Prime Minister Manmohan Singh [Images] was discharged early on Thursday morning from the All India Institute of Medical Sciences, where he underwent coronary angiography, as part of a series of heart-related tests.

"He has been discharged. He is hale and hearty and has gone back home," Dr K S Reddy, his personal physician, who is heading a multi-disciplinary medical team, said.

Though Dr Reddy did not specify the time the prime minister was discharged, security sources at the hospital said he was discharged at 6:30 am.

The 76-year-old prime minister had undergone coronary angiography along with a series of other tests at the hospital.

Singh, who had undergone a coronary artery by-pass surgery in the United Kingdom several years back, had complained of some chest pain after which a decision to carry out the tests was taken, according to hospital sources.

"Periodic evaluation of his medical status is done as a matter of routine and diagnostic tests are performed," Reddy said. He refused to share the results of the tests, including ECG and blood, citing medical confidentiality. 
                                                             
Specific treatment approaches are still being identified through careful consideration of several potentially available options because several effective treatments and therapies are available and each one of them will be considered," Reddy had said on Wednesday.

The Prime Minister's office in a statement earlier said Singh had undergone 'diagnostic evaluation'.

"Treatment procedures which have been recommended would be undertaken after a few days. During this period, the Prime Minister would resume his normal duties," it said.

Singh had visited AIIMS on Tuesday evening for an 'overall medical checkup' and had later gone back to his residence.

He returned on Wednesday morning for a further checkup and was taken to Centre for Cardiothoracic and Vascular Sciences at AIIMS, where the VVIP room was kept ready for him. During the entire morning, doctors conducted medical tests on him.

According to hospital sources, some blockages have been detected in his heart vessels in the tests conducted on Wednesday. However, Reddy refused to comment.

He said whenever the final treatment will decided, it may be conveyed, if appropriate.