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Biomedical subjects

J H Holt

Publications and source records attributed to J H Holt.

At least 19 recordsLinked to original sources
PubMed1979

Performance of conventional orthogonal and multiple-dipole electrocardiograms in estimating left ventricular muscle mass.

For estimating left ventricular mass (LVM), ECG criteria for left ventricular hypertrophy (LVH) were selected from conventional 12-lead ECGs, orthogonal three-lead ECGs, and multiple-dipole ECGs (MDECG). The three cardiograms were recorded in 139 patients for whom the degree of LVH was independently determined from biplane ventriculograms. Tested ECG criteria included Sokolow-Lyon measurements for the 12-lead ECG; for the orthogonal ECG, maximal QRS magnitude in the horizontal plane, R duration in the z-lead and Jxyz (spatial magnitude of point J); and for the 126 leads of the MDECG, the dipole activity (DA) of the septum and the free left ventricular wall. Correlation coefficients between LVM and the 12-lead ECG, three-lead ECG and MDECG were 0.61, 0.78 and 0.89, respectively, with corresponding errors of estimated LVM of 103, 82 and 60 g. More complex recording and analytic methods clearly led to increased accuracy in LVM estimates. However, the large error of estimate may limit practical applicability of such correlations. For classification of subjects into normal and above-normal categories, a likelihood ratio was also used and led to a maximum performance index of 86% with MDECG measurements.

Electrocardiography↗
PubMed1977

A study of the human heart as a multiple dipole source. IV. Left ventricular hypertrophy in the presence of right bundle branch block.

This report concerns the task of electrocardiographic (ECG) diagnosis and quantitation of left ventricular hypertrophy (LVH) in patients with right bundle branch block (RBBB). In 36 patients with RBBB the left ventricular mass (LVM) of each patient was independently known from quantitative biplane angiography. Two ECG techniques, standard 12-lead ECG and multiple dipole electrocardiography (MDECG), were evaluated. In diagnosing LVH, the best performance of the several standard ECG criteria was sensitivity = 29%, specificity = 100%, and that of the MDECG was sensitivity = 94%, specificity = 96%. In quantitating LVH, the standard ECG gave a correlation with LVM of r = 46% and a standard error of estimate of 98 g. The corresponding figures for the MDECG were r = 81% and the root mean square prediction error = 64 g. These results confirm other studies showing that the conventional ECG is of only marginal value in the task of diagnosing LVH in the presence of RBBB. In contrast, the MDECG performs well both in this task and that of quantitating LVH. The results provide further support of the accuracy of the model of the cardiac electrical generator and volume conductor used in the MDECG method.

Adolescent↗
PubMed1977

Long-term results of the medical treatment of coronary artery disease.

The natural history of patients with ischemic heart disease varies widely depending upon the anatomic lesion and extent of left ventricular dysfunction. Several clinical variables may also be used to help determine the likelihood of long-term survival. Individuals with high-grade isolated disease of the left anterior descending coronary artery, without significant impairment of ventricular function, have little morbidity and mortality for the 2-year period after arteriography. At the other end of the spectrum, medically treated patients with stenosis of the left main coronary artery or three-vessel disease without such involvement have a reduced life expectancy compared with patients treated surgically. Global judgments on long-term results of the medical treatment of coronary artery disease are meaningless. Efforts should be made to delineate optimal treatment for various subgroups of patients under the broad rubric of ischemic heart disease.

Adult↗
PubMed1976

Surgical versus medical treatment in disease of the left main coronary artery.

Data from 179 patients with a significant lesion of the left main coronary artery were reviewed to compare survival with and without bypass graft surgery. 149 patients were treated with bypass grafting. Of 38 patients treated medically, 24 were suitable for surgery but either had been evaluated before the widespread use of bypass grafting procedures or preferred medical treatment. Major prognostic factors in this group were comparable to the surgical patients. The survival-rate was consistently higher for the surgically treated group and differed significantly (P less than 0-02) for the total duration of follow-up. At twelve months, 89% of the surgical group were alive, but only 73% of the comparable medical group; at twenty-four months, survival-rates were 86% and 65% respectively. These findings, corroborated by other data, suggest that surgery prolongs life for these patients.

Aged↗