Frontal QRS-T angle predicts syntax score in patients with non-ST elevation myocardial infarction.

Background: Early risk stratification based on SYNTAX score plays a crucial role to identify the need for early invasive strategy in patients with NSTEMI. The predictive role of frontal QRS-T angle [f(QRS-T)] on the atherosclerotic burden of CAD is less clear in NSTEMI patients. In this study, we aimed to investigate the relationship between f(QRS-T) and SYNTAX score in NSTEMI patients.

Methods: A total of consecutive 269 patients with the diagnosis of NSTEMI transferred to coronary care unit were included in the study. f(QRS-T) was calculated as the absolute value of the difference between the frontal plane QRS and T axes based on automatic report of ECG machine. Syntax score was computed using an online SYNTAX score calculator by well-experienced two cardiologists blinded to the study data. The study population was divided into two groups based on the SYNTAX score low SYNTAX score (≤23), and high SYNTAX score (>23).

Results: Left ventricle ejection fraction (LVEF) (p = 0.001), hemoglobin (p = 0.03) and HDL-C (p = 0.04) levels were lower in the intermediate-high SYNTAX group. Age (72.1 ± 12.5 vs. 64.6 ± 9.4 respectively; p < 0.001), LAD as infarct-related artery 30 (%65.2) vs. 50 (%29.1) respectively; (p = 0.001), f(QRS-T) (100.5 ± 55.3 vs. 65.1 ± 53.1 respectively p = 0.006), troponin I peak (p = 0.06) were higher among patients with intermediate-high Syntax score. In receiver-operating characteristic (ROC) curve analysis, the value for f(QRS-T) to detect syntax score ≥ 23 with a sensitivity of 77% and specificity of 63% was 73,5° in NSTEMI patients(AUC = 0.69). Univariate logistic regression analysis identified that age, LVEF, HDL-C, hemoglobin, infarct-related artery, f(QRS-T) were significantly associated with SYNTAX score. Multivariate logistic regression analysis showed that age (OR: 1.135, 95% CI: 1.039-1.153, p = 0.045), infarct related artery-LAD (OR: 2.897, 95% CI: 1.023-8.209, p = 0.001) and f(QRS-T) (OR: 3.587, 95% CI: 1.093-11.772, p = 0.001) were the independent predictors of SYNTAX score.

Conclusion: In NSTEMI patients, f(QRS-T) has been found to be a useful decision-making tool to predict SYNTAX score to assess early invasive strategy.