Dobutamine-induced T wave positivization after uncomplicated myocardial infarction: a marker of myocardial viability and higher cardiac risk.
BACKGROUND
There is evidence that after uncomplicated acute myocardial infarction, T wave positivization during stress testing may unveil myocardial viability. We evaluated in a prospective study the clinical value of T wave positivization during dobutamine stress echocardiography in patients with recent, first uncomplicated acute myocardial infarction.


METHODS
Two hundred twenty-nine patients, who underwent dobutamine stress echocardiography within 10 days of uncomplicated acute myocardial infarction, were selected for exhibiting negative T waves in the infarct area. A mean follow-up of 2.1 +/- 1 years (up to 6 years) was obtained.


RESULTS
T wave positivization appeared during dobutamine test in 76 (33%) patients. The agreement of T wave positivization for myocardial viability was 65% (95% confidence interval 59-71). Compared to myocardial viability during dobutamine stress echocardiography, the combination with T wave positivization was more sensitive (55 vs 24%, 95% confidence interval 46-64 vs 17-33) for predicting cardiac events, albeit less specific. Kaplan-Meier survival curves showed 47 (62%) cardiac events in patients with T wave positivization and 70 (46%) cardiac events in the remaining patients (p < 0.05). Soft (n = 91) prevailed over hard (n = 26) cardiac events.


CONCLUSIONS
T wave positivization during dobutamine stress echocardiography after uncomplicated acute myocardial infarction identifies patients at higher cardiac risk, and is more sensitive, albeit less specific, for cardiac events than viability alone. T wave positivization is helpful in the case of inconclusive stress echocardiography. The pathophysiology of T wave positivization and its relative value among other variables warrant further analysis.
Rambaldi
R
R
Divisione di Cardiologia, Ospedale E Morelli, Sondalo. ricram@iol.it
Bigi
R
R
Curti
G
G
Occhi
G
G
D000368:Aged; D002316:Cardiotonic Agents; D004280:Dobutamine; D004452:Echocardiography / Q000379:methods / Q000706:statistics & numerical data; D004562:Electrocardiography / Q000187:drug effects* / Q000706:statistics & numerical data; D005080:Exercise Test / Q000379:methods / Q000706:statistics & numerical data; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D008297:Male; D008875:Middle Aged; D009203:Myocardial Infarction / Q000175:diagnosis* / Q000473:pathology; D009206:Myocardium / Q000473:pathology*; D011379:Prognosis; D011446:Prospective Studies; D012307:Risk Factors; D012680:Sensitivity and Specificity; D013997:Time Factors; D014022:Tissue Survival
D002316:Cardiotonic Agents; D004280:Dobutamine