There have been encouraging results in trials of the patches on primates and on one human patient.
The 46-year-old woman had a heart attack in 2016, then developed heart failure which got steadily worse. In 2021, after all possible treatments had been tried, she chose to have a heart patch.
The researchers say her condition was stable and she experienced no side effects from the implant, before having a heart transplant three months later.
The patch was able to “adapt, grow, mature and start to support the failing heart,” says lead author Prof Wolfram-Hubertus Zimmermann.
Her case shows that new muscle can be added to failing hearts “without safety concerns, such as tumours and arrhythmia [irregular heart rhythms]”, he added.
The patches of engineered heart muscle have to survive in the patient and be nurtured over several months, so are not useful for people who need emergency care, the researchers say.
In trials on monkeys, the research team found the patches were good at contracting, enhancing and thickening the heart wall, which improved the pumping of the whole heart.