Heartratevariaty(HRV)of85caseswithAMIwasobservedintheearlyphaseafteronsetandrehabilitationphaseatfirstmonthandsixthmonth,andwascontrastedwithsixtimethresholdindicesof111caseswithcoronaryheartdiseaseandthatof35normalcontrol.WefoundtheHRVofAMIwasapperantlylowerintheacutephasethanthatofcoronaryheartdiseaseandnormalcontrols.HRVrecoveredgraduallywithincliningtobestableafterhalfayear,butitwasstilllowerthanthatofcontrols.LowHRVinearlyphaseofAMIsuggestedthepoorprognosis.