Initially normal ECGs may be found in 8% of patients with an acute MI, and 35% of patients with acute MI may have an initially non-specific ECG. The sensitivity of electrocardiography increases with serial ECG testing, but never reaches 100% in terms of sensitivity or reliability. The bottom line is that although ECGs are very good for ruling IN acute MI, they are not so great at ruling OUT acute MI. The HPI is the most important tool. ["Prognostic Value of a Normal or Nonspecific Initial ECG in AMI," JAMA 2001]
