Athens QRS score flags false-negative exercise stress tests

By Eleanor McDermid

Patients with a low Athens QRS score are highly likely to have coronary artery disease (CAD) even if they have a normal exercise stress test (EST), say researchers.

Such patients "may warrant further evaluation with another imaging modality, such as nuclear EST, stress echocardiography, or cardiac catheterization", say Eduard Sklyar (Bronx‐Lebanon Hospital Center, New York, USA) and study co-authors.

The team found that CAD was present on coronary angiography in 77.0% of 56 patients with a low Athens QRS score (≤5), despite them having a negative EST.

By contrast, it was present in just 11.3% of 229 patients with a normal score and a negative EST, they report in the Journal of the American Heart Association.

Single vessel CAD was present in 47.0% versus 7.5% of patients with a low and normal Athens QRS score, respectively, and multivessel disease was present in 30.0% versus 3.8%.

The researchers found a low Athens QRS score to be 62% sensitive and 94% specific for CAD. They say the high specificity is partly because they excluded patients with ST-segment depression, whereas previous studies focused on patients with abnormal EST results.

"Our study extends the utility of the Athens QRS score in CAD detection in the group of patients who have otherwise normal EST, and may provide an additional noninvasive method for identifying patients with CAD", they observe.

The study participants were aged an average of 55 years, mostly Hispanic or African American, and had a high rate of cardiometabolic comorbidities. There were no clinical or demographical differences between patients with and without a low Athens QRS score, although older age and the presence of diabetes became significant predictors of CAD on binary logistic regression analysis.

And the only differences during EST were a significantly lower maximum heart rate among the patients with a low Athens QRS score versus those without (133 vs 149 bpm), lower maximum systolic blood pressure (162 vs 169 mmHg) and higher maximum diastolic blood pressure (101 vs 95 mmHg).

Low heart rate remained predictive of CAD on binary logistic regression analysis, as was a low Athens QRS score, with an odds ratio of almost 37.

The team concludes that patients with a low Athens QRS score need further evaluation, even if they have normal EST results. "Furthermore, patients with recurrent or persistent chest pain, but normal QRS score, and absence of ST depression, may not require further invasive testing", they suggest.

Source: J Am Heart Assoc 2016; 5: e002832

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