A Korean-American cardiologist arrived in North Korea last month to treat the aunt of North Korean leader Kim Jong-un, a source familiar with affairs inside the communist state said Thursday, prompting speculation about the state of her health.

   Kim Kyong-hui, the current leader's aunt and younger sister of late former leader Kim Jong-il, has been known to have a heart disease, but the doctor's alleged visit could be an indication that she has fallen into critical condition.

   "An American cardiologist arrived in Pyongyang around Sept. 28 to treat former secretary Kim Kyong-hui," the source said, speaking on condition of anonymity.

   The 68-year-old aunt served as a senior secretary of North Korea's ruling Workers' Party before she was apparently removed from the country's power elite following last December's execution of her once powerful husband, Jang Song-thaek, on charges of treason.

   It is unclear whether the doctor is still in Pyongyang or has returned to the United States, the source said.

   The source also denied speculation that the doctor's visit could be linked to recent reports that the young North Korean leader is suffering from gout.

   "Kim Jong-un isn't in critical condition, and it appears that he has gout," the source said. "It's unlikely that the cardiologist went to treat Kim Jong-un."

   If the U.S. doctor's visit is true, it's quite unusual, because North Korea is currently in deep conflict with Washington over a host of issues, including its refusal to lay down its nuclear programs and its detention of three U.S. civilians. (Yonhap)