Japan's former Emperor Akihito has been diagnosed with supraventricular tachycardia, a heart rhythm disorder that causes a rapid heartbeat in the upper chambers of the heart, the Imperial Household Agency said Friday.The agency said the diagnosis was made at the University of Tokyo Hospital, where the 91-year-old had been hospitalized until Friday for tests ahead of a new medication regimen to treat existing heart conditions.The former emperor's newly prescribed medication is also effective in treating symptoms of supraventricular tachycardia, according to his aides. The agency said it will…READ FULL ARTICLE