Systolic time intervals after phenylephrine administration for early stratification of patients after acute myocardial infarction

Abstract

This study was designed to assess the usefulness of the changes in left ventricular (LV) systolic time intervals after phenylephrine administration for detecting hightisk patients soon after acute myocardial infarction by correlation with the angiographic and ventriculogmphic findings. The procedure was performed in 76 consecutive patients (group I) on the fourth postinfarction day and in 12 normal subjects (group II) free of coronary artery disease. In 20 patients with LV ejection fraction ≤ 40% (subgroup IA) the preejection period (PEP)/LV ejection time (ET) ratio increased from 0.410 ± 0.107 to 0.535 ± 0.102 (p = 0.01) after phenylephrine, whereas in the remaining 56 patients (subgroup IB) with LV ejection fraction >40% and in the 12 normal subjects the PEP/LVET increased nonsignificantly. Of patients with LV ejection fraction >40% a subset of 20 patients was distinguished with proximal stenosis in both left anterior descending and either a dominant right or left circumflex coronary artery (subset IB-a). In these the PEP/LVET increased from 0.347 ± 0.056 to 0.445 ± 0.019 (p = 0.0001) after phenylephrine, whereas in the remaining 36 patients (subset IB-b) without proximal lesions in 2 main arteries the PEP/LVET increased nonsignificantly. In conclusion, the PEP/LVET response to phenylephrine administration early after acute myocardial infarction is a precise, safe, noninvasive bedside method for early stratification of these patients.