Does early reperfusion after acute myocardial infarction lead to delayed recovery of left ventricular ejection fraction?
Depressed left ventricular ejection fraction measured shortly after reperfusion therapy for acute myocardial infarction may show delayed recovery due to prolonged stunning, suggesting definitive assessment should be postponed beyond hospital discharge.
To assess whether myocardial dysfunction after acute reperfusion ('stunning') may show delayed recovery, 33 patients of the European Cooperative Study (rtPA vs placebo) had radionuclide angiocardiography on day 9 and after 3-6 months. Sixteen patients (13 inferior, three anterior infarcts) had a normal left ventricular ejection fraction (LVEF) which remained unchanged (55.4 vs 53.9%). In contrast, LVEF of 17 patients (10 inferior, seven anterior infarcts) with depressed values on day 9 improved during follow-up from 38.8 to 45.2% (P less than 0.01). Improvement was only observed in patients with early reperfusion defined a priori as peak creatine kinase value less than or equal to 15 h of pain onset (from 40.9 to 49.3%; P less than 0.05) in contrast to patients without reperfusion (from 34.0 to 35.2%; ns). Accordingly, LVEF increased in patients with open infarct-related arteries at hospital discharge (n = 8; P = 0.053) but not with persistent occlusion (n = 7; P = 0.11). Thus, a depressed LVEF observed 9 days after reperfusion may show delayed recovery due to prolonged stunning. Therefore, after thrombolysis, left ventricular function may not be evaluated definitively at hospital discharge; results of such studies should be interpreted with caution.
Pfisterer et al. (1991) studied this question.