed to support or completely replace the function of a failing human heart. These devices offer individuals facing severe cardiac conditions the ability to extend their lives and improve their quality of living. They provide new avenues for treating heart failure, a condition where the heart cannot pump enough blood to meet the body’s needs.
Yes, They Are Real
Artificial hearts exist primarily in two main categories: Total Artificial Hearts (TAHs) and Ventricular Assist Devices (VADs). A Total Artificial Heart completely replaces the heart’s lower chambers, the ventricles, and often the heart valves, taking over the entire pumping function of the native heart.
In contrast, a Ventricular Assist Device (VAD) is a mechanical pump that assists a failing heart rather than replacing it entirely. VADs are designed to support either the left ventricle (Left Ventricular Assist Device or LVAD), the right ventricle (Right Ventricular Assist Device or RVAD), or both (Biventricular Assist Device or BiVAD). These devices help the weakened heart pump blood more effectively to the rest of the body or to the lungs.
How Artificial Hearts Work
Artificial hearts, whether TAHs or VADs, operate on mechanical principles to circulate blood. These devices typically consist of a pump, cannulas (tubes that connect the device to the heart and blood vessels), a power source, and a control system. The pump component takes blood from a failing heart chamber or chambers and propels it into the body’s main arteries, ensuring adequate blood flow.
TAHs are implanted after the removal of the damaged ventricles and connect to the atria (upper chambers) and major arteries. An external driver, which can be portable, powers the artificial heart by pushing air through tubes connected to the device, maintaining a steady pumping rhythm. Some VADs can employ either pulsatile flow, mimicking the natural heartbeat, or continuous flow, providing a constant stream of blood. Continuous-flow VADs are generally smaller, more durable, and have improved reliability compared to earlier pulsatile models. The control system, often a small computer worn outside the body, monitors the device’s function and can adjust blood flow based on the patient’s activity levels.
Who Receives an Artificial Heart and Why
Artificial hearts are typically used for individuals with end-stage heart failure, where the heart can no longer pump enough blood to meet the body’s demands despite medical treatment. Patients may receive these devices due to conditions such as severe cardiomyopathy, massive heart attacks, or certain congenital heart defects. The decision to implant an artificial heart is usually made when other treatments are no longer effective.
These devices serve two primary purposes: “bridge to transplant” or “destination therapy.” As a bridge to transplant, the device temporarily supports the patient while they await a suitable donor heart for transplantation. Destination therapy involves the long-term, permanent use of the artificial heart for patients who are not eligible for a heart transplant.
Current Limitations and Future Directions
Artificial hearts currently present several limitations. Patients with these devices face risks such as blood clots, which can lead to stroke, and infections, particularly at the site where external power lines enter the body. Bleeding is another common complication, often due to the required anti-clotting medications. Device malfunctions, although less common with newer generations, remain a concern. The need for an external power source and its associated driveline can also impact a patient’s mobility and daily life.
Future advancements aim to develop smaller, more durable devices with reduced complication rates. Scientists are exploring fully implantable systems with wireless charging to eliminate the external driveline and lower infection risks. Additionally, the field of regenerative medicine is investigating ways to repair damaged heart tissue and regenerate heart cells, potentially offering biological alternatives or complements to mechanical devices in the future.