title: New method for measuring QRS duration using high-frequency electrocardiography.
abstract: Definition of QRS onset and offset is a basic problem in electrocardiography. Current techniques rely either on subjective estimates or on computer algorithms using QRS derivative or spatial vector velocity parameters. We developed a spectral method based on the observation that the QRS complex, unlike the P wave, PR segment, or ST-T complex is comprised of significant frequencies greater than 50 Hz. Accordingly, we adapted a microprocessor-based electrocardiograph (ECG) system with a signal-averaging program to reduce noise and a 50-300 Hz digital filter. Leads I and aVF were simultaneously acquired by computer in 40 subjects with a wide range of QRS duration (55.5-161 ms). Excellent correlation (r = 0.98) was noted between high-frequency QRS duration measurement and careful visual determinations made at high gain and expanded time scale. The high-frequency ECG appears to provide an objective physiological definition of the QRS complex based on spectral content not on morphology or slope.
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D004562:Electrocardiography; D005260:Female; D006321:Heart / Q000502:physiology* / Q000503:physiopathology; D006331:Heart Diseases / Q000503:physiopathology; D006801:Humans; D008297:Male; D008875:Middle Aged; D005082:Physical Exertion