“The heart of creatures is the foundation of life, the prince of all, the sum of their microcosmos from where all vigour and strength does flow”.

William Harvey De moto cordis 1628

The importance of the heart to human life has been known throughout the ages. When damaged beyond repair, life becomes intolerable or impossible. Heart failure is emerging as one of the most common causes of disability and death. It is estimated that more than 600,000 people suffer from the disease in the UK and the cost to the NHS is over £360 million per year.
Severe heart failure carries a very bad prognosis, with a one year survival of around 50 per cent. For these patients, heart transplantation has been a major success and results in improved longevity and quality of life.

Although heart transplantation continues to be an effective therapeutic modality, it is limited by the shortage of donors. This has stimulated research into alternative therapies, including the use of mechanical hearts and assist devices for total or near total support of the circulation for progressively longer periods of time. This has heightened the expectations of patients and clinicians and generated increasing commercial interest. To date, accumulating experience has provided some answers and begged more questions.

Currently the use of assist devices in parallel with the failing heart is preferred to the use of a total artificial heart, which necessitates explantation of the heart. The main indications for the use of an LVADs is as a bridge to transplantation in critically ill patients. This has been shown to enhance survival with an improved long term outcome.

The use of LVADs is also being evaluated for “permanent” use in patients who are not suitable for transplantation. One randomised trial for the use of Thoratec Heartmate I LVAD was documented to improve survival and quality of life in this particularly difficult group of patients. However the overall survival of the treated group was only 25 per cent at two years. This low figure is expected to improve with the introduction of technical refinements and new innovations in device design. The safety and efficacy of the newer devices however will need to be rigorously tested.

A particularly exciting use of the device is as a “bridge to recovery”. It has been shown by several groups that unloading of the left ventricle for prolonged periods can result in shrinkage of the heart, which is associated with varying degrees of improvement in function. This improvement in function can be sufficient to allow explantation of the device with excellent recovery of approximately five per cent of patients. In an attempt to enhance the durability of recovery, a strategy of combining LVAD support with drugs to initially help regression of heart enlargement, followed by stimulating heart muscle growth has been initiated in the UK. Initial experience has been encouraging, with approximately two thirds of patients receiving this therapy being bridged to recovery.

Currently, a multi-centre international trial of this protocol has been started. The use of LVADs is an expanding form of therapy with a great potential for benefiting the community. However, there are important limitations coupled with rapid advances. This necessitates careful evaluation without raising unrealistic expectations.