Further studies on the first derivative of the electrocardiogram, including instruments available for clinical use

Geselowitz, David B.; Langner, Paul H.; Mansure, Frank T.

doi:10.1016/0002-8703(62)90179-5

Cited by 30 publications

(7 citation statements)

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“…* Using this technique, Langner et al.,4' 8, 10, 18 Flowers et al '2-" and others8' 11,16,17 reported an increase in high-frequency QRS components in patients with prior myocardial infarction (MI) and also with ventricular hypertrophy.12 Analysis of the first derivative of the QRS confirmed an increase in notching in patients with ischemic heart disease. 6 7,11 *QRS notches were defined as changes in slope that interrupted the monotonic ascent or descent of the QRS. Slurs were defined as changes in QRS slope that did not interrupt the monotonic QRS wave form.…”

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Effect of myocardial infarction on high-frequency QRS potentials.

Goldberger¹,

Bhargava²,

Froelicher³

et al. 1981

Circulation

131

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SUMMARY Studies have shown that the number of high-frequency QRS notches increases after myocardial infarction (MI). To assess overall high-frequency (> 80 Hz) potentials more quantitatively, we adapted a microprocessor system capable of averaging 256 QRS complexes to reduce noise. The QRS was digitally filtered and the root-mean-square (RMS) voltage of the residual (80-300 Hz) signal computed. High-frequency RMS values were significantly (p < 0.01) greater in leads II, III and aV7 in normal subjects (n = 12) than in patients with inferior infarction (n = 12). Similarly, high-frequency RMS values were higher (p < 0.01) in leads Vs and V, in normal subjects (n = 14) than in patients with prior anterior MI (n = 14 According to classic theory, high-frequency QRS components after MI are increased due to fragmentation of the depolarization wave front by fibrous tissue. ', 12 However, MI leads to a regional loss of electrical potentials, sometimes reflected by diminished QRS voltage or abnormal Q waves; slowing of conduction velocity due to ischemia or infarction may also attenuate high-frequency potentials. Therefore, one might predict a decrease in overall high-frequency QRS voltage after MI. Data from our laboratory'8 suggested that infarction may decrease high-frequency QRS potentials as evidenced by diminished peak amplitude of a filtered (80-300 Hz) QRS signal. To test this hypothesis quantitatively, we developed three techniques for measuring high-frequency QRS potentials. First, a commercially available microprocessor ECG system (Marquette Electronics) equipped with a signal-averaging program to reduce noise and a high-frequency band-pass filter was adapted. The analog high-frequency output of this system was digitized to compute its root-mean-square (RMS) value, a direct index of high-frequency voltage. Second, high-frequency potentials were quantitated by performing Fourier analysis on the unfiltered, signal-averaged QRS complexes. Third, we used the first derivative of the ECG.However, in contrast to other investigators,8 7, 11 who only evaluated QRS notches with the derivative, we also measured the amplitude of the QRS derivative.Methods and Patients The Marquette MAC-1 electrocardiograph is a portable microcomputer system designed for ECG signal averaging and for recording low-amplitude, high-frequency potentials. This system records standard leads I and II (or any two bipolar leads) directly.

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confidence: 99%

Effect of myocardial infarction on high-frequency QRS potentials.

Goldberger¹,

Bhargava²,

Froelicher³

et al. 1981

Circulation

131

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“…These changes, which were reproducible in successive tracings, are abnormal and suggest myocardial involvement in this patient with systemic sclerosis. See figure 10 also. result.…”

Section: Resultsmentioning

confidence: 99%

“…In more recent patients were studied by simply pho the QRS complex on the face of an os using a sweep speed of 500 mm/secor tronix 502 dual beam oscilloscope al C-12 Tektronix Polaroid oscilloscop were used. The technique of recording ative of the electrocardiogram to acce high frequency components was used b and associates.9' 10 The circuit diagrar ified by the authors to give a frequenc 1,000 cps is shown in figure 1. In pr derivative aids in distinguishing a not slur in the electrocardiogram, since the In the group of 169 patients having five or more leads recorded, there were 76 normal patients with a mean age of 26 years.…”

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confidence: 99%

High-Frequency Components in the Electrocardiogram

et al. 1967

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SUMMARYExpanding the frequency response of the electrocardiogram and its derivative to 1,000 cps revealed notching in certain parts of the QRS complex which correlates with the presence of primary myocardial disease. Chi-square analysis of data from 169 patients with myocardial involvement indicated that notching on the downstroke of leads X, V4, and V6 separated abnormal from normal patients at the 1% level of significance, whereas fine and coarse slurring showed reverse correlation at the 1% level of significance. This suggests that notching and not slurring is the important evidence of disease. Neither notching nor slurring was significant at the peak of the R wave in any lead. Study of individual cases revealed that complete right and left bundlebranch blocks do not mask high-frequency components caused by myocardial disease nor do they produce high-frequency components. Conclusions regarding specific diagnostic criteria, however, should serve only as guidelines. ADD,ITIONAL INDEXING WORDS:Bundle-branch block Right ventricular hypertrophy M UCH of the clinically useful information derived from the electrocardiogram comes from gross alterations in the QRS complexes and T waves. These changes involve frequencies mostly below 100 cps' or in the low-frequency range, but patients with diffuse myocardial disease often will show reduced voltage and many high-frequency components in the QRS complexes. Oppenheimer and Rothschild2 first correlated these changes with a disseminated patchy sclerosis involving the subendocardial layer of the heart, and

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“…The use of high fidelity recording apparatus to quantitate the high frequency components of the electrocardiogram has been described by Langner (1952Langner ( , 1953, Langner and Geselowitz (1960), and Langner, Geselowitz, and Mansure (1961) who used Angelakos (1962Angelakos ( , 1963 and by Langner Geselowitz, Langner, and Mansure, 1962). While differentiating a curve does not add any information not present in the initial curve, it makes the information easier to extract by accentuating the high frequency components.…”

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confidence: 99%

“…These disturbances are accentuated in the differentiated electrocardiogram which records the rate of change of electrical potential. Differentiated electrocardiographic tracings have been studied by Angelakos (1962Angelakos ( , 1963 and by Langner Geselowitz, Langner, and Mansure, 1962). While differentiating a curve does not add any information not present in the initial curve, it makes the information easier to extract by accentuating the high frequency components.…”

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confidence: 99%