Spatial QRS-T angle and quantified ischemia burden in ischemia with nonobstructive coronary arteries

Area of Science:

• Cardiology
• Electrocardiography
• Ischemic Heart Disease

Background:

• Ischemia with Non-Obstructive Coronary Arteries (INOCA) is a recognized clinical condition requiring better risk stratification.
• The spatial QRS-T (sQRS-T) angle may offer a more accurate assessment of ischemic burden compared to traditional ECG markers.

Purpose of the Study:

• To evaluate the association between the spatial QRS-T angle and myocardial ischemic burden in INOCA patients.
• To assess the predictive value of various ECG dispersion markers for severe ischemia in INOCA.

Main Methods:

• Retrospective analysis of 1432 INOCA patients with reversible perfusion defects on myocardial perfusion scintigraphy (MPS).
• Quantification of ischemic burden as a percentage of left ventricular (LV) myocardium with reversible defects.
• Measurement of spatial and frontal QRS-T angles, QT dispersion (QTd), and other ECG parameters on resting ECGs.

Main Results:

• The spatial QRS-T angle, QTd, and Tpe/QTc ratio increased significantly with higher categories of ischemic burden.
• The spatial QRS-T angle was an independent predictor of severe ischemia (OR 1.27 per 10° increase, p < 0.001).
• A combined ECG model including sQRS-T angle, QTd, and Tpe/QTc demonstrated improved discrimination (AUC 0.83).

Conclusions:

• The spatial QRS-T angle is independently associated with myocardial ischemic burden in INOCA patients.
• An ECG-based model incorporating dispersion markers enhances the identification of patients with significant ischemia.
• This approach may aid in identifying INOCA patients who require closer monitoring and follow-up.