Age-related determinants of outcome after acute myocardial infarction: a dobutamine-atropine stress echocardiographic study.
OBJECTIVE
To investigate the cause of worse survival in older patients after myocardial infarction (MI).


METHODS
Prospective 18-month and longer follow-up study of a cohort of 167 patients (mean age +/- standard deviation 58 +/- 12, including 71 aged >or=65) with acute MI for cardiac events, defined as cardiac death, recurrent MI, or resuscitated ventricular tachycardia or fibrillation (VT/VF).


METHODS
Milwaukee County Medical Complex and the Zablocki Veterans Affairs Medical Center, Milwaukee, WI.


METHODS
One hundred sixty-seven patients who underwent dobutamine-atropine stress echocardiography (DASE) in the first week (2-7 days) after acute MI and were medically managed.


METHODS
Comparison of event rates in older (>or=65 years) and younger (<65 years) patients and of clinical, resting echocardiographic, DASE, and angiographic findings in patients with and without events. Coronary angiography was performed in 141.


RESULTS
Older and younger patients tolerated DASE well. During follow-up, there were 29 cardiac events (cardiac death in 17, nonfatal MI in 10, and VT/VF in 2). Events were more common in older patients (26% vs 12%, P <.05), especially death (19% vs 5%, P <.05). Scar size in the infarct zone by DASE was larger (4.0 +/- 2.8 vs 3.0 +/- 2.7 segments, P <.05) and remote wall motion abnormalities more common (47 vs 29%, P <.05) in older patients. Univariate determinants of outcome (P <.05) in older patients were diabetes mellitus; remote wall motion abnormalities; angiographic multivessel disease; scar size; ejection fraction; and resting, low-, and peak-dose wall motion score. Univariate determinants in younger patients were similar, but diabetes mellitus was not. Multivariate analysis revealed that remote wall motion abnormalities and scar size by DASE were independently predictive of outcome in older and younger patients and diabetes mellitus only in older patients. Low- and peak-dose DASE data enhanced (P <.01) the prediction of outcome in all patients with acute MI relative to clinical data and resting echocardiography.


CONCLUSIONS
DASE was more predictive of outcome than clinical data and resting echocardiography in both age groups. Scar size and remote wall motion abnormalities were the primary determinants of outcome irrespective of age. The worse prognosis of older patients correlated with diabetes mellitus, greater scar size, and higher incidence of remote inducible ischemia.
Division of Cardiovascular Medicine, Department of Medicine, Medical College of Wisconsin, Milwaukee, Wisconsin 54601, USA. scsmart@gundluth.org
Steven
S
Smart
Kiran
K
Sagar
Donald
D
Tresch
D000367:Age Factors; D000368:Aged; D000369:Aged, 80 and over; D000704:Analysis of Variance; D000889:Anti-Arrhythmia Agents; D001285:Atropine; D002316:Cardiotonic Agents; D016009:Chi-Square Distribution; D017023:Coronary Angiography; D004280:Dobutamine; D004452:Echocardiography / Q000379:methods*; D005080:Exercise Test; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D016015:Logistic Models; D008875:Middle Aged; D009203:Myocardial Infarction / Q000000981:diagnostic imaging* / Q000503:physiopathology*; D011237:Predictive Value of Tests; D011379:Prognosis; D011446:Prospective Studies; D012372:ROC Curve; D018570:Risk Assessment; D016019:Survival Analysis
D000889:Anti-Arrhythmia Agents; D002316:Cardiotonic Agents; D004280:Dobutamine; D001285:Atropine