For the past 40 years, medical research has attempted to improve and even replace the heart's function through the use of artificial support systems. Mechanical assist devices are usually used only as a last resort - when all other treatment options have been exhausted and the patient is at risk of dying from heart failure. This is because their implantation is associated with considerable risks due to the need for anticoagulation therapy. Mechanical pumps that permanently replace the function of the heart (the original artificial heart) never became established in routine clinical practice. All currently available systems are implanted into the patient's own heart.

A distinction must be made between internal and external pumps, pulsatile vs. nonpulsatile pumps, devices that support one ventricle (left or right ventricular assist device) vs. devices that support two ventricles (biventricular assist device), as well as temporary VAD support as a bridge to transplant vs. long-term VAD support.

Patients requiring short-term circulatory support as a bridge to transplant should be treated with external biventricular VAD systems, which are able to provide support to both ventricles, thus allowing the ventricles to recover fully or allowing the patient's condition to improve in preparation for surgery.

Other patients may require long-term support for a duration of months or even years, to allow the heart to recover, or whilst waiting for a heart transplant. These patients should be treated with internal VADs that support just one of the ventricles. Although the VAD is implanted, it has to remain connected to an external control unit and power supply, which means a connecting cable has to be permanently inserted via an entry site in the side of the abdomen.

Systems using inductive coupling for wireless control and power supply have not become established in routine practice. These devices usually use an internal spinning rotor or turbine to propel blood, resulting in a continuous flow of blood that is in stark contrast to the pulsatile action of the heart or pneumatically driven pulsatile assist devices. The body, however, appears to cope remarkably well with this type of non-pulsatile blood flow, even over the long term.

The results achieved by these mechanical assist devices, as well as the constant advances made in relation to this type of technology, mean that left ventricular assist devices (LVADs) are now used as destination (permanent) therapy in patients who cannot undergo a heart transplant as a result of their age or multiple comorbidities. This treatment option is, however, limited to patients with severely decreased ventricular function, and only after all other conventional surgical, pharmacological and electrophysiology measures have been exhausted. Although this treatment option is relatively new and study data are limited to follow-up periods of only a few years, data so far available suggest that patients can live with only minor limitations and achieve a good quality of life. As a result, this treatment option is gaining increasing prominence among the options offered as part of our interdisciplinary treatment concept for patients with severe heart failure (NYHA class III or above). As the next generation of assist devices is likely to be of reduced size and with further improvements, it is also likely that even patients who do not currently qualify for treatment will be able to benefit from this technology.

However, certain risks remain, mainly due to the need for anticoagulation therapy which requires close monitoring of the patient, as well as the risk of LVAD-related infections, which can have devastating consequences. A high degree of vigilance is therefore required for the duration of treatment. As treatment involves close and regular monitoring by specialists even after the patient has been discharged, this type of treatment can only be offered by large, specialist centers with an appropriate level of experience and expertise.