Full recovery of contraction late after acute myocardial infarction: determinants and early predictors

OBJECTIVES: To assess the relative value of electrocardiographic, echocardiographic, angiographic, and in-hospital therapeutic indices for predicting late functional recovery after acute myocardial infarction, and to determine the variables associated with absence of recovery, partial recovery, and full recovery. DESIGN: Prospective observational follow up study. SETTING: Teaching hospital. PATIENTS: 74 consecutive patients with a first uncomplicated acute myocardial infarct. INTERVENTIONS: Dobutamine-atropine stress echocardiography was performed mean (SD) 5 (2) days after the acute event. Quantitative angiography was available in all patients before hospital discharge. A follow up resting echocardiogram was obtained 12 (2) months later. RESULTS: Functional recovery (partial, n = 18; full, n = 27) was observed in 45 of the 74 patients. Recovery was associated with earlier thrombolytic treatment (p = 0.008), earlier peak concentration of creatine kinase (p = 0.009), greater contractile reserve (p = 0.0001), non-Q wave acute myocardial infarction (p = 0.002), and more frequent elective angioplasty of the infarct related vessel (p = 0.0004). Three independent variables were selected stepwise from multivariate analysis for predicting late recovery: contractile reserve (chi(2) = 24.2, p < 0.0001); non-Q wave infarction (chi(2) = 15.7, p = 0.0001); and the time from symptom onset to thrombolysis (chi(2) = 4.94, p = 0.026). Three independent variables predicted full recovery: contractile reserve (chi(2) = 17.2, p = 0.0001); non-Q wave infarction (chi(2) = 10.1, p = 0.0016); and elective angioplasty of the infarct related artery (chi(2) = 4.53, p = 0.033). Only contractile reserve (chi(2) = 17.0, p < 0.001) was selected from the multivariate analysis for its ability to distinguish between partial recovery and absence of recovery. CONCLUSIONS: Late recovery of contraction relates to earlier treatment, which is associated with lower infarct size unmasked by a non-Q wave event and the presence of contractile reserve. Elective coronary angioplasty of the infarct related artery before hospital discharge is associated with full recovery.