Potential influence of pre-infarction angina on myocardial viability and residual ischemia

Abstract

Background: The effects of recent pre-infarction angina on myocardial viability and residual ischemia are unknown. This study evaluates them in 90 patients with a first Q-wave myocardial infarction using early dobutamine stress echocardiography.

Methods: Patients were classified according to the absence or presence of recent pre-infarction angina, defined as chest pain lasting < 30 min during a period of 7 days before the acute myocardial infarction. The infarct zone wall motion score index was calculated at baseline and at low- and peak-dose dobutamine stress echocardiography. All subjects underwent coronary angiography.

Results: Patients with unheralded myocardial infarction showed, in comparison with patients with recent pre-infarction angina, a significantly higher peak of creatine kinase serum levels (2630 +/- 1360 vs 1865 +/- 1562 IU/l, p = 0.002) and a higher number of leads with pathologic Q waves (3.2 +/- 1.3 vs 2.8 +/- 0.8, p = 0.002). The groups did not differ with regard to the infarct zone wall motion score index at rest (2.15 +/- 0.42 vs 2.18 +/- 0.31, p = 0.72) and at low- (1.86 +/- 0.52 vs 1.80 +/- 0.41, p = 0.55) and peak-dose (2.24 +/- 0.55 vs 2.19 +/- 0.58, p = 0.68) dobutamine stress echocardiography. The prevalence of myocardial viability (31 vs 48%, p = 0.15), homozonal (52 vs 58%, p = NS) or heterozonal ischemia (36 vs 23%, p = NS) was not statistically different between the groups of patients without and with recent pre-infarction angina. The angiographic patterns were similar.

Conclusions: Recent pre-infarction angina is associated with a smaller infarct size but it does not seem to influence the ventricular contractile improvement or residual ischemia, detected at early dobutamine echocardiography, in patients with a first Q-wave myocardial infarction.