Assessment of Multivessel Coronary Artery Disease by Means of Stress‐Recovery ST/HR Index in Postinfarction Patients on Beta‐Blocker Therapy

Abstract

Objective: The aim of this study was to evaluate the influence of pharmacological therapy on the assessment of coronary anatomy by means of, respectively, conventional ST depression and comparative heart‐rate adjusted ST segment (ST/HR) analysis during exercise and recovery following acute Ml.Background: The withdrawal of therapy before stress testing is controversial. We previously demonstrated that a simple continuous variable (Stress‐Recovery Index [SRI] defined as the difference between the areas subtended to baseline and limited by ST trend against HR during exercise and recovery) can substantially improve the post‐MI identification of multivessel disease (MVD).Methods: Seventy‐five patients underwent maximal exercise ECG test on and off beta‐blockers with or without additional therapy, in random sequence, within 2 weeks of infarction. Coronary angiography was done within 1 month. The test was considered positive for increased risk of MVD in case of ST depression < 2 mm and, respectively, SRI > 5 mm × beats × min−1, as previously suggested.Results: Off therapy, ST depression was positive in 33 and negative in 42 patients, while SRI was positive in 35 and negative in 40; on therapy, ST depression was positive in 21 and negative in 54 patients, while SRI was positive in 44 and negative in 31. Forty‐four subjects had MVD. The sensitivity and specificity of SRI were, respectively, increased and reduced by therapy, while an opposite effect was found on ST depression. SRI on therapy was more sensitive (P > 0.001) and less specific (P > 0.05) than ST depression and was the most sensitive parameter in identifying only 3‐vessel. Positive ST depression and negative SRI on therapy were associated, respectively, with the highest and lowest Gensini's score.Conclusions: The SRI is superior to ST depression in identifying complex coronary anatomy in post‐Ml patients, especially during beta‐blockade therapy. A.N.E. 1999;4(1):60–66