Artificial Hearts

Artificial Hearts – the miracle machines giving cardiac patients heart

Heart failure affects over 23 million people worldwide every year and a proportion of patients will eventually require a heart transplant.

Only 6,000 donor hearts are available each year, a tiny proportion compared to the overwhelming need.

A lifeline exists for some of the sickest patients who are awaiting a transplant, or overseas in those who may not be eligible for a heart transplant, in the form of a ventricular assist device or a total artificial heart.

Both devices can buy time, but they are not yet permanent long-term solutions. That could soon change with the development of the BiVACOR Total Artificial Heart. The collaborative project, in which the Institute’s Professor Chris Hayward is playing a pivotal role in, has just been awarded a $50 million Medical Research Future Fund (MRFF) Grant. The Institute's Professor Chris Hayward is working with BiVACOR engineers and collaborators at Monash University to get the product ready for human clinical trials.

What is an artificial heart?

An artificial heart is a device that replaces both ventricles and all four heart valves, taking over the function of the native heart.

It is implanted in the body, replacing the native heart and is connected to an external power source (eg. portable batteries or external wall power source) through an electrical cable known as a driveline.

It restores normal blood flow to the other organs in the body.

Having both ventricles fail is less common in advanced end-stage heart failure with around 85-90 per cent of patients only having their left ventricle fail. This qualifies them for a smaller and less invasive pump know as a left ventricular assist device or LVAD.

What is a Left Ventricular Assist Device (LVAD)?

An LVAD is a type of artificial heart pump that takes over the role of the left ventricle which pumps blood into the aorta (large blood vessel) and around the body, supplying other organs with oxygen enriched blood. It attaches directly to the patient’s heart.

This device can generate up to 10 litres/minute of blood flow and is capable of supporting the human heart and essentially taking over what the heart does in terms of cardiac function and support, until the patient receives a heart transplant.

What patients are suitable for an artificial heart?

An artificial heart is considered for patients when both ventricles fail, until they get a heart transplant.

As the artificial heart is bigger than a normal heart, patients are required to undergo a CT scan to determine if there is enough room in their chest cavity for the implant. It may not be suitable for women or smaller people.

How long can a person live with a mechanical device?

LVADs can keep people alive for almost six years. Research shows that around 80–85% of patients are alive 12 months after having an LVAD implanted, whilst up to three quarter survive for two years.

This timeframe may just be what is needed for their wait for a heart transplant.

How long have artificial hearts been in use for?

The first artificial heart was implanted in a dog in the former Soviet Republic in the 1930s. The first successful human implant, known as the Jarvik 7, took place in 1982 in the US where a male patient survived for 112 days. The first Australian implant did not take place till 2010 at St Vincent’s Hospital in Sydney.

Can a person live a normal life with an artificial heart or LVAD?

Yes, a person with an artificial heart or LVAD can live a relatively normal life with a few adjustments. The batteries have a shelf life of a few hours, and need to be recharged, but backup batteries are available which means people can move around freely.

People have to be very careful not to get the pump wet which rules out water sports.

When showering, the pump is protected by a special “shower-bag” which protects it from getting wet.

The pumps also make a constant whirring sound which can affect sleep in some patients; most patients get used to this sound with time.

Are these mechanical devices safe?

Artificial hearts or LVDs on the whole are fairly safe. There are a few risks though that need to be considered.

One of the biggest risks is infection; the devices are powered by external batteries which connect to the body through a drive-line where the skin is pierced.

These pumps also affect blood components and angiogenesis, (or blood vessel formation) and research has shown that the pumps can contribute to increased bleeding. This risk is increased as all patients are also treated with blood thinners to reduce the risk of clots within the pump and to prevent strokes.

When will we see the world’s first single durable ventricular assist device that supports both ventricles?

For decades, scientists have been trying to build a long-lasting replacement for the human heart. It’s considered one of the Holy Grails of modern medicine and could save tens of thousands of lives every year

What was once a dream, is now getting closer to reality with clinical trials expected to start next year of a device developed by Australian engineer Daniel Timms.

The BiVACOR total artificial heart can replace the function of the failing heart. It’s smaller – designed to even fit in children, more powerful – to deliver enough cardio output to an adult male during exercise, more responsive and more durable than the existing devices on the market.

It’s hoped that future designs will have smaller portable batteries and in the future the electronics will be implanted inside the body with charging done through the skin using electromagnetic induction.

It’s being designed to provide more than 10 years of support. A game-changer for heart failure. It also differs from other artificial hearts by having a single spinning disk, suspended within a magnetic field, which sends blood to the lungs and around the body.

How has the Victor Chang Cardiac Research Institute been involved in artificial heart technology?

A team led by the Institute's Professor Chris Hayward is working with BiVACOR engineers and other collaborators to get the product ready for clinical trials planned for late 2022/early 2023. Thanks to the Australian government TTRA grant and the MRFF funding, Professor Hayward's team, based at the Institute and St Vincent's Hospital in Sydney, is conducting studies to prepare the BiVACOR device for transplantation. This includes placing the device in the chests of heart transplant patients to learn about its fit and placement. It’s hoped the first Australian human trial will take place at St Vincent’s in July 2024. Learn more about the breakthrough technology and the Institute’s pivotal involvement in this The Sydney Morning Herald feature.

The Institute’s A/Prof Kavitha Muthiah is also behind new research into the devastating side-effects that can plague patients who are supported with mechanical heart pumps, waiting for a heart transplant. Learn more about A/Prof Muthiah's research project in an interview that was done for our Women in Science series.