Revolutionary.

Here is an excerpt from a BBC.com article:

Scientists have halted the advance of heart disease in mice - and even reversed some of its effects.

The study provides hard evidence that tiny pieces of genetic material called microRNA can play a key role in the development of heart disease. The therapy, featured in the journal Nature, targets and blocks microRNA in heart cells. A US specialist said that, with trials under way in other animals, human tests may be only a few years away.

The importance of microRNAs to heart disease - and a host of other diseases - has already been suggested by other scientists. Their job is to regulate the activity of our genes, but with many different types present in the cell, scientists are trying to establish which plays the biggest role. The US and German scientists are focusing on one type labelled microRNA-21, and their role in a type of heart cell called the cardiac fibroblast, which helps provide the structure of the organ, and plays a critical role in the progressive scarring which stops it working properly in heart disease.

Until recently, that process was thought to be an irreversible one. The researchers found that cells in a failing heart had higher levels of this microRNA, and linked it to a chemical signalling pathway which leads to the tissue damage found in the condition.