The Lesser Electrocardiographic Signs of Cardiac Pain

Evans, William; McRae, C

doi:10.1136/hrt.14.4.429

Cited by 36 publications

(13 citation statements)

References 25 publications

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“…There is evidence that the mechanism for the production of notching and other high frequency deformities following myocardial infarction is the result of patchy myocardial necrosis with subsequent fibrosis. 9 " 11 We found notching more common in angina pectoris a disease in which Zoll, Wessler, and Blumgart frequently found multiple infarctions. 10 These cause interspersed patches of living and dead myocardium.…”

mentioning

confidence: 71%

“…Just as there is a diagnostic A'alue for lowfrequency Q waves, there is diagnostic value for low frequency notches, 9 ' 10 best revealed by equipment with somewhat better performance than the conventional machines, for instance, the new Viso 100. It has been shown that there is additional information to be gained from high-frequency characteristics as revealed by the cathode ray oscillograph and an expanded time scale.…”

Section: Scher and Youngmentioning

confidence: 99%

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Characteristics of the Frequency Spectrum in the Normal Electrocardiogram and in Subjects Following Myocardial Infarction

Langner

Geselowitz

1960

Circulation Research

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The results of a study of the sealar electrocardiogram, utilizing a wide-band recorder, expanded time scale and a low-pass filter, indicate that a recorder flat to at least 500 c.p.s. is required for faithful reproduction. With a high-pass filter, measurable residual signals are present at a cut-off frequency of 1,000 c.p.s., or higher. Therefore, to record these, an adequate response at 1,000 c.p.s. or more is reqnired. The high frequency energy of the electrocardiographic spectrum arises from the fast deflections contained in the original waveform. These may occur in a single fast deflection, notching, or both. Whereas, in the normal individual, high frequency energy usually arises from a relatively smooth, fast deflection, in abnormals the fast events may occur in conjunction with notching, and other deformities. Judging from the technic used in this experiment, a variable band-pass filter is valuable as an aid for studying the high frequency components of the electrocardiogram and establishing equipment requirements. Measurement of peak-to-peak voltage of residual signals gives partial but lot clear-cut separation of normal and abnormal subjects and would not seem to add to the value of high-fidelity electrocardiography per se in routine clinical diagnosis. It is possible that root mean square readings, reflecting the total energy content, might give a better separation between normal and abnormal subjects than peak-to-peak amplitude alone.

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mentioning

confidence: 71%

Section: Scher and Youngmentioning

confidence: 99%

Characteristics of the Frequency Spectrum in the Normal Electrocardiogram and in Subjects Following Myocardial Infarction

Langner

Geselowitz

1960

Circulation Research

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“…In some cases (groups A, B, C, and D), 24 additional unipolar chest and abdominal leads were recorded. These included leads made at levels 1 (V'), 2 (V"), and 3 (V"') intercostal spaces higher than the conventional V-lead level, as well as leads recorded at the level of the ensiform process (VE), and the epigastric level midway between the latter and the umbilicus (Vep). Esophageal leads were obtained in several of these cases.…”

Section: Methodsmentioning

confidence: 99%

XII. Polarity and Amplitude of the U Wave of the Electrocardiogram in Relation to that of the T Wave

1957

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The ratio of the amplitude of the QRS complex to the amplitude of the U wave varies in different leads of the same electrocardiogram. In the majority of electrocardiograms, the U wave has the same polarity as the T wave and the ratio of the U wave and T wave amplitude is relatively constant in all leads. The tallest positive U wave is usually observed in the area of leads V 2 to V 4 . The deepest negative U wave is usually observed in the area of leads V 5 to V 6 . Secondary changes of the T wave are very frequently accompanied by similar changes of the U wave. T-wave changes caused by myocardial infarction and digitalis are usually not accompanied by changes of the polarity of the U wave. The electrocardiograms of 297 cases of hypertension were divided into 6 groups on the basis of the relationship between the polarity of the T wave and the U wave. Both waves were positive in all precordial leads in 48.1 per cent of the cases. Negative U waves were found in 21.8 per cent of the cases and these were predominantly in the leads with negative T waves. A negative T wave in the left precordial leads was accompanied most frequently by a negative, less frequently by an isoelectric, and least frequently by a positive, U wave. An inverted U wave in the presence of an upright T wave was found in only 2.8 per cent of the cases. A change from a negative to a positive or isoelectric U wave was observed after slowing of the heart rate, a drop in blood pressure, and nitroglycerin administration.

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“…(Carter, 1914;Oppenheimer and Rothschild, 1917;Wilson and Herrmann, 1920;Weinberg et al, 1950;Evans and McRae, 1952;Durrer et al, 1961;Battaglia, Maschio, and Zotti, 1964).…”

mentioning

confidence: 99%