Signal averaging technique for noninvasive recording of late potentials in patients with coronary artery disease

• Published in: Computers in cardiology Vol. 13; p. 525
• Main Authors: Abboud, S, Blatt, C M, Lown, B, Graboys, T B, Sadeh, D, Cohen, R J
• Format: Journal Article
• Language: English
• Published: United States 1987
• Subjects: Algorithms; Coronary Disease - physiopathology; Electrocardiography - methods; Evaluation Studies as Topic; Heart Rate - physiology; Humans; Signal Processing, Computer-Assisted; Tachycardia, Ventricular - physiopathology; Ventricular Fibrillation - physiopathology; NASA Discipline Cardiopulmonary; Non-NASA Center
• ISSN: 0276-6574

An advanced non invasive signal averaging technique was used to detect late potentials in two groups of patients: Group A (24 patients) with coronary artery disease (CAD) and without sustained ventricular tachycardia (VT) and Group B (8 patients) with CAD and sustained VT. Recorded analog data were digitized and aligned using a cross correlation function with fast Fourier transform schema, averaged and band pass filtered between 60 and 200 Hz with a non-recursive digital filter. Averaged filtered waveforms were analyzed by computer program for 3 parameters: (1) filtered QRS (fQRS) duration (2) interval between the peak of the R wave peak and the end of fQRS (R-LP) (3) RMS value of last 40 msec of fQRS (RMS). Significant change was found between Groups A and B in fQRS (101 -/+ 13 msec vs 123 -/+ 15 msec; p < .0005) and in R-LP vs 52 -/+ 11 msec vs 71-/+18 msec, p <.002). We conclude that (1) the use of a cross correlation triggering method and non-recursive digital filter enables a reliable recording of late potentials from the body surface; (2) fQRS and R-LP durations are sensitive indicators of CAD patients susceptible to VT.