Implantable defibrillators that are used to treat cardiac patients may not help save women’s lives, according to a new study.

Researchers at the Providence Hospital Heart Institute and Medical Center analysed the results of five previous trials looking into implantable defibrillator trials conducted between 1950 and 2008 but looked only at the 934 women participants, according to

The study found that women who had been implanted with the devices and also received drug therapy were just as likely to die as women who had just been given drug therapy.

Installing one of the devices costs between $20,000 and $30,000, according to the news service.

Approximately 5.3 million people suffer from heart failure in the US alone while globally, the number is almost 22 million.

Defibrillators detect the abnormal quivering of heart and deliver an electric shock to restart the heart’s normal rhythm.