Predicting Reduced Left Ventricular Ejection Fraction in Patients With ST ‐Elevation Myocardial Infarction: Role of the Quick Forrester Classification

Introduction Cardiogenic shock, heart failure, and reduced left ventricular ejection fraction (LVEF) are major determinants of poor prognosis in patients with ST‐elevation myocardial infarction (STEMI). Rapid identification of high‐risk patients and subsequent provision of multidisciplinary care are critical. However, traditional risk scores mainly rely on infarct size, age, and hemodynamics, which may offer limited discriminatory ability at the time of hospital arrival. We developed a quick Forrester classification (QFC) using the respiratory rate (RR) and serum lactate levels upon hospital arrival and investigated its association with a reduced LVEF of patients with STEMI. Methods This retrospective cohort study included consecutive patients with STEMI from 2018 to 2023. Patients were divided into four QFC classes: Class‐1 (RR < 20 per minute and lactate < 2.0 mmol/L), Class‐2 (RR ≥ 20 per minute and lactate < 2.0 mmol/L), Class‐3 (RR < 20 per minute and lactate ≥ 2.0 mmol/L), and Class‐4 (RR ≥ 20 per minute and lactate ≥ 2.0 mmol/L). The primary endpoint was the LVEF < 45% measured by transthoracic echocardiography before discharge. Results Among 569 patients with STEMI (Class‐1: 118; Class‐2: 146; Class‐3: 92; Class‐4: 213), the QFC Class‐4 demonstrated the highest proportions of reduced LVEF (26%) and mechanical circulatory support use (13%). In multivariable logistic analysis, Class‐4 was independently associated with reduced LVEF compared with Class‐1 (odds ratio 2.47). Conclusion The QFC, based solely on RR and lactate levels, was significantly associated with reduced LVEF in STEMI. This simple bedside tool may support rapid identification of high‐risk patients on arrival and complement existing risk stratification strategies to facilitate timely multidisciplinary management. Clinical Trial Registration: Aso Iizuka Hospital/approval ID: 21068.