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Biomedical subjects

G E Dower

Publications and source records attributed to G E Dower.

At least 19 recordsLinked to original sources
PubMed1990

Limb leads of the electrocardiogram: sequencing revisited.

The six limb leads are normally presented in a format the logic of which is traditional rather than anatomical and does not allow visual interpolation such as is customary with the six chest leads. The sequence: a VL, I, -aVR, II, aVF, III was suggested years ago, and is used in some European countries, particularly Sweden. It provides a better impression of the extent of the changes of inferior infarction and makes the rather neglected lead aVR much more useful, though reversed in polarity. It also provides a more direct indication of the electrical axis, and simplifies comparisons with the frontal plane vectorcardiogram. Because modern digital electrocardiographs can provide the sequenced format, this seems a good time to review the advantages of adopting it.

Electrocardiography↗
PubMed1988

Deriving the 12-lead electrocardiogram from four (EASI) electrodes.

Computerized interpretation of the electrocardiogram has now advanced to computerization of the electrocardiograph, resulting in greatly increased versatility, including the capacity for adapting to a variety of lead systems rather than being tethered to the old Einthoven-Wilson-Goldberger (EWG) system. Many varieties of display beyond the 12-lead ECG are also available in software. To date, these new and interesting capabilities have scarcely been exploited. The EASI lead system uses the E, A, and I electrode positions of the Frank lead system, plus an electrode, S, positioned over the upper end of the sternum and, if necessary, ground (anywhere convenient). Its outputs form quasi-xyz signals, x'y'z', that can be approximately transformed into xyz signals by means of a matrix derived from the EASI lead vectors. The result forms a good basis for deriving the 12-lead ECG, using previously published coefficients for the Frank lead system. The match with the conventional ECG can then be improved by statistical means. The results are surprisingly good, and certainly of clinical value. Recent widespread interest in silent ischemia and its detection through Holter monitoring suggests an immediate application which has been rendered practical by the recent introduction of three-channel recorders. The EASI electrode positions give technically satisfactory Holter recordings. Very compact three-channel, multiplexed, radio telemetry equipment is now commercially available and provides another application for the EASI 12-lead ECG.(ABSTRACT TRUNCATED AT 250 WORDS)

Computer Systems↗
PubMed1979

Standardization of electrocardiographic interpretive statements: a menu for word processing.

Standardization of electrocardiographic interpretive statements is a goal of various coding systems, but word processing has not usually been considered. A simple, easily memorized system for clinical electrocardiography has been developed and used for approximately 60 000 interpretations. It takes the form of a "menu", in which boxes stand for various interpretive statements; the boxes are identified by mnemonics and marked by the interpreter when appropriate. The results provide better standardization, significant decreases in the numbers of descriptive statements and words per interpretation and considerable saving in typing time. Acceptance by the interpreters has been good. Features of the system allow for word processing as part of a polarcardiography computing system.

Computers↗
PubMed1979

XYZ data interpreted by a 12-lead computer program using the derived electrocardiogram.

The 12-lead electrocardiogram (ECG) derived from the Frank xyz signals was compared with the conventional 12-lead ECG using the Telemed computer system. In 100 cases studied. Telemed's interpretations were essentially similar in 77, but substantially different in 23. In the 23 cases, interpretations of the derived tracings tended to be more accurate in 14 cases, and less accurate in four cases. In the diagnosis of infarction the probability that the interpretation of the derived tracing will be correct more often was 90%. The better performance may have been related to closer agreement with the vectorcardiogram (VCG). As a substitute for the conventional ECG, the derived ECG offers the prospect of a computerized system that is more practical and more versatile than most currently used systems.

Bundle-Branch Block↗
PubMed1977

Polarcardiographic criteria for infarction evaluated by angiocardiography.

Out of a series of 1000 consecutive patients studied by angiocardiography, two groups were selected on the basis of the probability of having suffered myocardial infarction: an infarction group of 324 cases, and a non-infarction group of 112 cases. Members of the infarction group had complete occlusion of at least one major coronary artery; members of the non-infarction group had less than 50% occlusion in all coronary arteries, normal hemodynamics, and negative histories of infarction. The diagnostic performances of the independently-read 12-lead electrocardiograms (ECGs) and the polarcardiograms (PCGs) were evaluated in terms of sensitivity, specificity, validity and risk ratio. The performance of the ECG was significantly lower than the PCG. Corresponding figures were 56%, 99%, 67%, and 1.67 for the ECG, and 75%, 91%, 80%, and 2.23 for the PCG. There is a 99.9% probability that the PCG can detect at least 21% more cases of infarction than the ECG can.

Adult↗
PubMed1976

Polarcardiographic criteria for myocardial infarction in Chinese men.

Polarcardiograms (PCG) derived from xyz leads of the Frank electrocardiogram (ECG) were recorded in the supine position in 1264 initially healthy middle-aged Chinese men who had been under continuing medical surveillance and were re-examined seven years later. Polarcardiographic criteria for myocardial infarction (MI) were demonstrated in 97 men (7.7%), but only 15 of them showed diagnostic Q waves in the electrocardiogram (ECG). Polarcardiographic criteria for MI were independent of age, but ranged from 4.3% in 464 apparently normal men to 38% in 21 men with manifestations of ischemic heart disease. The possible association of polarcardiographic criteria and a history of smoking was limited to those with clinical evidence of heart disease. The "false positive" rate of 4.3% in clinically normal men was similar to that reported in younger Canadians and in Cretan population samples.

Adult↗