Silent ischemia and loss of reversible myocardial dysfunction following myocardial infarction.

Sixty-seven asymptomatic patients were enrolled after a first uncomplicated myocardial infarction (MI) so as to study the relevance of reversible myocardial dysfunction in determining left ventricular function soon after the acute episodes and 12 months later. Moreover, the potential role of silent ischemia in conditioning the evolutive aspects of contractile dysfunction has been investigated. Postextrasystolic potentiation during two-dimensional echocardiographic (2-D echo) monitoring has been used to detect the presence of viable myocardium in asynergic myocardial segments. Results of electrocardiographic (ECG) ambulatory monitoring at predischarge determined patient groups: Group A included 49 patients without ST changes during monitoring, while Group B included 18 patients with silent ischemia. Incidence of reversible myocardial dysfunction was similar in the two study groups (82 vs. 86%, p = NS). Group B patients were older (59.6 +/- 6.7 vs. 50.6 +/- 10.6 years, p < 0.015) and had lower ejection fractions (EFs, 43.4 +/- 6.4% vs. 51.2 +/- 8.3%, p = 0.026) and higher at-rest wall-motion scores (WMSs, 11.4 +/- 5.9 vs. 7.2 +/- 3.8, p = 0.019). Left ventricular end-diastolic volume (LVEDV) and potentiated WMS did not differ. At 1-year examination, Group B patients exhibited a greater LVEDV index (96 +/- 6.5 vs. 70.7 +/- 14 ml/m2, p < 0.002) with a worsening both in rest and in potentiated wall-motion score index (12.8 +/- 4.6 vs. 5.3 +/- 1.8, p < 0.001; 9.2 +/- 3.6 vs. 4.8 +/- 2.2, p < 0.001, respectively). Left ventricular EF remained significantly depressed in Group B patients (42 +/- 8.7% vs. 55.5 +/- 8.1%, p < 0.002).(ABSTRACT TRUNCATED AT 250 WORDS)