Comparison of high-frequency QRS components and ST-segment elevation to detect and quantify acute myocardial ischemia.

Objective: This study tests the ability of high-frequency components of the depolarization phase (HF-QRS) vs conventional ST-elevation criteria to detect and quantify myocardial ischemia.

Methods: Twenty-one patients admitted for elective percutaneous coronary intervention were included. Quantification of the ischemia was made by myocardial scintigraphy. High-resolution electrocardiogram before and during percutaneous coronary intervention was recorded and signal averaged. The HF-QRS were determined within the frequency band 150 to 250 Hz. ST-segment deviation was measured in the standard frequency range (<100 Hz).

Results: HF-QRS criteria were met by 76% of the patients, whereas 38% met the ST-elevation criteria (P = .008). Both HF-QRS reduction and ST elevation correlated significantly with the amount of ischemia (HF-QRS: r = 0.59, P = .005 for extent and r = 0.69, P = .001 for severity; ST elevation: r = 0.49, P = .023 for extent and r = 0.57, P = .007 for severity).

Conclusions: This study suggests that HF-QRS analysis could provide valuable information both to detect acute ischemia and to quantify myocardial area at risk.