Open heart surgery is carried out on a baby at the Narayana Hrudayalaya Institute of Cardiac Sciences in Bangalore, India, June 30, 2005.

A robot helped doctors carry out the world's first remote heart surgery in India – a "milestone" development, according to a study published in medical journal The Lancet's EClinicalMedicine.

From 20 miles away, the surgeon controlled a robotic arm to perform heart surgery on five patients, wrote Apex Heart Institute's cardiologists, Tejas Patel and Sanjay Shah, with Samir Pancholy, director at The Wright Center for Graduate Medical Education Cardiology Fellowship.

The five patients had coronary artery disease, a condition wherein blood vessels are damaged and the heart can't receive enough blood supply. The doctor placed a small structure in each patient's blood vessel to open it up, which allowed blood to flow through, according to the report.

The authors noted that this operation was "successful in all aspects" for the five patients and that none of them experienced procedural complications.

While surgeons have used robots in operations since 2001, the success of these surgeries could be a step forward for the treatment of heart disease. Cardiovascular diseases are the number one cause of death globally, according to the World Health Organization.