# Predictive value of the electrocardiogram exercise stress test for the presence or absence of left main disease

## TL;DR

This study shows that an electrocardiogram exercise stress test can reliably identify patients with very low risk of left main coronary artery disease.

## Contribution

The study identifies specific ECG-EST variables that reliably exclude left main disease with high negative predictive value.

## Key findings

- ECG-EST variables like peak heart rate ≥85% of maximal predicted and maximal ST-segment depression <2 mm indicate ≤2.5% risk of left main disease.
- The negative predictive value of ECG-EST for left main disease is very high for certain combined variables.
- Only 5% of patients in the study had left main disease confirmed by invasive coronary angiography.

## Abstract

The ability of the electrocardiogram exercise stress test (ECG-EST) in excluding the presence of left main (LM) coronary artery disease (CAD) has been poorly investigated.

We retrospectively selected patients who underwent both ECG-EST and elective invasive coronary angiography (ICA) at our Institution between January 2018 and December 2023 due to angina pain suspected of obstructive CAD. Preventively defined individual and combined ECG-EST variables suggesting no/mild myocardial ischemia were assessed as predictors of the absence of LM disease. Some ECG-EST variables suggesting extensive/severe myocardial ischemia were instead assessed as predictors of the presence of LM disease, defined as a stenosis ≥50% of the left main artery.

Overall, 515 patients were included (age 66.2 ± 11 years; 74% men). LM disease at ICA was found in 26 patients (5%). Individual and combined ECG-EST variables showed low positive predictive values for LM-CAD [maximum 15% for a combination of ST-segment depression (STD) in ≥ 5 leads and ECG-EST duration <360 s]. The negative predictive value, however, was very high for some combined ECG-EST variables. Very low risk of LM disease (≤2.5%) was particularly shown in patients with peak heart rate (HR) ≥ 75% of maximal predicted HR for age and STD < 2 mm (prevalence 63.1%; risk 2.2%) and peak HR ≥85% of maximal predicted HR for age and maximal STD < 2 mm (prevalence 46.2%; risk 2.5%).

Among patients with angina chest pain suspected of obstructive CAD, ECG-EST results can reliably identify those at very low risk of LM disease at coronary angiography.