# The Relationship Between Collateral Circulation and Electrocardiographic Frontal QRS-T Angle in Patients with Coronary Artery Chronic Total Occlusion

## TL;DR

This study explores how heart electrical patterns relate to blood flow in patients with blocked coronary arteries.

## Contribution

The study identifies the frontal QRS-T angle as a novel and reliable biomarker for assessing collateral circulation in CTO patients.

## Key findings

- Poor collateral flow significantly predicts an increased frontal QRS-T angle.
- Low serum albumin levels are associated with a wider frontal QRS-T angle.
- The frontal QRS-T angle is more reliable than other ECG parameters for assessing myocardial repolarization.

## Abstract

Background: Ischemic heart disease is the primary contributor to global mortality. The QRS-T angle at the anterior aspect of the heart serves as a significant biomarker of the heterogeneity in myocardial repolarization and the electrophysiological instability of the cardiac myocytes. A wide frontal QRS-T angle is associated with proximal vascular disease, coexistence of three-vessel disease, and increased mortality. Hereby, we aimed to examine the relationship between collateral circulation and frontal QRS-T angle in patients with chronic total occlusion (CTO). Methods: A cohort comprising 120 patients (17 females, 14.1%) who received a diagnosis of chronic total occlusion (CTO) subsequent to the administration of coronary angiography conducted for the evaluation of stable angina pectoris was incorporated into the investigation. The electrocardiographs of the patients were evaluated in detail, and the frontal QRS-T angle was calculated. The patients were categorized into two groups: subjects exhibiting an increased frontal QRS-T angle (>110° for men, >90° for women) and those presenting with a normative frontal QRS-T angle. Coronary angiographies of the patients were analyzed, and coronary collateral circulation was classified according to Rentrop classification. Results: Serum albumin level (OR = 0.711, 95% CI 0.564–0.896; p = 0.004) and poor collateral flow (OR = 17.7, 95% CI 12.2–85.3; p < 0.001) were significant predictors of raised frontal QRS-T angle. Conclusions: The frontal QRS-T angle is a novel parameter that is more reliable, consistent, and less sensitive to miscalculation and misidentification than other conventional electrocardiographic myocardial repolarization parameters. Revealing the bad collateral relationship with the frontal QRS-T angle may enable physicians to take more stringent precautions and change the risk factors related to the increased QRS-T angle in advance.