A new "gadget" to treat heart failure was widely reported in the media today, with the Daily Express claiming that the implant could "revolutionise the treatment of chronic heart failure and save millions of lives". The news was also reported by BBC News and The Daily Telegraph.
The story is based on a press release from the University of Leicester explaining that the device will be fitted for the first time in a UK patient with chronic heart failure today. The new implant stimulates part of the nerve supply to the heart (the vagus nerve), slowing the heart rate and reducing blood pressure. Researchers hope this will help to reduce stress on the heart and alleviate heart failure symptoms.
Heart failure is a relatively common condition in which the heart has difficulty pumping blood around the body. Although this new device sounds promising, it is important to point out that the UK operation is part of an ongoing, international clinical trial looking at its effectiveness. The new device is being used alongside standard medical treatment for heart failure. This trial will see whether, compared with medical treatment alone, the device reduces hospitalisation and mortality rates in people with heart failure. The results of this, and other trials of the device, will need to be reviewed before it is decided whether the device is safe and effective enough to become available as a treatment for heart failure.
What is heart failure?
Heart failure means the heart has difficulty pumping adequate blood to meet the demands of the body. This usually occurs because the heart muscle has become too weak or stiff to work properly. Heart failure is associated with a number of other conditions that include coronary heart disease (heart attack, which results in damaged heart muscle, is the most common cause of heart failure), high blood pressure, heart rhythm disturbances, heart valve disease and an overactive thyroid gland.
The symptoms of heart failure may include breathlessness, extreme tiredness and swelling of the legs, ankles and feet. Heart failure is also associated with an increased risk of sudden death from dangerous heart rhythm disturbances.
There are several treatments for heart failure that can help strengthen the heart, improve symptoms and enable people with the disease to live fuller lives. The treatment of heart failure typically involves a number of medical treatments and appropriate lifestyle changes (such as stopping smoking). Other treatments may be used depending on the underlying cause of heart failure, for example, some people may have surgery to repair or replace a damaged heart valve.
How does the new device work?
The press release describes that in patients with heart failure, the autonomic nervous system, which regulates involuntary functions such as heart muscle activity, is out of balance. There are two branches of the autonomic nerve supply to the heart, called the sympathetic and the parasympathetic nerves. They work together to regulate the heart, with the sympathetic system increasing cardiovascular activity, while the parasympathetic system decreases it. In people with heart failure, the balance between these two systems is disrupted, leading to added stress on the heart.
The new device, called CardioFit, is designed to restore balance by stimulating the vagus nerve on the right side of the neck. The vagus nerve forms the parasympathetic nervous supply to the heart, and its stimulation slows heart rate and reduces blood pressure, thus reducing stress on the heart. The CardioFit looks like a pacemaker and is implanted under the skin of the chest.
How far has it been tested?
So far, the implant has been tested for safety and performance in a pilot study involving 32 patients with heart failure from several European countries. According to the researchers, this study showed patients had improvements in key clinical measures including improved left ventricular function (the chamber that pumps blood out to the rest of the body), heart rate variability and quality of life. The BBC reports that, before this, it was found to be effective in improving survival in studies of the device in animals, although the press release only says that it improved heart function and reversed negative changes.
The new study is called the INOVATE-HF. It is a randomised controlled trial to assess whether the implant has any effect on hospital admissions and mortality from heart failure. The press release reports that the trial will enrol more than 600 patients at up to 80 centres worldwide. The study is recruiting patients who have been diagnosed with heart failure, who are aged 18 or over and who are being treated with medicines but continue to have symptoms, such as breathlessness and tiredness.
As part of the trial, the UK’s first operation to implant the device is reportedly being performed today.
To find out more about the trial, visit the INOVATE-HF details on the International Clinical Trials Registry Platform.