Spatial QRS-T angle as a predictor of low left ventricular ejection fraction

Objective. To evaluate predictive value of spatial QRS-T angle (sQRS-Ta) regarding low left ventricular ejection fraction (LV EF) among outpatients with cardiovascular diseases. Material and methods. We analyzed 4499 patients (2309 (51%) men and 2190 (49%) women) aged 58 [43; 68] years. LV EF was assessed via echocardiography. We assessed sQRS-Ta as a spatial angle between integral QRS and T vectors using vector-ECG synthesized from 12-lead digital electrocardiograms. Continuous variables are presented as medians and interquartile ranges. Results. Low LV EF (<40%) was present in 145 (3%) patients. In these patients, sQRS-Ta was greater than in patients with LV EF ≥40% (154 [133; 168] and 77° [51; 109], respectively, p<0.0001). Spatial QRS-Ta made it possible to separate patients with LV EF <40% and ≥40% in the entire group (AUC 0.90±0.02) and subgroups of men and women (AUC 0.89±0.02 and 0.90±0.04, respectively). Optimal sQRS-Ta cut-off values for low LV EF were >125° in the entire group, >128° in men and >118° in women (sensitivity 81—87%, specificity 85—83%). The highest positive predictive value was achieved at greater sQRS-Ta. Conclusion. Spatial QRS-Ta made it possible to separate patients with LV EF <40% and ≥40% with sensitivity 82% and specificity 85%. Further research devoted to predictive role of sQRS-Ta for left ventricular systolic dysfunction is advisable.