artificial heart

artificial heart
Name	Artificial Heart
MeshID	D001281

artificial heart. An artificial heart is a prosthetic device implanted to replace a failing biological heart. These devices are distinct from ventricular assist devices, which support a native heart, as they are designed for complete replacement of the organ's pumping function. Primarily used as a bridge to transplantation for patients awaiting a donor organ, some models are also approved for permanent use, known as destination therapy.

History

The concept of mechanical circulatory support dates to the pioneering work of Paul Winchell in the 1950s, who patented an early design. The first clinical milestone was achieved by surgeon Denton Cooley in 1969 at the Texas Heart Institute, who implanted the Liotta heart temporarily. The first permanent implant of the Jarvik-7, designed by Robert Jarvik, was performed on Barney Clark in 1982 at the University of Utah. Subsequent decades saw pivotal clinical trials, such as those for the AbioCor, the first fully implantable device, and the modern SynCardia temporary Total Artificial Heart. Regulatory approvals from the Food and Drug Administration and Conformité Européenne have been critical in advancing the field.

Design and function

Modern devices typically consist of pneumatic or electrohydraulic pumping mechanisms that simulate the systole and diastole of a natural heart. They are connected to the patient's remaining atria and great vessels—the aorta and pulmonary artery. An internal battery and controller manage pump function, while an external system, often including a console or wearable power pack, provides primary power. Key engineering challenges involve minimizing thrombosis through biocompatible materials like polyurethane and ensuring reliable, durable operation to support systemic and pulmonary circulation.

Types

Artificial hearts are broadly categorized by their intended duration of support and mechanism. The SynCardia temporary Total Artificial Heart is a pneumatically driven, biventricular replacement used as a bridge to transplant. The Carmat bioprosthetic heart incorporates biological tissues and sensors to automatically adjust cardiac output. The AbioCor was a notable fully implantable electrohydraulic system. Research continues on smaller, more durable continuous-flow devices, such as those pioneered by Cleveland Clinic, which use rotary blood pump technology. Distinctions are also made between devices for bridge to transplantation and those for destination therapy.

Clinical use and outcomes

Implantation is a major procedure typically performed at specialized centers like the Texas Heart Institute or Cleveland Clinic. Primary candidates are patients with biventricular heart failure who are ineligible for or awaiting a heart transplant. Post-operative management requires lifelong anticoagulation therapy to prevent stroke and regular monitoring for infection or device malfunction. While survival rates have improved, leading to successful bridge to transplantation in many cases, complications such as bleeding, sepsis, and thromboembolism remain significant risks. Landmark studies, including the REMATCH trial, have demonstrated the life-extending potential of these devices.

Ethical and social considerations

The high cost of devices and implantation surgery, often exceeding hundreds of thousands of dollars, raises questions about resource allocation within healthcare systems like the National Health Service or under Medicare. Patient selection criteria can involve difficult judgments about quality of life and prognosis. The psychological impact on patients, who must adapt to a constant external power source and the sound of the device, is substantial. Furthermore, the development of permanent devices intensifies debates about the definition of human enhancement and the technological pursuit of life extension.

Future developments

Current research focuses on creating fully implantable systems with wireless energy transmission, improved biocompatibility to eliminate anticoagulation needs, and the integration of artificial intelligence for adaptive physiological control. Organizations like the National Institutes of Health and companies such as Carmat and Bivacor are investigating next-generation designs. The long-term goal is to develop a permanent, reliable alternative to heart transplantation, potentially alleviating the critical shortage of donor organs. Collaboration between institutions like the Texas Heart Institute and Cleveland Clinic continues to drive innovation in biomaterials and mechanical engineering.

Category:Medical equipment Category:Cardiology Category:Prosthetics