Dr Singh underwent angiography as part of a series of heart-related tests at All India Institute of Medical Sciences (AIIMS) in New Delhi on Wednesday, the Daily Times reports.
He was declared fit by his doctor at AIIMS, but he is expected to resume work only after a couple of days.
"The prime minister underwent coronary angiography along with a series of other tests. He will be returning home tonight and will be resuming his duties from tomorrow," KS Reddy, a cardiologist said.
Dr. Singh underwent a 100-minute heart check-up at AIIMS after postponing his scheduled visit to Kolkata and cancelling other engagements for two days.
However, doctors at the hospital called it a 'routine check-up'.
"There is no need to worry, the PM is perfectly fine," Dr DK Sharma, AIIMS in-charge, claimed.
But other sources of the paper claimed detection of an artery blockage that prompted Singh to undergo a full evaluation diagnosis
Apart for a prostate gland surgery and a cataract treatment, Singh has been in good health since he was sworn in as prime minister in May 2004.&13;&13;