Hannah Montana star Miley Cyrus is suffering from a heart condition. The pop star/actress reveals in her autobiography "Miles to Go" that she has tachycardia, meaning her heart rate exceeds the range of a normal resting heart rate.
And although the condition isn't life-threatening, Cyrus admits she struggles to deal with the issue.
She writes, "The type of tachycardia I have isn't dangerous. It won't hurt me, but it does bother me. There is never a time onstage when I'm not thinking about my heart."