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.