Relationship of frontal QRS-T angle with coronary flow grade and advers events before percutaneous coronary intervention in patients with non-ST elevation myocardial infarction

OBJECTIVE
Electrocardiography (ECG) is used in the initial risk assessment of patients with non-ST-elevation myocardial infarction (NSTEMI). The frontal QRS-T [F(QRS-T)] angle is an ECG parameter that may be affected by the alterations in the coronary blood flow. The aim of this study was to explore the relationship of the F(QRS-T) angle with coronary flow grade and adverse events in NSTEMI patients.


METHODS
A total of 191 NSTEMI patients were divided into two groups based on the thrombolysis in myocardial infarction (TIMI) flow level on coronary angiography (CAG) before revascularization, namely TIMI 0/1 and TIMI 2/3. The F(QRS-T) angle obtained before revascularization was compared between the groups and its relationship with adverse events was examined. In-hospital all-cause mortality, repeat target lesion revascularization, new onset heart failure, ventricular arrhythmias and atrial fibrillation were defined as adverse events.


RESULTS
F(QRS-T) angle was wider in the patients with TIMI 0/1 flow compated to the patients with TIMI 2/3 flow (P <0.001). The F(QRS-T) angle was determined to be a predictor of TIMI flow grade 0/1 before revascularization in patients with NSTEMI (odds ratio [OR]: 1.51; 95% confidence interval [CI]: 1.30–1.75; P<0.001). The F(QRS-T) angle was a predictor of the adverse events during hospitalization in the patients with NSTEMI (OR: 1.11; 95% CI: 1.04–1.19; P=0.002). The cutoff values of the frontal QRS-T angle for TIMI flow grade and adverse events were determined to be 73.5°, based on receiver operating characteristic curve analysis.


CONCLUSION
Increased F(QRS-T) angle may be a useful ECG parameter for determining TIMI flow grade and the need for an early invasive strategy in patients with NSTEMI.