Does Transient Stunning Induced by a Stress Test Normalize Early or Late?

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Abstract

There is a controversy in the literature about the time required to the normalization of the myocardial function after induced ischemia.

Objective

The aim of this study was to analyze the left ventricular function (LVF), after induced ischemia, by stress test and to follow up the behavior of LVF one hour after the test.

Material and methodWe included 17 patients in the analysis, 14 with coronary artery disease (CAD) and 3 patients as normal controls (N). Sixteen were males (94%), mean age was 56 ± 13 years old. A radionuclide ventriculography (RV) was performed and the ejection fraction (EF) and wall motion (WM) were analyzed in basal conditions, during the maximal stress and 1 hour post-stress (PS). The week after patients were submitted to a stress-rest gated myocardial perfusion SPECT (GS). We performed the summed stress score (SSS), the summed rest score(SRS) and the summed difference score (SDS). SDS= SSS - SRS. Stunned was defined by RV when EF1 hour PS was less at rest, and WM was different at basal condition. For statistical purposes, values are given as mean ± 2 SD. Mann-Whitney U test was used for comparison. Values of p < 0.05 were considered significant.

Results

RV EF in N: 49 ± 1.7% and 1 hour PS 61 ± 9%. InCAD 50 ± 13% and 1 hour PS 53 ± 11%. GS EF in N64 ± 12% and 1 hour PS 69.7 ± 12.6%. In CAD 57 ±15% and 1 hour PS 54.6 ± 17.3% (p = NS). SDS instunned patients (5 patients), and in patients with-out stunning (9 patients) was 12.6 ± 7 and 6.6 ± 6.6,respectively (p ≤ 0.05).

Conclusions

SDS could differentiate patients with or without stunned myocardium, that normalize the LVF latePS. The severity and extension of ischemic myocardium was the best predictor of late normalization of EF and WM.