High frequency QRS

High frequency QRS (HFQRS) refers to the analysis of the high frequency spectral components of the QRS complex in an electrocardiogram (ECG). High frequency analysis of the QRS complex may be useful for detection of coronary artery disease during an exercise stress test.[1] It however requires special software.[1]

High Frequency QRS
ECG of a heart in normal sinus rhythm
Test ofElectrocardiogram

History
Left: Frequency band of standard ECG components is typically 0.05-100 Hz. HFQRS represents changes in the 150-250 Hz band (marked in red circle). Right: Depicts the physiological basis of HFQRS

HFQRS has been studied since the 1960s. The first studies correlate between incidence of notching and slurring in the QRS complexes to the existence and severity of coronary heart disease.[2] In 1979, a novel signal processing technique, including spatial filtering, averaging and alignment was used to show that HFQRS from patients in coronary care unit are less stable than in healthy subjects.[3] Later, Goldberger et al. identified reduction in the RMS (Root Mean Square) levels of the QRS (within frequency band of 80–300 Hz) in patients with Myocardial Infarction comparing to normal subjects.[4]

Research efforts during the 80-90s have shown that myocardial ischemia also induces changes to the depolarization phase and confirmed the use of HFQRS-RMS as a quantitative diagnostic measure of supply myocardial ischemia[5][6][7] and demand myocardial (stress-induced) ischemia.[8]


References
  1. Gerald, F; Philip, A; Kligfield, P; et al. (August 2013). "Exercise Standards for Testing and Training A Scientific Statement From the American Heart Association". American Heart Association (128): 873–934.
  2. Langner PH., Geselowitz DB., Mansure FT., Lauer JA. High-frequency components in the electrocardiograms of normal subjects and of patients with coronary heart disease. Am Heart J 1961;62:746–55.
  3. Uijen GJ., de Weerd JP., Vendrik AJ. Accuracy of QRS detection in relation to the analysis of high-frequency components in the electrocardiogram. Med Biol Eng Comput 1979;17(4):492–502.
  4. Goldberger AL., Bhargava V., Froelicher V., Covell J. Effect of myocardial infarction on high-frequency QRS potentials. Circulation 1981;64(1):34–42.
  5. Mor-Avi V., Shargorodsky B., Abboud S., Laniado S., Akselrod S. Effects of coronary occlusion on high-frequency content of the epicardial electrogram and body surface electrocardiogram. Circulation 1987;76(1):237–43.
  6. Abboud S., Smith JM., Shargorodsky B., Laniado S., Sadeh D., Cohen RJ. High frequency electrocardiography of three orthogonal leads in dogs during a coronary artery occlusion. Pacing Clin Electrophysiol 1989;12(4 Pt 1):574–81.
  7. Abboud S., Cohen RJ., Sadeh D. A spectral analysis of the high frequency QRS potentials during acute myocardial ischemia in dogs. International Journal of Cardiology, 26: 285-290, 1990.
  8. Beker A., Pinchas A., Erel J., Abboud S. Spectral Analysis of High Resolution QRS Complex During Exercise Induce Ischemia. Annals of Noninvasive Electrocardiology, 1(4): 386-392, 1996.
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