The clinical measurement of low level electrocardiographic potentials from body surface (e.g. His bundle potentials and delayed ventricular potentials) requires the use of signal averaging technique. The diagnostic importance of His bundle potentials is well established whereas the long term significance of delayed ventricular potentials is still unclear. In signal averaging technique, an average of multiple identical beats is taken which enhances the repetitive signal with respect to the random noise generated from various sources such as electromyographic potentials, power line interference and electrode and amplifier noise. The methodology, instrumentation, results and limitations of this technique are discussed. Signal averaging cannot successfully record His bundle potentials or delayed ventricular potentials in all patients. Spatial averaging may be one of the methods by which some of the inherent limitations of signal averaging can be overcome.
SchweitzerTWFitzgeraldJWBowdenJALynn-DavisP.Spectral analysis of human inspiratory diaphragmatic electromyograms. J. Appl Physiol.46 (1)s 152–165, 1979.
2.
SantipetroRF. The origin and characterization of the primary signal, noise and interference sources in the high frequency electrocardiogram. Proc, of IEEE.65: 707–713, 1977.
3.
BerbariEJScherlagBJLazzaraR.A computerized technique to record new components of the electro- cardiogram. IEEE Trans. Biomed. Eng.65: 799–802, 1977.
4.
WinterDARautaharjuPMWolfHK. Measurement and characteristics of overall noice content in exercise electrocardiograms. Am Heart J.74: 324–331, 1967.
5.
HuhtaJCWebsterJG. 60 Hz interference in electro-cardiography. IEEE Trans. of Biomedical Eng.20 (2): 91–101, 1973.
6.
GeddesLABakerLE. Principles of applied biomedical instrumentation. Ch 9. John Wiley and Sons - N.Y.1968.
7.
FlowersNCHandRCGranderPCMillerKBWaldenMOHoranLG. Surface recording of electrical activity from the region of the bundle of His. Am. J. Cardiol33: 384–389, 1974.
8.
PattersonS.The electrical characteristics of some commercial ECG. electrodes J. Electrocardiology11 (1): 23–26, 1978.
9.
TobeyGEGraemeJGHuelsmanLP. Operational Amplifiers: Design and applications. McGraw Hill Co. 1971. Chpt. 2: Input error signals and thermal drifts of a differential stage. Pg 51–89.
10.
EvanichMJNewberryOPartridgeLD. Some limitations of the removal of periodic noise by averaging. J Appl Physiol33, 536–541, 1972.
11.
SchmittOH: Averaging techniques employing several physiological variables. Ann NY Acad Sci 115: 952–958 1964.
12.
BrandonCWBrodyDA. A hardware trigger for temporal indexing of the electrocardiographic signal. Comput. Biomed Res.3: 45–57, 1970.
13.
VincentREnglishMJMackintoshAFStroudNChamberlainDAWoolonsDJ: A flexible signal-averaging system for cardiac waveforms. J Biomed Engng 2, 15–25, 1980.
14.
MehraRKelenGJZeilerRZephiranDFriedPGomesJAEl-SherifN.Non-invasive His bundle electrogram: Value of three vector lead recordings. Am J. Cardiol49: 344–348, 1982.
15.
BerbariEJLazzaraRSametP.Noninvasive technique for detection of electrical activity during the PR segment. Circulation48: 1005–1013, 1973.
16.
BerbariEJScherlagBJEl-SherifN.. The His-Purkinje electrocardiogram in man: an initial assessment of its uses and limitation. Circulation: 54: 219–224, 1976.
17.
BerbariEJLazzaraRScherlagBJ. The effects of filtering the His-Purkinje system electrocardiogram. IEEE Trans Biomed Eng.vol. BME-262: 82–85, 1979.
18.
McKennaWJRowlandEMortaraDDawsonREKriklerDN: Noninvasive recording of the His bundle electrogram. In Cardiac Pacing. Proceedings of the Vlth World Symposium on cardiac pacing (Ed. Meere), Montreal, 11–9, 1979.
19.
FlowersNCGurbachanSS: Surface recording of low-level signals from the conduction system. Cardiovasc Med 1183–1188, 1979.
20.
DamatoANLauSHBerkowitzWDRosenKMLisiKR: Recordings of specialized conduction fibers (AV nodal, His bundle, and right bundle branch) in man using an electrode catheter technique. Circulation 39: 435–440, 1969.
21.
HombackVBraunVHopp Hw, Gil-Sanchez D, Scholl M, Beherenbeck DW, Tauchert M, Hilger HM. The applicability of the signal averaging technique in clinical cardiology. Clin Cardiol. 5: 107–124, 1982.
22.
TakedaHKitamuraKTakanashiTTokuokaTHamamotoH.KatohTNikiIHishimotoY: Noninvasive recording of His-Purkinje activity in patients with complete atrio-ventricular block. Clinical applications of an “automated discrimination circuit”. Circulation 60, 421–426, 1979.
23.
MehraRKelenGEl-SherifN: Noninvasive beat to beat recording of diastolic & His-Purkinje potentials in man. Circ. 64 (Supp IV) 239, 1981.
24.
FlowersNCShvartsmanVKennellyBMSohiGS and HoranLG. Surface recordings of His Purkinje activity on an every beat basis without digital averaging. Circulation63: 948–952, 1981.
25.
BoineauJPCoxJL. Slow ventricular activation in acute myocardial infarction. A source of reentrant premature ventricular contraction. Circulation48: 702–712,1973.
26.
WaldoALKaiserGA. A study of ventricular arrhy-thmias associated with acute myocardial infarction in the canine heart. Circulation47: 1222–1228, 1973.
27.
El-SherifNScherlagBJLazzaraRHopeRR. Reentrant ventricular arrhythmias in the late myocardial infarction period 1. Conduction characteristics in the infarction zone. Circulation55: 686–702, 1977.
28.
El-SherifNHopeRRScherlagBJLazzaraR.Reentrant ventricular arrhythmias in the late myocardial infarction period. 2. Patterns of initiation and termination of reentry. Circulation55: 702–719, 1977.
29.
El-SherifNSmithRAEvansK.Ventricular arrhythmias in the late myocardial infarction period in the dog. 8. epicardial mapping of reentrant circuits. Circulation Res.49: 255–262, 1981.
30.
MehraRZeilerRHGoughWBEl-SherifN: Mechanisms of repetitive ventricular responses (RVRS): Reentry & dynamicity of arcs of functional conduction block. Circ64 (Supp IV): 172, 1981.
31.
JanseMJVan Capelle FJL, Morsink H, Kleber AG, Wilma-Schopman F, Cardinal R, D'Alnoncourt CN, Durrer, D. Flow of “injury” current and patterns of excitation during early ventricular arrhythmias in acute regional myocardial ischemia in isolated porcine and canine hearts. Circulation Res. 47: 151–158, 1980.
32.
JosephsonMEHorowitzLNFarshidiA.Continuous local electrical activity. A mechanism of recurrent ventricular tachycardia. Circulation57: 659–665, 1978.
33.
WaxmanHLSungRJ. Significance of fragmented ventricular electrograms observed during intracardiac techniques in man. Circulation62: 1349–1356, 1980.
34.
FontaineGGuirandonGFrankR.Intramyocardial conduction defects in patients prone to ventricular tachycardia. I. The post excitation syndrome in sinus rhythm. In management of ventricular tachycardia-role of Mexiletine. Pg39–55 Eds: SandoeEJulianDG and Bell JW. Excerpta Medica, Amsterdam Oxford 1978.
35.
FontaineGGuirandonGFrankR.Intramyocardial defects in patients prone to ventricular tachycardia. 2. A dynamic study of the post excitation syndrome. In management of ventricular tachycardia-role of Mexiletine. Pg.56–66 Eds: SandoeEJulianDG and Bell JW. Excerpta Medica, Amsterdam Oxford 1978.
36.
KleinHKarpRBKonchonkos, James T, WaldoAL: Ventri-cular mapping of abnormal myocardium in patients with and without arrhythmias. Circulation, Vo. 59 and 60. Supp. 2. pg 11–24, 1979.
37.
BerbariEJScherlagBJHopeRRLazzaraR.Recording from the body surface of arrhythomogenic ventricular activity during the ST segment. Am. J. Cardiol41: 697–702, 1978.
38.
SimsonMBEulerDEMichelsonELFalconeRSpearJFMooreEL. Detection of delayed ventricular activation on the body surface in dogs. Am. J. Physiol 241: H363-369, 1981.
39.
UtherJBDennettCJTamA.The detection of delayed activation signals of low amplitude in the vector-cardiogram of patients with recurrent ventricular tachycardia by signal averaging. In management of ventricular tachycardia-role of Mexiletine. Pg80–82 Eds: SandoeEJulianDG and Bell JW. Excerpta Medica, Amsterdam Oxford 1978.
40.
BreithardtGBeckerRSeipelL.Non invasive recording of late ventricular activation in man. Circulation62: Supp 3, pg 320, 1980.
41.
RozanskiJJMyerburgRJCastellanosA.A new ECG waveform identified by signal averaging in patients with recurrent ventricular tachycardia. CirculationVol. 59 and 60. Supp 2, pg. 11–22, 1979.
42.
SimsonMSpeilmanSHorowitzLJosephsonMKarkenAkasterJ.Slow ventricular activation detected on the body surface in patients with ventricular tachycardia after myocardial infarction. Am J Cardiol.47: 498–504, 1981.
43.
SimsonMHorowtizLJosephson j, Moore EN, Kaster J. A marker for ventricular tachycardia after myocardial infarction. Circulation 62: 262. Suppl. 3. 1980.
44.
MackintoshAFEnglishMJVincentRWoolIonsDJChamberlainDA: Low voltage electrical activity preceding right atrial depolarization in man. Br Heart J 42, 117–123, 1979.
45.
BerbariEJScherlagBJLazzaraR: Recordings of VA nodal potentials during junctional rhythms utilizing signal averaging. Am J Physiol 235, 110–115, 1978.
46.
GoldbergerALBhargavaVFroelicherVCovellJMortaraD: Effect of myocardial infarction on the peak amplitude of high frequency QRS potentials. J. Electrocardiol 13, 367–374, 1980.
47.
HonEHLeeST: Noise reduction in fetal electro-cardiography. Am J Obst Gynecol871086, 1963.
48.
OldenburgJTMacklinM: Processing the abdominal fetalEKG. IEEE Trans Biomed Eng BME-24, 501–507, 1977.
49.
DockerMF: Computing in the study of the fetal electro-cardiogram. In Computers for Analysis and Control in Medical and Biological Research. IEE Conference Publication7917, 1971.
50.
OmuraY: The relationship between the transmembrane action potentials of single cardiac cells and their surface electrograms. Trans NY Academy of Sciences2: 32, 874–910, 1970.
51.
El-SherifNGoughWBZeilerRHMehraR.Different mechanisms for spontaneous and induced ventricular rhythms in 24-hour-old myocardial infarction in the dog. Circulation 64 (Supp IV) pg 218, 1981.
