Though Prime Minister Manmohan Singh [Images] is undergoing a complex by-pass surgery, leading cardiologists on Saturday said it is a 'routine' operation and there is nothing to worry about.

"No, I do not think there is any reason to worry. Everything should be all right because this operation is a routine one, which is done at AIIMS since 1975," AIIMS former director Dr P V Venugopal, who carried out the country's first heart transplant, said.

His view is also backed by Dr Upendra Kaul, a leading cardiologist.

"I don't think there is room for any concern or problem," Dr Kaul, executive director (Cardiology) at Fortis and Escorts hospitals said.

"Any person who has undergone a by-pass surgery eight to ten years ago runs a chance of having the problem again and one of the solutions is repeat bypass surgery if there are multiple blockages. It is done regularly and it needs a little more care," he said.

Asked by when the Prime Minister would be able to resume his work, Dr Venugopal said, "In fact, we don't like patients to be on bed rest. After 48 hours (of the operation), we ask them to slowly start with their daily lives."

"Once, he (Prime Minister) leaves the hospital in about seven days; he would be able to resume his normal routine in about 4-6 weeks," he said.