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Severe heart failure has one feature that is hard to accept: heart muscle that has died after an infarction does not grow back. All existing medicines at best slow the deterioration; they do not return what has been lost. When the possibilities of drug treatment are exhausted, what remains is mechanical circulatory support and a heart transplant — and there are many times fewer donor hearts than people waiting. The idea of growing the missing muscle in a laboratory and sewing it onto the heart looks like science fiction. Over the past few years it has stopped being that — although it is still a long way from ordinary treatment.
What a “heart patch” is
The work is being done by a group at the University Medical Center Göttingen under Professor Wolfram-Hubertus Zimmermann. In outline the method is this: induced pluripotent stem cells are taken — ordinary cells of an adult which have been “reprogrammed” in the laboratory back into a universal state — and are directed to become heart muscle cells and connective tissue cells. The resulting mixture is poured into a collagen gel and grown in a mould that sets the required size. After several weeks a living flap of tissue is obtained which contracts of its own accord.
During an operation this flap is sewn onto the outside of the weakened part of the heart muscle. The logic differs from the familiar one: the patch does not replace the pump and does not support it mechanically, as an artificial ventricle does, but adds working muscle tissue to the heart.
What has changed since the first reports
When the method was first described, it was a matter of experiments in laboratory animals and of plans for the future. Since then the main thing has happened — the method has reached human beings.
In January 2025 a paper appeared in Nature bringing together two blocks of data. The first was a large preclinical study in monkeys: dozens of implanted patches, follow-up of up to six months, confirmed ingrowth of vessels into the transplanted tissue and, no less important, the absence of the two main fears about this technology — dangerous rhythm disturbances and tumour growth. The second block was the first use in a person with severe heart failure, where subsequent examination made it possible to show that the transplanted muscle tissue had taken and was working.
On the basis of these data the clinical trial BioVAT-HF-DZHK20 was launched — an early-phase trial, that is, one aimed above all at safety and at finding the dose (in this case the number of cells in the patch). It is running in Göttingen with the participation of the German Centre for Cardiovascular Research. By 2025 about fifteen patients with end-stage heart failure had been treated within it, and interim results were presented at the scientific session of the American Heart Association in the autumn of 2025.
What this does not yet mean
This is the most important part. The “heart patch” today is not a treatment but the subject of a clinical trial. You cannot book it as you would an operation: taking part in a trial is possible only on exact compliance with the selection criteria set by the protocol, and only through the centre conducting it.
What is involved is an early phase of testing and a small number of participants with a very severe course of the disease. Such studies answer the question “is it safe and does it take”, but not yet the question of how the method affects wellbeing and length of life compared with existing approaches — larger and longer studies are needed for that.
There is a practical limitation too: the tissue is grown not from the patient’s own cells but from a donor cell line, so that, as after an organ transplant, suppression of the immune response is required, with all the difficulties that go with it. The long-term safety of the method is still being studied.
The standard of care in severe heart failure today remains the same and is thoroughly established: a tailored drug regimen, where indicated resynchronisation therapy and an implantable defibrillator, mechanical circulatory support and a heart transplant. That is where the conversation begins when the disease has gone far — not with experimental methods.
This material is for information only and does not replace a consultation with a doctor. The method described is at the stage of a clinical trial and is not an available form of treatment. What help is possible, and to what extent, can be determined only after an examination in person.