Deep negative T waves (NTW) are a frequent finding following acute ST-segment elevation coronary syndromes but its possible relation with the status of regional contractility remains unclear. We studied 52 patients with a first ST-elevation acute coronary syndrome with or without NTW in anterior leads (> or =3 mm in > or=3 leads) and assessed the ejection fraction and regional myocardial contractility by contrast left ventriculography at baseline and during a low-dose dobutamine test (10 microg/kg per minute). Ejection fraction and regional contractility tended to be more preserved in patients with NTW, but dobutamine increased regional contractility in the jeopardized area in most patients with or without NTW and the improvement was similar in those either with or without enzyme elevation. In conclusion, deep NTW after ST-elevation acute coronary syndromes tends to be associated with a more preserved myocardium but it is neither a sensitive nor a specific marker of viable myocardium.