- Objectives High frequency QRS (HFQRS) analysis has been shown to be an accurate marker for myocardial ischemia. Our objective was to test the use of HFQRS in diagnosing ACS in the emergency department. Methods 324 patients presenting to the ED with chest pain were enrolled. Resting ECG was recorded and later analyzed by an HFQRS algorithm. Results were compared to the conventional ECG diagnosis by 3 independent interpretations: treating physician, expert cardiologist and an automated computer program. Results The HFQRS analysis demonstrated improved sensitivity (67.5%) for the NSTE-ACS group compared to the human interpreters (59.7% and 53.2% for the treating physician and cardiologist respectively) with similar specificity. The automatic program had significantly lower sensitivity (31%) with a higher specificity (77%). Conclusions HFQRS which has shown great promise in diagnosing stable CAD may also be helpful in the ED for diagnosing ACS.