Risk Of Future Ischemic Events Research Articles

Evolution of regional left ventricular wall motion abnormalities in acute Q and non-Q wave myocardial infarction

The evolution of segmental wall motion in Q and non-Q wave acute myocardial infarction was studied in detall in 15 patients without known prior ischemic events. Serial two-dimensional echocardiographic studies were performed beginning early after the onset of chest pain and continuing until 10 to 14 days after admission. An area of apparent infarction was identified on each initial study based on later correlation of ECG and echocardiographic findings. Wall motion of infarct-and noninfarct-related areas was graded in a semiquantitative fashion based on the scoring of a visual analysis. Sequential image data demonstrated significant spontaneous improvement in wall motion of the infarct area in non-Q but not in Q wave events. Patients with non-Q wave infarction and improvement in regional function were at high risk for recurrent infarction within 6 months. Improvement in wall motion inside or outside the area of infarction in Q wave events was related to future risk. We concluded that in patients with initial acute myocardial infarction, fallure to develop Q waves correlated with return of function in the apparent area of infarction. Improvement in regional wall motion after the initial study suggested risk for future ischemic events in both ECG types of myocardial infarction. Serial echocardiographic imaging may be a means to identify patients at risk for infarct extension in both non-Q and Q wave events.

Prognostic value of submaximal exercise radionuclide ventriculography after myocardial infarction

Submaximal exercise testing with radionuclide ventriculography (RVG) was performed in 117 patients before hospital discharge 17 ± 7 days (± standard deviation) after an acute myocardial infarction (MI). The hypothesis tested in these studies was that submaximal exercise testing coupled to RVG allows the identification of patients at risk for future ischemic events in the subsequent 6 months, irrespective of MI location and type. The sites of MI were characterized as anterior transmural in 33, inferior transmural in 39, limited nontransmural in 18, extensive nontransmural in 24 and indeterminant in 3. During 6 months of follow-up, 9 patients died, 14 had recurrent MI, 18 had refractory angina pectoris, 16 had limiting angina and 17 had congestive heart failure. Discriminant function analysis ranked exercise changes in left ventricular (LV) ejection fraction and end-systolic volume the most important of all clinical, exercise and scintigraphic variables for predicting future cardiac events. The predictive accuracy of changes in LV ejection fraction and end-systolic volume were 93 and 91%, respectively, for the entire group, and were significantly more sensitive than any degree of ST-segment depression or elevation (p < 0.001). These findings were generally independent of MI location and type. Thus, submaximal exercise RVG after MI is an accurate means of identifying patients at risk for major cardiac events in the 6 months after hospital discharge.