The heart of Frederic Chopin, pickled in a jar of brandy and encased in a stone pillar in a church in Poland, shows the Polish composer died from complications of tuberculosis, according to an early version of an article published by the American Journal of Medicine.

According to the article, to be published in its final form in February, researchers found Chopin's heart "submerged in an amber-brown liquid", thought to be cognac, which was often used for tissue preservation.

Frederic Chopin was only 39 when he died in Paris in 1849.

The researchers did not open the jar but they could see that Chopin's heart was "massively enlarged and floppy", they wrote in the article. It was also covered in a white substance that gave it a "frosted" appearance, leading the researchers to conclude that Chopin had suffered from pericarditis, an inflammation of tissue around the heart that was likely the result of TB. Previous theories held that he may have died from cystic fibrosis.

The heart has a long and contentious history. Chopin, who died in Paris in 1849 at the age of 39, dreaded being buried alive and asked that his body be opened before burial and his heart sent to Warsaw. Accordingly, his heart was removed, sealed in a crystal jar and smuggled past Russian authorities into what is now Poland.