TOKYO - Japan's former emperor Akihito was admitted to a hospital in Tokyo on Tuesday afternoon for detailed tests following an earlier checkup indicating a high likelihood of myocardial ischemia.

According to the Imperial Household Agency, although the former Emperor is not experiencing any symptoms, previous tests suggested insufficient blood flow from the coronary arteries to the heart muscle, a condition known as myocardial ischemia.

He will undergo further examination during his hospital stay.

Now 91 years old, the former emperor was diagnosed three years ago with right-sided heart failure caused by tricuspid regurgitation.

In 2012, at age 78, he underwent coronary artery bypass surgery after being diagnosed with angina. This is his first hospitalization since that procedure 13 years ago.