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Biomedical subjects

M Bible

Publications and source records attributed to M Bible.

6 recordsLinked to original sources
PubMed1983

Use of multivariate analysis to improve the accuracy of radionuclide angiography with stress in detecting coronary artery disease in men.

A multivariate analysis (MVA) system was derived retrospectively from a population of 76 males with coronary artery disease and 18 control subjects. Posterior probabilities were then derived from such a system prospectively in a new male population of 11 subjects with normal coronary arteries and hemodynamics and 63 patients with coronary artery disease. The sensitivity was 84% compared to that for change in ejection fraction (delta EF) greater than or equal to 5 criterion of 71% (p less than 0.01), the specificity was 91% compared to 73% for the delta EF greater than or equal to 5 criterion (p greater than 0.05), and the correct classification rate was 85% compared to 72% for the delta EF greater than or equal to 5 criterion (p less than 0.01). The significant variables were: change in EF with exercise, percent maximal heart rate, change in end-diastolic volume (delta EDV) with exercise, change in R wave, and exercise duration. Application of the multivariate approach to radionuclide imaging with stress, including both exercise and nuclear parameters, significantly improved the diagnostic accuracy of the test and allowed for a probability statement concerning the likelihood of disease.

Adult↗
PubMed1982

Prospective application of the multivariate approach to enhance the accuracy of the treadmill stress test.

Thirty normal subjects and 84 patients with coronary artery disease were subjected to stress testing and the results assessed by multivariate analysis. Probabilities for the presence or absence of disease were determined based on the results of a previous retrospective study. The multivariate analysis approach significantly improved the sensitivity, from 73% to 88%, and correct classification rate, from 78% to 88%, when compared to the ST response (P less than 0.05). The specificity remained significantly unchanged at 93% and 87% respectively in comparison to the ST response. The predictive value of a positive and negative test were not significantly different from those values from the ST response. Although the probability of disease could separate normal from diseased subjects, it could not separate single vessel from multi-vessel disease. The correct classification rate remained the same for all probabilities greater than or equal to 50% suggesting that a higher probability was not more accurate in detecting disease. The multivariate approach did not improve the accuracy of the stress test over the ST response in women, but the females in this study were a small and highly select group. Multivariate analysis appears to be a valuable method in detecting disease and appears to improve diagnostic accuracy over the ST response alone. However, further studies are needed to determine the final role of such a system, particularly in female subjects.

Adult↗
PubMed1981

Septal Q wave in exercise testing: angiographic correlation.

A study of septal Q wave response in lead CM5 was carried out to evaluate its usefulness in predicting coronary artery disease. Q wave amplitude was measured in 50 patients with coronary artery disease and 50 normal subjects before and immediately after exercise. In the 100 patients evaluated with coronary angiography, the septal Q wave in lead, CM5 was smaller in patients with coronary artery disease than in normal subjects at rest (probability [p] less than 0.001) and immediately after exercise (p less than 0.001). An embryonic (0.5 mm) or absent Q wave in lead CM5 was significantly more frequent in patients with coronary artery disease than in normal subjects both at rest (76 versus 48 percent) and after exercise (82 versus 16 percent). The sensitivity for S-T depression was 52 percent, the specificity 74 percent and the predictive value 70 percent. The respective values for Q wave were 82, 88 and 87 percent. These differences were not significant (p less than 0.05). When either a positive S-T or Q wave response was used, the sensitivity increased to 92 percent (p less than 0.05), and the specificity and predictive values remained unchanged (p less than 0.01). An increase in Q wave amplitude with exercise identified a false positive S-T segment response to stress in 75 percent of cases. Absence of the Q wave in lead CM5 with S-T depression after identified a true positive response in 100 percent of cases. These findings suggest that low Q wave voltage and it failure to increase after exercise imply abnormal septal activation, reflecting loss of contraction associated with ischemia. This finding may be a useful marker for ischemia; the increase in the septal Q wave with exercise may be of value in identifying a false positive S-T segment response.

Coronary Angiography↗
PubMed1981

Radionuclide angiographic correlation of the R wave, ejection fraction, and volume responses to upright bicycle exercise.

The change in the R wave and the response of the ejection fraction to upright bicycle stress testing with radionuclide angiographic studies were determined for 18 control subjects and 29 patients with coronary arterial disease (70 percent stenosis or more). In the control group, all had an increase in the ejection fraction from 64.8 +/- 7.7 to 75.7 +/- 9.4 percent with stress (P less than 0.01). All control subjects had a decrease in the R wave with exercise. In the group with coronary arterial disease, most patients had a decrease in the ejection fraction averaging from 63.5 +/- 10.9 to 58.6 +/- 12.8 percent (P less than 0.01). An appropriate response of the R wave and ejection fraction (decrease in R wave and increase in ejection fraction or increase in R wave and decrease in ejection fraction) occurred in 23 (79 percent) of 29 subjects (P less than 0.005). The sensitivity, specificity, and predictive value for the response of the ejection fraction were as follows: 83 percent (24/29); 100 percent (18/18); and 100 percent (24/24). Of the patients with coronary arterial disease and an increase in the R wave, 17 (94 percent) had multivessel disease, while six (55 percent) of 11 with a decrease in the R wave had multivessel disease (P less than 0.05). The systolic volume decreased in all control subjects by -15.9 +/- 8.6 units (P less than 0.01) and increased in most of the group with coronary arterial disease by 13.7 +/- 17.8 units (P less than 0.01) in response to stress. There were 20 of 29 patients (P less than 0.05) with an appropriate response of the R wave and systolic volume to stress (increase in R wave and systolic volume or decrease in both). The change in the R wave did not correlate with the change in the diastolic volume with stress (P greater than 0.05). Changes in the R wave with exercise correlate with the change in the ejection fraction (and hence ventricular function) and with the changes in systolic volume, which may be one of the mechanisms of the response of the R wave, suggesting that the change in the R wave is related to changes in contractility. Increase in the R wave with stress suggests multivessel coronary arterial disease.

Adult↗
PubMed1980

Use of heart rate responses to standing and hyperventilation at rest to detect coronary artery disease: correlation with the S-T response to exercise.

The heart rate responses to standing and to hyperventilation, expressed as a percent change over the sitting heart rate value, were measured in 48 patients with angiographic coronary artery disease (less than or equal to 70 percent luminal narrowing) and 50 young, healthy asymptomatic individuals. When an abnormal response suggesting coronary artery disease was defined as an increase in the heart rate of < 15% over the sitting value and < 20% increase in the heart rate to hyperventilation relative to the sitting value, the sensitivity of such a criterion was 56%, the specificity was 92% and the predictive value was 87%. These values were not significantly different (P > 0.05) from those for the S-T response to exercise, which were 77%, 98%, and 97% respectively. When either a positive S-T response to exercise or a positive response for control heart rate changes to standing and hyperventilation were used as criteria for a positive test, the sensitivity significantly increased to 98% (P < 0.01), while specificity and predictive value remained significantly unchanged (P > 0.05) at 90% for each. The use of the heart rate response to standing and hyperventilation may be a useful test in detecting coronary artery disease in patients unable to undergo stress testing. The use of such heart rate responses in addition to S-T depression with exercise results in a highly sensitive and specific test with great predictive value.

Adult↗