Former WWE manager Paul Bearer (a/k/a William Moody) died of a heart attack caused by supraventricular tachycardia (SVT), or rapid heart rate, according to his son Michael. SVT is a treatable condition and not generally life threatening, but it appears Moody ignored the symptons until too late. You can read more at http://www.tmz.com/2013/03/23/paul-bearer-heart-attack/.