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Biomedical subjects

S M Mohiuddin

Publications and source records attributed to S M Mohiuddin.

At least 73 records · Page 4Linked to original sources

High prevalence of symptomatic bradyarrhythmias due to atrioventricular node-fascicular and sinus node-atrial disease in patients with mitral anular calcification.

Mitral anular calcification (MAC) is associated with high frequency of conduction defects. To delineate this association in patients with symptomatic bradyarrhythmias, 68 consecutive patients requiring pacemakers (group I) and 56 matched controls (group II) were studied. The patients comprised 41 men and 27 women, whose ages ranged from 24 to 92 years (mean 68). The control group consisted of 56 subjects without bradyarrhythmias, whose ages ranged from 30 to 86 years (mean 70); there were 36 men and 20 women. MAC was detected in 59 patients (87%) with symptomatic bradyarrhythmias compared with 8 subjects (14%) in the control group. In group I, 15 patients (22%) had complete atrioventricular block, 23 patients (34%) had atrial fibrillation with slow ventricular response, and 30 patients (44%) had intermittent sinus arrest. The incidence of MAC was similar among these subgroups (93%, 83%, and 87%, respectively). Thus the present study confirms the strong association of MAC with symptomatic bradyarrhythmias.

Adult↗

Digoxin-induced positive exercise tests: their clinical and prognostic significance.

To evaluate the influence of digoxin on the results of exercise testing and the prognostic significance of digoxin-induced positive exercise tests, 98 healthy men, aged 22 to 70 years, were studied. All had normal initial exercise test results. All took digoxin, 0.25 mg daily, for 14 days, and then performed daily exercise tests until each had a negative test response. Five years after these initial tests, a medical history was obtained from 92 of the 98 subjects, and 76 subjects performed repeat exercise tests. Six subjects were lost to follow-up study. Twenty-five percent of subjects (22 of 98) had a digoxin-induced positive exercise test. There was a direct relation between age and the incidence of digoxin-positive tests. The incidence of digoxin-positive tests in men over age 60 years was 100 percent. By 30 seconds after exercise no subject had greater than 1.9 mm S-T depression. No test remained positive for more than 6 minutes after exercise was discontinued. No test was positive 12 days after digoxin was withdrawn. With logistic regression analysis, it was possible to estimate the probability that a subject would have a digoxin-induced positive test. No subject had had a cardiovascular event at follow-up study, but five subjects had a positive repeat exercise test. Four of these subjects had had a digoxin-positive test initially. It is concluded that (1) useful information can be obtained from exercise studies of patients who receive digoxin, (2) the probability that a positive exercise test is due to digoxin can be estimated, (3) to remove the exercise-induced electrocardiographic effect, the drug should be withdrawn for 12 days, and (4) digoxin may unmask subclinical coronary arterial stenosis.

Adult↗

Automated and nomographic analysis of exercise tests.

A study was conducted to evaluate the validity and usefulness of a commercially available microprocessor for automated exercise ECG analysis and to develop a nomogram for estimating the severity of coronary artery disease. Results of visual analysis, automated analysis, and coronary arteriography were correlated for the 107 patients studied. Automated analysis was shown to be valid and useful. The ST integrals (area of ST depression) recorded after exercise were superior to those recorded during exercise because they manifested higher specificity and predictive value, even though their sensitivity was slightly lower. Using postexercise integrals, it was possible to differentiate mild and severe disease. From multiple-regression analysis of ST integrals, duration of exercise, and the severity of coronary artery disease, a nomogram was derived to estimate severity of coronary artery disease.

Angiography↗

LDH isoenzymes and myocardial infarction in patients undergoing coronary bypass surgery: an excellent correlation.

To evaluate the efficacy of LDH isoenzymes in the detection of myocardial infarction in patients undergoing coronary bypass surgery, 73 patients were studied pre- and postoperatively by ECG, CPK, SGOT, total serum LDH, and LDH isoenzyme measurements. A reversal of the LDH1:LDH2 ratio was considered indicative of myocardial necrosis. Accordingly, the patients were separated into two groups: Group A (23 patients) who demonstrated an LDH1:LDH2 ratio exceeding 1.0 and Group B (50 patients) who failed to reveal an LDH1;LDH2 reversal. The two groups were similar in regard to preoperative evaluation and operative procedure performed. The postoperative ECG findings were significantly different. In Group A 18 of 23 patients (78 per cent) developed significant new Q waves. This occurred in only one patient in Group B. Significant arrhythmias occurred in 70 per cent of the patients in Group A as compared to 14 per cent of those patients in Group B. Severe congestive heart failure and/or clinical evidence of shock occurred in 39 per cent of Group A patients and in none in Group B. The results of our study indicate that the reversal of the LDH1:LDH2 ratio is a valuable tool for the evaluation of postoperative myocardial infarction.

Aspartate Aminotransferases↗

Significant sex differences in the correlation of electrocardiographic exercise testing and coronary arteriograms.

Two hundred fifty-one patients (195 male and 56 females) referred for evaluation of chest pain were studied by multistage submaximal stress testing and selective coronary arteriography. In men with positive exercise tests the incidence rate of true positive exercise test results--that is, positive tests associated with 75 percent of greater coronary stenosis--was 89 percent in contrast to a 33 percent incidence rate of true positive exercise test results in women. The incidence rate of false positive excercise test results--that is, positive tests associated with no coronary stenosis or less than 50 percent stenosis--was 8 percent in men in contrast to 67 percent in women. Conversely, the incidence rate of false negative exercise test results (that is, negative exercise tests associated with 75 percent or greater coronary stenosis) was higher in men (37 percent) than in women (12 percent). It is concluded that in men a positive multistage stress test is useful in predicting the presence of significant coronary artery disease although a negative stress test cannot be relied upon to rule out the presence of significant disease. In women, a positive exercise test is of little value in predicting the presence of significant coronary artery disease, whereas a negative test is quite useful in ruling out the presence of significant disease. New criteria should be developed for stress testing of women.

Adult↗